fire forming 300h&h, Overly optimistic?

[rp85]

good afternoon;

Overly optimistic? Need 375Weatherby cases. Given a very large number of 300h&h cases. Game plan was fire form 300h&h to 375h&h then fire form the 375h&h cases to 375 Weatherby.

300h&h cases, used 5.5 grain bullseye, filler to keep powder at base of case, fill case to mid-neck with grits, tight fitting plug of toilet paper. Fired in 375 Weatherby, case dimension did not change.

Any suggestions? Powders on hand: Bullseye, Red dot, Green dot, 2400, 4198, 5744. Have a Lee 150 grain bulleting casting mold.

Thx again for any input.

rp

cases were annealed before hand. did use a 1\4 sheet of toilet paper to keep powder in place. tried resizing to 375 but did not work, even using a rcbs rocker press. did not compress grits

[15meter]

Sounds like not enough uumph. Try here:

https://castboolits.gunloads.com/sho...ng-458-Win-Mag

I used 13 grains of Bullseye for 7 Mag to 458 Win Mag. I'd try the 13 grains, and it sounds weird until you do it, hold the rifle vertical while firing. I've had lumpy cases fired horizontally.

Gravity sneaks up on you at the most inopportune times.

I would suspect that 300 H&H to 375 Weatherby in one whack is certainly doable. And may work better than an intermediate fireforming to 375 H&H.

You may have to anneal before fire forming. Only trial and error will give you that answer, I've had MOST blowing cases out not need annealing until after fully formed, others it was absolutely mandatory.

When I was taking 500 N.E. to 500-450's, with one single pass through the die to reduce the neck to get it to chamber so I could fire form the the chamber, I had to anneal well past where the shoulder was going to end up or I split the majority of cases. Didn't expect that with one single pass through a die.

Absolutely you will have to anneal after fireforming if you want any case life at all.

Did you put anything over the powder before you put the grits in?

I always use a 1/4 square (or less) of toilet paper over the powder. I'll also use something to tamp down the corn meal. I want it packed tight. I use corn meal instead of grits because I can swipe from the kitchen, corn meal but no grits. We be way above the Mason-Dixon Line.


Keep Enquiring Minds informed

[charlie b]

Why would you not just neck up to .375 and then fireform to the Wby?

And, yes, due to cost of brass I'd anneal first and then again after necking up.

[Mk42gunner]

I have always had better luck fire forming cases with a moderately stiff charge of powder and a real projectile than by using the cream of wheat method.

In your case, having a bunch of .300 H&H and wanting to convert to .375 Weatherby, I would expand the necks in a couple of steps and then load some plinking ammo.

.30 to .35 using a tapered expander from the .35 Whelen die set and then I think the expander button from the .375 set will start in the case mouth.

This should also save primers which aren't all that cheap these days.

Good Luck,

Robert

[SOFMatchstaff]

Would the 300 Weatherby case be a viable starting point??

[MaLar]

I have always had better luck fire forming cases with a moderately stiff charge of powder and a real projectile than by using the cream of wheat method.

In your case, having a bunch of .300 H&H and wanting to convert to .375 Weatherby, I would expand the necks in a couple of steps and then load some plinking ammo.

.30 to .35 using a tapered expander from the .35 Whelen die set and then I think the expander button from the .375 set will start in the case mouth.

This should also save primers which aren't all that cheap these days.

Good Luck,

Robert

Don't do this with cast! You end up with a lead lined pipe with a hole in it the size of your boolit.
Done there bin that.

[MostlyLeverGuns]

I would neck expand in the press. Tapered Lee X-pander, start with .338, then .358, then .375. The Lee X-panders are $4-$5 at MidwayUSA, you'll need a Lee Decapper Die with them. LUBRICATE INSIDE CASE NECKS, I use Hornady Unique lube on a Q-Tip. Anneal after done expanding, then fire form using moderate loads, not particularly light loads. I have taken 30-06 out to .375 then sized to 35 Whelen, .308 to .375 then sized to .358 Win, .30-30 to .375 Winchester this way.

[TurnipEaterDown]

Don't do this with cast! You end up with a lead lined pipe with a hole in it the size of your boolit.
Done there bin that.

Why would fireforming w/ cast lead the barrel?
Any fireforming I do, where I have a mold of appropriate size, I will happily be cheap and use cast.
I do it fairly frequently.

Cast GC bullets can easily be pushed 2000-2200 fps w/o leading a rifle barrel.

[MaLar]

The OP is going from 30 CAL TO 375 CAL. I was going from 35 cal to 45 cal ended up with a bad case of leaded barrel. If your going to blow a case say from 300 H&H to 300 Weatherby. Then things should be great.

By the way it took me a week to get all of that lead out.

[TurnipEaterDown]

The OP is going from 30 CAL TO 375 CAL. I was going from 35 cal to 45 cal ended up with a bad case of leaded barrel. If your going to blow a case say from 300 H&H to 300 Weatherby. Then things should be great.

By the way it took me a week to get all of that lead out.

Were you using Undersized bullets? i.e. shooting 35 cal bullets down a 45 bore?

No, that is not snark, honest question.

I have necked 30 cal cases to 8 mm, loaded a 62 gr conical over Trailboss, shot in a 416 bore, to get major re-forming (straightening) of a case done, and it worked fine for me. No idea how "accurate" the bullet path was. Point at a berm, make go bang... The undersized bullet just made a resistive plug for me. I made sure what I chose was dimensioned such that no matter how it spun, turned, tumbled in the bore, it couldn't try to lodge -- i.e. no cross axis dimension of the bullet was near bore size.
Albeit, I did end up w/ some case stretch that I did not see when using a multi-step necking process to get to 416 and seat a 417 cast bullet. Inspection of cases did not reveal any internal ringing (concentrated stretch thinning).