Review: New .45 GAP Cartridge for 9mm/40 S&W Pistol Frames

“Like the other Glocks from which it [Glock37 .45GAP] came, it's tough, reliable, simple, accurate and, in this case, a real manstopper but without the controllability problems associated with the .357 Magnum, .40 S&W or 10mm. I prefer it to either the Glock 17 9mm or Glock 22 .40 S&W because it possesses all the same attributes and has, in addition, the superior stopping power of a .45.” -- Chuck Taylor, Handguns, Feb/Mar 2004

Gunny (Gunnery Sergeant R. Lee Ermey) states, “I have over a thousand rounds through my Glock 37 with no cleaning. It still shoots, no jams. The reason that the military needs to look at GLOCK is its simplicity. And they need to take a good look at the G.A.P. A service pistol has to stop close threats. You need a .45 to do that and the .45 G.A.P. is right there.” -- Autopistols 2006.

Walt Rauch stated, “I can see the .45 G.A.P. becoming well accepted by those who are not mesmerized by the .45 ACP and are able to see past their bias. Having a .45 in a smaller, easier-to-handle package is just too good an idea to ignore.” -- Autopistols

“Published June 20, 2007 08:23 am - POTSDAM, N.Y. (AP) — A trooper who was shot in the shoulder while investigating a domestic dispute dropped her assailant with a single shot as he ran at her fellow officers, according to Acting State Police Superintendent Preston Felton. ....Reif fired one round from her service weapon, the new Glock .45-caliber [.45 GAP] pistol recently issued to troopers as an improvement on the previous issue Glock 9 mm, Felton said.”

(Quick Summary): The short .45 GAP cartridge brings improved performance to smaller 9mm/.40 sized pistol frames (out of reach for the .45ACP); the .45 GAP is very accurate and its cost will continue going down as it catches on; the .45 GAP provides better safety with modern reinforced brass (superior to standard .45ACP brass); the .45 GAP uses a smaller more cost efficient cartridge (less case metal length, small primer, less powder, and the ability to fit into smaller grips, while the .45 ACP may require a paper thin, overly long grip to squeeze in the longer, heavier .45ACP cartridges; the .45 GAP uses a slightly improved pressure than the standard .45 ACP for an advantage with shorter barrels and for improved functionality; the .45 GAP provides equivalent power as the .45 ACP, holding 6 to 12 rounds of .45 GAP cartridges in various subcompact, compact, and full size pistols; the .45 GAP bullet creates a big hole even if the JHP does not expand; the .45 GAP has a quieter decibel sound rating and safer lower pressure rating than typical supersonic duty rounds; the .45 GAP is compact enough so more people with various hand sizes can easily handle the new .45GAP pistol/ammo duo; and finally the .45 GAP is flexible enough for maximum knock-down power with properly developed light, medium, and heavy duty loads to control pressure & recoil depending on the needs of the application and user. Meet the new .45 GAP!!!

Quick comparison (G21 & G37): The G21 (45acp) holds 13 + 1 rounds. The G37 (45gap) holds up to 11 + 1 rounds. The single stack 1911 (45acp) holds 7/8 rounds and is still quite popular after almost a hundred years. The typical large back strap on the Glock grip helps absorb energy by spreading the force out. If you slim down a G21 grip, the perceived recoil will also be affected. For example, the new XD 45 ACP pistol has slightly more felt recoil since the backstrap is smaller. The recoil of a G37 is similar to the G21 (16,000 psi up to 22,700 psi, depending literally on the ammo), although “full power” +P .45 ACP ammo can push a bullet 55 to 70 fps faster (using equivalent barrel lengths) than “full power” .45 GAP ammo – for more info see Comparing 45ACP and 45GAP velocities. The G37 grip size can provide better control of the pistol than the G21 simply because the fingers can wrap around the grip in a more secure and controlling manner.

Quick comparison (40S&W & 45GAP):The high pressure .40 S&W cartridge uses “adequate” case support and was created with a compromised bullet size, in between the .45 ACP & 9mm, to be fired in a 9mm sized pistol. The low pressure 45 GAP cartridge uses “superior” case support and was created with the exact same bullet size as the .45 ACP to be fired in a 9mm/.40S&W sized pistol, or a larger framed pistol if so desired.

