Any Ideas what caused this????

[Leon Garfield]

Shooting my shield 9mm today. Load is 120gr tc powder coated on top of 4.0grs of titegroup. Shooting fine then puff in my face and on my hand. Took gun apart checked everything put it back together shot another clip all was good. Loaded another clip puff again. This is some.brass i bought once fired. Took gun apart cleaned shot no problem. Checked wont fire unless in complete battery so i have no idea. What ya think?

[Ia.redneck]

Just curious, what is the headstamp on the brass? I had a similar experience last summer with light loads in some 9mm milsurp brass marked WCC

[Leon Garfield]

One is ww other looks like nic.

[CT-shooter777]

What was the pistol ? a S and W, some glocks have unsupported chamber issues not sure if that pistol has the same.

136745

here's some intel.

http://smith-wessonforum.com/smith-wesson-m-p-pistols/334878-s-w-9mm-shields-have-unsupported-chamber.html

[flyingmonkey35]

Glock factory barrels will do that.
http://www.wingman26.com/images/shooting/glock-brass.jpg

This guy dose a good job explaining it
Reloading tips with USPSA Master Carlos Anguiano (Glock Bulge): https://youtu.be/c9bgR2xLOYA

[CT-shooter777]

So will S/W shield pistols apparently, which the original post was about, I missed it since I never heard of it (shield) till now. the last S/W pistol I looked at was a Sigma which was pretty much a Glock copy that probably suffered the same issues.

Trim length is critical in these barrels and old brass/ once fired is probably not a good idea either, not sure if an aftermarket barrel is available to address the issue as is for glocks.

[jblee10]

Is all your brass bulged? And just a couple blown out? It seem likely to me that with an unsupported chamber that most cases would have a bulge, with only some actually blowing out. I wonder if your crimp is allowing the boolit to be shoved back into the case raising pressures.

[Leon Garfield]

Sorry yes its a smith and wesson m&p shield 9mm. I havent seen any bulge on other brass but i will take a better look. These are the only 2 that have blown out in 200 rounds i have fired. I am using a dillon square deal for reloading with the dillon crimp die. I will check and see if i can push any of them into case.

[runfiverun]

you generally see a little smile on the brass when you resize it.
that is usually a dead give-away of an unsupported case.

[CT-shooter777]

Sorry yes its a smith and wesson m&p shield 9mm. I havent seen any bulge on other brass but i will take a better look. These are the only 2 that have blown out in 200 rounds i have fired. I am using a dillon square deal for reloading with the dillon crimp die. I will check and see if i can push any of them into case.

if you can measure the case length, I am curious to OAL, those are some deep primer strikes on those cases.

[borg]

Could it possibly be roll sized brass?
Seen some problems back in the late 90's from roll sized brass on 5.56.

[rsrocket1]

Your loads should be well below max pressure so long as your COL is 1.10" or longer. They definitely look like kabooms but you can see that the primers aren't flattened although there is a bit of cratering in the firing pin mark. Most of the damaging kabooms are in the Shield 40's and most are attributed to overloads, but it looks like the Shield 40 may be less tolerant of overpressure rounds than other guns (which is why I chose a Shield 9 although I would have preferred a Shield 40). I'd be very concerned because you don't want to have the magazine blow out or get the frame cracked from a blowout like that. S&W will also not cover anything if you use reloads. If it's a brass issue, just be very careful of the range pickups you use. If it's an early unlock issue or unsupported barrel issue, that's another problem. I do notice that my Shield 9 barrel has a little less support than my M&P FS 9 barrel, but not much of a difference.

Shield on the left with the square LCI slot
136832

[Leon Garfield]

Eliminated all military brass and zero problems. I also loaded some new loads at 3.8grs and they shot great. No more military brass in this pistol. Thanks to everyone for your help.

[MtGun44]

Serious overpressure in that load. That is exactly what
you get with a double charge.

Check to see if you can push a boolit into the case by hand. Put
nose on the edge of the bench and push as hard as you can. If it
moves at all you need more neck tension and/or crimp. Pushed
in boolit in the tiny volume of a 9mm can cause large pressure
increase. That was a signal of severe overpressure, lucky it wasn't
a plastic framed gun, it would be toast with a fractured frame.

[nagantguy]

Try loading your ammo in a magazine instead of a clip that might help;-):kidding:

[Leon Garfield]

Mtgunn44 it was a plastic framed gun, was not a double charge almost impossible on dillon square deal, checked crimp no push back at all. Elimination of the mil spec cases no problems.

[typz2slo]

Looks like brass that was shot in a Glock and had a guppy belly due to unsupported throats. You can take this out once sized but the area has been stretched and will not be as strong anymore.

[MtGun44]

LOL! It is not too difficult to get a double charge in a Square Deal - speaking from someone
that owns one and has loaded on a SD off and on for 20+ years. Not super likely, but
definitely possible to short stroke due to a boolit falling sideways or a case
jamming on the sizer die and not index the shell holder and get a partial stroke.
Auto index helps, no doubt, but don't be lulled into thinking that double charges
are impossible with a SD. And I do see you said "next to impossible" - just be
vigilant, a double charge is the most common SERIOUS reloading error so needs
to be guarded against very carefully.

OK, I was under the impresssion that Solo had an aluminum frame. OK - went back
and re-read the OP - and you said Shield, somehow my brain got Solo. Congrats on
not nuking the frame, I have seen an aluminum framed SIG and multiple Glocks
totaled by a case that looks just like that. You were lucky. Hope you can avoid
a rerun.

In any case, all else aside you had a VERY high pressure round. It is
important to understand the cause. I hope you are right about the military case,
bit it seems a bit questionable to me, good luck. Glad to hear that your
boolits can't push back into the case, one more thing checked off from the
safety list.

[Bullwolf]

A boolit with poor case tension being pushed back into the case can also do that in 9mm.

I'd check the loaded rounds by pushing them downwards against a board or some other flat surface with your hand extremely hard, to see if you can push the projectiles into the case past your crimp/neck tension.

If you can do this by hand, your case tension is somewhat poor, and you are likely to experience that sort of case blow out again.

Perhaps the military brass has a thinner neck, and it's not providing enough case tension with your combination of expander, and your sized cast boolits.

I would try to reproduce the problem with the suspect cases so you are able to track down the issue, (whatever it may be exactly) and take steps to prevent it from happening again in the future.


- Bullwolf

[35remington]

MtGun beat you to it with that advice.

[Bullwolf]

I guess he did at that, and I missed it. Sorry for the double redundancy everyone.


- Bullwolf

[35remington]

Oh heck.....nobody was harmed!

[Leon Garfield]

I have been reloading for 30 plus years just to let everyone know im not a rookie. I do realize a double charge can be had and i have a light set and look in every case before setting a bullet to avoid that from happening. I did cut my load back to 3.8 grs to add a little more safety and have been checking the crimp preassure often. Trust nobody wants this to happen again less thab ME. This was purchased range brass so it could very well have been fired in a glock and weekend it as well, i have no way of telling now. Inspection of other brass shows no buldges. Thanks

[typz2slo]

If it was fired in a glock and then roll sized i dont think there would be any visible signs left.

[bruce381]

OR powder coat was too thick/ do you size again after PC coating?