(just had to throw that big word in there)

I was trying to work up a 7x57 load with 22.0 grains of H-322 under the Lee 130 grain RNGC in new Remington cases. Got some gas blowback. Nothing scary, just enough to make me take notice and I always wear safety glasses, anyway.

I checked the cases. Primers looked good and no signs of high pressure. Necks and shoulder were smokey. I deduced the pressure was not high enough to expand the necks and get a seal.

Checked my theory by loading five cases with 12 grains of Red Dot and the same bullets. Worked fine. No blowback, no smoked necks.

I'd rather work with the faster rifle powders, though. Occured to me that I might just need to anneal the case necks so they expand easier.

Thoughts?

Observations?

Good 7x57 CB recipes with pistol powders?

I like pistol powders for mild cast bullet loads in rifles. Can't really add much to that, other then anealing won't hurt so long as you don't get the cases too hot. I like to hold them in my fingers at the base over a 5 gal bucket of water, it insures I don't get the case too hot as you'll automatically drop it when it gets hot.

Leftoverdj, New Remington cases...prob'ly the culprit here. These loads didn't have enough pressure to expand and fill the chamber (as you figured out). I find it's best to use cases fired with loads approaching full power (pressure) and then only neck sizing enough to hold the bullet for reduced loads. Try it, you may not need to go the anealing route. Regards, Woody

I had a similar experience with my 375 Whelen. I was using cast bullet rejects to fire form my cases after forming them. I got smoky necks and primers that extruded. Scared the hell out of me.
When I put a full charge of AA 2520 or IMR 4895 everything was just as it should be.
So now I use a begining charge of what ever powder I have left over from load testing, these powders proved less then accurate. So I burn IMR 3031 right as that's what I have the most of. I think it's 42 or 46 grains for fire forming.
Jim

Had the same problem with H4895 and the Lyman 287377, 130gr. cast. Being a metallurgist, I did some serious checking during some down time and found the Remington brass is a tad hard to start out. I annealed them by dipping them neck first into my lead pot set a 800 degrees then into water. It dropped the hardness 14 points and I don't have the neck smoking on my 7 x 57 brass anymore.

I looked at my H322 data for some loads I tried in 7.62X39. I had to use 26.0gn with a 155gn bullet for 2045fps in that little case to get them to obturate. Ball powders are touchy with their pressure curves that way. In my experience for loads to 1400fps fast powders are best (unique,red dot,2400). Med loads 1400-1700 (RE-7,4759)Full house 1800-2000 (4895,4831).
This IMHO feel free to disagree.