.45 GAP Handloading Information
Disclaimer: If you wish to use any of the following data, use at your own risk! You are responsible for your own actions. Always refer to official handloading data.
.45 G.A.P. Characteristics
Maximum OACL (Over All Cartridge Length): 1.137 inches
230 gr. OACL (Over All Cartridge Length): 1.135 inches
200 gr. OACL (Over All Cartridge Length): 1.080 – 1.030 inches
185 gr. (Over All Cartridge Length): 1.060 inches
Maximum Case Length: .760 inches (.755 +/- .05)
Case Diameter at base: .476 inches
Case Diameter at mouth: approx. .473 inches
Safe Case Diameter after firing (educated guess): .477 to .4775 inches (still fits into barrel chamber completely)
Bullet Diameter: .451 inches
Presses and Die Sets
I use a Dillon 550 press and a .45ACP die set, with the exception of a Lee Carbide Factory Crimp Die. I could probably shave off .150” approx. since the Lee Crimp Die is really close to the shell plate.
Others are using:
One person with a Lee Die Set had to shave off .150” on the crimp die so it would work with the .45 GAP cartridge.
Dillon 650 with Dillon .45ACP dies; He had to "lower" the seating and crimping dies just about all the way – not much thread left. Dillon now has a new Dillon 650 drop tube adapter for the 45GAP. If your Dillon press has issues, order the update.
Dillon SDB press; he had to take 0.137” off the bottom of the crimp die to get it to work.
T handle press with Lee .45ACP dies.
Hornady Progressive with RCBS dies with the exception of a Lee Crimp Die; He had to go to the hardware store to buy some 6mm washers to extend the crimp sleeve. Lee dies barely reach because of the quick release style used. But if you get creative with the locking ring (i.e. change to another manufacturer) you can get them to work.
RCBS is the first company to acknowledge a .45 GAP handloading die set in the market at this time.
My Current Press/Dies Setup
Station 1: I adjust the resizer die to just barely touch the shell plate for a complete case resize. After This step, the case mouth normally reads approx. 0.467”. I've recently backed the resizer die off the shell plate a little bit since the lower part of the brass does not need resizing and it still easily fits into the chamber.
Station 2: Powder drop and belling: I adjust the belling so the case mouth is expanded to approx. 0.470 – 0.472 or so, depending on the requirements of the bullet. I try not to bell any more than necessary to get the bullet into the case cleanly, without shaving the bullet or damaging the case.
Station 3: I adjust the seating die to get the desired Over-All-Length of the cartridge (OAL). After the bullet is seated, the case mouth measures approx. 0.472.
Station 4: I adjust for a tight taper crimp (measure at very edge of mouth) of 0.470 - 0.471 depending on bullet used (.470 for hard Oregon Trail lazer cast bullets; .471 for plated bullets in general). This cuts a light crimp groove into plated bullets. You want a firm taper crimp, but not so much that it distorts the bullet.
Other Handloading Components
Brass: Starline began selling .45 GAP brass in May, 2004. Note: One shooter has stated that he always works up his loads with 5 different case brands since their strength varies. Winchester brass is the first to bulge, followed by Remington and then the last 3 (Speer, Federal, and Star) take a good bit more effort to bulge (as of this March 06 writing).
Dillon Blue Press is now selling a stainless steel case gauge for the .45 GAP (part number: B90-12672; $8.95)
Official Handloading Data
I highly recommend buying the Lyman Pistol & Revolver Handbook – Third Edition for some good official handloads with several different powders: http://www.lymanproducts.com/lymanproducts/books.htm
Hodgdon Powder Company was the first to publish official 45 GAP loading data:
http://www.hodgdon.com/data/pistol/45glockauto.php
M. D. Smith's Handloading Page:
http://www.reloadammo.com/45-gap-loads.htm
Clean and Inspect Brass
I clean my used brass in a vibrator tumbler (very lightly polished). Then I check each case and throw away any questionable ones, especially if the primer does not look normal or if the brass has cracks or creases (smilies), etc. This technique gives me more faith in using fired brass and the polished brass really helps my Dillon press run smoother and the OAL has very little variance. I also don’t have to worry about my dies scratching my brass. You should take precautions and wear a dust mask (hold your breath or whatever) when pouring dry cleaning media out of a tumbler. Lead residuals accumulate in cleaning media and therefore it should be changed occasionally. For more info on lead poisoning, please read http://markco.gunsnet.net/lead.html
If you like to handload in the hot max power arena, just remember that brass will wear out quicker and should be checked carefully after each firing.
Before using new
Starline GAP brass, make sure you tumble it for 30 minutes in a
vibrator such as the one Dillon sells, preferably with a little brass
polish. Then if you really want to be sure, lightly spray lube the
brass before using it for the first time. That means you should
tumble the handloaded ammo for approx. 12 minutes to get the lube off
as well. After the first firing, the brass is broken in and you won't
have to worry about it.
