Primer pocket magic or horse sense???
by rob 
, Friday, November 21, 2014, 17:14 (3660 days ago)
Actually, I've known a pretty smart horse or two in my day so that may not be an apt description...but I digress. In this article http://www.ammoland.com/2014/11/450-smc-ammo/#axzz3Jk5asatz the author talks about the 45 SMC (I guess it stands for short magnum cartridge?) produced, now, by Double Tap. Anyhow, supposedly, you can't just dump more powder in the .45 ACP case to get more power and do it safely so the trick is to manufacture a special acp (or SMC) case with a small rifle primer pocket making it possible to achieve about 6 thousand psi (if I remember correctly) than is safely possible in an acp case. Now, I'm no engineer or ballistian but my BS meter is going off the charts. The 45 Colt and .44 Magnum are capable of significantly more pressure than that with large pistol primers and 26,000 psi is still pretty darn mild for a modern brass cartridge case with any primer and IIRC brass doesn't start flowing until around 80k psi. And on top of that, I have several ACP cases that came with small primer pockets straight from CCI. And doesn't the 460 Rowland use factory acp cases with large primer pockets with only upgrades to the gun being a supported chamber, heavier recoil spring and muzzle break? Just curious what y'all think of this.
correction...
by rob , Friday, November 21, 2014, 17:32 (3660 days ago) @ rob
I know the Rowland case is 1/10" longer but if I recall correctly the rest of the case is the same (i.e. large pistol primers).
Thje ACP web is the weak part. 451 Detonics etc have a stron
by Rob Leahy 
, Prescott, Arizona, Friday, November 21, 2014, 18:17 (3660 days ago) @ rob
er web, than the ACP to hold pressure better.
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Of the Troops & For the Troops
Primer pocket magic or horse sense???
by Cherokee , Medina, Ohio, Friday, November 21, 2014, 17:52 (3660 days ago) @ rob
First I heard about the 45SMC was on a TV show earlier this week, claiming ~1300 fps for the cartridge. I'm sure the pressure is way more than the 6K you mentioed but I dont recall if the man from Double Tap gave a number. Sounds a lot like the 10mm, and I'l bet it would beat the H*** out of a 1911 if not set up properly.
Primer pocket magic or horse sense???
by rob , Friday, November 21, 2014, 18:21 (3660 days ago) @ Cherokee
It's only 1300 FPS with a 180 grain bullet. 230 is supposedly 1050. I'd much rather have a 10mm.
Primer pocket magic or horse sense???
by Sarge , Central Misery, Saturday, November 22, 2014, 06:48 (3659 days ago) @ Cherokee
In 2002 I received 40 rounds of Triton 450 SMC for T&E. I didn't have a chrony at the time and the guy I had lined up to chronograph it had a family emergency, so we never got that done. I ran it through an old West German Sig 220 with a 24# spring, and came away impressed. Definitely a step up from typical 45 +P and it shot well at 50 yards.
![[image]](http://www.thesixgunjournal.net/wp-content/uploads/2012/02/P220_2.jpg)
Thats pretty good accuracy...
by rob , Saturday, November 22, 2014, 11:21 (3659 days ago) @ Sarge
I'm not knocking the round at all, just not convinced there's any magic in going to a small rifle primer in gaining (what the article said was) another 6,000 psi. At the same time I'm not sure I'd just load me up some +P+ ACP's to those velocity levels either in a stock gun to test my theory either. I might consider it in a Glock or 1911 with a stiffer recoil spring and a barrel with a fully supported chamber. But, rather than deal with changing points of impact going from the SMC round to standard ammo and such, I think I'd rather just buy a 10mm (definitely more powerful, especially with genuine full power factory or handloads) or just leave my ACP an ACP and use a .44 Magnum for anything else where I wanted more power. You can hit the SMC 230 grain and 255 SWC velocities in a .44 mag with 9 grains of unique or less without beating the gun up.
Thanks...
by Sarge , Central Misery, Saturday, November 22, 2014, 12:59 (3659 days ago) @ rob
The old 220 was a shooter and probably capable of much better from a Ransom Rest.
I look at it like this... the SMC, Super etc basically give you a dual-purpose 45 Auto. The Doubletap 450 SMC sails a 255 SWC out at 1000 fps or a little better. This basically gives you warm, standard pressure 45 Colt ballistics from your 45 Auto. That load will knock a 3/4" hole through about 25 inches of wet newsprint. If I needed more, I'd go to 325's in the 45 Colt.
That is definitely true...
by rob , Saturday, November 22, 2014, 13:14 (3659 days ago) @ Sarge
No doubt about it.
.357 mag gets along fine with small pistol primers
by bj , Friday, November 21, 2014, 20:00 (3660 days ago) @ rob
I've read that rifle primers are hotter than pistol primers, and stronger which is why the .454Casull uses them. I don't know why either characteristic of the rifle primer would be needed in the ACP case size or pressure level.
Buffalo Bore lists 1150 fps for .45ACP +P with 185 grain bullets.
They list 1300 fps in .45 Super and 1500 fps in .460 Rowland.
The only advantage I can think of for small primers in the ACP case is if you carefully recontour the case web around the primer pocket you could get a tiny bit more powder capacity.