I found this shiny muzzle brake in a box of stuff for sale at the Toys that Shoot airgun show last year. I had no real plan for it at the time, but it was only $10.
I did like the undercut on the bottom, and I thought the machining was pretty clean for the price.
Surely, I had something that this 14mm diameter would fit. See the justifying? Brought it home and put it in a larger box of stuff with other shiny things where it sat waiting.
Some of my airgun projects never seem to be finished. My old CP1-M pistol from the now defunct M-Rod Air is a good example. It's worn iron sights, red dots, modified grips, triggers, barrel shrouds. A different configuration every few months. Changing needs and perspectives, changing interests, too many options--all in search of shooting perfection. At least that's the hope we have whenever we try a new airgun accessory. Maybe I'm just attracted to shiny things like a magpie.
Anyway, I was never really happy after sleeving the barrel in carbon fiber. It was supposed to just be a stopgap until something more appropriate came along. Something more air pistoley.
The other night, my brain made the connection:
Muzzle brake
+ CP1-M
= Amazing
All the brake needed was just a simple shim. There was a cut-off scrap of black acetal already on the workbench.
Quick and easy. Went to the lathe and faced the end.
Took the diameter down to 0.550"--just barely smaller than the bore in the muzzle brake.
I really like to machine acetal. Easy to cut and no razor sharp chips all over the floor.
Test fit.
Really snug. It's actually a light press fit.
Cut it off and chamfered what will be the front end of the shim.
I want to drill for the barrel with it installed in the body of the brake.
Pressed the acetal plug in, snugged the set screw then progressively through drilled for the muzzle diameter.
The muzzle of the CP1-M barrel is stepped down. A 25/64" drill bit is a good fit.
The insert is about 7/8" into the bore.
Some better pics of the brake.
A couple pics of the stepped barrel on the CP1-M.
Used an o-ring to close the gap at the rear of the brake.
Pushed up snug. A quick visual bandaid to hide an unsightly gap.
Done?
The sleeve presses into the brake, the brake then presses over the barrel. The set screw keeps it all from moving. This press fit works on a no-recoil CO2 pistol. After looking at this, I'm thinking about stripping the trigger guard back to bead blasted raw aluminum.
Whoops! Almost forgot. Always want to make sure there's no pellet contact with a newly installed muzzle brake.
Some electrical tape
Over the muzzle.
And a test shot. Looks OK!
More in a couple days.