Many different .45 cartridges: While this review is about the .45 G.A.P., because of shorthand jargon and ease of writing this cartridge name has many forms: GAP, gap, .45 GAP, .45GAP, 45 GAP, 45GAP, 45gap 45 gap. But rest assured, we are indeed talking about the .45 G.A.P. (Glock Auto Pistol) cartridge. Just make sure you do not confuse the .45 GAP with other 45XXXXX caliber names such as .45 Auto, .45 ACP, .45 Super, .45 Colt, .45 Auto Rim, .45 S&W Schofield, etc. Use the right ammo for your pistol.

SAAMI, www.saami.org --- Sporting Arms & Ammunition Manufacturer’s Institute Inc, has voted and approved the new .45 GAP cartridge according to a couple inside sources, although I haven’t seen anything in print yet. Apparently the official maximum length of the .45 GAP is 1.137 inches, not the original 1.100 inches as announced in a 2003 Shot Show Glock brochure --- (Early Glock Brochure). The approved 1.137” length also conflicts with the Speer Technical Brief which states only 1.070 --- (Speer Technical Brief). I’m not sure what the shortest Over-All-Length (OAL) is, although I’ve seen Hodgdon handloading data with cartridge lengths as short as 1.060 inches. The .45 GAP uses the same size bullet, .451 inches, as the .45 ACP/Auto. Unlike the .45 ACP, the .45GAP uses a small pistol primer.

45 GAP is rated at a maximum 23,000 psi by SAAMI which is the same maximum pressure as +P 45 ACP. Only “one” 45GAP case is required for equivalent “ACP standard pressure” and “+P ACP pressure” levels, while the 45ACP requires “two” cases. One case is rated up to 21,000 psi (most popular) and the 2^nd case is rated up to 23,000 psi for +P ammo (more expensive than 45GAP cases). Even though Starline +P .45 ACP looks the same as standard .45 ACP brass, +P brass is stronger because Starline uses a special metal tempering procedure. So don't make the mistake of assuming that regular .45 ACP brass is just as strong as +P 45 ACP brass.

Comparing ACP and GAP Pressures From Handloading Data: Hodgdon .45 GAP data shows pressures between 16,400 to 22,500. Winchester .45 GAP data shows pressures between 17,500 to 21,900. As a comparison, Alliant .45 ACP max pressure is 20,000 while +P max .45 ACP pressure jumps to 21,700 (Sorry, Alliant did not show starting pressures).

Suffice it to say that the 45GAP uses slightly more pressure (increasing reliability) to obtain its velocities than the 45ACP does to obtain the same velocities, and the GAP generally achieves it using less powder – more efficient. “Maximum pressure” GAP loads can be slightly faster than “standard pressure” ACP velocities and are generally about 55 to 70 fps slower than “maximum pressure” +P ACP loads, based on using the same barrel length, same barrel profile, same polygonal rifling, same pistol manufacturer, and same ammo manufacturer. For more information see Comparing 45ACP and 45GAP velocities

The .45 GAP case is .138” (approx. 1/7 inch) shorter than the .45 ACP case. As a fraction comparison, 1/7” is more appropriate since it is only 5/100” more than .138”, while 1/8” is 13/100” less than .138”.

Initially, Glock called their new prototype caliber the “.45 Glock”. When it was submitted to SAAMI, the caliber name was changed to “.45 G.A.P.” (.45 Glock Auto Pistol). This change made the new cartridge name more palatable so other manufacturers would not have to stamp “Glock” on their pistols, and helped alleviate confusion regarding the early proposed “.45 Glock” name versus the already well established “Glock .45 Auto” (.45 ACP) names.

Below, in “A Quick History” section, I have web links showing pictures of the early prototype .45GAP as well as the actual production version. The different case-head-stamps are quite obvious.

