One of these days I might try a 243 barrel in my little Blaser K95 break open single shot.

Extraction of rimless cases means that the case is held on to by a spring loaded extractor. I'd much rather a rimmed case not being held onto (easier to handle aswell) It would also have the advantage of being able to substitute extractors and use standard factory 243.

Was reading in the Belm site about rebating a rim into standard chambers for 223rimmed etc. This would work well with a K95 as all that would be needed would be a different extractor.

Before going down this route I thought I might try forming some 243R from 6.5x57R.

Annealing, running through a 6mm rem die produces flawless 6mm rem rimmed, subsequent shortening to 243 length is fine but the moment I try to form 243 in a 243 full length die, the shoulder collapses.

Questions:-

Rebating a rim into a 243 chamber and subsequently using a 243 full length die and rimmed shell holder - problems with dimensions?

How to form 243rimmed from 6.5x57R brass with acceptable losses?

ah..

wait a second

307 (308 rimmed) is commerial brass...

take a 243 sizer, trim it ~.050 from the bottom (rim thickness is the exact) and form away...


jeffe

There is no need to trim the .243 fl die,.307 and .308 Win. use the same die,use a .243 die with a .307 or .356 shellholder.

WC

for many years in Auz.There was a .303brit converstion to 243 Simplex still list dies for it.Under 243/303.To form the cases it was full length resize from 30 to 25 then down to 24. I hope this helps

quote:

Originally posted by jeffeosso:
ah..

wait a second

307 (308 rimmed) is commerial brass...

take a 243 sizer, trim it ~.050 from the bottom (rim thickness is the exact) and form away...


jeffe

Excellent idea but isn't 307win of appreciably less capacity due to construction differences?

quote:

Originally posted by 1894mk2:
Excellent idea but isn't 307win of appreciably less capacity due to construction differences?

nope...


or yes... you have 56gr in the 308, 54 in the 307... 4%

jeffe

1894,

you might also consider taking the 6x62 R Freres:
Blaser chambers it
brass may be available somewhere - or reform from 7x65R

But you might consider the cartridge as somewhat "overbore"

Fuhrmann

I would think there are GSs that have reamers for the 6mm X (303 OR 30-40) IMP. That should give you the rim and powder capacity. Dies may be a LITTLE problem.roger

quote:

How to form 243rimmed from 6.5x57R brass with acceptable losses?

Cartridges of the World lists a 6x57, and CH-4D lists dies for both it and a rimmed variant. I'd imagine case loss would be on the order of 0%.

quote:

Originally posted by asdf:

quote:

How to form 243rimmed from 6.5x57R brass with acceptable losses?

Cartridges of the World lists a 6x57, and CH-4D lists dies for both it and a rimmed variant. I'd imagine case loss would be on the order of 0%.

But Blaser will only chamber 243win!

quote:

I might try a 243 barrel in my little Blaser K95

Ah, yes, I see I didn't understand your original question. Hmmmm, the x57 case has a smaller shoulder diameter, so a simple rechambering won't work. It seems running .307 brass into a .243 die is indeed the cheapest solution. Or at least it would be until the supply of .307 brass dries up, then you'll have to form from .444 brass. No perfect solution. I agree that rimless cartridges in break-opens isn't for the best. I don't care for them in my Contender.

Full moon clips?