Why do this? Within 100 rounds of
handloading, I was getting external vertical scratch marks on the
brass and I thought my resizer was scratched. Fix: I had to buy some
600 grit sandpaper and clean the new brass residue garbage off of the
resizer, and I cleaned all my dies while I was at it. Then I lightly
oil lubed and used a patch to wipe off the grime & excess oil on
each die. The scratch marks can shorten the life span of the brass
because cracks can more easily start there.
Another reason to
prep your new brass? The brand new brass will cause a very hard brass
residue accumulation on the powder funnel, which eventually screws up
your case belling size. Fix: Use 600 grit sandpaper to remove this
hard residue off of the powder/bell funnel.
Note: This is not
Starline's fault. New brass often takes a little extra work, and
Starline does not fully prep their brass, hence the good price. With
some brass calibers, you can get away without doing any prep work. It
just depends.
Various Reloading Results
The gap cartridge is very sensitive to the primer brand. There is a wide variance of velocities due primarily to primer brands, combined with various components such as bullet types, etc.
For example, if you look at this data taken from the
Bull Dawgs Club at glocktalk.com, he used various primer brands for
purposes of comparison.
longshot 7.0 876 WSP 200 Speer GDHP
1.081
longshot 7.0 909 Fed 100 200 Speer GDHP 1.081
longshot
7.0 937 CCI 500 200 Speer GDHP 1.081
For his AA No5 230 grain
loads, he hit max hot loads at 7.5 grains with cci500 primers,
traveling at 950 fps, with a warning not to go any higher.
With my
AA No5 230 grain loads, I just started warming up with 7.8 grains
with WSP primers, traveling at 995 fps and the primer looked normal.
Another AA No5 story: One person handloaded with 7.2grs AA#5 with a 230 FMJ at 1.133 and Fed SPP. The cases were on their 4th handload. About 1/2 of the cases were showing signs of smilies (creases in the brass). He decided to back down to 6.8grs. This is just a warning that various components in different guns can act quite differently so always start low and work up slowly. By the time you notice over-pressure signs, it means you have already been there for awhile.
I don't believe my N320 200 grain data is a fluke. I tried several different bullet brands/types and they were all pretty close and consistent compared to each other, using the same powder charge and Winchester Small Pistol Primers:
200 West Coast flat point
200 Rainier flat
point
200 Rainier hollow point
200 Oregon
Trail laser-cast hard lead silver bullet
200
Precision black coated bullet
Another comparison:
One person found that the VV powders were creating excessive pressures and damaging his spent cases. Significant "Smileys" were exhibited on the cases loaded to the following specs: VV-N320, 4.8 grains, 845 FPS, CCI 500 primers, 230 grain Speer GDHP, new Speer brass, seating depth 1.090".
Comparing my VV-N320 data: 4.8 grains, 828 fps, Win. Small Pistol Primers, 230 grain West Coast flat point, reused Speer brass, seating depth 1.134 (quite a bit different here, although I haven't compared the shank on the Speer GDHP with the West Coast Bullet): The brass and primer looked fine after firing the rounds. The brass only expanded to .477 and I could drop it all the way into the barrel chamber even before resizing.
One more comparison:
One handloader worked up to this maximum load data: VV-N340, 6.1 grains, 934 FPS, CCI 500 primers, 230 grain Speer GDHP, new Speer brass, seating depth 1.123".
Another handloader got very different data: VV-N340 data: 6.2 grains, 932 fps, Win. Small Pistol Primers, 230 grain West Coast Jacketed Round Nose, seating depth of 1.074. His data looked fine and did not begin showing signs of heavy pressure until he got up to 7.4/7.6 grains, compared to the above mentioned 6.1 max grains! Huge difference here in the results!
So in summary, always be careful when working up loads. Component variations can cause huge differences, as can slight tolerance variations of pistols.
If you handload the .45 ACP: For those that pick up brass on the range, do not fret about the 45 GAP. Its short distinctive case and small pistol primer is pretty easy to spot. More importantly, some brands of 45 ACP ammo now use a small pistol primer! So it ain't just the GAP you have to worry about. Therefore, check your brass before handloading or you run the risk of flattening or setting off a large primer accidentally.
Regarding 230 grain .45 GAP loads: Be especially careful when handloading 230 grain bullets since they may cause over pressure conditions more readily than 200 and 185 grain GAP loads.
Handloading Updates
If you have any .45GAP handloading information you would like to share (additions and/or corrections), please email: petej@comcast.net
safety, safety, safety
.45GAP (.45 GAP) Caliber Page; Document Version 03/27/06