Calling the 45GAP a “short .45ACP” is a misnomer since the ACP and GAP cases are quite different, both inside and outside. The GAP has an entirely new design. Unlike the .45ACP, the .45GAP case rim is slightly rebated (smaller diameter) so the case can be easily extracted/ejected in a 9mm size pistol. The mild rebated rim adds reliability for using the fat 45 case in a .40 sized pistol frame. In other words, the extraction cannelure width is optimized for the 45GAP case length and web profile, giving a 10 degree difference in the lead-in angle (.45 GAP .45 ACP Cartridge comparison). The GAP internal case wall profile is different than the .45ACP in order to seat bullets without bulging the case. And the GAP case uses a small pistol primer, which puts distance between the primer and breech/action elements in 9mm frame pistols -- see cut-out comparison of the .45 G.A.P. & the .45 Auto/ACP cases for an excellent visual difference of these two cases.

Trimming a .45 ACP case to make a short cased 45GAP is a bad idea for a number of reasons. Most ACP brass uses a large primer which would over ignite the powder in a cut down ACP case causing severe high pressures. And since the GAP case has a very different internal taper, trimmed ACP brass would bulge since the bullets are seated significantly lower than in a regular sized ACP case.

Can the .45 GAP be fired in a .45 ACP semi auto? Under certain situations it might work but is not recommended. Both calibers headspace on the case mouth, but the short GAP cartridge cannot reach the chamber headspace index in an ACP barrel, although it might headspace off of the extractor sufficiently. Since both calibers have a similar external taper, the GAP might seat in the chamber correctly for the firing pin to ignite the primer as expected. If not, the primer could be pierced by the firing pin, or the firing pin may not have sufficient force to ignite the primer. Instead, either buy a specific .45GAP pistol brand, or buy an aftermarket .45GAP barrel as long as it functions reliably with your .45ACP pistol brand. Bar-Sto has announced that they will produce .45 GAP barrels.

Can the .45 GAP be fired in a .45 ACP revolver? Yes. While it is not officially approved by S&W, a number of revolver owners have reported very good success using moon clips (more detail later in this article).

Interestingly enough, a somewhat similar cartridge, called the Hirtenberger .45 HP, was created in Austria and manufactured during the years 1985 – 1987. The purpose of this round was to allow civilians in Italy to shoot a .45, since the actual .45 ACP was prohibited for civilian use. The Glock 45GAP has a very different agenda and is significantly different than the 45 HP, the former having a different web and extractor cut as well as different overall measurements. The .45ACP measures 1.185” – 1.275”. The .45HP measures 1.220” - 1.229”. The .45 GAP measures 1.060” - 1.137” (significantly shorter than the 45HP), in order to fit into 9/40 pistol frames. See http://www.thegunzone.com/glock/45hp.html for more information.

Being the first and only .45 GAP pistol released in 2003, the Glock 37 demands some decent coverage in my quick historical look, especially since this pistol and the .45 GAP ammo went through significant changes during that introduction year.

At the 2005 Shot Show two new Glock .45 GAP pistols were announced: the compact Glock 38 (eight rounds) and the subcompact Glock 39 (six rounds). The new G38 & G39 are equivalent in size to the M19/23/32 and M26/27/33 respectively, but with slightly heavier & wider slides. The medium frame Glock 37 (10/11 + 1 rounds) has been in the marketplace since Sep. 2003. The Harris Autopistols 2005 Magazine, has a front cover of all three 45 GAP pistols along with two related articles.

First, “Why did Glock do it”? Because Law Enforcement Agencies requested a 9mm/.40 sized pistol chambered in .45 caliber. Chuck Taylor has mentioned that he has been badgering Glock for years for the very same thing. So Glock partnered with Speer Ammo Company to figure out a viable solution regarding these customer requests. Some folks have stated that Mr Glock just wanted his name on a cartridge. Well, Mr Glock already has his name on 4.5 Million pistols, etc, and as such already has one of the most well known names on the planet.

As a result, in the first quarter of 2003 at the Shot Show, a surprise announcement was made by Speer and Glock that they had combined forces to create a new .45 G.A.P. caliber. This team decided that the compact .45GAP cartridge, which has equivalent performance to the .45ACP, would offer excellent functional reliability in 9mm/.40 sized pistols. A new Glock 37 model was announced to chamber this new caliber as well.

