Help fire forming load data. .257 SMACK

S

Sage Rogue

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First off hello all, this is my first post on this forum. I am preparing to have a rifle chambered up in a .257 SMACK, it's a cartridge design I came up with that is a cross between a 25-308(Souper) and a .257 DGR with a little more case capacity than both. I talked with Dave at PTG about what I wanted and he drew it up and built me a removable pilot reamer and go gauge. I blew the shoulder out quite a bit more than the Souper or DGR and went with a 32 degree shoulder for smoother feeding on a Rem700 short action. I wanted something different that I could run on a short action and use the .243 Lapua brass.
Since this is my first go at the unknown and not having a fire formed case to measure case volume. I was looking for input on where to start with a fire forming load. My thinking was to use a 100gr bullet slightly into the lands with a mid range .243 Win powder charge to fire form with. How do any of you feel about this? I'm open to any input.

Bellow is a pic of the go gauge compared to a .308 Winchester on the left and a .243 Winchester on the right.

http://i90.photobucket.com/albums/k269/landonmoses/DSC03076.jpg
 
Fireforming AI cartridges you start with what's about top end for the parent case and work up from there. The shoulder on yours is blown forward a lot. I'd use a hot 257DGR load as the starting point and go up. Seating into the lands to fireform won't do what you think it will and isn't necessary anyway. But you'll need to neck the cases up past .257, then go back down and create a false shoulder with some crush.
 
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What Ackman said. I'll add a suggestion. If I were doing it, I'd anneal the cases before fireforming. You have worked them a bit and blowing the shoulder forward that much may split a few. I did some 7 Alpo (shortened 280AI on a 444 Marlin case) cases some time ago. I may some mistakes and had to really push the shoulder forward, nearly 1/4". I split everything until I stopped and annealed the cases. I did not loose anymore.

YMMV,
Rick
 
.257 Smack

I am shootin a cartridge I call .25 Rudolf. Yes it is in my reindeer hunting rifle :D. Basically it is a 25-08 40 degree Improoved. Excellent cartridge, in my opinion one of the best allaround varmint and deer cartridge that you can build on a short action. 100gr bullet at 3300 fps and 75 grV-Max at 3900 fps. Quite an advantage over .243 Win. Previous advice is a sound one to use high end load for the parent round to fireform with. Just for comparison 48gr H-414 is about max load for the 100gr bullet and 49 gr N-140 is max load for the 75 V-Max. Those loads are of course way to hot to fireform I would reduce them at least 15% but I dont know the exact volume of your case in regard to the .25 Rudolf so you have to make your own conclution.

BA
 
25-08 Rudolf

I just neck up to .25 cal new unfired .243 Lapua and fireform them to 25-08 IMP with no loss of cases at all.

BA
 
25 Shooter,

Do you have any barrels in 25 BR? I am planning a 25 BR and then later extending it to the 25-08 or so.
 
I like the case, but I.......

would push the neck/shoulder back a bit to give it a tad more neck to better handle all bullets, & perhaps retard the onset of erosion a bit. Also, I'm not big on expanding .243, why not neck down .308 Lapuas, instead of expanding them??? The Lapua .308s are cheaper than the .243s:)
 
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Octopus

My 25-08 was at first chambered to 25BR Improoved. I shot about 1000-2000 rounds from it as such. I had fun with it but it was never able to compeat with 6PPC at short range Benchrest, probably because I didnt have the best light weight bullets for .25 I was shooting this on a full blown Benchrest rig. The general concensus is that the .25 cal bullets made by late Jeff Fowler were the only .25 bullets close to the custom 6mm bullets in regard to accuracy. Jacky Shmidt shot at one time .25 BR with those bullets an was according to him self competitive. If your aim in this .25BR project is to compeat with 6PPC at 100-300 yards then dont do it. If you are doing it for any other reason then go ahead it is accurate and fun to shoot.
My .25 barrel was 1:14 twist and will stabilize 100gr sierra flat base bullet for deer hunting so when I gave up on this .25BR project and needed deer rifle the barrel was rechambered to and the same reamer run in deeper to accept full length .243 so it is basically 25-08 improoved. I have also 25-06 improoved and it doesnt add much to the 25-08 ballistically (100gr Sierra 3300 with 25-08 200-300 fps more with 25-06 IMP) Incidentally the difference in velocity between the 25BR and 25-08 with 100 gr bullet was also not more than 200-300 fps. .25BR improoved will give at least the same velocity and energy with the same weight of bullet as the good old .243 Win. If you need more information regarding load or anything feel free to mail bergur@lsh.is

BA
 
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