Another Reason Not to Rechamber Same Round

[cobrasjp]

Bullet setback is the most common reason given for not chambering the same round a lot of times. And that is certainly a valid reason.

But, as these picture show, there is another reason.

https://dl.dropboxusercontent.com/u/54491382/DSCN1904.JPG

https://dl.dropboxusercontent.com/u/54491382/DSCN1907.JPG

These are both Speer Gold Dot 380 90gr GDHPs. The one on the right hasn't been chambered. The one on the left I had chambered many times when loading my P380, before I realized how bad that practice is. Notice how the bullet has deformed and closed up the hollow point by all the repeated times being slammed into the feed ramp when dropping the slide. The cartridge overall length is a little shorter, but it's hard to accurately measure the bullet setback because of the deformation of the bullet.

I noticed the damaged round on the left several years ago and put the bullet in a drawer on my reloading bench until I could take pictures and post them. Then I forgot about it. While straightening up my bench, I found the round and thought I would share it with you.

[RonW]

I've been shooting since 1989. I have never had this happen to me, just sayin'....

[cobrasjp]

Started shooting in 78 and have only seen this one time.

The Kahr 380s have really steep feed ramps. The angle of the bullet nose hits the feed ramp is just perfect for collapsing the hollow point.

[Ikeo74]

That deformation is more likely caused by using the wrong seating plug when reloading. I have experianced a similar roll over when loading gold dots and XTP bullets using a round shaped seating plug (for round nose bullets). The correct plug is a flat shaped plug with rounded sides. RCBS makes a plug especially for gold dots. That bullet is probably only deformed and not set back. It is probably safe to shoot because it is only shorter because the nose is rolled in instead of the bullet being push back into the case.

A round shaped seating plug in your die will round the nose of the gold dot bullet over as it is pushing the bullet into the case. I have seen it done on my own reloading bench before I bought the correct plug.

[RRP]

Here is yet another reason not to rechamber the same round, over and over again. In my opinion, it is the most compelling reason to avoid this practice.

Chambering the same round many times results in deformation (pulverization) of the priming compound. This is due to the physical trauma of the cartridge being stripped from the magazine, slammed against the feed ramp, rapidly diverted into the chamber, and stopped abruptly when seated. If done repeatedly, the priming compound eventually breaks down.

During normal operation, when the firing pin strikes the primer, the anvil within the primer crushes a cup of priming mixture, which is bound together in a tablet form. Because the priming compound is pressure sensitive, it explodes on the impact caused by the striker. However, if the priming mixture has been pulverized from multiple chamberings, it no longer is held in position to be crushed by the anvil. The result is a misfire.

This has been demonstrated many times by conscientious cops with young kids. For the safety of their children, they unload their service weapon every night when they get home. The next day, they reload, chambering the same round. After a few months, that round has been slammed into the chamber often enough to break down the priming mixture, and the gun will misfire.

[cobrasjp]

That deformation is more likely caused by using the wrong seating plug when reloading. I have experianced a similar roll over when loading gold dots and XTP bullets using a round shaped seating plug (for round nose bullets). The correct plug is a flat shaped plug with rounded sides. RCBS makes a plug especially for gold dots. That bullet is probably only deformed and not set back. It is probably safe to shoot because it is only shorter because the nose is rolled in instead of the bullet being push back into the case.

A round shaped seating plug in your die will round the nose of the gold dot bullet over as it is pushing the bullet into the case. I have seen it done on my own reloading bench before I bought the correct plug.

These are not reloads. They were new, factory-loaded rounds.

[Bawanna]

Some guns and some cartridges are worse than others in this rechambering scenario.
At my department I have a box left out of duty handgun ammo and rifle ammo, rifles do it too, sometimes even worse.

Officers are instructed to check for setback and bullet deformation and to use a new round when appropriate.

Myself I generally rotate the mag stack. I'll flip out some rounds and use a new one for the chamber, put the old one bottom of the stack etc. Not as diligent as I used to be. Used to swap and rest mags every two weeks, used to do a lot of things I don't bother with now days.

First I've heard of the primer compound pulverizing, could happen, never seen it myself but again there's lots of things I ain't seen too.

[Ikeo74]

I would think that primer pulverizing would be extremely rare. I have never heard of it either.

[RRP]

http://boloreport.com/officer-safety-ammunition-cycling-and-failure-to-fire

[Bawanna]

In an attempt to help avoid this we have started qualifying once annually using the duty ammo the officer carries. Then he is issued new duty ammunition.

Still carrying ammo issued in 2011 seems like an awfully long time for a duty gun to me. I didn't note when that article was written.

[RRP]

This occurred in 2011. The officer had been carrying the ammo for 6 months.

[Barth]

I noticed bullet set back particularly in 357 Sig.
After seeing that, I'm careful to not re chamber rounds in any caliber.

[wyntrout]

It makes sense not to punish the same round day after day. IF you must load/unload every day, put aside a box of your carry ammo and use one round for one day and then place it in the box and use the next one for the chambered round. Do this daily until you've used all of them and then start over with the first one from that box. At some point you might want to shoot those and start a new box.

It's like underwear or socks... I have several dozen of each, but use them in rotation spreading the wear out over years, instead of wearing one or two pair until they're threadbare from use and cleaning.

Wynn

[Bawanna]

Or just go commando, one less thing ya know?

[wyntrout]

Ya mean... no round in the chamber!! :eek:

[Exiledviking]

I was of the impression that repeat chambering of the same round could result in a Ka-Boom (technical term ha ha) from over pressure due to the set-back of the bullet in the case.

[Bawanna]

In certainly can under the right circumstances contribute to a kaboom.

[OvalNut]

I am glad now that I have been late to the party on carrying one in the chamber as a default. Admittedly, I had been carrying Israeli style empty chamber to date as I got 'used to' the live round in the pipe concept. I now get it and after my last concealed carry class I have stepped up to live carry. I am glad simply because I didn't realize the issues of setback and round deformity caused by repeated chambering. Now though I understand how to best mitigate these impacts on the live rounds I carry, through live round rotation and shooting my carry mag when I go to the range, and all is well.

Thank you all for your additional education.


Tim

[jocko]

[QUOTE=OvalNut;346592]I am glad now that I have been late to the party on carrying one in the chamber as a default. Admittedly, I had been carrying Israeli style empty chamber to date as I got 'used to' the live round in the pipe concept. I now get it and after my last concealed carry class I have stepped up to live carry. I am glad simply because I didn't realize the issues of setback and round deformity caused by repeated chambering. Now though I understand how to best mitigate these impacts on the live rounds I carry, through live round rotation and shooting my carry mag when I go to the range, and all is well.

Thank you all for your additional education.


you must be French, as they started the empty chamber during the war. Just sayin. Bougtht a new unused French war rifle at the last gun show. dealer had a sign on it that said, "New war rifle, carried alot, never fired, dropped many times..