Need direction for reloading 300 Win Mag

[Citadel99]

So, I inherited about 150 rounds for match grade brass for my 300 Win Mag and have never reloaded for a belted magnum. I've got brass, powder, bullets. I know I need to full length resize every round the first time as they were not fired in my rifle. But after that...

What is best practice for reloading belted magnums? Full length? Neck size? Any tips for adjusting/setting up dies? Any info is greatly appreciated.

Mark

 

[MEHavey]

Belted magnums should be resized just like any other non-belted case after the first firing -- shoulder set back just enough (0.002") to chamber cleanly. At this point you will be headspacing on the shoulder like any other case, instead of on the belt's forward edge.

Belted magnums got their start 102 years ago with the 375H&H which had a very tapered shoulder. To ensure reliable mass production chambering/fit on that shape, Holland & Holland effectively made it a "rimmed" case by using a belt, and things took off from there.

Nowadays, the "belt" is mainly a sales gimmick since it adds no strength -- and really isn't needed when you hand re-load for your own rifle. PLUS... purely headspacing on the belt often leaves the short shoulder hanging out in space -- stretching like mad on every firing.

 

[Savage99]

F.L. size the 300 WM just enough so that the bolt closes easily with a slight feel as the case shoulder meets the rifles chamber/shoulder.

It's easier to feel this if the safety controls the firing pin and it's in middle position on a M70 or Kimber.

 

[gamestalker]

It's not always necessary to FL size bottle neck brass, just because it wasn't from your firearm, belted or other.

The way I do it is, I chamber each piece of brass first, if there is no issue closing the bolt, then I just neck size. Simply put, there is no reason to FL size, unless it's necessary to facilitate chamber fit.

GS