LRH Special in 7RM

[xsn10s]

Here is why I say the shoulder is pushed forward on the long version. Peterson also gives this description on their 300 win mag long version.

Peterson 7mm Remington Mag "Long" Brass 50 count (New)

Peterson 7mm RM Brass 50 count

www.submoashooting.com

.300 Win Mag – Long

With Peterson .300 Win Mag- Long casings, we make them with a longer L-T-S dimension. All the other dimensions are SAAMI spec. But the longer L-T-S prevents the casing from stretching excessively on the 1st firing.

www.petersoncartridge.com

 

[bamban]

Here is why I say the shoulder is pushed forward on the long version. Peterson also gives this description on their 300 win mag long version.

Peterson 7mm Remington Mag "Long" Brass 50 count (New)

Peterson 7mm RM Brass 50 count

www.submoashooting.com

.300 Win Mag – Long

With Peterson .300 Win Mag- Long casings, we make them with a longer L-T-S dimension. All the other dimensions are SAAMI spec. But the longer L-T-S prevents the casing from stretching excessively on the 1st firing.

www.petersoncartridge.com

They are long at the shoulder, but not overall length. What I compared was a fired case against a virgin one at both shoulder datum, and overall length.

Disregard the Hornady comment, it was a 7RM, not 300WM

However, comparing a virgin 7RM to a fired one, here's what I read. I don't have 7RM Long to compare yet

 

[xsn10s]

All I know is I can't wait to see that beautiful rifle will shoot with your handloads.

 

[bamban]

All I know is I can't wait to see that beautiful rifle will shoot with your handloads.

Thanks, bud.

Load work might not be till the first week of Oct.

 

[ARlife4me]

Not trying to hijack, but with the datum dials/adapter I was wanting to check on something? Is datum calculated by shoulder diameter - 1/2 neck diameter? If so, then why are some cartridges of the same type (wsm for example) use a different go gauge? A more specific question is I'm trying find out on a 7saum (381 datum if correct) is use the closest (375) for answer/testing?

 

[ARlife4me]

Sorry, I typed in the wrong formula! I think this is the correct 1? Shoulder diameter - neck diameter / 2 + neck diameter?

 

[ntsqd]

There may or may not be a correct diameter, but since the whole thing is comparative, i.e. from one case to another or from one case before firing to the same case after firing, I think what's most important is the the same size hole is used on those cases every time a measurement is taken. Cones being what they are I would choose the hole diameter to be the largest one that still contacts on the shoulder and not the transition radius or the body.

 

[bamban]

While waiting for the Peterson 7RM Long I decided to play with 1X fired Hornady brass.

175 Elite Hunter
N568

At 74.5 still easy bolt lift.

 

[ARlife4me]

That's over 3,500 #s of muzzle energy!

 

[bamban]

That's over 3,500 #s of muzzle energy!

We ran the pressure test twice.

 

[ARlife4me]

We ran the pressure test twice.

Looks like you can speed it up some more?

 

[bamban]

That's over 3,500 #s of muzzle energy!

We ran the pressure/ladder twice, the 2nd string 74.5 charge velocity was 3030, the POI at 200 were within 1/2 inch. We shall see what happens when the Peterson brass come.

It looks promising though.

 

[USAFRet]

We ran the pressure/ladder twice, the 2nd string 74.5 charge velocity was 3030, the POI at 200 were within 1/2 inch. We shall see what happens when the Peterson brass come.

It looks promising though.

Oh boy! This is getting good!

 

[xsn10s]

I wanna see that thing shoot out to distance!!!