.243 Win up to .300 Savage?

[Skofnung]

Is it possible to re-form .243 Winchester brass to .300 Savage? I know it can be done with .308 brass, is there any reason why it would not work with annealed .243?

The reason I ask is that I’ve found some old .243 brass and I want to make up some dummy or snap cap type rounds for my rifle, but I don’t want to use up my good .300 Savage brass. The .243 headstamp would help to identify the rounds should the black marker wear off.

Thanks.

 

[steveno]

I think you had better check the shoulder location as I think it is different. personally I don't think it is worth the trouble as 300 savage ammo and brass will be available for a long time to come. there are a lot of 300 savage riifles out there

 

[goon]

Why not just invest in a couple hundred new casings from Midway and never have to worry about it?

 

[Skofnung]

Well...

I know new brass is available, and I even have a fairly decent sized stash of it along with some factory ammo. I want to save the real brass for real loads. I don't have a .243 and I found a bunch of cases the other day in amongst some shooting stuff.

I also would simply like to try my hand at re-forming cases. I've got a Lee Classic Cast press and I've heard that it is strong enough to handle it... Curiosity I guess.

Comparing the cases, it looks like I could cut 2/3rds of the neck off the .243 and run it into my .300 Sav. sizing die. The shoulder starts at 1.560 on the .243 and 1.559 on the .300 Savage.

So by running the cut case into the .300 Savage die, the expander ball should expand the case mouth and the shoulder would be set back... right? Then I could trim it to real length.

My biggest question is am I going to hurt my die if I try this?

 

[Skofnung]

Well, I've done it.

You can form .243 Winchester brass into .300 Savage, and it is quite easy.

Cutting 2/3rds of the neck off is too much.

The second try yeilded great results. I cut half the neck off the .243 case with a dremel cut off wheel. I then de-burred the case, lubed it up, and ran it through the .300 Savage sizing/decapping die. I encountered only slightly more resistance than normal, and I may not have even detected it had I not been waiting for it.

The case came out a little long, so I chucked it up in my case trimmer and let fly and all was good.

I've weighed the case in opposition to a standard .300 Savage empty. Both cases are Remington, if that matters. The .243 case is quite a bit heavier: 157.2 grains as opposed to 154.6 grains for the real case. IN OTHER WORDS, THE CASE CAPACITY IS REDUCED. THIS COULD LEAD TO PRESSURE PROBLEMS IF LOADED.

This is fine with me, as I don't plan to load powder in these cases as of yet. They are to be made into true weight snap-caps.

 

[goon]

On the other hand, I hate to throw anything away too.
I have heard of people reforming from .308, and IIRC .243 and 7mm-08 are both based on .308 casings. I am wondering if a trim die may be an easier and more consistent way to shorten the casings but I have no knowledge at all of reforming anything.

Cool.

 

[George1951]

I have made several attempts at forming .300 Savage brass from .308 brass.... Thus far, I have not been able to get the bolt to close on my K-98 Mauser.... tight chamber, I guess...the .300 Savage brass, new or 1x fired, is expensive, so I have been looking for alternatives...