Fireforming 338LM to Improved

[warbird2006]

I have 338LM Improved and a bunch of 338 LM brass. Whats a good way to fire form the brass without shooting bullets? I fireformed 223AI with little bit of powder, cream of wheat and cleanex successfully.

What would you recommend for this big mama magnum? The Lapua brass is pretty tough.

Thanks

 

[GlennK]

I have 338LM Improved and a bunch of 338 LM brass. Whats a good way to fire form the brass without shooting bullets? I fireformed 223AI with little bit of powder, cream of wheat and cleanex successfully.

What would you recommend for this big mama magnum? The Lapua brass is pretty tough.

Thanks

The lapua brass is very tough. I would shoot a normal bullet with a stiff charge and try to get the cases formed up nicely.

 

[Nellej12]

If its a new barrel you need to shoot break in rounds before load development. So fireform and break in at the same time.

 

[ronemus]

Just buy the cheapest bullets you can find and shoot them with a stiff load; anything else will only get you part way there.

 

[moondog]

Like everyone else said. That's what I did with mine. The brass is tough and will take a couple of firings before you have to touch the shoulders on resizing.

 

[rogina]

I have 338LM Improved and a bunch of 338 LM brass. Whats a good way to fire form the brass without shooting bullets? I fireformed 223AI with little bit of powder, cream of wheat and cleanex successfully.

What would you recommend for this big mama magnum? The Lapua brass is pretty tough.

Thanks

Is the brass unfired?

 

[284winner]

I think fireforming that 338 LM improved will need 2-3 firings before brass is fully formed to the chamber. It did for mine.

 

[DiffEQ]

I think fireforming that 338 LM improved will need 2-3 firings before brass is fully formed to the chamber. It did for mine.

+1

 

[Matches]

You can use 15 grains of 700X and then fill the rest of the case with cream of wheat and add your toilet tissue on top to keep it from spilling out.
Or 96 grains of H1000 and a 300 Sierra touching the lands.

 

[ronemus]

It is better when fireforming to to have the bullet seated into the lands to minimize case stretching near the base. Brass is generally short by 0,006" or more at the shoulder from the factory and will have to stretch by that much unless the bullet is seated long enough to hold the case head against the bolt face; otherwise the firing pin strike will push the shoulder against the shoulder of the chamber where the thinner brass will hold the front of the case as pressure builds. At higher pressure the case will stretch near the head forming a ring of thinner brass.

 

[WAMBO]

I agree, load some bullets and shoot.
When I was fire forming mine it shot sub moa groups and was fun banging steel.
Also like previously mentioned seat the bullets into the lands