setback with .45

DUB · April 30, 2015, 01:02 PM

Is setback a significant problem in .45 caliber ? I'm thinking about it being a low pressure round.

**44 AMP** · April 30, 2015, 02:57 PM

If you are talking about the bullet being pushed back into the case during the feeding cycle, the answer is no. Not with CORRECTLY made ammunition.

The sad fact is that not everyone does this. Some even sell them. And its not restricted to one caliber.

RickB · May 1, 2015, 10:29 AM

Is it a significant problem, as in, is it likely to happen, or, is it a significant problem, you have set-back and you want to know if you should be concerned?
Low-pressure rounds have pressure limits just like high-pressure rounds, so set-back is always a problem.

DUB · May 1, 2015, 12:02 PM

Answer to rickB:
I meant,how likely is it with .45 caliber.

Axelwik · May 1, 2015, 12:53 PM

Probably less likely than something like 357 SIG or 400 Corbon with their shallow necks resulting in less "bearing surface," but certainly something to consider with any semi-automatic. Revolvers have the opposite problem.

Once you find ammo that you like, take a cartridge and push the bullet end into something solid to see if it will set back. If you can't do it with a lot of thumb pressure you're probably okay. Also, if you're constantly unloading and loading the top round in a magazine (unloading and loading your carry gun every day for example) check for setback... you should be able to see it when comparing to another cartridge from the same box.

**Aguila Blanca** · May 1, 2015, 01:20 PM

Quote:

Originally Posted by DUB

Answer to rickB:
I meant,how likely is it with .45 caliber.

But there are a number of different cartridges/chamberings that are all ".45 caliber." For example, are you asking about the .45 Colt revolver, round, or the .45 ACP semi-auto round -- or one of the many derivatives of the above?

T. O'Heir · May 1, 2015, 02:04 PM

Assuming you're asking about .45 ACP, the taper crimp is there to hold the bullet in place. The manufacturers would have kittens if any of their ammo had bullets being pushed into the case.
Like 44 AMP says, "Not with CORRECTLY made ammunition.".

**Aguila Blanca** · May 1, 2015, 09:17 PM

.45 ACP ammo is particularly susceptible to bullet setback, but not from recoil. Even with factory rounds, often the impact of the bullet nose hitting the feed ramp pushes the bullet back in the case. If it happens only when chambering and firing a round, it's typically not a problem. It does become a problem with a carry pistol, if the owner clears the pistol for cleaning, and then reloads with the same round as the first one to go into the chamber.

**44 AMP** · May 1, 2015, 10:24 PM

Quote:

45 ACP ammo is particularly susceptible to bullet setback, ..

While I won't argue that it does happen, and happens more today than in the past, I lay the entire blame on the ammo makers. They have allowed it to become as common place as it is today.

I've seen it talked about a lot in recent years, where decades ago it was a very rare thing, and normally only mentioned in connection with reloads that weren't correctly made.

Maybe its a sign of the times, or the profit above all corporate mentality, or maybe just simple economic needs to stay competitive, I can't say. What I see is ammo often made "good enough" and not made the best it can be.

The fact is that ammo made "correctly" does not suffer bullet setback, no matter how many times you chamber it.

DUB · May 2, 2015, 12:02 AM

To everyone:I mean .45ACP

**Aguila Blanca** · May 2, 2015, 11:30 AM

There are many discussions of bullet setback in .45 ACP over at M1911.org.

http://forum.m1911.org/showthread.ph...bullet+setback

http://forum.m1911.org/showthread.ph...bullet+setback

**44 AMP** · May 2, 2015, 07:25 PM

I looked at the linked material, did not find anything useful. The swinging hammer weight smacking the bullet to "measure" setback was interesting, but meaningless without something proving it replicates or correlates to the force undergone by a chambered round.

First of all, the force is not consistent through all semi auto pistols. Second, I could not find where Daffy's hammer was matched to any pistol.

Setback happens, but it does not have to. I have personally seen (and measured) some 1980 Federal 185gr JHP that was chambered hundreds (maybe more) times over a couple decades. The nickel plated cases had brass stripes on them. NONE of the bullets ever moved a detectable amount.

And when the owner finally fired them, they all worked flawlessly.

it CAN be done.

RickB · May 3, 2015, 11:52 AM

Quote:

Assuming you're asking about .45 ACP, the taper crimp is there to hold the bullet in place

Case neck tension holds the bullet in place. Taper crimp reduces case mouth diameter sufficient to allow the cartridge to completely chamber.
I know a guy who had a Para Ordnance P14 that shortened every round .010" on feeding, so he'd just load as long as would fit in the magazine. I don't know that I'd be satisfied with that?
One reason that it wasn't much of a problem in the past is that G.I. ammo has bullets glued in the case, so they're unlikely to move prior to firing.
I've also measured rounds after multiple feed/eject cycles, concerned about multiple chamberings of individual self-defense rounds, and have never seen any difference after five cycles (but I still rotate the order of rounds in the mag to reduce the number of cycles for each round).

mete · May 3, 2015, 06:51 PM

There are two things holding the bullet in the case , Tension from the case and crimp. Both must be considered !
Holding the cartridge with fingers of one hand , push down on the bullet with reasonable force . If the bullet moves into the case there's not enough case tension. Then don't use the expander die or have a special one made .
Crimp ; the role crimp is used for a revolver and the taper crimp used for the Semi-auto. It's fairly easy to over crimp especially with roll crimp. That will effect accuracy !! Magnum revolvers also need a crimp when using slow magnum powder so there is proper combustion of the powder.

**44 AMP** · May 4, 2015, 10:46 AM

Quote:

the role crimp is used for a revolver and the taper crimp used for the Semi-auto.

