M1871 Springfield Spencer Shooting 50-45 Cartridges

[ndnchf]

FWIW - I have a M1871 Springfield Spencer that is nominally chambered in .56-50, but it actually takes a .50-45 length cartridge. I put a centerfire block in it and shoot .50-45.  Not the same as a .50-70, but a bit more powerful and could be suitable for a bison at close range.  Here are the two rounds side by side.

[El Supremo]

Hello, Ndnchief:

Thanks fot the photo of the two ctg's.
Fascinating length difference.
Does the longer one cycle from magazine into the chamber, please?
Thanks.
El Supremo/Kevin Tinny

[ndnchf]

Hello, Ndnchief:

Thanks fot the photo of the two ctg's.
Fascinating length difference.
Does the longer one cycle from magazine into the chamber, please?
Thanks.
El Supremo/Kevin Tinny

Yes, the 50-45s cycle fine. The 56-50s will not cycle in it.  Here is a video I made about it with a shooting demo.

[ndnchf]

I have not done a chamber cast. The rifle bore is 52 cal. It is still a rimfire.

You really need to slug the bore to find the actual bore and groove diameter.  Then you'll know what you are dealing with.  Its a great rifle, I hope you will get it shooting!

[El Supremo]

Thanks, Ndnchief:

Viewed your video before, but did not know of the longer ctg.

I recall reading that one significsnt limitition of the 1860 and 1865 Spencer's was that ctg's longer than 56-50 would not cycle.  Your work proves otherwise!

What are the OAL's of the case and longer ctg, please?

Since a shorter 56-50 will not cycle, what is the mechanical change that enables the longer round to fully cycle, please?

Many thanks.
El Supremo/Kevin Tinny

[ndnchf]

Thanks, Ndnchief:

Viewed your video before, but did not know of the longer ctg.

I recall reading that one significsnt limitition of the 1860 and 1865 Spencer's was that ctg's longer than 56-50 would not cycle.  Your work proves otherwise!

What are the OAL's of the case and longer ctg, please?

Since a shorter 56-50 will not cycle, what is the mechanical change that enables the longer round to fully cycle, please?

Many thanks.
El Supremo/Kevin Tinny

-case length is 1.355"
-O/A length with the Rapine 350 bullet is 1.683.
-Mechanical difference - I'm really not sure, I see no obvious differences. But it may have to do with the bullet's ogive shape -and flat nose.

-It shoots particularly well with 45gr of Goex 2F when my old eyes can see the sights. I've tried Swiss and Old Eynsford, but it likes plain old Goex.

[ndnchf]

Sorry about the thread drift. I do want to hear more about the OP's buffalo rifle. El Supremo - PM me if you have any more questions.

[El Supremo]

Hello, Ndnchief:
Please check your PM's. Smiles and thanks.
El Supremo/Kevin Tinny

[El Supremo]

Tx, Nfnchief:
Your previous posts about your unaltered, long chambered 1871 answer my questions. 
Amazing and helpful info.
Smiles,
El Supremo/Kevin Tinny

[Blair]

Thanks to Two Flints who created this thread.  I am glad to see this is now it's own thread.

ndnchf,

If you are interested (or anyone else for that matter), I believe I know what it would take to modify various parts of the block system to allow for a longer cartridge to run through a Spencer breach block.
With a new bbl & chamber one could not get the original 56-50 or 52 ammo to cycle with these changes.

My best,
Blair 

[ndnchf]

Thanks Blair. I'm quite happy with mine as-is. But feel free to share your thoughts. Maybe others would be interested.

[El Supremo]

Hello, and thanks, Two Flints, Ndnchief and Blair:

Ndnchief helped me with a PM about his three Threads:

24 AUG13: Need help with feeding problem.

31AUG13:  Shooting the Model 1871 Springfield Spencer Infantry Rifle.

21FEB18:  M 1871 Springfield Spencer chambered for .50-45 Cadet?

Those revealing Threads ADD important details, including the longer chamber, longer case and round, AND that Ndnchief's original, unaltered 1871 cycles the longer, but not the standard 56-50.

Marcot's 2nd Edition includes, as best I can find, only a passing comment:

On page 158, he recounts design limitations, but includes that the action will cycle ctg's up to 2" long. That's a lot longer than the usual 56-50 and the 1.683" round of Ndnchief's 1871. Marcot does not say what allows up to a 2" ctg.

This 2" aspect makes me wonder if the Spencer design was not taken to its maximum potential. I recall that during the CW, there were maximum case diameter and length limitations due to lack of case drawing skills even for the Federal side.  By 1871, perhaps that had been solved, but the Ord. Dep't. wanted a round over 2"?

