Holes in primers

[tjanik21]

My AR-10 .308 hits the primers pretty hard along with some bolt swipe on the face of the brass. Sometimes the firing pin will punch through the primer and sometimes it leaves a deep dimple. I'm currently using 39.5 gn of SW TAC Rifle with 168gn ELD MATCH. I do have a Hiperfire Power trigger which seems to have a strong spring but unsure if that plays into anything

 

[Big Mc]

My AR-10 .308 hits the primers pretty hard along with some bolt swipe on the face of the brass. Sometimes the firing pin will punch through the primer and sometimes it leaves a deep dimple. I'm currently using 39.5 gn of SW TAC Rifle with 168gn ELD MATCH. I do have a Hiperfire Power trigger which seems to have a strong spring but unsure if that plays into anything

Witch primer .??

 

[243winxb]

Your powder charge would seem to be ok, if using Hornady brass/ data & a bolt gun?
Different brass may produce higher pressure.

Hornady 308 Gas Gun data may use less powder? Cant find online. Is there any?

Pierced primer may be caused by, high pressure, excessive head clearance, firing pin protrusion to long, damaged tip of pin.

 

[tjanik21]

Witch primer .??

These are what I've been using. I've run them through my 45-70 govt as well with no issue.

 

[tjanik21]

Witch primer .??

Your powder charge would seem to be ok, if using Hornady brass/ data & a bolt gun?
Different brass may produce higher pressure.

Hornady 308 Gas Gun data may use less powder? Cant find online. Is there any?

Pierced primer may be caused by, high pressure, excessive head clearance, firing pin protrusion to long, damaged tip of pin.

View attachment 1706412

 

[Doom]

Which case. It matters. TopBrass is not a manufacturer but supplies reconditioned brass. Read the Headstamps.

 

[tjanik21]

Which case. It matters. TopBrass is not a manufacturer but supplies reconditioned brass. Read the Headstamps.

Lake City brass. LC 12 is on the headstamp

 

[tjanik21]

Your powder charge would seem to be ok, if using Hornady brass/ data & a bolt gun?
Different brass may produce higher pressure.

Hornady 308 Gas Gun data may use less powder? Cant find online. Is there any?

Pierced primer may be caused by, high pressure, excessive head clearance, firing pin protrusion to long, damaged tip of pin.

View attachment 1706412

Currently am shooting the brand "TopBrass"

I'm well below max IAW hornady which is the manual used. I'm firing from an AR-10 semi-auto. The firing pin doesn't have e any visible damage but as far as protruding length goes I'm unsure, I will post a picture of that. Maybe try to reduce the powder charge a few grains

 

[SeabeeKen]

According to sw, 39.5 is the starting load with 168 gr with tac rifle powder so not likely over pressure. Are any primers protruding above the case head? Sounds like that hammer spring might be the issue.
That firing pin looks like it sticking out an awful lot. Can you measure the amount its sticking up above the bolt face?

 

[tjanik21]

According to sw, 39.5 is the starting load with 168 gr with tac rifle powder so not likely over pressure. Are any primers protruding above the case head? Sounds like that hammer spring might be the issue.

I thought the same about the hammer spring, but there is a small amount of bolt swipe on the head. As for the primers protruding, not at all. They are flush, maybe even very slightly below the head.

 

[243winxb]

https://www.accurateshooter.com/cartridge-guides/308win/

Brass & bullets used can make a big difference in pressure.

May want to try a different brand of primer?

The most important thing to remember about military brass is that the internal capacity will probably be less than commercial .308 Win brass, because military brass often has thicker webs or casewalls. Montana Marine reports his fire-formed milsurp cases hold 56 grains of H20 on average compared to 58 grains for fire-formed Winchester. Given the reduced capacity of military brass, you should reduce posted max loads by 1.5 grains when loading with Lake City or most other milsurp brass

 

[tjanik21]

https://www.accurateshooter.com/cartridge-guides/308win/

Brass & bullets used can make a big difference in pressure.

May want to try a different brand of primer?

I will probably try that since the current ones seem to be a softer metal. I used to have some remmington No. 9 1/2 but ran out and starting using the S&B LR. I remember there being a decent pin strike but can't recall any holes in those. If it continues with a different brand then I will reduce the powder charge.

 

[Doom]

Drop the charge a couple of grains. That LC brass has less volume that the Winchester brass (a couple of grains worth) used in the SW load data.

 

[tjanik21]

Lake City brass. LC 12 is on the headstamp

Correction, the loads fired today were hornady brass. I have LC loads but did not get a chance to fire them today

 

[Kracken McGraw]

Witch primer .??

If it’s not that Witch primer it could be the Devil one.

 

[Fire Dog]

If it’s not that Witch primer it could be the Devil one.

I was hesitant to point that out… Just so many folks here use such bad grammar, syntax and just ignore the red underline indicating a misspelling…
People often react badly to having their errors pointed out…
In the end, we just want to keep this forum from turning into a “shouting match/agro pissing match…

 

[Kracken McGraw]

I was hesitant to point that out… Just so many folks here use such bad grammar, syntax and just ignore the red underline indicating a misspelling…
People often react badly to having their errors pointed out…
In the end, we just want to keep this forum from turning into a “shouting match/agro pissing match…

I

I was hesitant to point that out… Just so many folks here use such bad grammar, syntax and just ignore the red underline indicating a misspelling…
People often react badly to having their errors pointed out

I don’t imagine Big Mc minds a little leg pullin.
Ever post I make spellcheck gets me and I have to go back and redo .

 

[Fire Dog]

I

I don’t imagine Big Mc minds a little leg pullin.
Ever post I make spellcheck gets me and I have to go back and redo .

Perhaps you ment EVERY post….

 

[XTR]

My AR-10 .308 hits the primers pretty hard along with some bolt swipe on the face of the brass. Sometimes the firing pin will punch through the primer and sometimes it leaves a deep dimple. I'm currently using 39.5 gn of SW TAC Rifle with 168gn ELD MATCH. I do have a Hiperfire Power trigger which seems to have a strong spring but unsure if that plays into anything

How much is the shoulder moving on the brass when fired? Is this brass that you sized or did you buy it processed? If this is processed LC Brass (I.e., not new) it’s not uncommon for it to be over sized (shoulder pushed back too far). It’s possible that you have over sized brass and the primer is pushing back before the brass expands back to the bolt face.

I’ve run into over sized military brass often enough that I have a suspicion that a lot of the processed military brass on the market was first fired in machine guns and is over sized to get it back to a size that fits in bolt gun chambers.

 

[chop house]

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