Fireforming .50BMG without a projectile question

[jbs2014]

A while back I had a thread that inquired about fireforming brass to the chamber of my .408 and .375 CT without a projectile. Forum members recommended 25 grains of Red Dot, cream of wheat, and cotton to plug the neck. The method worked like a charm and my new brass was fit to my chamber and ready to have the shoulders bumped back .001.

That said can the same thing be done with .50 BMG? If so how much and what type of powder?

The reason I ask is that I want to get one of the Werner Tool .50 BMG full-length adjustable bushing sizer dies. But Werner Tool needs three fired cases. With COVID19 restrictions I can't go to the range and shoot full charge rounds. But with this method, I could get the three fired cases without going to the range.

Any help would be appreciated.

 

[MagnumManiac]

General rule of thumb is 1/3 of a full charge with a fast pistol powder...I ran into excessive pressure twice doing this, however.
First time was with my 375 Bee, forming H&H brass with COW and candle wax, last 5 rounds of 50 had ejector marks due to wax build up in the chamber/bore.
Second time was with my 338-416 Rigby Improved 45° shoulder, 1/3 of a full power load was too much for Universal powder, it was too fast for that case size.

Work up slowly is my advice.

Cheers.

 

[jbs2014]

Thank you

I don't use wax just the cream of wheat and cotton ball in the neck.

What was the powder charge that gave you pressure?

 

[Dmagna]

Is there a specific reason you want to fire form? Is it an improved chamber?

 

[JMW67]

A while back I had a thread that inquired about fireforming brass to the chamber of my .408 and .375 CT without a projectile. Forum members recommended 25 grains of Red Dot, cream of wheat, and cotton to plug the neck. The method worked like a charm and my new brass was fit to my chamber and ready to have the shoulders bumped back .001.

That said can the same thing be done with .50 BMG? If so how much and what type of powder?

The reason I ask is that I want to get one of the Werner Tool .50 BMG full-length adjustable bushing sizer dies. But Werner Tool needs three fired cases. With COVID19 restrictions I can't go to the range and shoot full charge rounds. But with this method, I could get the three fired cases without going to the range.

Any help would be appreciated.

I would fire full charge loads twice before having the dies made your brass will be much closer to your chamber dimensions this way

 

[MagnumManiac]

Thank you

I don't use wax just the cream of wheat and cotton ball in the neck.

What was the powder charge that gave you pressure?

The loads were 35gr Universal in the 375Bee, the load in the 338-416 was 38gr of the same powder, had to drop it back to 35gr and then fire a normal load to finish forming the case.

Cheers.

 

[codyadams]

I usually don't get a true reading on my datum line until I have 3 rounds fired through a piece of brass. If your having custom does made, I wouldn't use the cow type method. Or if you do, fire them at least 3 times per brass. Just my opinion.