Carbon Fiber Shroud for the S&W 78G Part 1

After seeing Nick's recent Smith & Wesson 78G post, it gave me an idea to try on mine.  Want to increase the barrel length to gain velocity, but the extended soda straw look leaves much to be desired.  Thought about covering the extended barrel with a shroud.  The shroud will simply cover the barrel.  Note:  There is absolutely, positively no possibility of sound suppression as the barrel will run all the way through the shroud from end to end.  None.  The muzzle will be visible at the front end of the shroud.
















With that out of the way, I hit my scrap box and found a carbon fiber tube approximately 1.125" OD and just shy of 7" long.

It was a bit too shiny, so it was scuffed with a scotch brite pad to produce a matte finish.

Need a couple aluminum end caps so it can be attached to the airgun.  Faced some 1.5" 6061 aluminum rod.

Turned down to match the OD of the carbon tube, then stepped the end to fit into the tube's ID.

This is a good time to spot and through drill.

Used a 1/4" bit.

This is the clearance hole for the .22 cal pellet.

The rearmost end cap is up first.  Drilled partially through with a 7/16" bit--this will allow a Crosman 22XX barrel to pass through.

Parted off.

Cleaned up the face and beveled the edge.

On to the front cap.  Again, turned to match the OD of the carbon tube and stepped for the ID.   Drilled partially through with a 25/64" bit.

Followed by a 7/16"-20 tap.  Ran the thread right to the bottom of the hole.

Parted off the front cap.

Faced and beveled.

Chucked the rear cap in the Taig and cut two o-ring grooves.

This is a snug press fit over the barrel.

Here's the thread on the inside of the front cap.  Deburred all the edges and did some test fitting.

So, there's no thread accessible from the outside.  The barrel has to pass completely through so the muzzle can thread into the front cap.

The double o-rings will isolate the shroud and keep it from rattling against the barrel.

 Painted the end caps then glued them into the carbon with J-B Quik epoxy.

Next up is machining a Crosman 2260 barrel to fit the shroud and Smith & Wesson air pistol.


More in a few days.

October 29 Miscelaneous What-Nots

Numero Uno:
Just a couple quick projects today that I've been meaning to finish.
















Added a set of Uncle Mike's sling swivels to the Benjamin Sterling HR-81.  No pics of the install.  Just had to drill a hole. (Of course, there was a bit more to it than than, but only due to my agonizing about getting the hole properly centered.)

 Used kit #1071-2.  The cocking lever measured 0.432" in diameter.

Found that the supplied 3/32" allen wrench in the Uncle Mike's kit was a bit undersized. Threw it away and found one in the tool box that fit substantially better.  Helpful tip installing the band:  Get the hollow, flat head screw where you want it first, then snug down the upper allen head screw to lock it in place.  If the band rotates slightly when you load the sling (some barrels are hard to get a grip on due to high polish), sandwich a small piece of 320 to 350 grit emery paper between the barrel and clamp.  Put the abrasive side facing outward against the clamp.  Cut the emery paper just smaller than the clamp so it's completely invisible.

Also wanted a better sight on the Sterling ever since I saw Precision Airgun owner, Chuck's, personal HR-83 wearing an Anschutz diopter.  It made my Beeman (Williams made) target sight seem somehow, you know, inadequate.  Even with the old, adjustable Merit aperture, it wasn't quite what I envisioned. Attempting to do this without spending any money,  I scrounged around the parts bin, and came up with the recently removed diopter from the Tech Force TF-79.

This particular sight made the cut because it would clear the radius on the top of the Sterling.  The only problem was the dovetails on the sight body were too narrow by just a few thousandths.

Set it up in the milling machine.

Barely kissed each side with a 60 degree cutter.

Was a very snug fit--almost needed to tap it on.   Probably still fits the TF-79.

Project dos:
The other project was making a jam nut for the chopped down IZH 61 rifle.  Wanted to try a standard M-16A2 rifle flash hider, but when tightened down, the slots didn't center up.


























No pics of the process,  it was simply a matter of drilling a piece of steel, milling two wrench flats and threading it.  OK, actually did have to make the 1/2"-28 tap from a piece of tool steel...




















Jam nut screws on first, followed by the flash hider.  Align the flash hider then tighten it against the jam nut.  Done.

More soon.

An Extended Magazine Catch for the IZH 61

Still playing around with the short-barreled IZH 61 rifle.
















Unless you use some kind of riser adapter, adding either a scope or red dot severely limits access to the magazine release tab on top of the receiver.

There's about half an inch of clearance.  Probably fine if you're a six year old, but I can't seem to change magazines without some effort.

Off with the dot.

Small pin punch.  The pin comes out left to right.

Looks simple enough.  The bar pivots as the bolt is retracted and the 5-shot magazine advances until it's caught by the front bevel.  It's clever in its simplicity.

Lacking a better suited piece of raw material, I found a chunk of angle iron in the scrap box.

I should mention that this was an off-the-cuff project.

Two minutes (or less) with a hack saw.

Some eyeballing and more hacksaw and I'd rough cut the point.  The point at the bottom rides against the loading bolt.  As the loading bolt moves forward to load the pellet, the angled edge of the point lifts the magazine release.  The mag doesn't move sideways (yet) because the nose of the bolt is already going through the magazine as it loads the first pellet into the breech.  After firing, while the gun is being cocked a second time, the loading bolt retracts and when it clears the rear of the magazine, the magazine is pushed left under spring pressure. When the bolt is pulled far enough backward, it clears the point on the bottom of the catch. The catch pivots downward under spring pressure and catches the next index ridge on the top of the mag after it's moved left far enough to index the second shot.  It's a lot going on in a few fractions of a second.  

Used the mill to get the piece closer to size.  This was done entirely by eye against the stock part.  Here, I'm removing the radius on the inside corner of the angle iron leaving a ninety degree edge.

Had to thin the catch to fit the slot in the top of the receiver. 

 Cut the slot for the spring.

And eyeballed the forty-five degree angle on the front to catch the magazine index ridges.

Drilled the pivot pin hole.

And did some test fitting.  Filed it to length.  Also needed some additional clearance under the catch so it had more travel.

This was done by hand with a file.

Still in the rough.   Here it is compared to the original.

After getting it to function and actually cycle the magazine, I hand filed the lever portion.

Got to here, then sanded the top and sides of the lever to 400 grit.

Blued with Van's cold blue.

Installed.  Was going to serrate the top, but it seemed like...overkill(?)

Re-mounted the red dot.  Clears the sight.

And projects far enough on the right side.

Good clearance to the magazine housing.

An easy reach without breaking my grip on the gun. Many five-shot mags later without a single hiccup, it works perfectly.


 More soon.