I got a bunch of .470 NE brass and was starting to get ready for some elephant hunting later this year.

The brass is a bit of a mixed bag...but all either federal or Norma head stamped (my understanding is Norma makes it for Federal anyhow)

In the past I just selected only the same col cases to work with, reserving the really short ones for practice use, but now with this new supply the cases measure after resizing anywhere from 3.265 to 3.230, and they seem to be about 1/3 of them shorter than the 3.240 trim to length.

I realize with headspace off the rim that it won’t be much of an issue for headspace, but do folks see much difference in accuracy with brass that short in the mix?

you gonna roll crimp them?

I suggest you trim all to 3.230 and be done with it.

Then you will not have to worry about the crimp, as all cases are the same length.

Doc, you may know that i just acquired a 470 NE and am learning to load and shoot it.

As a new guy to this caliber here is what i am finding with my Demans / VC.

Chamber size is quite a bit larger (sloppy) and therefore I just neck size about 0.75 inches. The case and ammo look strange but the fit is easy and the brass is worked far less.

As per Greame Wright's book, I am annealing the brass after 3rd firing. Just holding the rim by hand over a gas flame until it is too hot to hold - heating only the neck and shoulder.

470 NE Brass costs me NZ$8 each - about US$5.50 each. I have decided to keep some new brass aside in case I do get a chance to hunt.

I am trimming my brass after 4 shots to 3.237 - as that was the least common factor of all brass. Some were expanding as long as 3.248.

I am crimping with seating die - rolled into the canelure

To answer your real question; no accuracy won't be affected in a double rifle; too many other variables in the mix to worry about a few thousandths of case. You won't notice it, except, as mentioned if you want to crimp. Then of course, they all need to be the same length.

I always crimp double rifle cases and normally use a powder that pretty much fills the case, therefore all cases must be the same length to crimp the same..For this I only use a file trim die as its more accurate..

Why do I do this, because being in the business, I have seen more double rifle failures because the hunters bullets jumped from recoil and when they open the action with loaded rounds in one barrel the round is extracted and the bullet is stuck in the throat, so now were cutting a branch to poke it out if possible but I carry a folding rod for just such an occasion

Always trim and crimp double rifle loads, a lot can be at stake with DG rifles, and Ive seen those failures, but hey I got to shoot an extra wounded buffalo on two ocassions while the fiddled with their out of service gun, My shot killed the buff with brain shots in both occasions, one bull ended up between the PHs legs the other pushed mud over the clients shoes..You can just wait so long and you have to save the bacon..It happens..

Ray:
Bet they both had to clean their drawers.

George

no problems - the rifle was trained to never miss by the former owner