In reality, the first half of 2003 was development time to test, fine tune, and make the final production updates to the new .45 G.A.P. ammo and Glock 37 pistol. Thus, a number of significant changes were made to both the .45 G.A.P. ammo and the Glock 37 before being released to the public market in the second half of 2003.

Originally, .45 GAP ammo was announced using a large pistol primer and we were told that the .45 GAP caliber could only use 185 and 200 grain bullets (not 230 grain bullets). The production .45 GAP ammo that was released to the public now uses a small pistol primer, and we have factory loadings beginning at 140 grains and going up to and including 230 grain bullets. Lyman Pistol & Revolver Handbook Third Edition, has some good official handloads with several different powders. M. D. Smith's Handloading Page has GAP data: http://www.reloadammo.com/45-gap-loads.htm Hodgdon has data: Official Hodgdon .45 GAP Reloading Data.

Duane Thomas stated on brianenos.ibforums.com, “According to Ernest Durham, the ammunition development engineer at Speer who designed the .45 GAP, the reason they went to a small instead of large pistol primer was so the stripper rail (the portion of the underside of the slide that depresses the top cartridge in the magazine when the slide is forward, and strips a round out of the magazine during feeding) wouldn't hit the primer and detonate it with the action open.”

Originally, Glock was hoping to use the same size slide as a Glock 22 (.40 caliber pistol). Since there were issues with slide cycle time, etc, Glock ended up mating a re-contoured, highly beveled, shorter (by 0.27”/7mm) Glock 21 heavy slide to a Glock 17/22/31/37 sized frame. In fact, the nicely beveled G37 slide looks very sleek compared to a huge G21 blocky slide. The new Glock 37 weighs 3.03 oz./85 g. more than a Glock 22. Going with the heavier slide really was the best solution to maintain long term reliability and durability of the pistol, instead of relying too much on springs alone to tame the high momentum slide action. Other manufacturers will be able to take advantage of Glock’s pioneering effort of creating the first .45 GAP pistol.

If you compare the width of the G17/22/31 slide to frame fit, the slide is actually a little bit narrower than the frame! On the other hand, the Glock 37 slide is actually flush with the frame and looks quite symmetrical, and is not over sized at all. The slide width measures 1.125 inches and is certainly in the same ballpark as a number of pistols manufactured by other companies. While this is somewhat disappointing because of possibly having to purchase a new G37 holster (for example a Glock 21 .45 caliber holster), it’s not a show stopper. If your Glock 17/22/31 holster has enough slop, a G37 might still fit. Glock 22 (.40 caliber) magazine pouches are still compatible with Glock 37 magazines.

Note: the Springfield XD45 GAP pistol slide is exactly the same width as their XD40. In fact, the XD40 and XD357 are both .05 inches wider than their XD9. You can't argue with Mother Nature and there isn't much difference between the GAP slide widths of the XD and Glock.

Springfield Armory is now offering the XD 45 ACP 13+1 pistol. I'm sure this will make the ACP fans quite happy, especially with the ingenious grip engineering. The XD 45ACP grip is just a little longer but without comparing it right next to another XD, the extra size is almost unnoticeable, although one must remember that the grip is often the most difficult part to conceal. The only downside to the new grip is that SA has removed the thicker backstrap which helps absorb the recoil into the hand. If SA creates a hi-cap 45GAP version, they have more flexibility because of the short cartridge, to put that backstrap back in. And the low bore axis of the Glock is still a winner after all these years. These are a couple reasons why the Glock 21 45ACP pistol is so comfortable to shoot, and why the G37,G38, & G39 are comfortable to shoot as well.

Now the question is, “Will SA create a similar 14 round XD GAP model for those that want to carry maximum big caliber rounds with a reduced grip and decent backstrap?” This would really round out the lineup for the XD GAP from excellent sub-compacts (taking advantage of the short cartridge) to full sized models (and would give Glock a run for their money). Is SA brave enough to fight Goliath or will they simply cave in to the large ACP base? Time will tell.

What the new XD 45 ACP has done is start a revolution in answer to Glock's solution of a reduced grip to house the famous 45 bullet. This has to be good for the consumer if nothing else.

