50-70 to 50-90?

ligonierbill · January 2, 2021, 09:15 AM

I have 2 rolling block rifles in 50-70 Gov't (1 3/4"). One is professionally built on an original action. The other is one of the old Val Forgett replicas made by Pedersoli. This Italian is "plus sized", larger in all dimensions than the original.

I intended to sell the second one, but thought it might be interesting to have the chamber bored to 2 1/2" to take a 50-90 Sharps. Same bullets, and I only load blackpowder. Is this as straightforward as it appears, or am I missing something?

ballisticxlr · January 2, 2021, 09:27 AM

Should be about that straightforward. It's a rolling block so there's no amount of length you can't use. Black powder pressures are only so high so I don't see an issue there with the extra snot. If you're not worried about 4759 based smokeless loads then I can't see a problem.

Jim Watson · January 2, 2021, 12:17 PM

There IS a limit to the length a Rolling Block will accept, the round has to chamber at an angle over the top of the hammer and breechblock. I THINK a .50-90 will fit.

BUT, I do not recommend rechambering a gun you mean to sell; the alteration will reduce its desirability unless you already have your customer identified and he wants a .50-90 after you are through playing with it.

ligonierbill · January 2, 2021, 12:57 PM

To be clear, it's sell or keep it and rechamber. The hammer spur on the original does limit cartridge length, and I doubt a +3/4" would fit. The Navy Arms, however, has a slightly different shape to the hammer, and it appears that length is indeed unlimited. Will certainly verify that before I do anything.

Jim Watson · January 2, 2021, 05:51 PM

Please do. Ken Waters had a .458 RCBS (.45 x 2 3/4") on the Navy Rolling Block and said he had to hold the hammer back past full cock to get a round in the chamber. He said George C. Nonte ground a bit off the hammer nose to clear.

I found a reference to a .44-100 2 5/8" bottleneck Remington target model having a scallop in the hammer nose, although the poster said it would chamber over a regular hammer.

There was some enthusiasm on the Shiloh board for a 2" .50 cal, intermediate between .50-70 and .50-90.

ligonierbill · January 8, 2021, 10:09 AM

Closing out, it's sell. Posted on Gunbroker and getting a good response. I did check the Navy Arms hammer clearance, and any length will clear it. There is a little scallop cut into the hammer. I don't know whether that is original or a mod. I haven't touched it. Never heard back from the shop I contacted.

Jim Watson · January 8, 2021, 10:54 AM

Probably smart.
There was a guy here who lengthened chambers coming and going.
A .45-70 became a .45-90 or longer.
A really weird one was the repro 1876 Winchester reamed from .45-60 to .45-70 with the intention of seating bullets deep to feed through the action. I never heard how that worked out and he is recently deceased so I can't ask him.

January 2, 2021, 09:15 AM	#1
ligonierbill Senior Member Join Date: May 20, 2007 Posts: 2,456	50-70 to 50-90? I have 2 rolling block rifles in 50-70 Gov't (1 3/4"). One is professionally built on an original action. The other is one of the old Val Forgett replicas made by Pedersoli. This Italian is "plus sized", larger in all dimensions than the original. I intended to sell the second one, but thought it might be interesting to have the chamber bored to 2 1/2" to take a 50-90 Sharps. Same bullets, and I only load blackpowder. Is this as straightforward as it appears, or am I missing something?

January 2, 2021, 09:27 AM	#2
ballisticxlr Member Join Date: April 25, 2020 Posts: 83	Should be about that straightforward. It's a rolling block so there's no amount of length you can't use. Black powder pressures are only so high so I don't see an issue there with the extra snot. If you're not worried about 4759 based smokeless loads then I can't see a problem.

January 2, 2021, 12:17 PM	#3
Jim Watson Senior Member Join Date: October 25, 2001 Location: Alabama Posts: 18,541	There IS a limit to the length a Rolling Block will accept, the round has to chamber at an angle over the top of the hammer and breechblock. I THINK a .50-90 will fit. BUT, I do not recommend rechambering a gun you mean to sell; the alteration will reduce its desirability unless you already have your customer identified and he wants a .50-90 after you are through playing with it.

January 2, 2021, 12:57 PM	#4
ligonierbill Senior Member Join Date: May 20, 2007 Posts: 2,456	To be clear, it's sell or keep it and rechamber. The hammer spur on the original does limit cartridge length, and I doubt a +3/4" would fit. The Navy Arms, however, has a slightly different shape to the hammer, and it appears that length is indeed unlimited. Will certainly verify that before I do anything.

January 2, 2021, 05:51 PM	#5
Jim Watson Senior Member Join Date: October 25, 2001 Location: Alabama Posts: 18,541	Please do. Ken Waters had a .458 RCBS (.45 x 2 3/4") on the Navy Rolling Block and said he had to hold the hammer back past full cock to get a round in the chamber. He said George C. Nonte ground a bit off the hammer nose to clear. I found a reference to a .44-100 2 5/8" bottleneck Remington target model having a scallop in the hammer nose, although the poster said it would chamber over a regular hammer. There was some enthusiasm on the Shiloh board for a 2" .50 cal, intermediate between .50-70 and .50-90.

January 8, 2021, 10:09 AM	#6
ligonierbill Senior Member Join Date: May 20, 2007 Posts: 2,456	Closing out, it's sell. Posted on Gunbroker and getting a good response. I did check the Navy Arms hammer clearance, and any length will clear it. There is a little scallop cut into the hammer. I don't know whether that is original or a mod. I haven't touched it. Never heard back from the shop I contacted.

January 8, 2021, 10:54 AM	#7
Jim Watson Senior Member Join Date: October 25, 2001 Location: Alabama Posts: 18,541	Probably smart. There was a guy here who lengthened chambers coming and going. A .45-70 became a .45-90 or longer. A really weird one was the repro 1876 Winchester reamed from .45-60 to .45-70 with the intention of seating bullets deep to feed through the action. I never heard how that worked out and he is recently deceased so I can't ask him.