308 to 243

[zacharoo]

I was given over 400 once fired remington 308 brass. How safe is it to just run these through a 243 small based die and cut to length for use in a 243 remington 700. I have a 308 but not much 243 brass. With the brass situation. Hard to find I am wondering about resizing to 243. What other steps do I need to be safe and still use the brass?

Zacharoo

[mjbgalt]

you would need another step, probably a .260 or .257 in the middle, because going from .308 to .243 is going to stress the brass way too much and you will have to trim and turn the necks and maybe even anneal them.

would be way easier to trade or sell the .308's and get what you need.

-Matt

[Lloyd Smale]

theres also a good possiblity that you will have to turn your necks as they could get to thick.

[mjbgalt]

try the classifieds too.

[dakotashooter2]

I have done this with mil surp brass. I used my seating die (minus stem) as the intermediate sizer. I run the brass into the seating die and it would reduce the neck  about 90% and leave a step in the shoulder. The down side is that it would put a crimp the case mouth. I would then run them into the sizer die. If you could get your hands on a tapered sizer button and dry lube it would make this slightly easier but even with the crimp it was still easier than doing the sizing in one shot. This would leave a just barely visible step in the shoulder. Then load and fireform. You don't have to worry about trimming them as the neck will be a bit short at first but it did not seem to affect accuracy in my guns. I have not had to turn the necks for my guns (factory) but you'll want to measure the OD of the finished round to be sure it is within specs. The mill surp brass is nice for this because it has no caliber designation on the case to cause confusion and I found my loads to be more accurate in those cases than WWs or Feds. I did not anneal them yet as I am testing some to see how many loadings I get before the necks crack. So far I have only loaded them a couple times.

I have done a few factory brass this way (nickle) and the results seem about the same. I wouldn't hesitate doing it with mil surp brass but I doubt I would do it with factory brass unless I was really hard up. It shouldn't be that hard to swap your brass for what you need.

[jhalcott]

Another thing to consider is the work hardness of the .308. IF it has been fired many times it COULD be getting brittle. If it is fairly new the above comments are good. IF you want to get rid of some of them ,I'd like a chance to get 100 or so .308 cases for my Lone Eagle!

[Siskiyou]

Long time back I bought a tool that works on my Forester trimmer to turn the necks of 308 cases because I had a good supply of 7.62 NATO cases.  Fortunately a good supply of bulk 243 cases came on the market and I bought a couple hundred. 

I believe Lloyd is on the mark.  Earlier a brother had some issues with 308 cases necked down to 243 Winchester.

One of these days I need to try the tool just for the experience.
I found dakotashooter2 post of interest.  I am thinking about using other dies to step down the next diameter.

I called my wildcatter brother and he is in agreement with Lloyd that neck thickness might be an issue.

[SHOOTALL]

I use 30-06 brass comm and military. to make 25-06 rounds all the time . I do trim after sizing but nothing else .

[Siskiyou]

I have not taken 30-06 commercial and military base down as far as shootall.  I have been using it for .270 base brass for over 40-years without a problem. 

I think there is a point in neck reduction when addition steps maybe needed.  The brother who tried it had pressure issues using the same powder weight he had successfully used in factory cases.  Times were not as desperate and he found commercial .243 cases.

You might want to load a couple of dummy loads and see if you have a chambering issue after a bullet is seated in the case.  Chamber the dummy load with caution, if there is any resistance do not force it.  If the dummy round is forced into the chamber it could become lodged.  Then the fun begins. 
Before getting to the chambering, measure the outside diameter of the case neck.  I believe it should not exceed .276.  Check your reloading manual(s) to be sure.  You do not want to deal with a jammed case.

[mechanic]

Might be simpler to offer a trade on the classifieds.  You might get lucky and save a lot of work.  Trade off a hundred for a hundred or some such.....just my idea.....

[wncchester]

" I am wondering about resizing (.308) to 243."

I did it for many years with GI 7.62 brass, it's not difficult at all.  I mostly did it in a single step, lost a few cases but not many.  In more recent years I've used 7-08  and 260 sizers as intermediate steps and lose no cases that way.  The challange can be fun in itself.

Necks MAY need turning afterwards but, in my experiece, that's never been true.  It is always a good idea to anneal the finished necks to reduce premature splits tho.

Using a good case helps save cases.  I know that Lee's white case lube in a toothpast tube, Imperial Die Wax, Hornady's Unique and STP oil treatment all work good.

[zacharoo]

 i traded the brass off no longer have it.

[mjbgalt]

your brother got pressure problems from the necks being too thick...


-Matt

[Siskiyou]

Today I pulled out a couple 7.62 NATO (308) cases.  As I stated earlier I had thought about Necking them down to .243 Winchester. 

I used a Lyman Mag-T turret press which has a lot of leverage.

I made a pass with a full length Lee 308 Winchester Die after lubricating the case, and inside the case neck.  Next I made a pass with a RCBS full length 243 die.

The new case had a slight ridge of brass at the base of the neck.  I do not think the ridge was as pronounce as the one that is created when I manufacture 30-06 cases into 270 Winchester cases.  The ridge normally creates a little resistance when closing the bolt.  On first firing the ridge will disappear and the case will be fire formed to the chamber.

I checked the over length of the case in a gauge and it was maximum for the .243 Winchester.  This is the length I normally trim to.

I slipped the case in to the chamber of my Remington 788 in .243 Winchester.  There was very light resistance when I closed the bolt.  Next I seated an 80-grain Speer Hot Cor in the case.  The dummy round was not primed nor was a powder charge put into the case.  The 788 action cocks on closing.

The dummy round was loaded into the magazine and feed into the chamber several times without a problem.

I resized a second case, but I ran it into the 243 Winchester die twice.  The second pass removed some of the ridge and the case feed smoothly into the rifle.  The second run is not necessary and may shorten the life of the case.

I took a few measurements with my calipers of the resized cases and an empty Winchester head stamped case.  There was not major difference.  I compared the resized case to a loaded Federal case and there was no difference.

I have no need to load a batch of 243 cases at this time.  In the future I will have no problem using cases resized from 7.62 NATO to 243 Winchester.  Starting low and building up to a usable field load.

I could not find the unused outside neck turning attachment I have for my Forester Case Trimmer, but I do not think it is needed.