Still, the Glock 37 with a baseplate is a 12 round pistol compared to the 14 round XD45 ACP --- not much of a difference. And the Glock is still the easiest pistol to maintain since you can completely dissassemble and reassemble it after watching or reading a thirty minute video or manual. And I enjoy the phenomenal easy to get Glock parts and accessories that are universally available. Heck, the GAP even uses the same powders as the ACP, except it needs less -- more efficient. The GAP has stronger, less expensive brass (less metal) --- The ACP requires two brass styles to support either standard pressure or +P pressure loads while the GAP cartridge only requires one brass style. The Glock uses polymer magazines which take more abuse than XD steel magazines. I believe the Glock trigger reset is a tad better than the XD regarding pure factory models, and Glock has several trigger options.

Pistol	Barrel	Length	Height	Width	Weight	capacity	Full backstrap
XD45 ACP	4.04	7.25	5.75	1.16	30	13+1	no
G37 GAP	4.49	7.32	5.51	1.18	28.6	10/11+1	yes

The G37 has a 0.45 inches longer barrel for greater velocity, yet the G37 length is only 0.07 inches more than the XD. The height of the G37 is 0.24 inches shorter than the XD. The G37 weight is 1.4 ounces lighter than the XD45. Capacity difference is not hugely significant, especially since SA could create an XD45 GAP model in the same frame as the XD ACP version.

The M1911 slide is only .090" wide and it measures a huge 1.450" in height compared to the GAP slide height of only .890". The 1911 slide is just as big & heavy in another way. Overall height of the G37 measures 1/4 inch less than the M1911's 5.25 inches. A full size G37 and full size M1911 are literally tuned to easily fire a 1000 rounds per month, which is pretty common in the sports – two different slide shapes to accomplish the necessary slide/spring combination to maximize durability and reliability. Glock prefers the low bore axis slide for their subcompact, compact and full size pistols while the nearly century old M1911 uses the slim tall slide to accomplish its tasks. They both work and you can of course buy what you prefer.

Yes, you can make a thinner .45 slide but the pistol will not hold up over the long run like a full size slide version (as discussed above) since it would depend more on heavier spring tension to tame the short, fast slide cycle time as well as require ever-vigilant spring tuning to assure functionality. Such pistols are geared more for carry a lot and shoot a little because they tend to be more high maintenance IMHO. On the other hand, the new subcompact G39 and compact G38 should hold up fine because they are using full size contoured big bore slides with a tuned recoil spring to tame the slide cycle time in a reasonable fashion. And the shorter GAP cartridge is ideal for smaller pistols that have a short slide cycle.

Have you checked out the size of the HK USP .45, although the trigger reach is just a tad too long for some, and the Glock 21 grip is a little too thick for some, yet they are both excellent .45 pistols. The bottom line is that there really is a valid place for the new .45 GAP pistols.

The Glock 37 frame has a longer steel locking block and a different ejector than the Glock 22 frame.

Specifications for the .45 GAP pistols can be found at www.glock.com and www.teamglock.com .When I first bought a Glock 37, the Owner’s Manual had no information about this new pistol, as well as no addendum specification sheet. The 2004 Glock Annual (AKA Autopistols Glock Buyer’s Guide) did however have a front cover picture of the Glock 37, along with a main article by Walt Rauch, and is actually the first pistol listed in the catalog section.

Support for the .45 GAP continues to expand. Winchester, Speer, American Eagle, Federal, Remington, Double Tap, Magtech, Sellier-Bellot, and Cor-Bon provide at least twenty-seven individual cartridge loadings ranging from 140 grain bullets up to 230 grains (see .45 GAP Factory Ammo Listing). Hodgdon even has some official GAP handloading data for bullets as light as 155 grains. Alliant also has official 45GAP reloading data. Springfield Armory has released the XD .45 GAP pistol in 4 inch and 5 inch barrel lengths. Winchester and Starline both produce bulk .45 GAP brass. Barsto has stated that they will make .45 GAP barrels if the caliber can be made to function reliably in given pistols. There’s a healthy dedicated .45 GAP talk forum at www.glocktalk.com (page down to Gun Related Forums - Bull Dawgs Club). And law enforcement agencies are beginning to use this new caliber (see item 6 below). Even A-Zoom 45GAP snap caps are available.

