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Discussion Starter #1
Can turn .308 win brass into .243 win with satisfactorily results?

I already pressed one .308 case into my .243 full length sizing die, it worked, without having to anneal but the case is hard to chamber.

I know that the .308 cases are a bit shorter than the .243 and after being formed the neck wall is a wee bit thicker,

Am using Hornady Custom-Grade New Dimension dies and this sizing die gives a fair amount of head space flexibility, so IF "at the end of the day" the only real problem is the difficult chambering, I should be able to fix it by lowering the sizing die some more?

Any hints or advice? Or should I abandon the idea altogether?
 

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Well the .308 is where the .243 started life from. I have used plenty of necked down cases but there are a few things to watch for.

One is the doughnut forming in the neck when you size them down. It generally really shows up after the first firing but can also be an issue after the sizing depending on your chamber. The chamber in one of my rifles allows me to size a bit longer on the neck, leaving enough to keep this from happening, however the other is a bit tighter and I see it on just about every one.

The other issue is how tight the neck is in the chamber according to the reformed cases. You might want to measure a standard fired case neck and compare it to a formed case with a seated bullet. You need at least around .0015 room for expansion, in order to keep from having the bullet be squeezed when you chamber and fire the round. This will give you a pressure spike real quick.

Of the ones I have done I actually found that different makes of brass were easier to use than others, with surplus being the most work. Winchester or Federal were the better two in my rifles.

They do make a good alternate source of brass if your on top of these things, and also work your loads up accordingly, due to different internal capacities of the different makes of cases. Similarly I am using Lapua 30-06 cases necked down and blown out for my 25-06 AI. I have found that even with this brass being as fine as it is, I need to anneal it after forming to keep things on an even keel with the standard 25-06 cases I use to form from.

Give it a try with a couple of rounds of different makes, it won't cost much to see how they work in your rifle, and you could easily end up only having to purchase one type of brass for a couple of rifles.
 

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41 Mag alluded to it, but it might bear repeating: After sizing a 308 case down to .243, you may very well need to turn and/or ream the neck, so that it fits your chamber properly. The difficulty in chambering the case is a dead give away and a potentially dangerous situation. You mention the dies you're using, but not the source of your brass. Is it military surplus, new, unfired commercial cases, range scroungings? I rarely try to make different cases from anything but brand new brass, because of a variety of potential problems. If you're using mil-surp or scrounged cases, you may go to a lot of effort to make them work, only to have split necks within just a few firings.

I know how tight money is for a lot of folks right now, though. If you're trying to save quite a bit by not buying new brass, I totally understand. Read up on annealing, if you haven't done it before, as that will help a lot to make your cases last longer. Also, try to run something less than full-throttle loads and case life will be much better.
 

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Can turn .308 win brass into .243 win with satisfactorily results ?
I don't have a .308, but I do have a 7-08, and a .243. As I'm a chronic "brass buzzard" I tend to accumulate shiny empty's left by the majority of shooters, and there's way more .308 brass than just about anything else.

Squeezing it down in one pass is a manly exercise, but I picked up a .260 neck sizer for the jump to .243. I pass the brass through a 7-08 neck sizer die, a .260 Rem neck sizer, and finally through a .243 small base FL die. Some cases may need the neck turned a bit, but they work just fine.
 

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i have been using mil-surp 308 necked down to 7/08 & recently started also necking down to 260 and so far no issues in regards to neck thickness. naturally i had to trim them after i necked them down...
there may be some extra messing around involved but it's a small price to pay. a couple winters back i took 1k pieces of that mil-surp 308 that had been laying around for a few years, sorted it by date and them sized and trimmed about half of it too 300 savage. a LOT of trimming but it was a nice winter project and i have enough brass for the rest of my life for my 300.
 

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Discussion Starter #6
Thanks all, I think now I know enough to make the right choices and move forward.

I will post my results on this thred.
 

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Discussion Starter #7
Alright then. First off, to answer an earlier question, I will only be using range droppings or other source or free .308 brass. .243 is quite plentiful off the shelf.

So far I only found 6 rounds of .308 brass marked 1K .308W or IK .308W can't tell which.

Lowered my die to the point that I get a good strong cam-over and ran all six through then took some measurements:
Normal fired (winchester) case neck measured .277 o.d.
Formed .308 neck measured .274 o.d.
Normal sized case neck measured .268 o.d.

With the adjustment of the die, all six cases chambered just as easily as any normal brass.

I am considering a test load of 100gr Sierra sp, 37.3gr Reloader 19, winchester LR primers. I'll wait for feed back before continuing.
 

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Good work getting the cases down to a nominal size so that they chamber well! That test load looks very conservative to me, and according to the books/QL. Where did you come up with 37.3gr of Reloder 19? QuickLoad shows a 100% full case at 46grains and 55K psi.
 

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Discussion Starter #10
37.3gr Re-19 is the suggested starting load in the Lyman reloading handbook with 100gr bullets and a max load of 41.5gr Re-19 at 57,400 psi. Whereas the Sierra book shows 37.0gr min. I'm not familiar with Quick Load but I'll check it out.

Thanx,
Chase.
 

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I guess maybe I need to buy a newer Sierra book, but if that's what yours shows, then maybe the newer pressure testing equipment indicates slightly less powder than before. What is the recommended seating depth for that recipe?
 

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Discussion Starter #12
For 100gr bullets, Lyman shows c.o.a.l. of 2.630. Sierra shows 2.650 which is where I seat my bullets.
 

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Discussion Starter #13
Spent all of saturday at the range and as it just so happened, the guys next to me were going all out with their .308 assault rifles and left 150ish rounds of brass for me to pickup! The guys said they had NOT been hand-loading and I watched them take their bullets from new boxes. What that means to me? 99% guarantee of once fired brass!

About half is Remington, the rest, a mix of fed and win. So far, I have concluded that RP is the best standard-off-the-shelf brass until you get into stuff like Norma or Star Line. I don't have any experience with that high end stuff anyway so what the heck, I'm happy!
 

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Discussion Starter #14
Oops, I almost forgot. The six, necked down cases that I started with worked out great, no problems.
 

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perfect! i'd consider gettin chummy and seeing if they'd pick up their brass and hang on to it for you when you aren't there when they shoot... heck you could offer them a box or two of their favorite brand and still be money ahead!!
 
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