45acp bullet set back once loaded.

[stand125]

What does it mean when a bullet in a magazine gets set back about .005 inch after going into battery. I have loaded dummy rounds between 1.22 and 1.25 ( a factory round ), they all set back on every round. The gun is a Mil spec Springfield stainless with trigger work and a polished feed ramp. There is a definate mark where the bullet hits the feed ramp. I have tried WIlson combat, Mchormic and Mil spec magazines. The milspec gets the most setback followed my the Wilson and then the mildest is the Mchormic with about .005 inch setback every time. I have a very mild taper crimp that is barely visible around the plated bullet. I am just looking for opinions. I started noticing the set back when shooting SPP and noticing that I would have stove pipes due to a long AOl mixed with a light powder charge and SPP.

I assume that it is the bullet smacking the feed ramp, which is why I shortened the AOL to have a higher pressure for the SPP and to feed smoother. It definately helped, but I am still getting the set back of about .005 inch to .01 inch with the Mil spec magazines. I am no where near max load, so I am not worried about the pressure, I am just curious if other people have ever noticed any set back on their 45 ACP 1911's.

[NotEnufGarage]

Not enough crimp?

[EL_NinO619]

To much bell and not enough crimp. Load up a dummy round and crimp till you see a mark on the bullet and back off until its gone or barley there. May take a few rounds. "Dummy rounds"

[EL_NinO619]

Oh ya may not have your sizing die down far enough, turn down until contacts shell plate and turn up 1/4 turn,,

[stand125]

Done all that. It even did it with an aggresive crimp. I checked a factory new round and the same thing happened. I know that a previous owner did some work throated/polished barrel, polished feed ramp. I have loaded thousands of 45ACP and all have fed and shot very well untill I tried a new load and AOl for SPP, I never would have noticed if it was not for trying out the SPP. I did some research and it seems to be common ( not definate, but common ). I would think that it was my loading, but factory rounds do it as well.

[EL_NinO619]

Done all that. It even did it with an aggresive crimp. I checked a factory new round and the same thing happened. I know that a previous owner did some work throated/polished barrel, polished feed ramp. I have loaded thousands of 45ACP and all have fed and shot very well untill I tried a new load and AOl for SPP, I never would have noticed if it was not for trying out the SPP. I did some research and it seems to be common ( not definate, but common ). I would think that it was my loading, but factory rounds do it as well.

Really... Its because they have special access to special powder and primer, I'm sure they also have magic bullets and brass also...

Refer to SPP thread

[stand125]

Really... Its because they have special access to special powder and primer, I'm sure they also have magic bullets and brass also...

Refer to SPP thread

I may have missed something because I have no idea what you are talking about

Are you talking about how the companies say not to reload SPP brass. I don't think it has anything to do with the SPP brass since the factory round is an unfired PMC LPP 230gr FMJ round that I wanted to see if it would set back. Since the factory round is doing the same thing as my reloads I am not sure what is causing it besides the feed ramp.

UPDATED: I reduced the bell to where the bullet just sits on the case and the setback has reduced to .002 when I release the slide. I don't think I can reduce the bell anymore or else I may start shaving lead or copper plating. Thanks for the input, I am going to tweak some more and hopefully can get it fixed.

[rsrocket1]

So you put a taper crimp on the bullet and it still consistently sets back 2 mils?

Why not seat the bullets 2 mils long?

First of all, I am surprised that you can actually seat the bullets to 0.002 repeatability off of the cannelure and secondly, 2 mils is not going to change the pressure or muzzle velocity by any measurable amount. (about 130 psi and 2fps) If it's knocking the bullet out of concentricity (off center), you may have a problem.

Are the bullets keyholing or flying all over the target?

[robert101]

Bullet setback of .005 after loading into a chamber is fine. Nothing to change. Shoot it.

[Fishslayer]

UPDATED: I reduced the bell to where the bullet just sits on the case and the setback has reduced to .002 when I release the slide. I don't think I can reduce the bell anymore or else I may start shaving lead or copper plating. Thanks for the input, I am going to tweak some more and hopefully can get it fixed.

That is actually the proper amount of bell/flare. More and you are working the brass more than necessary & will shorten case life.

Too much crimp can actually cause setback, so I'm told. Something about the difference in elasticity of brass & lead.

FWIW PMC is my favorite brass for loading .451 bullets. It has the thickest walls. Remington is the thinnest. I only use it for .452 cast boolits.

Bullet setback of .005 after loading into a chamber is fine. Nothing to change. Shoot it.

I would agree.