New rifle brass seems short?

[WEATHERBY460]

300 Win Mag with new Nosler brass measures 2.597. Trim length is suppose to be 2.610.

If I full length resize, will this stretch the brass? I did resize the mouth to make sure the hole was uniform.

I wasn't sure if I could just load and shoot. Thanks

 

[MudRunner2005]

Being a belted magnum, the brass headspaces off the belt, not the shoulder. So when it is fired, it should blow the brass forward and out to fill up the chamber walls (fire-forming).

It will eventually grow. You're only about 0.013" short. Don't worry, it'll eventually grow enough to need trimming.

 

[RT2506]

One thing I will pass on to you about new brass in a belted mag is it may not be accurate. I bought a new Rem 700 7 mag and 100 new cases. Tried lots of different loads and bullets just loading from the NEW cases. Best that rifle would shoot was about 1 1/2 inch. Thought I got a lemon rifle. Ran out of NEW cases and started using the fired cases sized in a FL sizer but just bumping the shoulder. Tried the most accurate load so far and BINGO. I put the first three shots into the same hole at 100 yards. Turned out to be one of the most accurate factory rifles I have ever owned. Really did not matter which bullet I tried it seemed that you could fill up a case with AA3100 and it would shoot in the same hole as long as you used a case that had been fired and sized just bumping the shoulder.

 

[g0rd0]

that's normal. Shoot em, then if possible neck size if not then just shoulder bump em.

 

[scottishkat]

FWIW I always full length resize new brass it can be a bit of work but all new brass will require dissimilar effort to resize and it starts with everything going through the same process.

The last new Nosler brass I used all of it was shorter than the published trim length in most manuals. I think it was also 300 win mag as well. I wouldn't worry about it as stated by others it will get longer.

Good luck and shoot straight

Bob

 

[jlreff]

try putting a false shoulder on it, then fireforming. it will help keep the area ahead of the belt from thining. then neck size after that.

 

[Lefty7mmstw]

just shoot it.... you are over thinking this... the brass will grow at least a couple of thou. a firing...

 

[Edd]

300 Win Mag with new Nosler brass measures 2.597. Trim length is suppose to be 2.610.

The SAAMI spec for 300 WIN Mag brass length is 2.620" -.020".

 

[barefooter56]

Weatherby460,
New brass and factory ammunition has to fit ALL the chamber dimensions listed in its range in the SAMMI specifications for that cartridge. And so it is undersized. Now, there are some situations where the rifles chamber is at the very minimum or slightly lower than the SAMMI specs and the new brass has to be resized to fit. In most cases however , when you run new brass through a FL die only the neck is sized to accept the bullet. The shoulder and case body usually are not touched until the case has been fired by the FL die. Hope this helps!

 

[Deleted member 46119]

300 Win Mag with new Nosler brass measures 2.597. Trim length is suppose to be 2.610.

If I full length resize, will this stretch the brass? I did resize the mouth to make sure the hole was uniform.

I wasn't sure if I could just load and shoot. Thanks

Nosler brass is short. End of Story.

It's a bit of a PIA and it usually stays short for a long time.

Go figure.lightbulb

 

[Deleted member 46119]

just shoot it.... you are over thinking this... the brass will grow at least a couple of thou. a firing...

That too.