50/70 problems

[pacomdiver]

my father in law has a swedish rolling block 50/70, hes shot some on his own store bought ammo then wanted me to reload for him, when he first got it, i got him a box of ammo from a commercial loader and he said they shot good ( i wasnt with him so i dont know what "good" is. the reloader gave me the load recipe so i could load them the same as what i bought from him

i got the lyman dies, the once fired starline cases and 50 commercial made 515141 sized to 512 and loaded them with 50 gr (weighed like the commercial loader but when put in the volume measure i have, they showed 60 grs ) , hodgden 777 2F and cci large rifle primers, i loaded up 50 of them and we took them to the range today. he shot some at 25, they were hitting at the bottom edge of the bull (point of aim) but when we tried 100, the only hit out of 5 was a sideways hit, so thats saying to me that the bore is larger than 512, but also had 3 cases seperate halfway up and 2 more cracked all the way round but didnt come apart, so thats saying it has a headspace problem. am i correct in my thoughts?

i will try to slug the barrel soon and see what the bore diameter is, so i can size the future bullets to the bore

i tried to upload pics of the case seperations 6 times and it says it failed

[john.k]

Starline cases are left hard from drawing,for cost reasons......therefore I advise you to anneal the cases before loading......the whole case ,down to the base,and you should not have any more splits...(note...this is dangerous with a 50K psi case,safe with a 10kpsi case)..Second,use pure soft lead bullets,and preferably some filler,and the bullet will slug up to groove diameter ,even if greatly undersized.If you cant shave lead from the bullet base with a thumbnail,its too hard to slug up.....If you must use hard bullets,try a much larger size,like say a .53 Sharps bullet......provided the loaded round fits the chamber ,bullet size is ok with cast............EDIT ..is 777 a black sub,or a nitro type?......you may need a lot more lube ,and a softer lube .....try olive oil and beeswax mix.

[curator]

Pacom diver:

A Swedish "50-70" is really a 12.7X44R cartridge that is somewhat different. Cracked and separated cases in a rolling block are a clear indication that more than the head space is bad. American .50-70 brass has a .060-065" rim thickness. The 12.7X44R has a.074 rim thickness and the chamber's rim recess is usually cut to .080 deep. This in itself would give excessive headspace but the case separation is resulting from the breech block not locking up tight and perpendicular to the chamber. You can check for movement of the breech block with the hammer all the way forward. Any movement when the hammer locks the breech block into place allows the head of the cartridge to move back and be bent at a slight angle. This can be caused by a poorly fitted breech block/hammer, or wear to the breech and hammer axis pins.

Check out the Dutchman's info on reloading the 12.7X44R cartridge: http://dutchman.rebooty.com/12744r.html

[pacomdiver]

John,
i dont know what the hardness of the commercial cast bullets i got, but being it was from an all black powder shop (no smokeless or modern weapons) i would hope it was pure, now that i got a 515141 lyman mold, i can make sure they are pure lead. also the case fill is too much for any filler, the bullet is seated to the top groove and slightly compresses the powder.

777 is a blackpowder sub, kinda like shockeys, but doesnt suck like it

do you have a link to a decent annealing thread? i searched a bunch here in the case forming thread and couldnt find any decent ones

Curator,
ill check to see of theres movement in the breechblock next time i can get over there. in that link you provided, it says some of them were converted into 50/70, maybe thats what he has


ETA: tried to upload those pics of the cases again, and it says it failed again, so someday it might pull its head out of its *** and let me post the pics

[john.k]

Even so,Starline cases in any calibre will split if not annealed before use.....and I believe Starline dont deny it.To anneal straight cases ,simply stand them up in a large flat tin tray,with about 1/2" water in the bottom,and gently heat with a propane/butane/heat gun/blow lamp...play the flame over the cases until they look clean,no need for red heat,(lead melt temp plus a little is good).As you heat each one,tip it into the water to cool.Dont worry about getting the heat even,brass conducts rapidly.Dont heat intensely in one spot.If you heat too hot,the cases may become so soft they suffer damage in reloading......after they fireform,neck anneal every 20 or so loads is good.

[john.k]

To check your barrel size,simply place one of the bullets into the muzzle,and thumb it in.It should be a double up thumb push,not an easy fit.Then,knock it out with a rod.If the whole surface isnt shiny from the rifling,ie just some light grooves,its too small....but if soft enough ,it will slug up when the powder goes off,filling the grooves ,and sealing off gases,which gas cut hard bullets,and cause leading.

[varsity07840]

John,
i dont know what the hardness of the commercial cast bullets i got, but being it was from an all black powder shop (no smokeless or modern weapons) i would hope it was pure, now that i got a 515141 lyman mold, i can make sure they are pure lead. also the case fill is too much for any filler, the bullet is seated to the top groove and slightly compresses the powder.

777 is a blackpowder sub, kinda like shockeys, but doesnt suck like it

do you have a link to a decent annealing thread? i searched a bunch here in the case forming thread and couldnt find any decent ones

Curator,
ill check to see of theres movement in the breechblock next time i can get over there. in that link you provided, it says some of them were converted into 50/70, maybe thats what he has


ETA: tried to upload those pics of the cases again, and it says it failed again, so someday it might pull its head out of its *** and let me post the pics

Most if not all commercially cast bullets for BPCR are cast 20:1.

[jugulater]

I second everything Curator said, especially the lock-up of the breech. A proper Rolling Block action should have absolutely no play when locked. The rim thickness difference is also going to be a issue, the 12.7x44R was originally a Rimfire round and as such had a thick rim, much thicker than the CenterFire 50-70.

i would be very suspicious of the gun because it has already been modified a fair amount as a 50-70 Gov't will never fit in a 12.7x44R chamber, the 50-70 is longer and has a bigger case head.

Hopefully its just weak cases and a Rim headspace issue and not anything more serious.

[enfield]

A lot of Swedish 12.7's had the chambers recut to 50-70 in more recent times ( I have one ). some of my unaltered ones will chamber a shortened 50-70 case with the rim trimmed down but I have never had any that separated cases ( all my brass has been annealed at least one time ). It's possible that headspace is a problem but a couple I have do have play at the breach block without causing problems. Definitely accuracy will go to pot if your not blowtubing between shots or inadequate lube ( or both )

[pacomdiver]

talked to him today, he said there is no play in the breechblock, so im gonna anneal some of the brand new cases i still have and shoot them and reload then see if they seperate, if not then there might be the answer