So I have a bunch of new 300 RUM brass that I'll be resizing for my 338 Edge. I was reading Carlock's write up on how to fire form for a 338 Terminator. Question is, do any of you do the same for the Edge where cases are loaded with powder and cornmeal, then plugged with TP and fired. I haven't read every blurb about fire forming, but I haven't seen any articles where brass is fire formed without using a bullet. Thoughts on this...
Fire Forming 338 Edge
- Thread starter Triple BB
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I don't fireform for edge. I buy Bertram 375 brass and run it thru a 338 fl sizing die ran up to fit the chamber. No way I was spending $200 on edge dies. Lots of ways to make it work. Also used 300rum brass, but decided on 375 because I shoot 300 rums also.
Is yours a +p? Is that why you want to ff?
Is yours a +p? Is that why you want to ff?
Some will say you technically fire form a case to your chamber the first (or first couple) time you fire it in that particular rifle, as long as you minimize the sizing when run through the sizing die. That is with any standard case. That may be what you are referring to with the Edge, I definitely seen the shoulders get sharper after at least the first firing. However that is not what is happening with the .338 Terminator. That is an "improved" .338 Lapua, so you are restructuring/reforming the case into something totally different by pushing the shoulder out and probably removing taper. I would not consider those two the same thing. One is minimal and one can be severe in some cases. With a cartridge like the .338 Edge (you making them from .300 RUM) I would just run it up through the sizing die to expand the necks to .338 and start load development. From the first firing to the second you may have an ever so slight increase in case capacity but that's going to happen most anytime anyways firing new brass. If you had a .338 Edge Improved then that's a different matter...maybe.
J E Custom
Well-Known Member
The 300 or the 375 RUM have the same case body dimensions as the 338 edge except the neck dia. so fire forming is straight forward. Simply run the cases (Ether the 300 or the 375 RUM ) through your 338 edge dies and load. I recommend a medium pressure load for the 338 edge firing the first time. that forms well without pressure and is usable at the range to break in the barrel or even hunting if accuracy is good. (Many times it will be below 1 MOA)
You are not forming a wildcat as mentioned so special fire forming is not necessary.
J E CUSTOM
You are not forming a wildcat as mentioned so special fire forming is not necessary.
J E CUSTOM
