BR99: non-standard rail?

[Odd Job]

I don't know. I can find out/measure it when next I am at the range...

[Odd Job]

According to their spec sheet there is 115 MOA total elevation adjustment (so let's say 57 MOA from center).

[ovenpaa]

So something closer to 3,0mm up at the back would work. You could always machine the top of the top rail off and then machine a taper on a spare section, screw and blend it and finish with a coat of black as a low cost option.

....or build a new one to suit.

[Odd Job]

I don't have the skills for that, would have to send the job out. But it looks like it needs the rear raised. The other thing I thought of was a small wedge between the sight and the flat top adapter. The sight would have to be modified with a new larger countersink and the screws would have to be changed for longer ones but it may be a simpler solution as the rails would then be left alone.

[Odd Job]

I checked the Yankee Hill Machine Riser on the BR99 vs my SIG52 and they are both square, no problems there.
Both of them are parallel to one another and the host rail of the firearm.



When I checked the two Burris Fast Fires, the one on the shotgun doesn't adjust as much in the UP direction as the one on the SIG522.
However I am not convinced that the difference in elevation on the two dots is enough to get me on target, and I am also reluctant to swap the sights because I will be operating at the upper limit of adjustment even if it works.

In the interim I have taken off the Burris and put on a well-used Mueller Quickshot. This sight has much more adjustment range but is lower quality and won't stand up to the recoil over time. It should get me through the next range session and in the meantime I think I will have to get a 30 MOA riser for the Burris.

I am not sure what the reason is why I can't get on target, but I don't think it is a fault of the YHM rail or the Burris.
It may be that the barrel is angled down with respect to the receiver rail. I've looked at the X-rays and can't see anything obvious, but X-rays may not tell the whole story...

[Blackstuff]

Out of curiousity, have you checked the screws that hold the sight onto the mount? I was talking to a friend who also has a FastfireIII and the screws that came with his to attach it to the mount were too long and protruded out of the bottom of the mount, which in turn interferred with the way it mounted on the picatinny rail.

[Odd Job]

Hello mate

I checked the Fast Fire IIIs in both types of mounts (one is a plain Picatinny clamp and the other is the AF3 Flat top adapter). They both sit perfectly flush with the mount, there are no gaps or screw protrusions.

[Blackstuff]

Worth a shot! Just checked mine and they were a shade too long but the rail i've got it on was spaced so they fit into another gap on it. I've ground them down now though so they're flush

[Odd Job]

The Mueller is a non-starter for this gun. After only 10 shots the whole front of it was loose.
My 30 MOA rail has arrived and as soon as I have sorted my light strikes, that new rail will be installed.