What is bullet setback?

[timeisrelative]

Ok so as a stupid question, if you find setbacks, and have the right equipment, couldn't you use your impact puller hammer to lengthen the round, then put it in your press for proper length? I know its only 1 bullet, but I am just curious.

[Urban_Redneck]

I checked and chucked some ammo back in October and took some photos, it's a good practice to save a round from a new box, or at least record the OAL somewhere so you can check your ammo down the line.



A bullet setback into the case will increase pressure at firing, in some cases pressures can spike to a level that causes a KaBoom or catastrophic failure.




Five of the rounds above were what I consider "out of spec" . For me that's 0.010" shorter than a brand new round. Two were over 0.020" shorter.



The only fix is to pull them from service and deactivate them.
A good rule of thumb is "3 and out". Good self defense rounds cost up to $1ea but it is still cheaper to scrap them that having to buy a new gun or worse, a trip to the ER

[Orlov556]

I would like to point out something that wasn't covered in the video. When bullets "set back," every thousandth of an inch will increase the pressure of the round exponentially. I wont bore you with the numbers, but i think that firing set back rounds is not a wise idea, and can be very dangerous. I would suggest taking them out of service permanently, not shooting them at all.

[alpacaheat]

This is apparently the cause of at least some of the exploding S&W Shields from what I've gathered.

[Just1more]

Very informative and important to know (wonder why the NRA basic classes don't include this type of safety issue)
I learned something new today (-:

[Deleted]

Very informative and important to know (wonder why the NRA basic classes don't include this type of safety issue)
I learned something new today (-:

I don't think anyone wants to take on the liability that is going to come with it... unless you say, "Here it is... if you see it, throw your bullets out." If the topic gets into prevention, the instructor screws himself. He can't talk about leaving the gun loaded and he can't talk about rotating bullets as it's only encouraging more setback in more bullets. So just be ignorant of the issue.

[Just1more]

You have a point there regarding the NRA rules and their classes ." Always keep the gun unloaded until ready to use." That could complicate their safety rules !!

Thats really unfortunate as its such an important safety concern that I didn't even know about. I am sure many others also don't realize that occurs rechambering a cartridge in a firearm.

[Deleted]

Thats really unfortunate as its such an important safety concern that I didn't even know about. I am sure many others also don't realize that occurs rechambering a cartridge in a firearm.

And it's an even bigger issue depending on the type of gun. I think 1911's have some of the worse setback I have ever seen if you are using JHP's. That's why I load up when I get new ammo after quals and I only unload the gun when I need to clean it. When I clean it I rotate rounds. Other than that... loaded in a holster 24/7

[dkf]

Ok so as a stupid question, if you find setbacks, and have the right equipment, couldn't you use your impact puller hammer to lengthen the round, then put it in your press for proper length? I know its only 1 bullet, but I am just curious.

Not a stupid question at all. You can do it and I have done it many times. However you often lose some tension on the bullet after it starts slipping thus the bullet will setback easier the next time around. What I usually do is bump the set back rounds back to factory COAL or longer (at or below SAAMI max COAL) and then shoot them at the range for practice ammo. Take the ammo out of carry rotation but it is not worthless.

This is apparently the cause of at least some of the exploding S&W Shields from what I've gathered.

I got some Remington like that already. Had to bump quite a few back to proper COAL with the bullet puller. Always inspect the ammo before loading it into magazines.