Spencer Bullet Gauge

[Dana]

Here is a Bullet Gauge that Ron came up with will we were working on trying to determine correct cartridge size, what we did was disassemble the breech block and reverse engineer it, we determined that the deflection angle was 45 degrees. The pictures that Two Flints will be posting for me shows different length cartridges that will chamber in our rifles, we know that the overall length is an important factor, but we also learned that the deflection angle plays and important role in cycling of cartridges, anyway this gauge worked for us, we both have originals, no way of trying it on any other except originals.





This picture show the cartridge before contact with the indicator.                                 

                                      (Photos posted by Two Flints)

[Two Flints]

Dana,

Of the three cartridges shown how would you rank them in terms of a "chambering success rate"?  Does one cartridge cycle better than the other two?  They are all very different in terms of appearance.

Would you explain in more detail how the gauge works?  With only one screw holding the metal to the wood isn't there a greater chance of unwanted movement of the metal when measuring the bullet angle?  Wouldn't two screws secure the metal to wood better?  Just curious.

Two Flints

[Dana]

Two Flints,

First of all, thanks for posting the photos.

The pointer on the gauge is made to move, the bullet is slide toward the indicator until the rim of the bullet touches the wood, at this point the indicator moves, if the indicator points straight as shown, than the cartridge will cycle. If the pointer moves either left or right toward the other pins, than the cartridge will not cycle.

What we looked at was the length of cartridge sizes that was originally made to worked in our rifles, our thought was that Mr. Spencer designed the breech to contact the bullet at 45% angle at a specific point on the bullet. This simple gauge was made to show the contact point of breech to bullet without having to cycle bullet in rifle.

Dana

[Bead Swinger]

This is really cool. 
I wonder what it would take to redesign it so you could figure out the proper OAL for a new bullet design.
Has anyone had fun 'ranking' the cycling success with the different bullet designs?

Thanks for your work.

[PvtGreg]

I've been doing same some of experiment on my ArmiSport - but nothing as thoughtful and through as this - my hats off.

My Armi sport has a VERY narrow range of OAL - from 1.55 to 1.6 with the Lyman 515-139.  Anything over is progressively harder to chamber.   I have a Carbine from Romano and the OAL is much more generous - like 1.5 to 1.65, but Romanos are built like swiss watches.  Shoot like them too, just not fast enough to single load for cowboy shooting because of the blade extractor.

You can get already cast Lyman 515-139, SPG lube, 330 gr from Track Of The Wolf (www.trackofthewolf.com).  50 count for $15.  I forget the hardness scale off the top of my head but its was on the harder side.

I also tried ones from Buffalo Arms - http://www.buffaloarms.com/Detail.aspx?PROD=157726&CAT=4137 They were 350s and have a blunter nose, which I think effects the range of OAL you can chamber.  For my armisport the range was 1.55 to 1.57.

[Herbert]

To alow the Armie Sports(56-50) Spencer to feed longer OAL cartridges you have to modifey the cam and the extractor.I have done this with my rifle and it will feed very smoothly from 1.56 to 1.69

[PvtGreg]

Thanks a lot Herbert -

My optimum length seems to be 1.57 and I'm not skilled enough to do more on the gun.

I'm pleased with everything; I feeds butter smooth and I'm pleased with the gun now.

Thanks again