My Lapua 300 prc brass experience......

[Eeegadd]

I have to agree Alex. Your reamer has larger base spec as well correct?

I'm having a 300prc machined as we speak but I have lapua brass. I noticed the full size die was right at .529 at the base which is the same as the brass. Not good? I mentioned this to the gunsmith. He's looking into it. What should I be paying attention to? Thanks

 

[FUDD2.0]

My order of Lapua brass just showed up Also. I've been using Hornady brass (that's all I could get). So far the Hornady has been doing fine but gonna try the Lapua brass. Had good luck with it in my 223, 308 and 338 Lapua. I just finished fire forming ADG 6.5 needmore and 338 Lapua brass. Too soon to pass judgment.

 

[ontarget7]

I'm having to chamber all my Lapua brass and sort, as some are just to tight in my SAAMI spec 300 PRC. I'll shoot the tight ones still in dry weather but no way will I take them on a hunt where you have the potential for moisture.

 

[parshal]

Ontarget, my Lapua brass measures exactly the same as my go gauge. It sounds like your chamber is right at saami minimum. I usually chamber to go +.001"but ended up at go .003" on this one which is probably a good thing given the brass length. Not shooting many saami chambers I was surprised the brass was the same length at go.

 

[ontarget7]

Ontarget, my Lapua brass measures exactly the same as my go gauge. It sounds like your chamber is right at saami minimum. I usually chamber to go +.001"but ended up at go .003" on this one which is probably a good thing given the brass length. Not shooting many saami chambers I was surprised the brass was the same length at go.

thought about getting a set of dies from whidden made to .001 - .002 smaller for the Lapua brass.
Thoughts ?

 

[parshal]

That or take a couple thousandths off the bottom of your current die. I'd probably size one of the new cases first, though, to see if what you have will work as-is.

 

[highdrum]

thought about getting a set of dies from whidden made to .001 - .002 smaller for the Lapua brass.
Thoughts ?

Not all saami min dies are created equal, I think the Redding type S dies are tighter at base than Horandy. When I ran new unfired ADG in the die it was noticeably contacting case, actually doing a little sizing. Horandy match dies didn't contact the case enough to leave witnesses marks. I know the rcbs matchmaster dies are typically small at base as well.

 

[ontarget7]

Not all saami min dies are created equal, I think the Redding type S dies are tighter at base than Horandy. When I ran new unfired ADG in the die it was noticeably contacting case, actually doing a little sizing. Horandy match dies didn't contact the case enough to leave witnesses marks. I know the rcbs matchmaster dies are typically small at base as well.

I mainly run Redding dies and do as well on my 300 PRC. They are definitely contacting the case. More than likely even more contact .001 to .002 smaller will probably due, I'm thinking. I'll probably contact Whidden and get their take on it as well.

 

[ontarget7]

That or take a couple thousandths off the bottom of your current die. I'd probably size one of the new cases first, though, to see if what you have will work as-is.

Haven't thought about that. Might not be a bad idea.

 

[highdrum]

I mainly run Redding dies and do as well on my 300 PRC. They are definitely contacting the case. More than likely even more contact .001 to .002 smaller will probably due, I'm thinking. I'll probably contact Whidden and get their take on it as well.

The die may be enough to keep the smaller base dimension lapua brass in spec. Since it's starting at a smaller dimension than ADG, the die may keep it smaller. Saami chamber is 535, new lapua is 529, adg was 531. Maybe the die would keep fired lapua at 531 after sizing? Trial and error will tell the tale I guess.

 

[ontarget7]

Would varying dimensions in the extractor groove area cause some of the issues I'm referring to ? I'm a little puzzled to be honest as everything measures within reason to be honest. That's the only area I'm seeing a wider range of variances

 

[ontarget7]

That and the Hornady brass has always been softer so it just seems to size easier. Same amount of reloads on the Hornady brass vs Lapua and the base of the case is still holding true to dimensions where the Lapua has gained a touch and after sizing, it won't come down that touch extra I need with my current Redding dies.

 

[parshal]

Isn't this why Alex made his customer PRC reamers with a larger dimension at the datum (.537")? We are talking about not being able to size brass enough for a saami chamber, correct?

 

[ontarget7]

Isn't this why Alex made his customer PRC reamers with a larger dimension at the datum (.537")? We are talking about not being able to size brass enough for a saami chamber, correct?

This sounds like my problem to be honest.
I may take a touch off the bottom of the die to see if that makes my situation an easy fix per say