Testing squib loads

[bradhe]

Question is what powders can be safely downloaded to zero.  I want to test for action cycling and sticking a bullet in the barrel all the way from full squib (primer, no powder) all the way up to full loads in small increments.  I seem to remember that very reduced loads are dangerous with some powders but don't have a source.  I am working  on this in 9mm and 45 ACP

 

Thanks for any help

[iflyskyhigh]

Why?

Not being condescending. Legit just asking why?


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[bradhe]

In a subgun, a squib that cycles the action and fires the next round with a bullet in the barrel will at least ring the barrel and often worse.  (often fills the barrel...)  Painful and expensive on a 100 year old gun.  That said there appear to be lots of stories on this but no data.  I suspect that the real issue is that someone has a squib and then cycles the action by and and keeps going, but want to know.

[Hi-Power Jack]

The three squibs I've had in 9mm Major have all been cycled by hand - 

not enough zip to extract the case and reload the chamber.

[lonestardiver]

H110 is one you need to be careful with, but based on the subject you should not have an issue since it is not a appropriate powder for those cartridges.

[TrackCage]

The only squib I've ever had was primer only, no powder. It did not allow another round to be chambered. The squibs I've seen in USPSA were also the same. I have never personally witnessed a squib where the bullet went deep enough to cycle the gun and allow another round. 

[anonymouscuban]

The only squib I've ever had was primer only, no powder. It did not allow another round to be chambered. The squibs I've seen in USPSA were also the same. I have never personally witnessed a squib where the bullet went deep enough to cycle the gun and allow another round. 

I've had 2 squibs personally and this is what happened. Primer, no powder. Didn't cycle.

I've seen 2 squibs during matches. Same. No cycle.However, in one case the shooter manually cycled but was stopped by the RO before he fired the next round.

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[Guy Neill]

I have witnessed primer only squibs that left the bullet about an inch from the muzzle of a 5" 45 Auto - at least with lead bullets.  Jacketed will likely not go as far.  Different primers will have differing power.

 

I've examined numerous other guns that were damaged from having a BIB (bullet in bore) squib, but I don't know that they were primer only or contaminated at this point.

 

Don't assume squibs (whatever the cause) will always prevent chambering the next round.

 

Guy

[iflyskyhigh]

I’ve been lucky.

I’ve on had a couple squibs. Both rifle and pistol, but I caught it due to failure to feed the next round, as the round didn’t go deep enough in the barrel to allow the next round into the chamber.

They were all due to 0 grs of powder.


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[chevrofreak]

 

[superdude]

You might find the article below of interest. It shows that some semi-auto guns can have a squib with a bullet stuck in the barrel, will still cycle the gun and chamber another round. 

 

https://americanhandgunner.com/handguns/the-extreme-danger-of-squibs/

[bradhe]

Thanks Superdude.  That article is very interesting and gets to what I am trying to test.  Whether a load can both stick a bullet in the barrel and cycle the action which will specific to a particular firearm..  It is less problematic in a pistol (as long as you don't rack the slide and fire again) but I am working with Thompsons and MP5s where you can't possibly get off the trigger fast enough.  Trying to figure out if handloads are safe (again assuming someone is not stupid and racks the bolt and keeps firing after a potential squib).  I am trying to find any data on the "secondary explosive effect" with pistol powders which gets a lot of internet speculation but there appears to be little data.

[admcd]

On 12/6/2019 at 8:25 PM, TrackCage said:

The only squib I've ever had was primer only, no powder. It did not allow another round to be chambered. The squibs I've seen in USPSA were also the same. I have never personally witnessed a squib where the bullet went deep enough to cycle the gun and allow another round. 

I've been holding the gun when it went far enough down the barrel to chamber another round.  Think it was either a light charge or contaminated powder.

 

Shooting Titegroup in my 1911 at a match.  RO didn't hear it.  Had to stop myself.  Bullet got half way down the barrel.

[Corrado_kid]

Worst squib I’ve ever seen...

[Jim Watson]

Many moons ago, NRA told how to load squibs.  In those days a squib was a very light load suitable for basement shooting, not a screwup.  But a stuck bullet was still involved. 

Working with a .38 revolver, they said to reduce the lightest listed load of Bullseye gradually until a stuck bullet resulted, then add back a quarter or half grain. Results would vary widely depending on barrel length and cylinder gap, so they couldn't just give a number. 

So I recommend Bullseye for your experiment. Fewer surprises there than with "clean," "modern" powders. 

 

Anecdote alert:  I can tell you for sure that one (1.0) grain of 700X will get a .38 wadcutter  out the barrel.  A foot low and sideways on a B27 target.  

A similar underload will clear a 9mm cast but hardly budge the slide. 

Pistol loads of 700X do not meter reliably in a CH or Dillon bar measure. I never got a zero load, but one grain cropped up every once in a while. 

I improvised a vibrator for a while but eventually gave up and stayed with finer granulations.