Tweaking the IZH513M Rear Sight, Part 2

On I go...

You can see there's a bit of a deformity in the elevation bracket, as well as ample play.

It wiggles side to side with a huge gap.

This shows how the left side is not parallel to the right. I tweaked it by bending it gently.

The pivot holes have a nasty burr...that got filed off.

I made some thin delrin washers to try and eliminate any play.

Drilling...

Parting off each washer...

The washers in place.

Then I found that I needed another washer between the knurled head of the but and the outside of the bracket.

In place. This thickness was hard to get right, as the screw has to securely lock the sight to the dovetail and allow the elevation bracket to move.

Just right, the spring can push the sight up but there's a small amount of drag.

Reassembled, you can see there's a lot less twist. And I'll probably end up putting a scope on it after all of that!

Tweaking the IZH513M Rear Sight, Part 1

I know, I'm a bit sight obsessed...

The sight on the 513M was a bit twisted off perpendicular.

The sight is fairly simple.

It mounts on a dovetail milled into the breech.

The main reason it's twisted is the elevation screw bears on one side of the sight and there is enough play in the pivot that it twists upwards on the other side...

The elevation screw underside.

One screw is both the pivot and the mounting screw for the sight base.

Screw, knurled nut, spring and elevation screw. Notice the dimple that locates the spring.

The base slides off.

The leaf sight is mounted as a unit to the elevation bracket. Notice the little dimples and the screw that bears against them? You can adjust side to side for gross windage, and there are two rows so you can alter the presentation of the leaf sight...

Angled back...notice the burr on the end of that screw...

Or perpendicular...

The sight unit.

Fairly simple again, just a screw, stamped sight and spring in a tube.

Machined from solid round stock...
More to come...

Reassembling an IZH Baikal 513M, Part 2

Almost there!

The holes in the tube and the bushing are lined up.

And the pins inserted.

You can see the plastic bushing has been pushed out of the spring guide, having done its job.

The trigger has a spring loaded plunger that needs to get shoehorned back into place.

A 1/4" leaf gage works admirably for this.

Then I held it in position with a rubber band.

Aligned with the mounting screw holes.

The blocking lever is put back into place.

The pivot screw is put back in. You'll notice that I accidentally put it in backwards. It doesn't matter.

The end of the pivot screw.

With circular nut and lock washers in place.

The blocking lever was hooked back onto the cocking arm.

Getting that spring back into place was hard! But it all sort of slips into position.

The polymer bushing reinserted into the stock.

And where we started, with the front stock screw back in place.

Preliminary testing shows a slight reduction in velocity with the rifle shooting CP 14.9 gr. pellets at around 770-780 fps. We'll see how that changes after I put a hundred or so through it. As I told Derrick in an email,the rifle has a lot less "grumpy" in it now. It still recoils but isn't nearly as harsh and there's a lot less mechanical noise.

Reassembling an IZH Baikal 513M, Part 1

I cleaned the oil from all the parts and commenced reassembly.

The end of the spring was very rough. That's a sharp square end on the spring and the surface was far from polished. You can see tiny bits of paper towel caught on the burrs!

Some time on a unitized wheel smoothed everything out, at both ends.

Ah yes, the sear...I put the balls in their holes, slid that plastic bushing over and inserted the piston sear.

The bushing captures everything in preparation for insertion...

I put a very thin coat of lube on the washer and rear bushing.

All is ready and has a very thin coat of Maccari clear lube. I put a thin smear of moly on the piston head skirt.

I used the Maccari black spring tar sparingly on the spring.

On it's way to completion.

Mounted in the spring compressor and ready for final assembly.

There's only one way the trigger assembly can mount to the rear bushing but the bushing can be mounted in the tube upside down if you don't pay attention...more to come.