308 to 243

[zacharoo]

I was given 1000 primed 308 military brass. I have a 308 win. and a 243 win.  Is it safe to just re size the primed 308 into 243 with out depriming them? Do they have to be cut to lenght? I have very little 243 and this would solve a problem and a little money too.

[RugerNo3]

If you pull the decapping pin from your 243 full length sizing die, run a 308 case in. Worst case will be too long and a too thick neck wall. Carefully measure the resized 308 and compare it to your resized 243 cases you have. If the neck on the 308 is too long or too thick, you'll have pressure problems. Really the simplest answer to your question.

[zacharoo]

I decaped one and ran it threw the resizer. Tried a lee case length cutter and it was not to long. Tried the case in my rifle and it chamber great. I ran it threw a RCBS small base 243 die. The rifle is a remington model 700. I 243 bullet fits OK

[Savage]

Sounds like you're "good to go". Be sure and check case length on all the cases. You'll find some that are ok, but I'm betting some of the cases will need trimming. For now, I'd just take the decapping pin out of the expander plug and size away. Good shooting!
Savage

[beemanbeme]

For what it's worth, I would never have two different calibre rifles at the same time with re-formed brass with the same head stamp. I have owned a .243 with reformed .308 brass and I have owned a 7-08 with reformed .243 brass but I have never owned them at the same time.
I don't know if it possible to chamber a .308 round in a .243 or not but the hassle of keeping the stuff seperate would be a pain. 

[Cheesehead]

I have considered the opposite angle. I have a quantity of 243 brass and am considering running it through my 308 die in one step. Is it possible.

Cheese

[jhalcott]

  There is ALWAYS a chance of some thing going wrong when reforming brass. While i do not think you COULD chamber a 308 into a 243 ?? As for sizing the brass DOWN ,you might thicken the necks some. Then when the bullet is seated ,the necks will be tight in the throat area. Another problem is the necks are not always even and square . This can hurt accuracy. Going up is easier as the necks tend to get thinner when going from a .243 to a .308 BUT the necks might be out of square and uneven here too. Just because ONE case seems to work fine doesn't mean they all will. You have to check each one of them for evenness,squareness and thickness for safety. Then there is the probability that different makes and lots are NOT going to weigh the same. Requiring a slightly different load for best accuracy. Of course if all you want them for is light plinking loads this separate load thing can be ignored. MAYBE!

[wncchester]

"Is it safe to just re size the primed 308 into 243 with out depriming them?"

Yes.  Nothing will come in contact with the primer IF you just raise the decap/expander rod up a half inch or so.   

I agree with jhalcott that it's possible the necks may be too thick but I doubt it, factory chambers are pretty loose and factory cases are pretty thin.  The thickening from necking down can be overrated but you do need to check the loaded rounds with a micrometer to make sure.  If they are thick, get a neck turner and you will end  up with better fitting necks than factory stuff.  A case trimmer will square the necks easily.

I can identify any of my cartridges across the room, I don't have to look at the headstamp to know what I'm chambering but doing it yourself is up to you.  I have been forming .22-250, 6mm International, .243, .244, 7x57, 270 and .308 from bulk .30-06 for maybe twenty years and have never had a problem of not knowing which ammo was what so that "hazard" is sort of dependant on how much attention you pay to your shooting. 

For sure, you can't chamber a .308 in a .243, nor can you "accidentally" reload one case instead of the other without knowing it.  If you reload  your ammo and then put it in a correctly labeled box you shouldn't have any problem.  I sure don't.

[beemanbeme]

Cheese, I've gone from .243 to 7-08 without a problem. Of course, once I was done, I trimmed things up nicely to the shortest one. But then I'm sure you know that. I did hone a little of the shoulder off of the resizing ball in the 7-08 die and used a good bit of lube inside the neck. If you're using new or 1x brass, it oughta work.
As far as the necks being too thick from necking down, that's an easy check. Fire a .308 in the subject rifle and measure the neck, seat a bullet in the necked down case and measure it. If it's smaller, it's okay. The rebound of the neck of the actual .308 case will give you enough neck clearance to work. After being fired, you should be able to slip a .308 bullet into the neck of the fired case. If not, the neck is getting too thick and needs to be tossed or turned.

[Catfish]

I never worry about what the head stamp say, because around here it is wrong abt. 50% of the time. I have a .222 mag. and .204 brass with the same head stamp. I have a .223 and a .17-223 with the same head stamp. I had a .22 Hornet and a .17 AH with the same head stamp. I did have a .30-06 and .270 ammo with the same head stamp.

[beemanbeme]

Anyone that has read my post would have to agree that I am certainly not a chicken little but having several different calibre cartridges laying about with the same headstamp is an accident waiting to happen. Good luck.

[Savage]

In the case of .243/.308 or anything formed on the same parent case, head stamp should be no big deal. If you were to fire a .243 rd in a .308 chamber, it'd fire form the case and the .243 bullet would rattle down the bore and wind up somewhere down range. Worst case scenario the case neck splits. No big deal. A .308 case won't chamber in a .243 chamber, so no problem there. I'd form um, load um, and shoot um.
Savage

[stimpylu32]

A little trick that i use when forming brass is to take a SHARPIE marker and color the heads of the formed brass , so as soon as i see it i know that it is diffrent than what it is stamped on the case .

Also in my 45 LC and 45/70 the hot loads are colored RED so as to not fire them in the wrong gun .

stimpy