Sorry Another OCW results question 4064 175's

[doctordoctor]

Hey guys where would you pick up for step 2 of testing? I am also tempted to maybe try to see if there is a higher node above 45 as I had no pressure signs...yet. As always THANK YOU!!!

I think I find a node 42.5 to 43.5 maybe up to 44grains if it wasn't for that darm flinch shot which I called!
4064 powder
COAL was 2.8"
rifle factory Rem 700 XCR 1:12 26" bbl

 

[918v]

What brass are you using? What are your fireformed brass dimensions: base, shoulder, neck? Case volume is important.

 

[918v]

.5gr increments are too broad for OCW testing. But it looks like 42-43grs is the range you should be looking at. I want to warn you that if you are using FC brass you are way over max past 44grs.

 

[doctordoctor]

Using new never fired Lapua brass.

 

[918v]

OK, but what are your fired brass dimensions? I'm assuming .469" at the base, .455" at the shoulder and .346" at the neck. The reason I ask is it seems Remington is using several different chamber reamers. The above dimensions are what I think is their standard 308, but if yours is more generous you can get away with more powder in the case. Your 42gr load agrees with what I'm seeing in my gun when using new Lapua brass. I found 42.2 is better ES wise.

 

[doctordoctor]

When I wake up from my nap (on 3rd shift now) I will measure it. Thanks!

 

[doctordoctor]

OK, but what are your fired brass dimensions? I'm assuming .469" at the base, .455" at the shoulder and .346" at the neck. The reason I ask is it seems Remington is using several different chamber reamers. The above dimensions are what I think is their standard 308, but if yours is more generous you can get away with more powder in the case. Your 42gr load agrees with what I'm seeing in my gun when using new Lapua brass. I found 42.2 is better ES wise.

Yes those are my dimensions.

 

[918v]

I would develop the 42gr load first, then try the 43. I'm getting very low ES at 42.2grs in my gun and 2600 FPS is fast enough.