Just got my second Rolling Block.I was told it was a 43 spanish, so I went and got cases dies and bullets for it, load five rounds up and went out to shoot it. Well guess what shoot one round and the case expaned so much I had to use a cleaning rod to get it out. So I took a chamber casting and I got base .532, shoulder ,.514, neck .472, bore .443, from the base to the rifling is about 2.50. Is this right. Thanks

12.7x44R Swedish ???

Is your Rolling Block Remington made or Spanish made? Spain tended to use a slightly larger chamber. Geo. Hoyem, in his "History and Development of Small Arms Ammunition Vol 2" lists the 11mm Reformado as having the following measurements (taken from specimens): base: .519"-.521". Case mouth (does not list "neck"): .470"-.486". My own specimens have: base:.519"-.522". The Reformado has a tapered neck so measurements vary depending on where measured but go from about .481"-.492". I'm going to guess that your rifle is chambered for the 11mm Reformado. From a lot of experience casting chambers on these rifles I have developed a "theory" that rifles rechambered from 11mm Remington to the Reformado ctg AND done in an armory have fairly uniform chambers. But, due to widely fluctuating chamber measurements I have seen I believe that Spain sent reamers to various outposts where rechambering was done by whoever was available and with whatever tools may have been at hand. Generally, my Reformado chambered rifles that I shoot I have been able to use BELL 11mm Spanish brass (or Bertram or JASS or whatever) and, after the case is fireformed, I neck size only for reloading. I have one rifle with the "Fluer de Lis" on the side of the barrel (indicating it was in the 1st order from Remington) that I had to use BELL 450/400 brass and these had to have the base taken down a little on a lathe until they would chamber. I have yet to see a Uruguay/Francotte that that could be shot with any brass except worked over 450/400 brass. Their chambers are just too large for the 11mm Spanish brass to work. The 1st Rolling Block carbine (11mm Spanish) I bought a lot of years ago was in real nice condition. After the deal was made and I'm walking away the guy who sold it called me back to give me ammo to go with it. It was 80 rounds of 11mm Mannlicher (Werndl) ammo. That should have been my 1st clue. At home an 11mm Spanish ctg got lost in the chamber. At one time Mannlicher ammo was real common here but few rifles to shoot it is. Some folks reamed out Rolling Block chambers to shoot it. Some stamped the barrel "11Mann", some did not. When dealing with old timey guns remember, a LOT of years have passed since it was made which means that there was ample time for someone to play with or bugger up a chamber.

TJACK Thanks for the info going to take another casting with cerrosafe and what I get. Don