The 1377 Carbine Project Continues

The next part of my 1377 carbine project was the "muzzle brake". I put that in quotes because the brake doesn't actually do anything except hide the flat spot at the end of the barrel, protect the muzzle and look cool.

A long piece of aluminum rod stock was chucked up. I put the steady rest on to minimize vibration.

Turning the diameters at the muzzle end.

Drilling out the end as far as I could go with a 1/4" bit.

Drilling 1/2" diameter for the barrel.

I bored for a slip fit over the barrel.

I flipped the stock and chucked it true in the 4 jaw chuck, with a shim wrapped around the turned portion to protect it from the jaws.

Turned to a cylinder.

Drilled out.

Countersunk at the end.

Turning a taper on the end. I started doing it at 30 degrees, but settled on 10 degrees for a rather long taper.

Filed and scotchbrite to finish.

As you remember from last time, I had done a rather casual job of indexing the two holes on the pump plug, this time I remembered to use my 5C collet block to fixture the work. The stop locates the block for each successive operation and the dial indicator tells me when I have travelled the same distance each time.

Starting to slot the brake.

This is one of my prouder moments. I had to drill for a set screw at 45 degrees from the slots, so I put the collet block on a vee block, then clamped the end of the brake in a vise. I unclamped the brake from the collet block and drilled the hole on the drill press.

Another view showing the vee block.

I drilled for a #6 setscrew and tapped by hand.

I filed and used scotchbrite on the slots.

The finished brake.

As you can see the slots are at 45 degrees from the set screw.

Mounted to the barrel, continuing my Sci-fi theme for the conversion.

Prototype Cocking Aid for the Predom Lucznik

Cocking the Predom Lucznik results in an incredibly uncomfortable sensation of the front sight trying to tear a hole in your palm. The Walther LP53, which the Lucznik is patterned after, was supplied with a cocking aid. If you look at this German page, scroll down to the picture showing how the LP53 is cocked with the aid attached. So I decided to make a prototype out of plastic.

A chunk of Nylon rod faced and chamfered before cutoff.

A brass rod, 1/4" diameter, chamfered before filing the end to a half round.

The two pieces fresh from the lathe.

The plastic was tightened up in the vise on the Taig mill and the centerline was found. I milled a flat across.

I then drilled slightly undersize for the brass pin.

Next I pocketed it out to clear the barrel and front sight.

The pin was pressed into the hole.

It covers up the front sight and makes for comfortable cocking.

This is what I'll change in the future - the pocket doesn't change width, I should have narrowed it where the sight is so that it can't twist from side to side. Only after I made it did I find an end on view of the Walther one in an auction on Gunbroker, showing the narrowed slot width. I'll be making the next one out of wood, when I get a blank disc made by my friend Rudi, the wood turner.