.308 to .243

hadjii

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.

hadjii

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

MIKE WISKEY

1st, .308 to .243 in one step is too much you should go .308-.260-.243 or something like that, next you will have to neck turn your resized brass as the neck walls will be thicker than standard (you MAY get by with this if it is a factory chamber and you are using commecial brass)

JustC

your die body is not far enough down,..screw it in further to size the whole shoulder.

hadjii

JustC, I don;t think that is the problem. I have the die body screwed down so that it makes slight contact with the shellholder. I'm thinking Mike Whiskey is right, that I ought to add an intermediate step. I'm thinking that it might be more trouble than it's worth.Thanks men.

JustC

Mike is a very experienced person,..one whom I have solicited advice from in the past[8D] BUT if you have a bulged lower section of the neck,...that tells me there is NO DIE BODY present at "full stroke" of the press, and therefore you are getting the "bulge" at the lower neck.

You could remove some of the shell holder,..or some of the die body,..but the better choice is to find a shorter die to see if that can can be remedied,...because I doubt a 308 dia false shoulder will chamber in a 243 rifle.

and of course the neck turning suggestion from MIKE is very recommended for concentricity as well as reducing outside dia.

hadjii

JustC, what you said makes sense, but thatis kind of weird isn't it? Would that be a die that wasn't machined right or what? You're right about it not chambering. I tried it for some silly reason, and it won't chamber. At first I thought it might have been the nickel plated brass I was trying to resize, so I tried a regular brass case and got the same result. do you think I should try a different die, or just not even fool with it?

JustC

can the die body be advanced down any further? or does it hit the shellholder at "full stroke"?? if there is clearance between the die and shellholder,..then run the die body down some more. If there isn't any clearance, then you will have to find another die. I can't say for sure that it was machined wrong,..but a FL die should size all of the neck unless it has been set up for Partial Full Length sizing.

If you can't get it to size the entire neck,..you can have a machine shop remove some of the die body,...but I would look at other dies first rather than spending the money it will take to cut the die on a lathe.

Ross

. . .it makes slight contact with the shellholder . . .
You have a pretty common problem. Fortunately the cure is usually quite simple. Screw the die down even more, beyond mere contact with the shellholder.
All structural materials give under stress, even the O frame press flexes a few thousandths, allowing a gap between the die and the shellholder.
The cure is just a variant of the Bigger Hammer Principle.
Cheers from Darkest California,
Ross

Mobuck

The case neck area will almost certainly be too thick and/or uneven in thickness. I made 243 from 308 years ago when I had more time than money. After sizing, I had to ream the necks to even them up and allow expansion in the chamber neck. Unless you have free 308 brass and extra time on your hands, it's not cost effective to mess with when 243 cases are $25/100.

hadjii

Yup. I think you're right Mobuck. I just happened to have a bunch of 308 cases laying around and no 308, so thought I'd try it and see what would happen. I did the same thing a while back necking down 30-06 to 25-06, and it worked like a charm, so thought it would be the same here. Guess not. Oh well. Nothing ventured, nothing gained. I guess the only other thing I could do is buy another 308 to use the brass in. Hmmm. Now there's a thought. Thanks Everybody.

Mobuck

Any time you reduce the neck diameter a significant amount-like 30 to 24/25 the brass has to go somewhere. The result will be thickening of the neck or slight lengthening. Some chamber necks are big enough diameter to handle overthick necks. If there is not enough room for the neck to expand to release the bullet, pressure will go way up- maybe enough to damage the rifle.

dcloco

You need to neck turn the brass AND screw the die over center.

0.065" being further squeezed INTO a round hole...it has to go somewhere.

dakotashooter2

I have resized quite a bit of surplus brass this way. What I do is remove the stem from the seating die and use it as the intermediate die. It will size the neck down without setting back the shoulder and will leave a slight "bump above the shoulder. I then lube the inside of the necks (they are crimped when you run them all the way up the seating die)and run them through the FL sizer. Load and fireform. I have not had to turn the necks for either of my guns. They will be shorter than standard 243 cases but I am still getting quarter to dime size groups with little effort. I have found the necked down cases to be more accurate in my encore than factory brass.