Several Law Enforcement Agencies are testing the .45 GAP right now. Since Glock is pushing the .45 GAP, others will more than likely want to compete with Glock's lock hold on the Law Enforcement market. See item 6 below for a list of new .45 GAP pistols and barrels from various manufacturers, as well as agencies using this new caliber. (If you have additions and/or corrections regarding .45GAP pistols/barrels, and/or Agencies using the .45 GAP, please email: petej@comcast.net)

Here are some links to early pictures & info on the Glock 37 and 45 GAP (early 2003 development time frame):

Here’s a link to pictures & info of the released production Glock 37 and 45 GAP cartridge (late 2003, officially released to public)

Here are some pictures of the 1^st production 45GAP pistol, the Glock 37 (notice the beveling at the front of the slide & how the beveled bottom of the slide blends nicely into the frame with no over-hang), plus the new kid on the block, a Springfield .45 GAP XD (available in 4” & 5” barrels)!

Thanks to Bob & engineer151515 on www.glocktalk.com (page down to Gun Related Forums - Bull Dawgs Club) for the Glock pictures

#1. The new 45 GAP brass is very strong/reinforced, adding a level of safety (more detailed info below).

#2. The nominal velocity of the 45 GAP generally has a lower decibel sound rating than several other duty calibers (especially mangnums) at their more popular velocities, although some calibers such as the 9 and 40 do have subsonic loads as well. However, the .45 GAP can obtain supersonic velocities with lighter bullets as well.

#3. The 45 GAP makes a large hole, even if Hollow Point technology fails. A large hole in the target can give a slight advantage in sport competition events as well. A .451 inch metric value is 11.5mm, versus 10mm for the .40, versus the small 9mm.

#4. The 45 GAP works at much lower pressures than most other duty calibers, although it has a slightly higher pressure than the .45 ACP which can increase reliability.

#6. Because of the characteristics of the .45 GAP, other companies could build compatible pistols fairly quickly without large R&D costs. It may be cheaper to modify existing pistol parts rather than build a new pistol from the ground up. As one example, the Springfield XD .40 was easily modified into an XD .45GAP pistol since the XD .40 slide already has sufficient slide mass. There are several intriguing possibilities that come to mind with compact GAP auto pistols and revolvers that could house the new short powerful cartridge. The S&W 625 revolver and moon clips already work well with the GAP cartridge, as another example (unofficial test only). I believe S&W, Sigarms, Kahr, and others could make some really nice .45Gap auto pistols and revolvers if so inclined. Just look what Glock did when S&W announced the .40 S&W.

The Glock 37 is a very solid, sturdy pistol with a heavy slide and strong recoil spring. The G37 means business and will be a formidable challenge to any and all competitors. And the new compact G38 and subcompact G39 GAP pistols will just fuel the fire.

(Note: If you have additions and/or corrections, please email: petej@comcast.net)

Quoting a Denver Police Officer: "Denver PD approved the GAP in early 2005. Out of the 200 officers that were hired that year, more purchased the GAP than ACP. I believe that it will find a nice place in law enforcement. We love the round and the Glocks made for it."

#7. The .45 GAP is proving to be a very reliable, accurate, and flexible caliber, whether using full-power duty loads (equivalent to +P 45ACP pressures), or more moderate medium-power duty loads and target/competition loads (equivalent to standard 45ACP pressures). 45GAP handloaders have been successfully experimenting with loadings from 16,000 psi to 23,000 psi, covering the full gamut of light, medium, and maximum full power loads (see more related info below).

