bullet got pushed into brass case too deep

[bryan28]

i was testing out a sig 9mm at the range by locking the slide back and putting in a full magazine and letting the slide slam to test the mag and feed ramp. it worked fine but after doing this for about 5 times with the same round, the normally showing part of the bullet was pushed back about 1/3 way into the brass.

I don't know anything about re-loading ammo, so I threw it away that round to be safe. But I am wondering if that round would have been safe to shoot?

[swerv512]

your guess is as good as mine. probably wasnt crimped enough. better safe than sorry...

[Milsurp Collector]

Even if the risk is small, one round of ammo is not worth risking your gun or your hand on. You did the right thing.

http://www.youtube.com/watch?v=PC3wC3u5U60

[IrishPirate]

you can't shoot it just a little.....better safe than morbidly crippled for life

[J-cat]

your guess is as good as mine. probably wasnt crimped enough. better safe than sorry...

Crimp does nothing for bullet setback. Not enough case tension here.

[XDRoX]

i was testing out a new sig 9mm at the range by locking the slide back and putting in a full magazine and letting the slide slam to test the mag and feed ramp. it worked fine but after doing this for about 5 times with the same round, the normally showing part of the bullet was pushed back about 1/3 way into the brass.

it was factory ammo, not reloaded stuff. I don't know anything about re-loading ammo, so I threw it away that round to be safe. But I am wondering if that round would have been safe to shoot?

Probably not safe to shoot. I certainly wouldn't have shot it. This is what's called bullet set back. Shortening a rounds length causes more pressure. So because that round had noticeable set back it definitely had more pressure than your other rounds. How much more is hard to say.

This is why people that carry a gun daily with one in the chamber rotate their rounds so that the same round is not constantly being re-chambered. It also sounds like the round should not have done this after 5 chambers, unless they were too long to begin with.

[XDRoX]

Crimp does nothing for bullet setback. Not enough case tension here.

The expanding die opens the case. The crimping die closes the case back to normal or slightly more.

Isn't then correct to say that crimping does hold a bullet in place? Not trying to argue, just want to learn.

[Bug Splat]

Probably not safe to shoot. I certainly wouldn't have shot it. This is what's called bullet set back. Shortening a rounds length causes more pressure. So because that round had noticeable set back it definitely had more pressure than your other rounds. How much more is hard to say.

This is why people that carry a gun daily with one in the chamber rotate their rounds so that the same round is not constantly being re-chambered. It also sounds like the round should not have done this after 5 chambers, unless they were too long to begin with.

+1.

This will happen if you keep dropping the slide on the same round over and over again. Bullet gets pushed in deeper and deeper. Not safe to shoot at all.

I tried this on a 380 and after about 10 drops the bullet actually came out of the case . When I racked the slide to clear it I got a bed full of powder and an empty case and a bullet still in the chamber.

[ar15barrels]

Crimp does nothing for bullet setback. Not enough case tension here.

If there is a cannelure, a crimp that pushes the case into the cannelure eliminates setback.

[J-cat]

If there is a cannelure, a crimp that pushes the case into the cannelure eliminates setback.

9mm bullets do not have cannelures.

Ant the only way a cannelure prevents bullet setback is when the cannelure has a sharp shoulder to catch the edge of the case mouth. Most cannelures do not. They are concave in profile and the casemouth just slides out as the bullet is pushed in.

[J-cat]

The expanding die opens the case. The crimping die closes the case back to normal or slightly more.

Isn't then correct to say that crimping does hold a bullet in place? Not trying to argue, just want to learn.

The sizing die shrinks the case. The expanding die opens the case so that the inner diameter is about .002" less than the bullet diameter. It also flares the case mouth and creates a "bell". The crimp die only closes the bell. It does not alter case tension.

If the expander die is oversized (due to manufacturing tolerances) or the bullet is too small (also due to manufacturing tolerances) or the case walls are too thin (thereby resulting in an excessive inner diameter after sizing) there will not be enough case tension on the bullet to hold it in place and it will set back no matter how much crimp you apply.

In addition, applying too much crimp will buckle the case walls away from the bullet about .100" south of the case mouth, further diminishing case tension. Use crimp sparingly. Use the case to hold the bullet.

[FieldsofFire]

If the round looks significantly set back into the case, just forgo shooting it. It's only one round and not worth shooting if the pressure is going to be significantly increased because of the shorter overall length. It is more of a problem in some calibers than others.

[LexLuther]

Interesting, thanks for clairifying

Crimp does nothing for bullet setback. Not enough case tension here.

[tteng]

I reload my 44-40 (180gr plated bullet w/ 8.25 gr unique or 6.6 gr titegroup) and single load/shoot them out of a 24" barrel Henry rifle. I've had them 1/2 and full setback before (due to no-crimp and rattling around in can), and noticed no difference in terms felt-recoil nor point of impact at 100yrd.

[xrMike]

The crimp die only closes the bell. It does not alter case tension.

Are you sure that's true?

I always thought that a crimp works by either:

• forcing the top edge of the case slightly into a cannelure on the bullet (for rifle rounds), or
• rolling the top edge of the case into a bullet without a cannelure (for pistol)

And the purpose of a crimp is to increase tension between case and bullet, mostly to prevent bullet setback during feeding (from a magazine), but also to increase bullet starting pressure, which gives you a more complete and consistent powder burn.

When I load for pistol, I do a roll crimp with the Lee Factory Crimp Die as my last step. I aways thought that when I seat the bullet was when the "bell" was eliminated.

When I load for rifle, I do not crimp at all because I use match bullets with no cannelure. How is the bell being eliminated here, if there is one?

Anyway, set me straight if I have it wrong... I just want to understand what's happening and when.