New rear mount for a Malcolm scope

[Cap'n Morgan]

I finally found time to make an adjustable rear mount for my Uberti 1985 replica. Once it was finished I couldn't resist coming here bragging about it - Sorry!

After replacing the front mount some years ago the scope worked as intended, but the original rear mount pretty much limited the rifle to a one-range affair.
A rear mount - easily adjusted in height - seemed as a good idea, and I came up with a simple, but sturdy, design:



Next step was to actually produce the various parts. Since it's almost CNC mill work only, I decided to make an extra set for my Swedish RB while at it.



A few parts from an old Schulz & Larsen sight came handy as well.



The final result.

I still need to have the parts blued - and calculate witness lines for the different ranges.
The scope have about 2.5 degree max tilt, which should give a max sighting range slightly over 600 yards. More than enough for both the rifle & me.

[Reg]

Very nice work! One question. When getting the elevation at the rear how do you compensate at the front? In other words is the front part of the scope tube solid in the mount or is there some “ float” so as to prevent bending the tube?

[elk hunter]

Great job. I like it!

[Bent Ramrod]

Wow, very nice workmanship. No apologies needed; as they say, “It isn’t bragging if you can do it.”

[Cap'n Morgan]

Very nice work! One question. When getting the elevation at the rear how do you compensate at the front? In other words is the front part of the scope tube solid in the mount or is there some “ float” so as to prevent bending the tube?

Reg, I stole the idea of a "ball bearing" from a SAKO mount. This gives you total freedom for movement in both axis.
The front mount was made from stainless steel - which was a stupid thing to, now that I'm having the rear mount blued.
Perhaps I'll make a new one and use the SS mount for my Swedish RB. Some doofus reblued the gun, refinished the stock and buffed the frame to a silver shine.
Since any trace of the original finish is gone I may as well keep the mounts in the white to match the frame.

[Reg]

Now that is one heck of a good idea!!

[marlinman93]

Excellent work on the Malcolm style mount! Looks very sturdy, and better than many made by large companies doing this!
I have an original Malcolm scope from the late 1800's that I've been trying to come up with an original mount, or a reproduction that I can adapt. The killer is the original Malcolms are a tiny 5/8" tube, so the usual 3/4" mount wont work.

[snipin101]

That does look really nice! Good and sturdy looking mount. Looks so much better then the hi-lux mounts on my sharps.

Sent from my moto g power (2021) using Tapatalk

[405grain]

That is a very excellent mount. I'm going to be rebarreling a 1874 Sharps replica soon, (once I get some other gun projects out of the way) I want to mount a scope on it, as my eyes aren't as sharp as they used to be. I'm a retired machinist with a lathe and Bridgeport mill, and had planned to machine the scope mounts. Your mounts look better than what I had in mind. Do you have prints for your scope mounts, and if so, would you be willing to post pdf's of them? Also, I've got a buddy with machine tools that likes to build rolling blocks, and I know he'd be interested in something like this too.

[Cap'n Morgan]

405, I don't have any drawings with measurements since most work is made directly from the solids in the design.

I can post some close-ups of the assembled mount, which should give you a good idea of how the thingamabob is constructed.
I can also include a 2-D drawing with some basic measurements. Give me a day or two to come up with something.

[405grain]

Cap'n Morgan: Thank you. Please take your time as there's no hurry at all. Any information that you can provide would be helpful. I use Autocad Mechanical and Autocad Inventor, so if a part has a dimension I can scale other parts off that. The photos that you've already posted are really helpful. I'm not looking to make an exact copy of your design, but mostly to make something similar. Because the set up is usually more involved than the machining (with manual machines), when the time comes to make the jigs and fixtures it doesn't really make sense to produce only one of each part. After I make prints and do the set ups I'll probably make enough parts to build half a dozen mounts. In the future ( a couple of years from now) I plan to machine some falling block actions, and they're going to need scopes.

[Cap'n Morgan]

Yesterday I added a scale on the mount. I calculated the witness lines using QuickLoad's ballistic program (which will give the angel between bore & sight line for any chosen range).
Then it was just a matter of trigonometry to calculate the rear scope movement with a 7" distance between front- and rear mount.

Now it remains to find where on the mount frame the zero-line has to go. Once the mount has been blued, I'll polish the left side and slider to give a better contrast to those tiny numbers. 75 (meters) seemed to be a good starting distance. Hopefully, the calculations will pan out as hoped - otherwise a new slider will have to be made.

[marlinman93]

Great looking work! Will the fixed side of the rear mount have the usual multiple witness marks like a tang sight has, or just a single mark?

[Cap'n Morgan]

Great looking work! Will the fixed side of the rear mount have the usual multiple witness marks like a tang sight has, or just a single mark?

Just a single line - maybe some sort of arrowhead or triangle. I'll always strive not to make things too complicated I like a scope with just a cross hair and nothing else - perhaps a 30-30 reticle. Some of the "tactical sniper" scopes with sooper-dooper milldot christmas threes for reticles confuses me to no end.