Durability: Chuck Taylor performed a 10,000 round torture test of the Glock 37. The G37 was repeatedly exposed to rain, grit, mud, sub-freezing temperatures, and clogged with snow on several occasions, and the G37 was “never” field stripped, detail stripped, or cleaned during this 10,000 round test. Each morning he would subject the G37 to a hazard such as freezing it for three hours, tossing it into snow banks for twenty minutes & then firing it (repeated ten times), burying it in sand, washing it & then firing it (repeated ten times), tossing it into a creek and then firing it (repeated ten times), tossing it into a mud bottom & then firing it (repeated several times). Each afternoon he tested the G37 with the tough high-speed/low-drag shooting test (ASAA Handgun Combat Master Evaluation Course). This nine stage course entails “high speed weapon presentations from the holster on single targets from one to 50 meters; multiple targets; responses to the right; left and rear; hostage situations and small, partially obscured and angled targets....speed loads, tactical loads and malfunction clearance drills”. 360 points (90%) out of 400 is needed to pass this course. Chuck passed the tough HCM course each afternoon despite the abusive morning torture tests. (see Harris Autopistols 2005 Glock magazine for details).

#8. The compact 45 GAP cartridge has a definite size advantage for use in the standard 9mm/.40 pistol frame category.

The 45GAP is directly attacking the 9mm, 357Sig, and .40S&W, USING THE SACRED 9/40 PISTOL FRAME SIZE AS THE BATTLE GROUND. And yes, the 9, 357, and 40 all work well. But the 45GAP adds another dimension that some will prefer (making really big holes whether the bullet expands or not, with large, slow, quieter, high momentum 45 bullets, and with lots of .45 caliber rounds in an easy to grasp grip, as well as using reinforced brass and much lower pressures than the 9, 357, and 40).

#9. Comparing the 9mm: With excellent modern bullet technology, the 9 works fine (35,000 psi SAAMI limit). But there is an awful lot of 9 crap out there too. The 9mm is easy to control, enjoys worldwide popularity, and the G17 (9mm) holds 7 more rounds than the same size G37 (45GAP), although several 9mm brands such as the Springfield XD9, SIG SP2340, P226, P229, etc only hold fifteen 9mm rounds. I believe the new Glock 37/.45 GAP (11.5mm bullet) combo will give the G17 (9mm bullet) a run for its money in the non-kaboom category.

#10. Comparing the 357Sig: The 357 has proven itself well, although some folks may choose the lower pressure (23,000 versus 40,000 psi) and much lower decibel sound rating of the 45 Gap for their needs.

#15. Speer, Winchester, American Eagle, Federal, Remington, Double Tap, Magtech, Sellier-Bellot, and Cor-Bon are the main ammo brands supporting the 45 GAP at the time of this writing, from 140 to 230 grain bullets, with over twenty-seven individual cartridge loadings so far --- see .45 GAP Factory Ammo Listing. You can buy 45 GAP ammo for $10 - $13 a box; not bad for a brand new cartridge! I remember paying $36 a box for the first lot of 357 Sig ammo that hit the market.

Obviously a new product may be harder to find initially. Most likely, stores such as Walmart can special order .45GAP ammo if requested. The best deals are usually online at places like:

#16. .45 G.A.P. information and discussions can be found at the following special interest talk forum, The Bull Dawgs Club:

It’s not my goal to convince folks that the new .45 G.A.P. blows everything else away. There are very strong lobbies for each caliber: 9mm, 40S&W, 357Sig, 10mm, and especially the hallowed .45 ACP/Auto cartridge. According to ammo tests, all the main duty calibers are getting the job done, from the “small, fast, higher energy rounds”, to the “big, slow, high momentum rounds”. The 45 GAP is simply another viable alternative. Time will tell how successful it is. From what I’ve seen, it’s looking pretty good so far.

Chuck Taylor stated, “Finally, after nine-plus decades of unquestionable superiority, the M1911 faces the first serious challenger in its history --- the new Glock 37 chambered for the proprietary .45 Glock Automatic Pistol (GAP).” www.arotek.com and a few others provide excellent trigger jobs for Glocks as well. I would like to add that other manufacturer’s .45 GAP pistols such as the new Springfield XD .45 GAP pistol (with 4” & 5” barrels) will also challenge the venerable M1911 significantly.

Glock 37 VS M1911 Chart (based on Handguns, Feb/Mar 04, “Glock 37 .45 GAP” by Chuck Taylor)

Referring to the above chart, Chuck stated, “So, as you can see, from a size standpoint, the Glock 37 compares favorably with the M1911 and is certainly no less concealable or convenient to carry.” The 45GAP is ever bit as accurate and controllable as the long cased .45ACP.

