12.7x44r to 50-70

[conor_90]

Just daydreaming, looking at intersurplus

I have heard about guys rechambering rolling blocks to this so they don’t have to form 348 brass

Can it be done on a drilling/ Cape gun?

Who was doing the work in the rolling blocks?

 

[fingers284]

I have done it myself in a RB barrel. two ways you can make 50-70 usable. one is chuck the barrel in a lathe and open up the rim cut in the barrel chamber to fit the 50-70 rim or you can chuck up all your 50-70 brass one at a time & turn a bit off the rim to fit your original chamber.

Just a point about the brass that I have found, most brass rims from extruded cases are very uniform and fit well but the very odd one will be too thick for easy chambering. I also have some of the 50-70 machined brass that was sold at gun shows a few years ago and the rims on a "lot of them" is a thou or more thicker than they should be...just enough that when the block is closed, the hammer will engage the block enough to slow it down and you may have frequent FTF.

 

[conor_90]

Thanks

Is the difference the dimension of the rims only? Or is rechambering or trimming the brass short for the 12.7x44r chamber necessary?

 

[fingers284]

I have never done a chamber casting in my RB. In my rifle, 50-70 will "plunk" right in mine after the rim modification but I have read of others having to trim brass, but that may be just a "all 50-70 brass" comes from different manuf and some is shop machined so might differ slightly.

It's been a long time since I messed with it in 50-70 ( it has a new 45-70 barrel spun on now) but it think the slugs i used were .512 dia and when seated, still chambered...I have a .509 mold as well but think I used the fatter slugs.