300h&h to larger caliber

[rp85]

good morning;

Was given a very large number of 300h&h cases to expand to 375 weatherby. Tried fireforming with 5.2 grains of bullyseye powder which did not work. Reason maybe not enough powder.

Decided to try to expand 300h&h cases in steps. Ordered a .338 & 358 tapered expanders from RCBS. The .416 was not in stock. RCBS said when the .416 become available they will send one to me.

With a little effort, not a problem to expand 300h&h case to .338 then to .358. Have lots of .358 bullets, all kinds cast and jacked. 100 grain jacked to 200gas checked cast.

New game plan, seat a .358 bullet in the case then fireform with that bullet.

Request input on bullet weight, style and a suggested power. Have red dot, green dot & bullseye powders.

Thanks for any input

[pworley1]

I have made 458 Win mag from them using the progressive expanders, It will be easy when you get the 416 expander. I have a lathe just made mine.

[stubshaft]

15.0 grains of Unique and COW filler turned 338 WM to 458 WM in one go.

[15meter]

Wow, this sounds familiar:

https://castboolits.gunloads.com/sho...rly-optimistic

[rp85]

good evening;

yes it's semi related to a previous post, after failure with grits and tissue paper going to try fireforming with an actual bullet. different world when using an actual bullet.

Another variable in the mix. Have a friend that reloads for 375h&h and he offered me his Lee 375h&h sizing die. If i'm able to size cases from 300->338 ->358 -> 375 then i can use 375 cast bullets. should be interesting 375 cast bullet in 300h&h case that has been resized, resized & resized again fired in a 375 weatherby. case have been annealed and will be annealed again after all the resizing.

looked at data in Lyman's book on cast bullets for guidance. good starting points but would feel more comfortable with data from others using actual bullet to fireforming 300h&h their cases. Thanks for your input.

rp

[15meter]

How far up did you go on your fire forming charge?

I've gone from 7 mag up to 458 Win Mag in one whack.

Curious if the Weatherby shoulder is the problem.

[lar45]

https://youtu.be/vwV0WYn52Ik

I made 375 win from 30-30 in one step using a small charge of fast powder and grits, couldn't find cow in Arkansas, .
I think the cereal irons the case out as it's blown forward.

[lightman]

I'm thinking a case that size needs more powder than that. I'm thinking 15 grains and then pack the case full of Cream-of-Wheat. Lar45 says you can't find COW in Arkansas but maybe you can find it in your State or order it.

[15meter]

I'm thinking a case that size needs more powder than that. I'm thinking 15 grains and then pack the case full of Cream-of-Wheat. Lar45 says you can't find COW in Arkansas but maybe you can find it in your State or order it.

Doesn't have to be specifically Cream of Wheat.

I formed a number of 30-30's to 38-55's using the little nibs that break off shelled corn when run through a grain dryer and fall on the ground under the dryer.

Filled up a small can with the nibs from a buddy's drier. Worked great until I ran out. And he quit drying his own corn.

Moved on to corn meal swiped from the kitchen when the wife wasn't looking. Worked almost as good as the corn nibs.

Corn meal would have worked just as well as the corn nibs if it had been the same price as the corn nibs.

Did I mention I'm frugal?

And as for using cow, I think the humane society probably wouldn't be happy. Even in Arkansas.

[rockrat]

I use grits when fireforming.

[Harter66]

It took 2 goes to get 303 to 410 .
I didn't have any trouble getting 308 out to 358 but as I recall I blew out necks trying to get it from 308 to 45 Raptor .

I use 7-9 gr of Unique and the balance in Grits/CoW/cornmeal and a half neck wax plug that readily converted everything in 06' cases to whatever the bolt closed on .

I'd size w/o an expander to close the bolt . Over anneal the neck and shoulder and try blowing the case that way . If you're going to neck up and shoot it to blow it out I would think a RB would work as well as anything else .

