What a wonderful group here, several people have offered a few pieces of brass for something this hard to come by. uscra112 offered also and I requested only a couple of pieces to start with. I found two Winchester molds (25-20 Marlin and 25-20 S.S.) in my pile so I am hopeful this will be good enough to get a start. It would be nice to know if the 25-25 is capable of reasonably good accuracy for offhand at 200 yards. We shall see once the temps get out of the basement here in Minnesota.

BTW ssboomer thanks for showing the photos of your chambering set-up. My lathes are a bit short for that but my old Sebastian May (mid-1800's) is and all it needs is the rollers in the steady rest. Yours look like roller tappets which would make the conversion simpler.

Thanks all,
Charles

And this is why I don't buy Bertram any more. The base is 0.295 while the 25-25 is more like 0.323 and these are from first firing.

So I pin gaged the 25-25 and it was 0.302 at the base and my period rebarrel was 0.303.
The bore of this 25-25 is 0.249 at the muzzle.

Charles

Let's put things into perspective...and it may well be lousy brass!  25-20 Winchester, similar (sorta) capacity, similar pressures. SAAMI standard for the chamber at .200" forward of the back of the cartridge is .3465" with a tolerance of minus .008", for a minimum case diameter of .3385". The chamber is shown as .3475" at the same place, with a tolerance of plus .002", for a max diameter of .3495". This gives a range of .011" difference and would still be within the acceptable limits. Since 25-20S, 25-21and 25-25 all pre-date SAAMI, tolerances on original chambers could be much bigger than the nominal of the day. It's probable that today's ammo makers and reamer makers worked from a survey of original rifle chamber casts and original cartridges, and tried to come up with a safe compromise. But again, it's Bertram brass that was shown and they had (still have?) a reputation for iffy brass quality. 

I bought 60 peices of Bertram 28 30  last year. 7 out of 10 split just like the ones in the picture. The case heads were long and a little small so as solid brass will not expand to the chamber but the brass forward the head will and it splits. When I bought the rifle it had 2 boxes of Bertram with a much shallower head thicknesss and they were fine , the new ones not so much. Breech  seating RMC brass now , several firings , no splits.

Don't forget about Rocky Mountain Cartridge. Last year I bought 40 pieces of .25-25 that were in inventory. I've been very pleased with it. They make it to order too.

bohemianway wrote on Jan 25^th, 2024 at 1:53pm:


Mine has the .253" groove size. Its a pain, but I use multiple dies to size down the bullets. But it works well.