I am about to size and fireform some 300 H&H for my 300 Apex. In the past I have used resized 308 Norma mag to fireform cases.

What should I trim the length of the 300 H&H cases? The fireformed case of the 300 Apex is 2.5 inches. The parent 300H&H is 2.85.

Although I have several fireformed 300 H&H cases( they came with the rifle), this is my first use 300 H&H starting afresh!

Thanks in advance for your help.

Rusty
We band of brothers!

Trim to the length of your chamber fireform (with a moderate load) one and see how it comes out. Adjust from there.

[ 11-11-2003, 05:39: Message edited by: Swany ]

Rusty,

You might also need to reduce the thickness of the new neck before you do your fireforming.

Also, it is well to remember that the initial blowing out of the case generally shortens the length a bit, hence the suggestion to fire one and adjust from there.
Cheers from Darkest California,
Ross

[ 11-12-2003, 23:28: Message edited by: Ross ]

This sort of answered my question also. I’m making 7x64mm cases out of 280 Rem brass. The resizing picks up most of the reshaping, but only moves the new shoulder about half way back along the old shoulder. This leaves a bit on the outer shoulder unformed and needs to be fire formed out. This new case head sizes just fine, it’s just caused by the two different shoulder angles.

Due to the outer shoulder needing a little blowing out to accommodate the new steeper shoulder angle, I was unsure if the case will lengthen or shorten. I’ll have a better idea now were to trim the cases after forming.

Sorry, I meant the new case "head spaces" just fine when formed from .280 Rem to 7x64mm. It's just a bit long and requires trimming and a bit of fire forming.

Be sure to trim *after* fire-forming. When the case is blown out to chamber dimensions the case will shorten and usually be out of square. Trim just enough to square the shortest one.

Thanks to all for your advice. After ordering the 300 H&H I thought it would be easier using 338 WinMag brass. It is! There is no need to trim the cases before fireforming, as I had to do with the 300 H&H. Will load and head for the range this weekend..I'll let you know how it goes.

As a result of my using the 338 brass I seem to have 98, 300 H&H brass cases that would like a better home.

Let me know if you are interested, I think we can work a deal.

Rusty
We band of brothers!

[ 11-14-2003, 03:12: Message edited by: Rusty ]