I was under the impression, mags aren't really my forte, that the H&Hs were beltless mags so the 410 makes sense for a false shoulder but y'all have mentioned belted mags . I would think , having only made 264 WM from 300 WM and the much simpler 7RM ,that with the neck and shoulder anneal the COW method would move it out pretty close to a full form .
For what it's worth 15 gr of Unique might only be enough to get started on its way I had data that showed 26 gr under a 120 cast in the 264 which is 1-1/4oz 12 ga volumes .

[15meter]

I was under the impression, mags aren't really my forte, that the H&Hs were beltless mags

An FYI, 300 H&H was one of the earliest belted Magnums, if not the first. Almost think it was the first but I'm too lazy to look it up for verification.

I'm pretty sure most, if not all the domestic Weatherby/Remington/Winchester belted Magnums are descendents of the 300 H&H.

Took the time to look it up.

Boy, was my memory wrong, the 300 H&H was 3rd generation after the 375 H&H which was proceeded by the .400/375 Belted Nitro Express.

[MostlyLeverGuns]

I have used the tapered Lee X-Panders for such exercises, probably the most important consideration for success is lubricating inside the neck before expanding, I use Hornady Unique Case Lube on a Q-tip. Annealing after all the expanding is done extends case life considerably. SOMETIMES, with SOME lots of brass annealing MIGHT be needed somewhere in the middle of processing to prevent split case necks, but LUBRICATION really helps avoid many problems like split necks and collapsed cases. Polishing the tapered expanders with 400-600 grit paper also makes things run more smoothly.

[Willbird]

I have been playing around opening 240 Weatherby up to a tapered 375 case. First try was 7.0 Clays with 1/4 square of TP on top, packed that down tight, then filled case with corn meal, then a twist of TP in the case mouth. They fire form OK. They fire form better if I anneal the necks first.

Bill

[Kestrel4k]

[...] probably the most important consideration for success is lubricating inside the neck before expanding, I use Hornady Unique Case Lube on a Q-tip. [...]

That Hornady Unique is really the ticket; wish I had gotten started with that case lube in the beginning.

[rp85]

good morning;

UPDATE;

Rifle & caliber; sako L61R (L\H) ACTION, 26.5” long barrel.

Others have suggested running the cases into the RCBS sizing dies but did not work. My RCBS 375 wby sizing die does not have a tapered expander. Using a RCBS rock chucker press I would crush the neck\shoulder area of case. Used Hornady sizing product to size cases.

Got a Lee 375 h&h dies from friend. Read somewhere the Lee sizing has a tapered expander but it did not work with 300 h&h cases. It would slightly bell mouth of the case then shove the expander out the top of die. Yes, used the biggest wrenches I had to tighten top of die.

IMHO the key, in my situation, to expanding to a larger caliber was using a tapered expander. These tapered expanders allowed sizing cases from 300->338 ->358 -> Lee 375 and then ran cases through the 375 wby sizing die. Cases were annealed before resizing and after all resizing was completed.

Shot the rifle today using 16 grains Red Dot powder, using a gas checked 285 grain bullet, speed 1450 fps. In the past this load is extremely accurate.

Will cast some Lee 250 grain bullets tomorrow. They come out at 258 grains. Will shoot with Red Dot load Wed.

Not sure if fire forming cases made a difference in speed. Group (10 shots) was 2.5”. Resulted in a perfectly form 375 wby case. Only real difference between cases the new 300 -> 375 cases they are. 040” shorter. Length of neck is where the difference located.

Thanks for all input.

rp

[15meter]

[rockrat]

I am forming 458 from 7mag brass. I use a 416 Rem Lee size die and can open them up to .416 in one pass without any trouble. Lose a few cases now and then with split necks. Then run over a 44-40 expander which if I run them past the 44cal part, opens them up to about 46 cal. Run them thru the 458 sizer and trim. Will anneal before I load them.