Can you form 243 Win brass out of 308 win brass?

If so, what do you need to do it?

A case forming die set from Redding or RCBS. Pain in the arsch, plus the case forming set is expensive. Just buy 243 brass.

You'd probably also have to neck-turn the reformed brass.

You need a bench, a press, a .308 sizing die, a shellholder, and some lube.

Yes, but not worth the trouble.IMOJust run the 308 brass into the 243 flrs die. Use a lot of lube, have a strong press. (Rock Chucker) You may get a donut and need outside neck turning to correct the brass neck. Some dies may not push the shoulder back enough, giving hard chambering.Can also be dangerous if the loaded rounds neck diameter is larger the .276"

Yes you can, but at 38 cents a piece it's not worth it, even if the 308 brass is free.

http://www.midwayusa.com/viewProduct/?productNumber=1390350119

I agree with the other posters. Yes you can. You may or may not have to turn the necks. Much easier to buy .243, unless you just have a metric butt load of .308 and want to use it. :)

I had a metric butt load of .308 years ago and no .308 rifle. That's a good reason, and it worked just great.

One thing though, I was told to resize twice (I'm thinking it was in an old Speer manual), once with the .308 sizer, and then with the .243 sizer. I only remember reaming the necks after the first firing of the case-formed brass, to thin the necks a bit before the second reloading.

I don't do that to my LC brass anymore. I have a Remington R-25 in .308 now.:) Do check for neck clearance in the .243 chamber! My gun was a then new Remington 600 Mohawk. I can tell you that it (the gun and the fireforms) shot really really well!

Balrog: "Can you form 243 Win brass out of 308 win brass?"

Not only can you do it, that's how the original .243 was made. And .358, and 7-08, and .260.


"If so, what do you need to do it?"

As said above, lube it and simply ease it into a .243 sizer.

If it's hard to chamber afterwards it's only because you didn't have the sizer screwed in quite far enough. The new neck may need turning but that isn't likely. Sure it will thicken some but rarely enough to make it crimp in the chamber, most of the people who say that have never done it. That change will add about .0035" to the neck walls, not a lot, just make up a dummy and mike the finished diameter to see what you end up with. And, with a good case lube like Imperial or Lee, it can be done in most any press, it surely doesn't need to be done in a 'Chucker.

Sizing down from .30 to .24 in one step is likely to lose some percentage of cases, it will help a lot if you anneal them first. And, if you can, use a 7-08 and/or a .260 sizer as an intermediate step but no special set of "case forming dies" is necessary for that very simple change.

Saying it's much easier to just buy factory cases is true but it's no more valid (and as pointless to a reloader) as saying it's easier to forget reloading and just buy factory ammo, is it?

I have a 243 case forming/trim die, neck sizer and full length sizer dies with a 243 neck reamer die.

When necking a 308 to 243 it is believed the neck gets thicker by those that do not measure before and after, could be something they heard or read on the Internet, I do not know, my experience with case forming has convinced me when a case is necked down it (the neck) gets longer and when necked up the neck gets shorter, again, when necking up 30/06 to 35 Whelen the case length shortens .030 thousands +. when forming 30/06 to 30 Gibbs the case shortens as much as .040 thousands, that is necking up to 35 Whelen and necking back down to 30 cal, and as always when fire forming cases do not always get longer, when the case fills the chamber to form the case body and the forward shoulder the case pulls back, in this situation the worst thing a wildcatter can have is a tight neck.

I do not use collet dies, again no one measures the length of the case before and after, if I had a name for the collet die it would be 'stuffer', the base of the case is held by the shell holder, the neck is held by the collet, when sized the case is not sized it is stuffed together between the head of the case and neck, or it could be magic.

F. Guffey

I have done this before, and it works. It's just a serious pain in the butt. You really have to lube the hell out of the brass and even then it's tough. I felt that it would have been far easier if I sized to an intermediate step first - like 7mm-08 Rem. This would require an additional die set, which I do not have.

I measured the necks after sizing, and the differences in thickness was pretty negligible. The cartridges fired fine. Ultimately, I decided that it was just as cost effective for me to buy cheap factory loaded .243 and re-use that brass for reloading rather than buy another die just to use as an intermediate sizing step.

Most of the free .308 brass I was finding was cheap stuff anyway which I only wanted to reload once or maybe twice.

http://www.leeprecision.com/cgi/faq/index.cgiForming vs. Sizing

Case forming dies are usually cut to size the case slightly smaller than the minimum SAAMI (Small Arms Ammunition Manufacturers Institute) dimensions, to account for the brass case's tendency to spring back after sizing.

Our full length sizing dies are cut to size the case closer to the middle of the SAAMI dimension, because that is where most rifle's chambers are made, and to size to the minimum would shorten case life. Whether or not our full length sizing die will work as a case forming die depends upon the chamber dimensions of your rifle, and how much spring back there will be when sizing the case.

'"You really have to lube the hell out of the brass and even then it's tough."

Bluntarski, NOT saying you're wrong but I don't see how the lube need be so extensive unless the donor case was first fired in a large chamber. Then it could be difficut but not due to sizing the neck down.

The bodies of the .308, 7-08, .260, .243 are the same so that doesn't make any difference when reforming. Necks are quite thin and need very little lube when squeezing them down a few sizes. I've tried several commercial case lubes for such resizing and some home brew stuffm as well, they have all worked very well. I prefer Imperial Die Wax (or Hornady's Unique) because it's clean and easy to apply by finger. The reduced necks will certainly get a little thicker but not by a lot, as Guffy points out.

Most of my .243 reforming has been with .30-06 donor brass. I've done it that way to get much thicker necks deliberately so I could then turn them for a snug fit in my factory chambers. Snug necks do allow for somewhat improved accuracy but it's not automatic, loading skill matters. Good shooting ammo comes from the total process, not just a single component.

The economy of making .243 from .308 shouldn't be over looked and it certainly isn't difficult to do.

Case forming/trim dies if described and compared with something that reloaders can relate to try to compare them with a chamber that is roughed in and a chamber that is finished, the forming die when used first requires the case to be full length sized, measure the length f the case after forming and again after full length sizing. Spring back, jump back or recovery is not a consideration, most of my cases have no memory of what it was before I ran it into a die, and as they say I am the only one that understands what it is that I do. the body of the formed case is larger in diameter, the shoulder is forward and the angle of the shoulder has less angle than the finished full length sized case, again with all the grass movement reloaders pass up a good change to correct the effect the case has on head space before the case is fired.

F. Guffey

forgive, it should have been brass movement not grass.

F. Guffey

Yea, they frown on moving grass.