Feeding Improvement in Armi Sports 56-50 Spencer - *** Added to SORI #17 ***

[Herbert]

I have always noticed that original Spencers have fed much smoother than the Armi Sports 56-50,so I decided to conpare measurements on A-S against original 56-50, which feeds much smoother. I found that the cartridge rocker( A-S calls it cam part no 54 in there pamhlet) in original is 0.127 inch high in A-S it was 0.147 in my rifle, i filed this down to the height of the original and now it is almost as smooth feeding as my original

[Two Flints]

Herbert,

Very interesting.  Please post photos of the part you filed down, please! Or send them to me and I will do it for you!

Two Flints

[Herbert]

when you take the action out of rifle it is the curved thin peice directly in front of the uper breach block.between the face of uper block and extractor,the cartrige rokes over this curve by presure of the spring loaded cartrige guide to line up with the chamber,if you want to reduce the height 0.020inches it can easly be achived without any further striping just follow the existing curve and measure often

[.56/50 Iron]

Can you confirm? Part #54 in my instructional manual is the  Upper Block. If it is the little curved part, that is part #51 and is called the Cam. Don't want to file until I am sure! I doubt whether you could even touch the upper block with a file anyway as mine is very hard. Will await answer. Thanks very much!
.56/50 Iron

[Herbert]

I have the older pamflet the numbers may not be the same but it is the part that AS calls the cam

[Jbar4Ranch]

AGGHHH! Somebody post some pice, PLEASE!

[Herbert]

I have no camera just now but i will try to explain how to do the job, fist remove the action pivot screw,remove the action from the frame,now the part to be filed is the thin rounded plate between the spring loaded lane type extractor(this bit swivels towards the uper breachblock)and the face of the uper breachblock,now you need to measure the hight it is above the lower breachblock which it is atached solidly to( the best way to do this is with digital or dial vernia calipers)take note of the highest reading and the curve of the cam now with a fine file take .o2 of the hight of the cam this is not much so go slow and measure oftern,when you have the hight right creat the curve again by slowly filing from the curved surface to the center of the filed bit ,no need to go to the end of each curve,just mack a new curved surfac.Dont atemt this unless you have the right measuring gear if you dont have a digital or dial set of vernias borow some and get the person to show you haw to measure  the curv with the depth gauge end of the vernias by yousing finger presure and tacking note of the highest reading.this worked very well in my AS spencer but as always if yours is working well leave well enough olone,the fix is so the cartrige goes into the chamber as clean as posible,before i did this the bullet would somtimes hit the top of the chamber and hang up unless you snaped the action closed now cartriges go straight in and it feels nealy the same chambering a cartrige as wen you work the action emty,just lick my original .A litle more studing revealed if the front of the curve, bit closest to the extractor is filed down to 0.06 ( keep the curve even from the high point)it also keeps the cartrige coming out of the magizine straiter,making it harder for the breachblock to dig into the bullet also inproving feeding,i have tryed this with difrent cartrige lenths from 1.515 inch to 1.62 inch and all feed much beter ,i am now confedent this fix will inprove feeding in 56-50 spencers( it does not aply to other calibers)and recomend you try it

[.56/50 Iron]

Without doing this fix as Herbert describes, here's another way you can possibly go. I use basically 3 differant types of lead alloy: very soft lead, wheel weight alloy, and linotype alloy. These go from very soft to very hard. As the breechblock is starting to come up and close behind the cartridge that will eventually go into the chamber, the top front edge of the block nicks the side of the bullet that is just starting to come out of the magazine tube. The block is designed to rise and push that round back into the tube as it completes chambering the first round. When the sharp edge of the block nicks the lead slug, the action hesitates unless you use "extra force" to complete the chambering. This is where most of the jamming occurs in the action. Herbert also found that some jamming occurs as the round is trying to chamber. I have tried to round the sharp edge of the breech block a bit so it slides over the lead bullet as it is pushing the first round, but the breechblock is so hard that even with emory paper I didn't make much impression on the metal. The nicking of the bullet is most pronounced with soft lead. It is 100% better making the bullet out of wheel weight metal, but the little nick is still there. I tried some dummies that I put together with bullets made of linotype metal and it is 99% cured! No marking on the bullet either. Now I am giong to watch how they chamber and if I see one catch on the edge of the chamber, I am going to try Herbert's cure for that. The profile of the original Spencer 350 grain bullet was sloped enough so the the block did not cut the bullet metal. Also, if you look close at the original patent drawings, you will see that the front top edge of the breechblock is noticeably rounded. The block of the repro Spencers is tall and sharp edged at the front. I don't think we could use a bullet made like the original as the original had almost a pointed tip. That would possibly be hazzardous with today's centerfire priming. Can't wait to get some more shooting done this weekend!
.56/50 Iron

