.308 to .243

SW 357Mag

last night I thought I would try to neck down some .308 brass to .243. It didn't work out so good. Looks to me like the die didn't resize the whole neck. Looks like a double shoulder sort of a case now. What did I do wrong, or can I even do it? Seems like I ought to be able too. I necked down 30-06 brass to 25-06, and it worked just fine. Thanks.

SW 357Mag

Is it possible to size .308 brass down to .243?

JustC

doing so in several steps would be prudent so as not to overwork the brass. I would think annealing afterwards would be a good idea as well.

Cubslover

Takes three steps...

1.) Run through a full length 270 die
2.) Run through a full length 243 die
3.) Trim to length

Use plenty of lube, but be careful not to overlube the shoulders/neck.

Maybe need to throw another die somewhere in the middle. Maybe the 260 Rem? Start with a 7mm-08 die, then down to a 260, then the 243.

Inspect each and every case.

It would be more cost efficent to sell/trade your 308 cases for 243 or just buy new 243 cases.

HandgunHTR52

I would use the 7mm-08 and then the 260 Rem. before the 243.

Cubs - I am not sure that the 270 die would work because of the cartridge length. I am not sure the 308 case would make it up to the neck sizing area of the die before the shellholder hit the bottom of the die.

SW 357Mag

Thanks for the quick help. I think I'll just buy .243 then.

bpost

I did it to several hundred military cases by just running it into the .243 die and trimming length from there.

I did not know stepping down would have been better. [:0][:I]

I do have a big ole' honkin' RCBS big MAX press; maybe that is why it was so easy. [:D][:o)]

MIKE WISKEY

you will also need to turn the neck area as this will thicken considerably.

dakotashooter2

I have done several hundred mil surp without a problem. The first step was to run them into the seating die with the stem removed. This die is slightly larger than the sizing die and the shoulder is higher. It reduces the neck and forms a "false shoulder on the case.Then I run them through the FL sizing die which finishes the neck sizing and sets the shoulder back just a bit more. I then trim them but it is not for length but for consistency as they will be shorter than factory bass untill fired a couple times. load and fireform. It should be noted that the seating die may crimp the necks some making running them through the sizer a bit tougher. A 6mm die may be better but I have not tried it. I found no need to turn the necks with my 2 guns but each gun may be different. Accuracy seems to be comparable to most factory brass and better in a few instances.