10mm - Too Hot?

[Mountain]

Re-sizing some 10mm brass tonight and noticed this:


Full boat load of 12 grains Blue Dot pushing 155 JHP's. I have a couple pound heavier main spring assembly and a KKM barrel in that particular Glock 20. Primer cratered a bit? Otherwise no other signs of excessive pressure. Thoughts?

 

[TrashcanDan]

SIG brass is one of those headstamps I've always tossed.
I think it was the primer pockets that gave me trouble, kind of tight or undersized like Aguila brass.

Blue Dot was one of those powders I used in .44 mag that had to be used at the top end of the charge. And it had to be 240 gr or better. I had some 300's that it worked really well in.
Anything less than max or close to max charge and lightweight heads, I'd get the unburnt tell tale flakes on the table. Must've been the burn rate.

Can't tell what that is in the middle of where the striker hit. Doesn't look flattened.
Anyways, if it works, run it!

 

[Tallahassee]

Re-sizing some 10mm brass tonight and noticed this:
View attachment 675661

Full boat load of 12 grains Blue Dot pushing 155 JHP's. I have a couple pound heavier main spring assembly and a KKM barrel in that particular Glock 20. Primer cratered a bit? Otherwise no other signs of excessive pressure. Thoughts?

I see you are a man of culture and class.

Looks good to me, I would run it. I don't think 12gr is near max either. 10mm likes to be pushed hard. Sig brass is good as well.

 

[Mountain]

Thanks @TrashcanDan and @Tallahassee .

Agreed primer is not flattened. Primer metal is flowing a bit around the striker. These are "zesty' loads a la 10mm as God intended, not the Devil's brew of weak sauce that was cooked up by ammo company lawyers.

Next up will be some hard cast Kodiak killers. Of course won't be near 1300 fps like the 155's but will hit HARD.

 

[Tallahassee]

Thanks @TrashcanDan and @Tallahassee .

Agreed primer is not flattened. Primer metal is flowing a bit around the striker. These are "zesty' loads a la 10mm as God intended, not the Devil's brew of weak sauce that was cooked up by ammo company lawyers.

Next up will be some hard cast Kodiak killers. Of course won't be near 1300 fps like the 155's but will hit HARD.

I like the underwood 200gr hard cast, nice power. They have been having sales regulary as well.

 

[TrashcanDan]

Next up will be some hard cast Kodiak killers. Of course won't be near 1300 fps like the 155's but will hit HARD.

Now I'm interested, because I have a .40 Mag.
Tell me about these Kodiak Killers

 

[Mountain]

Now I'm interested, because I have a .40 Mag.
Tell me about these Kodiak Killers

LOL simply some hard cast around 200 grains.

 

[Road_Clam]

Re-sizing some 10mm brass tonight and noticed this:
View attachment 675661

Full boat load of 12 grains Blue Dot pushing 155 JHP's. I have a couple pound heavier main spring assembly and a KKM barrel in that particular Glock 20. Primer cratered a bit? Otherwise no other signs of excessive pressure. Thoughts?

I'm wondering if you got some cratering as a result of the blade style firing pin ? The primer does not look flattened. I've run some full bang 200 gr loads with 12+ gr of AA9 and not had any pressure signs from my Kimber Target long slide 1911. Only concerning issues I had was with 800X

 

[Mountain]

I'm wondering if you got some cratering as a result of the blade style firing pin ? The primer does not look flattened. I've run some full bang 200 gr loads with 12+ gr of AA9 and not had any pressure signs from my Kimber Target long slide 1911. Only concerning issues I had was with 800X

View attachment 676718

I assumed the blade type firing pin was the issue but thought it worth double-checking on the forum. Agreed, primer doesn't look flattened. I had some bad 'Oath' factory ammo blow the unsupported area (when chambered) of a 10mm case. The blown case plus the ones I had fired previously all had flattened primers.

Standard factory ammo- Sig, Armscor, Winchester, etc., doesn't leave as pronounced of a crater. Of course most 10mm factory ammo is watered down compared to the original performance of the cartridge. My Blue Dot load is pushing 155's around 1300 fps, so it has a bit more oomph to it.

 

[widnerkj]

I posted up some of my 10mm experimenting a while back. This pic looks just fine to me. My G20 liked the 180 grain XTP's with 14.3 grains of AA9 behind it. It was a little weird, because the lyman book was going for more than the hordady book for the same load. But with that load I was getting 1350 FPS without flattened primers. That glock firing pin does make it look funny sometimes though.

 

[Mountain]

I posted up some of my 10mm experimenting a while back. This pic looks just fine to me. My G20 liked the 180 grain XTP's with 14.3 grains of AA9 behind it. It was a little weird, because the lyman book was going for more than the hordady book for the same load. But with that load I was getting 1350 FPS without flattened primers. That glock firing pin does make it look funny sometimes though.

Thanks, much appreciated.