[locosmith]

We need Pictures here. Thanks Loco

[.56/50 Iron]

Here you go. This is a drawing from General John Pitman's volume "Breechloading Carbines of the United States Civil War Period"copyright in 1930 and reprinted in 1987. I have seperated out the part of the drawing I need. This illustrates how the upper leading edge of the breechblock (sharp edge colored Green) strikes the side of the bullet near the tip (colored Red) and digs into the lead and either slows down the chambering of the round ahead of it or jams the action. Normally, the block would gently nudge the 2nd cartridge a bit backward into the tube. The url of this photo is:
 
Maybe Two Flints can use his magic and put the photo right here and make it easier to see. A hard bullet ignores the sharp edge of the block. Hope this part helps a little.  

.56/50 Iron

[Two Flints]

A--B--R--A--C--A--D--A--B--R--A


                                     (posted by the magician, Two Flints)

[Herbert]

The green marked top edge is were you polish a radious,it does not take much emery paper then stoning works well to achive this quickly,if breachblock is still cuting bullet increase radious slitly,rember it is the sharp top edge to be worked on ,not the face of the breachblock that suports the cartrige wen locked in chamber,the curved bit that the cartrige is resting on in the picture is the cam and the bit that i sugest you modify to inprove feeding,i now have my rifle feeding as smooth as a original,you can hardly tell a cartrige is being chamberd no mater what speed you cycle the action

[.56/50 Iron]

Thank you Two Flints!

Now we are coming along a bit! Thank you Herbert from Australia. I will try the Spencer outside in the awful winter here in NW Wisconsin this Saturday. If I have any kind of slow down with chambering a cartridge, I will round the top edge of the breechblock some and then use your fix on the cam also. I will also target the linotype bullets and see how they work for accuracy at 75 yards. I was relieved to find the rifling twist in the carbine is one turn iin 26 inches. This is fairly close to the one turn in 36 inches it should be for the short bullet I am using.
.56/50 Iron

[El Tigre]

The green marked top edge is were you polish a radious,it does not take much emery paper then stoning works well to achive this quickly,if breachblock is still cuting bullet increase radious slitly,rember it is the sharp top edge to be worked on ,not the face of the breachblock that suports the cartrige wen locked in chamber,the curved bit that the cartrige is resting on in the picture is the cam and the bit that i sugest you modify to inprove feeding,i now have my rifle feeding as smooth as a original,you can hardly tell a cartrige is being chamberd no mater what speed you cycle the action

That is a great support and improvement. With my Spencer have to move the action quickly. If I do it slowely the bullet will not match the chamber. I think that this fact will not be solved with bove mentioned rework.

El Tigre

[Herbert]

That is a great support and improvement. With my Spencer have to move the action quickly. If I do it slowely the bullet will not match the chamber. I think that this fact will not be solved with bove mentioned rework.

El Tigre

if wen cycling the action slowly the bullet is catching on top of the chamber,the fix i described will defintly inprove feeding

[El Tigre]

Hallo Herbert,
if I move the action slowly the bullet will be positioned below the chamber.
However, I will try the proposal.

El Tigre

[Herbert]

have you put a small radi in the leading edge of your uper breachblock ,if so cycle the action faster,you will notice it feeds smoother out of the magizine,now if the cartrige is hiting the top of the chamber modify the cam, you should be able to cycle the action at any speed and and cartrige should chamber with hardly any felt resistance

[locosmith]

I did the radius thing and it helped, its pretty smooth, I also found a lip where the magazine tube meets the action, its off set there I polished all that too. I may try the to lower the cam, to me that looks like it should be the right place and would lower the cartridge and could help. Loco

[locosmith]

Hello El Tigre.. One other thing, I made sure where the mark is, top whould be the chamber, bottom would  be the block. I took the cartridge from mine out after it hung and the mark is on the bottom, so I think its not on the chamber of mine. Lowering the cam may not fix that but it could if its the angle going into the chamber and the mark was on top. If that makes since? But all in all mine is smooth, sometimes I have to wiggle it a little or tilt it down. Loco

[panhead pete]

Howdy All,

Is the cam removable from the block?  If so, I am guessing that you take the .020" off of the bottom.  Or, do you take it off of the radius side?

Thanks, this is great info!!

Panhead Pete