I really want something like a Glock 30 or an Officer's size 45ACP pistol. Mainly because the shortest 45ACP I own has a 4.25" barrel.

I like big bullets but I also like them to go fast -- hence why I am a 10mm fan. Spare me how you don't need speed. My first pistol was a 5" 1911 and that was a long time ago. I don't need to be sold on the fact 45ACP it works. I am not debating that. However, the 45ACP is an incredibly LOW pressure round @ ~18,500 CUP (how old school is CUP?) it WILL lose velocity quickly with shorter barrels. It is one of the main arguments that 45GAP has going for it (loses little in say a 3.5" bbl platform).

Conventional wisdom would say that, on average, a round will lose 20-30-40-50 fps per 1/2" or barrel loss. I know quite a range, no?

Doing a little looking I was able to find some info posted by the late Stephen Camp. I trust his #'s 100%. For those that didn't know him, he was a gentleman and also a HiPower guru. It comes from this THR thread: http://www.thehighroad.org/archive/index.php/t-102573.html. This is good info and is pretty close to BBTI's estimate of 787fps.

The most significant result is that, at least to me, (very) short barrel ballistics for the 45ACP is virtually identical to short barrel 40S&W. The 40S&W loses little in a 3.5" platform--in some loads as little as 30fps from a 4"--when comparing 40/180 to 45/185. Keep in mind that a 40/180 gives you the same sectional density of a 45/230. I know that to a lot of folks 45/230 is still king and might think it blasphemy to move away from 230gr you might find it noteworthy that John M. Browning actually designed the 45ACP to be a 200gr bullet. Anyway, I find 45/185 to be very accurate. A 40/180 just as accurate, much more common and cheaper to shoot.

Stephen A. Camp
September 21, 2004, 12:45 AM
Hello. As part of a project I'm doing, I recently borrowed a Colt Defender, a compact variation of John Browning's 1911. Several different commercial loads were chronographed to see just how much velocity these short barrel pistols lost.

http://www.imagestation.com/picture/sraid139/pd1df4a71d3bb361154843750ed5db12d/f70042cd.jpg
The gun's owner replaced the factory grips and installed/fitted Swenson ambis as he's left-handed.

I had a ballpark idea but had never checked any of these over a chronograph as I don't own any 1911 pattern pistol with shorter than a 4 1/4" barrel.

That does not mean that other folks don't and I figured the results might be of some interest to them. Figures are based on 10 shots fired approx. 10' from the chronograph screen.

Remington 185-gr. MC-Flat Nose:
Average Velocity: 923 ft/sec

Federal 185-gr. Classic JHP:
Average Velocity: 885 ft/sec

Corbon 200-gr. JHP +P:
Average Velocity: 958 ft/sec

Sellier & Bellot 230-gr. FMJ:
Average Velocity: 722 ft/sec

Winchester USA 230-gr. FMJ:
Average Velocity: 765 ft/sec

Federal 230-gr. Hydrashok:
Average Velocity: 799 ft/sec

Winchester Ranger 230-gr. JHP:
Average Velocity: 797 ft/sec

Winchester Ranger 230-gr. JHP+P:
Average Velocity: 866 ft/sec

http://www.imagestation.com/picture/sraid139/p1d156f457cdd806908ddd0a8721f5c65/f70042d4.jpg
The Federal 185-gr. JHP (left) and the standard pressure Winchester Ranger SXT (RA45T) were fired into water and both expanded nicely. The Federal JHP's jacket separated. This is more common in water than in tissue. The SXT round expanded slightly less than when fired out of a 5" barrel. A police officer who attended a Ballistics Seminar
put on by Winchester advises that they do recommend use of the +P version in pistols having less than 4" barrels to insure more certain expansion should the bullet pass through barriers before striking the target.

Best.

Since I mentioned the Glock 30 here (from http://www.firearmstactical.com/test_data/45acp/rem45-185gs+p-g30.htm) is the Remington Golden Saber 185gr +P clocked:

.45 ACP Remington 185gr +P Golden Saber Brass JHP
Test Weapon: Glock 30, 3.8" bbl Bare
Gelatin Denim Covered
Gelatin
10 rd Avg. Velocity: 1034 fps
General-Purpose Combat Capability Optimal Satisfactory

and

GL 30 230gr HydraShok average 813fps

and some more...

Some Kimber 5" Custom vs 4" Kimber Pro (15' from muzzle):
5" 185gr Remington Golden Saber 1153fps
4" 185gr Remington Golden saber 1007fps

5" Corbon 185gr +P 1185fps
4" Corbon 185gr +P 1041fps

Here is a really good page with Kimber CDP 3", Cold Commander 4.25", Ruger BH 4.6", and Colt Govt 5" (!) chronograph ballistics: http://stevespages.com/page8f45acp.html

Wondering about the G21 vs G20? Well, I have some data from a website no longer available too:

Corbon 165gr BHP+P ----------------------------- 1160 vs 1096
Federal 165gr Personal Defense ----------------- 1083 vs 1023
Remington 185gr Golden Saber ------------------- 961 vs 913
Remington 185gr+P Golden Saber ----------------- 1040 vs 993
Win 185gr SilverTip ---------------------------- 922 vs 875
CorBon 200gr+P JHP ----------------------------- 1072 vs 1019
CorBon 230gr+P JHP ----------------------------- 937 vs 904
Fed 230gr HydraShok ---------------------------- 919 vs 860
Hornady 230gr+P XTP ---------------------------- 943 vs 886
Rem 230gr Golden Saber ------------------------- 852 vs 825
Win 230gr SXT ---------------------------------- 889 vs 840

Now I am off to find some 357magnum short barrel ballistics. Have a good night.
Settle down, Angus!