The .45GAP will probably catch on even faster when folks realize it can be downloaded to equivalent standard ACP pressures, making it very tame with fast follow-up shots for USPSA Production Division & Limited 10, Bulls-eye events, Bowling pins, and medium-power duty loadings. The full-power duty loadings (equivalent to +P ACP pressures) is just icing on the cake. This new caliber appears to have a lot of potential that has yet to be tapped.

The .45 GAP requires less powder and case metal than the .45 ACP and is more cost efficient.

The short, stubby .45GAP may even prove to be one of the best in its class for speed and efficiency during the feeding and extraction/ejection process. And it will be interesting to compare the .45 GAP and .45 ACP out of short barrels.

If you keep affirming, “The 45GAP is a solution in search of a problem”, over and over again, you might be able to convince yourself and a few others. However, with the continuing proper ammunition development of this new, compact, modern 45 GAP cartridge that allows a capacity of 10+1 .45 caliber rounds (with the same practical ballistics as the tried and true 45 ACP) in a 9mm/.40 sized pistol-frame, the very opposite of your affirmation will most likely occur.

As I mentioned before, the real target of the .45 GAP is the .40 S&W. The .45 GAP will easily match the capabilities of the .40, and is a safer cartridge because of its reinforced brass and 34% lower working pressure than the .40S&W. The .45 GAP also has an accuracy edge over the .40 S&W. Just as the new .40 S&W split the difference between the 9mm and the .45 Auto, the new .45 GAP splits the difference between the .40 and the classic .45 ACP. The .45 GAP cartridge was engineered to be safely fired in the typical unsupported barrel chamber. The stronger GAP case has more of a safety buffer than both the .45 Auto and .40 S&W in order to protect against out of spec ammo and/or pistols.

“New Glock 37 .45GAP” by Gary Paul Johnston, Guns & Weapons for Law Enforcement, Feb 2004

“.45 GAP Versus .45 ACP: The .45 GAP Wins!” by Dick Metcalf, Shooting Times, May 2004

“The XD Goes XL” & “Filling the GAP” by Wiley Clapp, American Rifleman, June 2004

“The First-Generation GAP” by Daniel T McElrath, American Rifleman, June 2004

“Glock 37: Exploring the .45 GAP”, by Robin Taylor, Front Sight, Sep/Oct 2004

Case Type	Max. Case Length	Case Size Comparison	Max. Cartridge Length	Bullet Diameter
.45 ACP	0.898”/22.81mm	0.138”/3.51mm longer than the .45 GAP	1.275”/32.39mm	11.5mm
.40 S&W	0.850”/21.59mm	0.09”/2.29mm longer than the .45 GAP	1.135”/28.83mm	10mm
.45 GAP	0.760”/19.30mm	0.138”/3.51mm shorter than the .45 ACP	1.137”/28.88mm	11.5mm
9 mm	0.754”/19.15mm	0.006”/0.15mm shorter than the .45 GAP	1.168”/29.67mm	9mm

	Glock 37	M1911 Colt
Weight, empty:	24.5 oz.	39 oz.
Weight, loaded:	34 oz. (185-gr. JHP)	45 oz. (230-gr. FMJ)
Weight, one-rd. ammo:	.69 oz. (185-gr. JHP)	.72 oz. (230-gr. FMJ)
Weight, empty mag:	2.7 oz.	2.4 oz.
Weight, loaded mag:	6.6 oz. (185-gr. JHP)	8.5 oz. (230-gr. FMJ)
Length, overall:	7.8 ins.	8.2 ins.
Length, slide:	7.4 ins.	7 ins.
Length, barrel:	4.5 ins.	5 ins.
Height, overall, w/o mag:	5 ins.	5.25 ins.
Height, slide:	.890 ins.	1.450 ins.
Width, slide:	1.125 ins.	.90 ins.
Sight radius:	6.5 ins.	6.6 ins.
Rifling twist:	RH	LH
Mag capacity:	10 rounds	7 rounds
Maintenance:	Low	Medium - High