Manual forming an improved case
I’m very familiar with fire forming an Ackley Improved. I have several.
A friend of mine has an ELR rifle in 375 SnipeTac. This is an improved 375 Cheytac, but unlike an Ackley, the neck-shoulder junction gets moved forward.
He has been necking down 408 brass so that he has a slight crush fit in his chamber, shoots a load for plinking with a less expensive bullet, and this results in a nicely formed case. He then used the formed case to shoot in matches.
Normally, I would find an accurate fire form load, and shoot it in matches, but this hasn’t been an easy load to figure out in his rifle. The other flies in the ointment are this case burns a lot of powder, which is costly. The gun is a barrel burner, and he doesn’t want to burn up the barrel on case forming. He also doesn’t want to risk barrel erosion with a cream of wheat forming in a Precision barrel.
I thought about a hydroforming die. Also considered necking it further up first to form more shoulder prior to necking down. A second rifle as a fire form mule would be fun, but there are no easy answers for an inexpensive donor action.
Would a hydro die work well in such a big case? It will take a big press, but I have one.
Would it be easier to neck 408 in steps to 585 and then back down?
He has an annealing machine and can easily anneal after forming if necessary.
Looking forward to responses concerning suck a large case.
