Fireforming Brass 338 Lap Imp and 6.5 Lap Imp.

[bholtmeyer]

Having a 338 Lapua Imp and 6.5 x 47 Lapua Imp built and need some load data to fireform brass without sending bullets down the tube. Plan on using cornmeal for filler on top of powder charge. Any help would be awesome.

Thanks

[trueblue]

I can't help you much on this , other than to say I think guys are using pistol powders like Unique. Having said that, I just shoot my brass while doing barrel break in and load developement and fireform it then for my wildcats. Also shoot fireform rounds for fouler shots.
Also, I find that my fireforming rounds are just as accurate as my one fired.

[dirtball]

Here is a previous thread, I use Boss Hoss's suggested method, about 2/3 the way down the page. Works GREAT! Just clean often as you will get considerable build up in the barrel if you don't, but you will get that with corn meal also.
Dave

best brass fire forming method?

[J E Custom]

Originally Posted by trueblue

I can't help you much on this , other than to say I think guys are using pistol powders like Unique. Having said that, I just shoot my brass while doing barrel break in and load developement and fireform it then for my wildcats. Also shoot fireform rounds for fouler shots.
Also, I find that my fireforming rounds are just as accurate as my one fired.

+1

Use a good quality bullet ,Use a reduced load (10 %).and seat the bullets against the
lands(For the best concentricity and zero head space).

If the case is not held perfect to the center line of the bore the cases "can" expand
with the head and neck off center.

I also use break in ,fouling and some preliminary load development to fire form.

J E CUSTOM