Overpressure?

[nucular]

124 grain Berry's round nose 9mm @ 1.16 OAL out of a S&W Shield MP2

Does this look like a sign of overpressure? I tried out several different powders and loads the other day and most primers seemed to have this little bubble on them. None of the charges were at or above max according to the Lee guide. These 2 examples are with Accurate #7 @ 6.5 grains and 572 @ 5.5 grains. S&B primers.

 

[Leo]

Are the Berry's bullets the copper washed lead variety? Are you using the lead bullet data? What kind of primers are they and have you ever used them before? I cannot imagine getting too over pressure in that short barrel pistol. That light of a pistol will also really let you know it it is a hot load, does it feel right?


I just looked up the AA#7 data, That looks like a good, safe load. What do the primers look like from different brands of factory ammo?

 

[nucular]

Are the Berry's bullets the copper washed lead variety? Are you using the lead bullet data? What kind of primers are they and have you ever used them before? I cannot imagine getting too over pressure in that short barrel pistol. That light of a pistol will also really let you know it it is a hot load, does it feel right?


I just looked up the AA#7 data, That looks like a good, safe load. What do the primers look like from different brands of factory ammo?

new box of S&B primers. They are old (probably 10+ years) but have been stored in an air tight ammo can. Bullets are copper and I am using lead data (actually listed as copper plated in the lee guide). Feels right when shooting and is accurate. I will have to run some factory ammo through and inspect the brass.

 

[Leadeye]

Looks more like something related to the firing pin and the back of the chamber. Overpressure usually comes with the primer being squeezed into the space where the back of the chamber contacts the case. I don't see that in the pictures.

 

[AmmoManAaron]

Doesn't look overpressure to me. The edges of the primer where they meet the primer pocket of the case are nice and rounded. The primer isn't cratered in the traditional over-pressure sense either. Some of these new polymer pistols, plus Glocks, leave odd marks on fired primers because of either the design of the firing pin hole in the breach face or the shape of the firing pin itself. Firing a variety of factory ammo and examining the results would be a wise move to put your mind at ease. I would not make any decisions based on the results of only a single factory load since different brands and loadings can vary significantly in how they react in a particular gun.

 

[nucular]

By the shape of the bulge, it looks like it must be expanding into the firing pin hole. Is that normal?

 

[Jeepster48439]

By the shape of the bulge, it looks like it must be expanding into the firing pin hole. Is that normal?

View attachment 144107

If you shoot some factory rounds, you will probably see the same shape on those primers.

 

[nucular]

Thanks, guys. Sounds like this is normal. I will shoot some factory ammo at the next outing and if i get the same marks, I will go back to loading up some more rounds.

 

[BE Mike]

High pressure looks more like a flattened primer. That "M-1 thumb" looks pretty nasty.

 

[nucular]

High pressure looks more like a flattened primer. That "M-1 thumb" looks pretty nasty.

LOL that's actually a "the idiot didn't keep his hand out of the way while hammering in the tent stake" thumb.

 

[johntheplinker]

LOL that's actually a "the idiot didn't keep his hand out of the way while hammering in the tent stake" thumb.

Good way to learn new and interesting words...
BTDT

Back on topic. Correct me if I'm wrong, but IIRC I've heard that S&B primers tend to be a little softer or thinner than most makes.

 

[Wolfhound]

I have seen that with a combination of very hot loads and a large firing pin opening. The primers actually expand into the firing pin opening where they aren’t supported. I have even seen shavings build up and cause light strikes by interfering with firing pin travel. YMMV

 

[Karl-just-Karl]

Is it wrong of me to say that I've never seen a firing pin hole shaped like that?

Is it supposed to be that way?

If it is, it wouldn't surprise me that your primers look the way they do.

 

[nucular]

Is it wrong of me to say that I've never seen a firing pin hole shaped like that?

Is it supposed to be that way?

If it is, it wouldn't surprise me that your primers look the way they do.

I have 2 shields. I never looked at the primers on the first shield because I didn't reload for it but I just looked at the slide on it and they are both the same. Not sure what the reasoning behind it is.

 

[BE Mike]

I have 2 shields. I never looked at the primers on the first shield because I didn't reload for it but I just looked at the slide on it and they are both the same. Not sure what the reasoning behind it is.

It looks like wolfhound has the answer. The shape is to prevent primer shavings from building up and causing light primer strikes.

 

[Karl-just-Karl]

I have 2 shields. I never looked at the primers on the first shield because I didn't reload for it but I just looked at the slide on it and they are both the same. Not sure what the reasoning behind it is.

Huh, learning something new...I have a buddy with a Shield. I'll have to check it out.

ETA: Discussion on the S&W forum from 2016

S&W Shield Firing Pin Hole Shape

Dear all, I am new to this forum and I need your expertise and sincere advice. Very recently I got my brand new S&W 9mm Shield and so far I have had about 300 rounds through it. Shape of firing pi

smith-wessonforum.com

 

[Jaybird1980]

Looks like primer flow into the firing pin hole to me also. The primers may just have thin cups, try some CCI primers if you can get ahold of a few to see if that helps. Also pay attention when you deprime and deprime to make sure the pocket isn't loose.

 

[nucular]

Looks like primer flow into the firing pin hole to me also. The primers may just have thin cups, try some CCI primers if you can get ahold of a few to see if that helps. Also pay attention when you deprime and deprime to make sure the pocket isn't loose.

That's a good point. I have some CCI and Winchester primers I can try out. I only have a handful of cases to inspect but I will do that to the ones I have. I was at an indoor range and most of them ended up down the line or mixed up with other brass.