Is this bullet setback?

[kd7nqb]

I noticed my carry ammo has developed a new "feature" it has a new crimp in it. Looking at it, I dont think it has lost any overall length. I have always tried to make sure that I rotate my ammo around a bit so I dont end up chambering and rechambering the same round. Out of the 16rnds I carry at least 3 have developed these new crimps.

For reference my ammo is 40 S&W HYDRA-SHOK JHP 135gr they are loaded into a .40s&w M&P. I carry pretty much everyday and only load/ unload once per day. I dont leave a round chambered at night when I put the gun away but I do keep the loaded magazine in it.

I am particularly worried because I know .40s&w is already a high pressure round so I dont want to risk a ka-boom.

My questions are,

Is this ammo safe to shoot?

Should I find myself a pair of calipers and measure OAL if so what is a safe OAL?

Should I switch brands of carry ammo?

Is there a better way to avoid this issue in the future without just leaving a round in the pipe.

 

[Sgt.Dusk]

Do they still fit your chamber?
If they do and you check that your OAL is OK
then shoot them (my opinion only).
To avoid bullet setback you should not let the slide slam the cartridge in the chamber
but to slowly guiding the slide with you hand load the gun
Safe OAL by the vihtavuori reloading charts is 1,126 inches check yourself from them link below.
http://www.lapua.com/fileadmin/user_upload/esitteet/HandgunReloadingData2006.pdf

 

[Sir Aardvark]

That does not look good.

The only time I have seen cartridge cases get creases in it like this was when I was handloading and the bullet was having issues seating properly in the case, such as when you do not properly expand the cartridge mouth to accept the base of the bullet, or you get a little wild on the crimping die.

Generally speaking, with my .40S&W CCW handgun, a SIG 229, I keep it loaded all of the time. I do not unnecessarily load and unload it.
I do not know why you are unloading yours everyday, but excessive loading and unloading of rounds could cause bullet set-back.

Your post suggests that this is a condition caused by your firearm itself and that these cartridges did not come from the manufacturer in this condition.
You do not state if this condition has occurred in the past or is now a new problem, nor do you state if this occurs with all of the ammo you use or only this particular brand/lot.

Possible causes for your condition may include :

1) The OAL of these cartridges could be slightly too great, causing the creases to form after slamming into the chamber too many times.
The .40S&W headspaces on the mouth of the case, so the overall trim length of these cartridges might be just a bit too much. Are these reloads?

2) An obstruction in the throat area or headspace area of the chamber, such as excess carbon build-up, could possibly be causing an area for these cartridges to strike against, thus creating the crease.

3) Weak brass or or very thin cartridge cases that just cant take it. Maybe try new ammo from a different lot number or change to a new manufacturer.

4) Headspace issue with the barrel - this can be measured, but since the .40 S&W headspaces on the cartridge mouth, you would expect to see this issue on multiple occasions with multiple brands of ammo if the barrel was manufactured wrong.

Bullet set-back that I have seen looks like the bullet is just pressed too far into the cartridge - when compared to a normal round it looks shorter in OAL.

I would think that these creased cartridges of yours would have a hard time feeding and an even harder time exracting from your barrel in the condition they are in.

I would thoroughly inspect the barrel and give it a good cleaning, especially the chamber throat were the case headspaces.

I would also try different ammo and see if this is a recurring issue.

Also, if available, use a micrometer to measure both the OAL of the these rounds and the case length - they may not be correct.

Measure the headspace of the barrel - it might be off just a bit, but I would think that this is unlikely and the problem would rest in your ammo or cleanliness of the barrel.

Good luck! Let us know what you figure out.

 

[Coronach]

Our Federal .40 HST rounds look like that all the time after being loaded in a mag, and not just the top two that get cycled. We also use the M&P40.

I was informed it was no problem. I'm dubious, but my gun has yet to kB, so who knows?

Mike

 

[Mizar]

Hello. I thing that this is a sign from a "stem-bind". As the cartridge enters the chamber, the bullet nose is striking the upper part of the chamber. When I load blanks in my pistol, the cases did get such marks, because there is no bullet to support that area of the case. If your pistol shoots well with that cartridge I do not thing that there is a problem to worry.
Best, Boris.

 

[W.E.G.]

That ammo is damaged.

It might fire fine... or it might cause problems you don't need.

None of my Glocks do that with any of the ammo I've tried.

Maybe a different brand of ammo is all you need.

Be absolutely sure your pistol is in full battery if you try to fire those damaged rounds.

 

[Bullet]

kd7nqb
Is this bullet setback?

It looks like to me that you probably have some bullet setback. Only way to know for sure is to measure OAL compared to other rounds. I believe this is caused buy repeated chambering of the same cartridge. I reload 40 S&W and used dies that reduce the case diameter more than regular dies to help prevent bullet setback. I think the (new crimp) your talking about is the case trying to prevent bullet setback. Looking at your picture it seems that the case length and OAL has been reduced. I’d measure the OAL and then call HYDRA-SHOK (Federal 1-800-322-2342) and see what they say about firing these cartridges and I would not chamber my cartridges repeatedly. Probably lots of KB’s in 40 S&W have been caused by bullet setback. At least you caught this before you had a KB. If you must chamber the same cartridge repeatedly try easing the slide down, but as stated above - be absolutely sure your pistol is in full battery.

 

[JDGray]

Thats what happens when you rechamber the same ammo over and over. The stuff will shoot just fine, I've got some 9mm Hydrashocks with the same lines. I don't drop the slide while rechambring carry ammo, but ease it forward. And than you can do a press check if your paranoid, but I've never missed a case head with my extractor.FYI, 40 cal runs the same pressure as 9mm

 

[Coronach]

Stem-bind makes sense. The crease only happens on one side, unless the round has been chambered multiple times. Plus, the M&P is sensitive to bullet profile and while fail to strip/go into battery with "truncated cone" style ammo (which basically binds up in the manner described, "sticking" before it aligns and chambers).

I know I said earlier that rounds in the mag did it without being chambered, but the more I think about it, the more likely it is that the ammo I saw had been chambered at least once.

FWIW, I've only seen it with Federal ammo, and both of my guns run that ammo (even the creased ammo) flawlessly.

Mike

 

[rbernie]

All my carry ammo looks like that eventually, and it all shoots just fine. This is true for Rem GS (9mm and 45ACP) and the Win PersonalProtection fodder in 9mm and 40S&W.

So long as the OAL is not noticably shorter - you should be fine shooting it.

 

[berkbw]

I bought a box of factory Federal in .45, and most of the rounds looked as if they had been seated at an angle. Shot OK.