Case forming 338 Lapua Improved

[Shooter ----/]

I am needing some help on this topic. What is the easiest / safest way to do this? I am a little unsure of wanting to fire pistol powder loaded with breakfast cereal down the brand new & very expensive barrel of my project.

I have heard that you can get some kind of dies to create a fake shoulder to hold the shell in position while fire forming? This sounds like the most logical way to do this. IMO Does anyone have such a thing?

Thanks in advance for your help.

 

[Cummins4x4]

I fire formed 250 brass for my Cooper 25-06AI with 13gr of lilgun, 22 cal patch, fill with corn meal, another 22 patch in the neck, lube body of case with Imperial sizing wax (very important) and shoot. The pressures are so low it won't hurt your barrel, you may need more powder in the 338 case.

I havent heard of the die your referring to.

 

[Shooter ----/]

Does the wax keep the case in proper position?

 

[Cummins4x4]

When firing the blank unlubed the firing pin will drive the brass forward slightly and the case will not be headspaced properly and the primer will be protruding. we are talking maybe 5-10 thou but enough to make the case unsafe. The lube allows the brass to move back against the bolt face instead of grabbing on the chamber wall and results in a nicely formed case. Check them for length, trim only if required and reload.

 

[Shooter ----/]

So does this method have any adverse effects on the throat?

 

[Cummins4x4]

Not that I know of, let the barrel cool, I shoot 5 then cool, make sure you clean the barrel before shooting any bullets to make sure there isn't any particles stuck to the wall. Its way easier on your barrel than shooting a few hundred bullets, wast of bullets too IMO

 

[Splatter]

From my reading, the thing that seems to cause the worst throat erosion is long grains of extruded powder, and the faster it squirts through the throat the worse the erosion.
Apparently ball-type and flake powders cause less erosion, and bullets are a very small factor.
So, I would think that something relatively soft, like cornmeal or Cream of Wheat would pass-by the steel leaving it largely untouched, and the few grains of pistol/shotgun powder at the bottom of the case would be gone before it gets to the case neck.

But frankly, it'd be interesting to run some sort of test to be able to put some sort of empirical evidence out there.

 

[Shooter ----/]

Sounds like a possibility. Pain in the rear to spend a day at the range blowing off 100 rounds worth of powder and primers.

Anyone try hydro-forming?

 

[dan belisle]

Load 100 rounds with Sierra 250 gr bullets and max standard 338 Lapua loads. It's called practice, works quite well. I have used the filler and pistol powders method for some oddball wildcats I use, but with an improved cartridge it is just so much easier to just fire the standard cartridge in the rifle that all the messing about is hardly worth it. FWIW - dan

 

[Shooter ----/]

That's what I thought I would be doing but I have since learned that I may not be able to. I guess with the improved chamber, the shoulder has been moved enough that the factory case may not be held in place properly thus stretching the case at the web and / or adding large amounts of bolt thrust.