Going to be blowing out the shoulder and body slightly in the
.300RUM and was looking for an inexpensive alternative to jacketed bullets.
$26.00 or so and I can get 250 175 grain or 210 grain cast, gas-checked, sized
and lubed bullets.
Accurates reloaing guide lists 38 grains max of XMR-5744 for the 180 grain
bullet. Would there be any advantage to going to the heavier projectile?
I have tried emailing Accurate but have yet to get a response.
Any comments appreciated.

Roger,
Can't help you with your question, but where did you get the neat picture you use in your signature?

Generally . . . GENERALLY . . .

You want to use near full velocity loads to fire form brass to "improved" dimensions. It's possible to form using reduced loads, but in some instances the brass does not balloon tightly against the chamber.

I have a .223 Ackley and shoot standard .223 Rem ammo in it for fire forming. I don't get the velocities of the Ackley loads, but the accuracy is OK for most purposes.

I was shooting Win. 55 gr. FMJ "bulk" plinking bullets to fire form. Getting 6" groups and wasting a lot of my time/money.

When fire forming brass, it's nice if you can do a large lot of the stuff. I started with about 250 rds and by the time I got done neck trimming, turning, and otherwise preparing the brass, I was down to about 175 cases. Some were just plain too short after fire forming.

The cast will work fine, and with the ductility of brass, you don't need a heavy load for forming. if the rifle has been previously fired with condum bullets, be sure you remove all signs of copper fouling before firing the lead, and you shouldn't have any problems. i would suggest you keep the loads in the 1800 fps range ifyou are unsure of the lube, hardness,and diameter of the bullets. The bullets should be .001 - .002 over groove diameter for good accuracy. With a good lube, you should be able to go to 2200-2400 fps with no special tricks. With a proper flat nosed bullet, this will also be a good velocity for hunting deer with the lighter bullet and elk at ranges under 150 yards with the heavier bullet.
I know you are going for more velocity with what you are wildcatting, but don't discount the lower velocity cast. You can tailor the bullet to the game much better than any commercial bullet will ever do for you, plus with the lower cost, you can afford to shoot a few thousand a year, rather than a few hundred.

Thanks for the info. I intend to continue to try to get in touch with Accurate. I got the idea of fireforming with the cast bullets when I noticed on IMR's page the SR-4759 runs at the same pressures as do the heavy loads.
I wish they would answer my question.

There is an advantage to using a powder that allows the case to be full when fireforming, and thats to keep the bullet from being pushed back in the case, this is especially important when improving rimless cases.

I'd go with the heavier bullets, as they will be longer, and thus you shouldn't have any problems jamming them into the lands.

I firefomred many cases for my 35 whelen ackley, and had many less then positive results. Knowing what I know now, I'd go with a slower then normal powder, loaded to fill the case, and a bullet jammed into the lands.

Thanks for the replies.

I was finally able to get through to Accurates ballistics techs. They said using the 180 grain cast gas-checked with max 38 grains XMR-5744 will give about 28,000 psi. The other option is going with a jacketed bullet, their load is around 50 grains with a 150 grain jacketed (I forget which brand) will run about 62,000 psi.

The 210 grain cast bullets from LeadHeads are $26.00 per 250. I did not want to run 200 rounds down the tube before beginnning looking for a good combination. I figgered 200 lead bullets would be almost the same as nothing in terms of wear.

I will anneal the necks and shoulders before doing this. 28-30k psi should have no problem blowing out the shoulder.

I will ask for 10 bullets to try for a test, if it doesn't work I'll go with 150 grain bulk bullets. I want to use the XMR as it only takes a little bit and I have a couple pounds of it.

It sounds like a 300 Ultra Improved so I guess the full powered loads you finish with in the improved will fit a standard Ultra case.

When I had 358 STAs for different reasons I wanted to use some full power loads using Varget.

I used the same loads in new Winchester 375 cases as I did in the fireformed case.

However, I was full lenght sizing to get a bout .003" headspace which was also the heaspace I had on new 375s necked down.

Obviously I could not use full loads built around slower powders in the new 375 cases because they would not fit. But I don't imagine you will have that problem with 300 Ultra.

Mike

A friend used to use a bunch of red dot topped with tiolet paper in his 257 weatherby. Just a blank. It seemed to work fine. No wear on the barrel! : )

Red dot loads? Sounds like a dirty load. It can do some interesting things for reduced loads for small game hunting though.