Squib question from Gunsmith perspective

[jeepmor]

All,

I was pondering about a squib post and had some thoughts to ask the gunsmiths. In my brief readings, I am finding that the squib round binds up the gun to non functionality. For example, a primed cartidge that misses a load of powder. My question lies in this example.

Are the primers and barrel to bullet tolerances designed into the firearm such that if a powder load IS missed, the gun remains somewhat safe because the primer power level is such that it will not force the bullet very far into the barrel.

For the examples I have read, one revolver and one auto. In the revolver, the bullet made it out, into the barrel, but not far enough to allow the drum to rotate. And in the case of the auto, 1. the action did not cycle. and the stuck bullet just barely made it into the barrel, but not far enough for another round to successfully chamber.

Is this by design for safety? I see how it could be, but am not certain. Was just curious.

jeepmor

 

[Jim Watson]

Nope, sheer chance.
I have seen bullets stuck between cylinder (not "drum") and barrel of a revolver, tying up the gun completely, and I have seen their noses sticking out the muzzle.
I have seen bullets stuck in the chamber throat of an autopistol such that another round could not be chambered, I have seen them stuck to where the slide recoiled about an inch before the barrel bushing wedged against the bulge in the barrel formed by the following shot.
I have seen pictures of bulges and splits about everywhere along the length of a gun barrel.
Just luck, as to whether the primer was hot or weak, the bullet slick or tight, no powder or a quarter of a grain.

 

[slopemeno]

Its strictly by chance. Dont think that those are the only squibs possible either...I've seen rounds in an autos barrel anywhere from barely into the rifling all the way up to about 3" down the barrel. In revolvers I've seen them tie up the cylinder, just make it past the gap, or way up the barrel.
Theres huge variations in the ammount of bearing area, bore fit, barrel/cyl gap, primer intensity, etc...

 

[jeepmor]

thanks

That answered my questions, thank you.

jeepmor

 

[edwardh1]

when

do these happen- more often when gun is new - ie as barel wears less chance?

 

[HSMITH]

Edward, new or old really doesn't matter. To try and predict where the bullet will stop is like trying to pick winning lottery numbers, you might get it right but if you do it will be only by chance and the odds are overwhelmingly against you.

A bad round can come from anywhere, but most squibs are handloaded and the result of poor quality control on the part of the handloader. 95%+ of squibs are caused by no powder or very little powder in the case.