265 ABLR looking good

[sp6x6]

That load in mine would be above pressure,retumbo,and send a 300 at F215 @2812=90.5

 

[Westernhuntr]

I would make a false shoulder or jam the bullets on the first firing. That is excessive and you will have early case head issue's. Peterson brass is short on headspace, Lapua is better.

I did not realize this
Maybe I don't have excessive headspace then.. I'm using Peterson brass.
Do you know what the shoulder should measure?

 

[Westernhuntr]

That load in mine would be above pressure,retumbo,and send a 300 at F215 @2812=90.5

I'm shooting a 265 Ablr not a 300

 

[sp6x6]

Ya I know,was just throwing it out as a referance

 

[Elk Hunter 338]

Its always a great idea to check virgin length at shoulder on new brass when going away from norma for the 300 and 338 norma mags. there have been many people including myself that have noticed they are coming up much shorter than Norma at shoulder peterson being the worst of them followed by lapua. as Rhovee stated you'll get premature case head separation

 

[Westernhuntr]

Its always a great idea to check virgin length at shoulder on new brass when going away from norma for the 300 and 338 norma mags. there have been many people including myself that have noticed they are coming up much shorter than Norma at shoulder peterson being the worst of them followed by lapua. as Rhovee stated you'll get premature case head separation

How long are the Norma cases at the shoulder?

 

[Westernhuntr]

So I measured case capacity of new brass and once fired and here's my average.
New -106.2 grains
Once fired-109.5
I'm gaining over 3 grains of capacity, is this normal?

 

[elkaholic]

I did not realize this
Maybe I don't have excessive headspace then.. I'm using Peterson brass.
Do you know what the shoulder should measure?

I would check

So I measured case capacity of new brass and once fired and here's my average.
New -106.2 grains
Once fired-109.5
I'm gaining over 3 grains of capacity, is this normal?

That seems like a lot! Even though its a large case, 3% seems a bit much.
Thats what a lot of improved cases gain.
I would check headspace and body dimensions on a virgin case vs a fired case.

 

[Westernhuntr]

I would check

That seems like a lot! Even though its a large case, 3% seems a bit much.
Thats what a lot of improved cases gain.
I would check headspace and body dimensions on a virgin case vs a fired case.

Yes I thought it was quite a bit of volume increase.
I'll have my shoulder gauge tomorrow to compare virgin cases to once fired.
In the meantime I'm going to jam some bullets and basically treat this like fire forming a wildcat

 

[elkaholic]

Yes I thought it was quite a bit of volume increase.
I'll have my shoulder gauge tomorrow to compare virgin cases to once fired.
In the meantime I'm going to jam some bullets and basically treat this like fire forming a wildcat

Sounds like a wise plan!

 

[sp6x6]

I just checked one of my fired norma brass 107. I have two and feed them same load,chambers are probably as close as you can get if you want to match.Based on me checking brass when I bump shoulder back.

 

[Rhovee]

That is a lot of volume. My 338 Norma Improved is 109. But I zero the case with a primer in it first. Then fill to top with water. Lapua brass and ADG. Just wondering how you are getting your volume. Virgin 300 Norma ADG and Lapua and Peterson are all 103-104 for me.

 

[Westernhuntr]

That is a lot of volume. My 338 Norma Improved is 109. But I zero the case with a primer in it first. Then fill to top with water. Lapua brass and ADG. Just wondering how you are getting your volume. Virgin 300 Norma ADG and Lapua and Peterson are all 103-104 for me.

I'm zeroing a primed case and filling with water.
Again virgin brass comes in at 106.2 grains if you're around 102-103 that seems really low
Edit: I just saw you were talking about 300 NM volumes. The 338 is supposed to be 107 grains so it definitely holds more than the 300 NM

 

[Westernhuntr]

I jammed some 250 Berger's today with mild loads, I'll be using them up untill all my brass is fire formed.
Good news is they're shooting .5 moa at 200 yards.
I recovered a few to compare to the 265 ABLR'S that were shot through the same stump.
The biggest pieces I found from two separate bullets weighed 70 grains, total fragmentation and separation from the jacket.