Rocky Mountain Ctg, per Cheri Outland, has a 56-56 "Special" headstamped case, not on the usual list, that is a close OAL to Ndnchief's.  Could be someone went down the 56-45 Cadet path several years ago.  I use that case with its greater capacity in non-Spencer rifle. 

At this point, I am hoping that someone can please share useful details on what differences are in the 1871 that cycles the longer ctg.  Larry Romano said he has no clue. My suspicion is that different dimensions or separations of the projections on the lower block are involved. 

Perhaps Herbert, Arizona Trooper or N-SSA Spencer wizards will please enlighten us?

Again, I am most grateful for everyone's work.  Smiles and respect.

El Supremo/Kevin Tinny

[ndnchf]

It is an interesting question. I don't currently have a normal Spencer to compare it with. But I'd be glad to measure parts of mine, just tell me exactly what is needed.
Steve

[El Supremo]

Thanks, Ndnchief/Steve:

Perhaps Blair can describe what he suspects. 
He's whittled on a Spencer or two.

In the meantime, perhaps you could take and share a close-up photo of your lower block with a scale laying along its top so the front cam/hump and rear "hook" are visible. 
That might give him some clues.

Thanks so much for your extra efforts.  Smiles.

El Supremo/Kevin Tinny

[ndnchf]

When I first got this rifle and began cartridge development, I did not have an original cartridge. I made mine from 50-70 and several different bullets. But none were pointed like the original's bullet. I now have one original cartridge. I just loaded it in the magazine and it cycled fine. But without several more behind it, I cant tell what difference it makes. But this could all come down to the bullet's pointyness and ogive shape.

[Blair]

I am glad we got this thing going.

Here is what I suspect,,,
Longer cartridges can be set up for use in a normal Spencer based on the location of the 'cartridge stop' on the front lower section of the breach block.
The cartridge stop keeps the cartridge from cycling right at the point where the next round in line can be eased back into the mag tube as the block is being closed. The upper breach will he pick up the back o the cartridge and chamber it.
If the 'stop' is modified to allow the cartridge inter the breach too deep, the next round would bind up action with normal Spencer ammo. If all the ammo were longer this would not happen. Here is where a new chamber and/or barrel would come into play. This is what I believe Springfield did using the 50-45 Cadet barrels.
I hope this helps?
My best,
Blair

[ndnchf]

Does this look different than normal?

[El Supremo]

Tx, Ndnchief:

Nice photo and info on cycling.

I have tried cycling rounds with different ogives, including a straight cone from case mouth to a .375" meplat with no cycling effort changes.  Am so puzzled about which cycling factors matter(that can be turned on and off). 

The usual OAL and harder 18Bhn alloy bullets with and without a bit of grease on ogive helped a lot. 
All of my 56-50's now cycle fine, but with cycling "effort" variations that range between effortless to a bit balky.

Blair just reminded me, so here's another bit:
I found a ctg feed guide spring with a shorter than normal leaf in one of my Spencers that was quite stiffly cycling rounds that cycled fine in other Spencers!
A replacement with correct leaf length made cycling normal.
So, I suspect that the feed guide's pressure also matters.
FWIW: There are wide variations in the tempers of CW era flat and "V" springs. 
These variations can change trigger pull weights a LOT.

I have reduced the typical "martial" trigger pull weights of 12# or more to between 3.5# and 5# by substituting a softer, more uniform temper Shiloh Sharps mainspring and placing a flat 1/8" by 1/4" .011" - .015" shim under the mainspring screw head.

Accuracy is fine with a casefull of 3Fg, no wad and Win large RIFLE primer.  SPG lube. My bullet is a 315gr, single lube groove Romano sized .0005" over groove OD. ACCURATE BULLET MOLDS has a close copy.   I BALLISTIC RECREATIONS salt bath anneal after each use and do not loose either RMC or cut dn Starline 50-70 cases to splits with CH4D dies.  No mouth reaming needed on the Starlines!
Slightest crimp, but bullets are tight.

Spencers are, by far, my favorite.  So many interesting aspects and history. 

Am grateful for Two Flints and our SSS members. 

One more favor, please:
Can you please attach another photo taken from alongside like the first one, but with a bit of an angle that SHOWS the projections on the upper surface of the lower block?  Many thanks.

Revised to add ctg feed guide spring tension factor. Jkt.
El Supremo/Kevin Tinny

[ndnchf]

Does this help?

[El Supremo]

Yes, Ndnchief:

Lots better.  Thanks.
Am chatting w Blair, so he may post later this AM.

He shared stuff about the ctg feed guide SPRING, and possible profile differences between the Spencer and Burnside versions that requires me to revise my prior post. Will do that now.

Kevin