Pressure Question

[sigma2chi]

I'm running a BAT action with a Krieger #10 MTU.

.308, 175 gr Berger OTM in Lapua Brass with 42.1 gr of H4895. Fed 210 primers

That's 1.1 gr over Berger's manual suggested max. My groups are excellent at all ranges and my only signs of pressure are "semi" flattened primers (not near as flat as others I've seen and I've NEVER had any cratering) I've heard Fed primers are kinda soft anyway. One other thing I've noticed is that some of my Lapua primer pockets seem to loosen up after 4-5 firings. Maybe 4 out of 50 cases will do this.

A Few questions:

1. Can't some actions that are beefier such as a BAT handle more pressure than a smaller thinner one like a Rem?.?.?

2. Would these intermittent pressure signs be enough to make anyone here completely change their load from 42.1 gr some something milder?

3. Or are these intermittent primer pockets loosening up just natural attrition of brass and not hit and miss signs of pressure??

Thanks

 

[searcher]

The BATs are beefier than the Rem700's and "can" be subjected to heavier loading. The Lapua brass is also pretty beefy in respect to holding primers much longer than most brass. I'd say you are close to the max of what would be considered "safe" loading - perhaps a bit beyond. I'd back off a minimum of a full grain and if that takes you down yet another to the next node down- I'd shoot that over where you are. Then again, I'm considered the "conservative" among my shooting buddies.

 

[Turbulent Turtle]

I'm running a BAT action with a Krieger #10 MTU.

.308, 175 gr Berger OTM in Lapua Brass with 42.1 gr of H4895. Fed 210 primers

That's 1.1 gr over Berger's manual suggested max. My groups are excellent at all ranges and my only signs of pressure are "semi" flattened primers (not near as flat as others I've seen and I've NEVER had any cratering) I've heard Fed primers are kinda soft anyway. One other thing I've noticed is that some of my Lapua primer pockets seem to loosen up after 4-5 firings. Maybe 4 out of 50 cases will do this.

A Few questions:

1. Can't some actions that are beefier such as a BAT handle more pressure than a smaller thinner one like a Rem?.?.?

2. Would these intermittent pressure signs be enough to make anyone here completely change their load from 42.1 gr some something milder?

3. Or are these intermittent primer pockets loosening up just natural attrition of brass and not hit and miss signs of pressure??

Thanks

The Berger data is irrelevant, you should look at the Hodgdon website for loading data. For 175gr bullets, Hodgdon data shows a minimum of 40.0gr of H4895 and a maximum of 42.7gr. You are not near maximum load.

I still don't understand why people don't go to the powder manufacturer site to get powder loading data.

 

[Lapua40X]

... I still don't understand why people don't go to the powder manufacturer site to get powder loading data.

Yeah, me too.

 

[Old Navy]

Know one here can tell you what max is in your gun. You must suspect you are running hot or you wouldn't be asking. Loose primers after only four or five loads would be enough for me to change what I am doing. Later! Frank

 

[savageshooter86]

Another sign would be hard bolt lift and cratering firing pin strike on primer. Each barrel/gun is different pressure max. Also chrony numbers can help show if your velocities are way up there


Losing primer pockets this early would also tell me to back off unless I was shooting for some trophies/$$

 

[savagedasher]

What is the water capacity of the case. If it is around 56.0 gr and your not less the 2.800 oal or jamming the bullet the load looks ok. I feel you have a carbon ring. Larry

 

[sigma2chi]

Thanks for all the help so far guys!!! I'm always learning and I sincerely appreciate the guidance.

My muzzle velocity is 2688fps which didn't seem fast to me. The Berger manual got me connecting dots that may have not been overly related.

I check my chamber and barrel every month with a Hawkeye and I'm free of any carbon ring.

 

[243winxb]

High Pressure Signs - See number 3.

I've noticed is that some of my Lapua primer pockets seem to loosen up after 4-5 firings.

 

[stgw77]

Just my 2 cents from my experience...I also use Lapua brass with Feds 210M, it is my go-to primer in 308WIN...after second firing some primer pockets seems loose. But - federal primers are very soft (not sure about diameter also) and I can seat them easily. Do some testing as I did. Try to seat some other primer (CCI BR2...). I found out that my primer pockets were not loose actually, BR2s seated very nicely with firm grip.