Monday, October 22, 2012

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.