While that is generally correct, it is not entirely correct. It does NOT depend on the gun (revolver or semi auto). It depends on the cartridge.

Cases that headspace on the rim may be roll crimped. Or they may be taper crimped. generally he roll crimp is used by reloaders for these rounds as it is easier to "get right" for their needs.

Cases that headspace on the case mouth are taper crimped, so that there is still an "edge" to headspace on.

I have revolvers that shoot the .45ACP. Taper crimp.
I have semiautos that shoot .357 & .44Mag. Roll crimp.

and just further FYI, bottlenecked cases can be roll or taper crimped, your choice, since they headspace on the case shoulder.

April 30, 2015, 01:02 PM	#1
DUB Member Join Date: June 25, 2014 Location: Texas Posts: 43	setback with .45 Is setback a significant problem in .45 caliber ? I'm thinking about it being a low pressure round.

April 30, 2015, 02:57 PM	#2
44 AMP Staff Join Date: March 11, 2006 Location: Upper US Posts: 28,833	If you are talking about the bullet being pushed back into the case during the feeding cycle, the answer is no. Not with CORRECTLY made ammunition. The sad fact is that not everyone does this. Some even sell them. And its not restricted to one caliber. __________________ All else being equal (and it almost never is) bigger bullets tend to work better.

May 1, 2015, 10:29 AM	#3
RickB Senior Member Join Date: March 1, 2000 Location: Boise, ID Posts: 8,518	Is it a significant problem, as in, is it likely to happen, or, is it a significant problem, you have set-back and you want to know if you should be concerned? Low-pressure rounds have pressure limits just like high-pressure rounds, so set-back is always a problem. __________________ Runs off at the mouth about anything 1911 related on this site and half the time is flat out wrong.

May 1, 2015, 12:02 PM	#4
DUB Member Join Date: June 25, 2014 Location: Texas Posts: 43	.45 setback Answer to rickB: I meant,how likely is it with .45 caliber. Last edited by DUB; May 1, 2015 at 12:03 PM. Reason: add stuff

May 1, 2015, 02:04 PM	#7
T. O'Heir Senior Member Join Date: February 13, 2002 Location: Canada Posts: 12,453	Assuming you're asking about .45 ACP, the taper crimp is there to hold the bullet in place. The manufacturers would have kittens if any of their ammo had bullets being pushed into the case. Like 44 AMP says, "Not with *CORRECTLY* made ammunition.". __________________ Spelling and grammar count!

May 1, 2015, 12:53 PM	#5
Axelwik Senior Member Join Date: March 12, 2012 Location: Land of Enchantment Posts: 436	Probably less likely than something like 357 SIG or 400 Corbon with their shallow necks resulting in less "bearing surface," but certainly something to consider with any semi-automatic. Revolvers have the opposite problem. Once you find ammo that you like, take a cartridge and push the bullet end into something solid to see if it will set back. If you can't do it with a lot of thumb pressure you're probably okay. Also, if you're constantly unloading and loading the top round in a magazine (unloading and loading your carry gun every day for example) check for setback... you should be able to see it when comparing to another cartridge from the same box.

May 1, 2015, 09:17 PM	#8
Aguila Blanca Staff Join Date: September 25, 2008 Location: CONUS Posts: 18,467	.45 ACP ammo is particularly susceptible to bullet setback, but not from recoil. Even with factory rounds, often the impact of the bullet nose hitting the feed ramp pushes the bullet back in the case. If it happens only when chambering and firing a round, it's typically not a problem. It does become a problem with a carry pistol, if the owner clears the pistol for cleaning, and then reloads with the same round as the first one to go into the chamber.

May 2, 2015, 12:02 AM	#10
DUB Member Join Date: June 25, 2014 Location: Texas Posts: 43	setback with .45 acp To everyone:I mean .45ACP Last edited by DUB; May 2, 2015 at 12:05 AM. Reason: fix

May 2, 2015, 11:30 AM	#11
Aguila Blanca Staff Join Date: September 25, 2008 Location: CONUS Posts: 18,467	There are many discussions of bullet setback in .45 ACP over at M1911.org. http://forum.m1911.org/showthread.ph...bullet+setback http://forum.m1911.org/showthread.ph...bullet+setback

May 2, 2015, 07:25 PM	#12
44 AMP Staff Join Date: March 11, 2006 Location: Upper US Posts: 28,833	I looked at the linked material, did not find anything useful. The swinging hammer weight smacking the bullet to "measure" setback was interesting, but meaningless without something proving it replicates or correlates to the force undergone by a chambered round. First of all, the force is not consistent through all semi auto pistols. Second, I could not find where Daffy's hammer was matched to any pistol. Setback happens, but it does not have to. I have personally seen (and measured) some 1980 Federal 185gr JHP that was chambered hundreds (maybe more) times over a couple decades. The nickel plated cases had brass stripes on them. NONE of the bullets ever moved a detectable amount. And when the owner finally fired them, they all worked flawlessly. it CAN be done. __________________ All else being equal (and it almost never is) bigger bullets tend to work better.

May 3, 2015, 06:51 PM	#14
mete Senior Member Join Date: June 14, 2004 Location: NY State Posts: 6,575	There are two things holding the bullet in the case , Tension from the case and crimp. Both must be considered ! Holding the cartridge with fingers of one hand , push down on the bullet with reasonable force . If the bullet moves into the case there's not enough case tension. Then don't use the expander die or have a special one made . Crimp ; the role crimp is used for a revolver and the taper crimp used for the Semi-auto. It's fairly easy to over crimp especially with roll crimp. That will effect accuracy !! Magnum revolvers also need a crimp when using slow magnum powder so there is proper combustion of the powder. __________________ And Watson , bring your revolver !