PDA

View Full Version : Burris Fastfire 3 - I ran out of elevantion adjustment!



DethMyst
03-18-2017, 10:46 AM
Gun: Sig P226 Elite
Mount: Cadex (goes into rear sight dovetail)
Red dot: Burris Fastfire 3

Testing it at 30ft, using standard 50ft pistol slow fire targets, aiming the dot at bullseye puts rounds at very bottom of the paper. Aiming at the top of the paper puts bullets in bullseye area.

I've already maxed out the UP screw but it's still shooting about 6" low.

Should I try a new mount? (they're not cheap!) Does anyone know of a shim that is available in Canada?

Rory McCanuck
03-18-2017, 12:06 PM
There must be something wrong in the mount setup, somewhere.

Is this it?

http://www.cadexdefence.com/wp-content/uploads/2014/03/red-dot-mount-sig-p226-cadex-spec-1.jpg

If so, there doesn't seem to be much that jumps out as easily adjustable.
Maybe a burr in the dovetail?

As an experiment, what happens if you reverse the piece that goes into the dovetail, does it suddenly aim 6" high?

DethMyst
03-18-2017, 12:14 PM
There must be something wrong in the mount setup, somewhere.

Is this it?

(snip)

Yep - that's it! Mine doesn't have the big CADEX lettering on the side, but apart from that, that's my mount.


If so, there doesn't seem to be much that jumps out as easily adjustable. Maybe a burr in the dovetail?

Nah - it was smooth. That 'key' (silver) piece slide into the dovetail with lots of room, and didn't fasten in to the dovetail until the 2 screws were put in.

As an experiment, what happens if you reverse the piece that goes into the dovetail, does it suddenly aim 6" high?

It doesn't reverse. There's slots on the bottom of the piece that fit in to the dovetail, nothing on top. And if I turned it around of course, the red dot would be facing the wrong direction :)

I found 2 small washers to lift the rear-end of the red dot up a tad (and thus, pushing the red dot DOWN on the target more). It's a real hillbilly way of a fix, but just might work.

I can order a Fastfire 3 shim from the US, but the shim is $10US, and shipping is frickin $35US. I'd rather get a piece of thin aluminum flatbar and just make my own on a belt sander.

Here's the hillbilly fix so far (haven't tested it out yet) :

http://thumbnails117.imagebam.com/53893/f6ba07538926458.jpg (http://www.imagebam.com/image/f6ba07538926458)

Rory McCanuck
03-18-2017, 12:57 PM
Ah, so the screws push in the bottom and forse it tight into the dovetail, gotcha.
That means that you can't hide the screw heads.

Coke can aluminum is about 0.004", and easily cut with scissors, if that helps.
It'll fold nice and flat, too.

Rory McCanuck
03-18-2017, 01:02 PM
Hmm, unles you cut a thin strip of aluminum, and put it on the front slope of the dovetail.
Then, when you tighten it up, it would push the front of the mount down a good bit.
Even 0.004" might be enough to get you back on target.
As a plus, it would be hidden, and the red dot would still mount flat to the mount.

DethMyst
04-19-2017, 07:27 PM
I got a 1.5 degree shim. Works perfect. I had the elevation on the red dot maxed out (high) and actually had to lower it down a bunch of clicks. Good stuff.

lone-wolf
04-19-2017, 08:09 PM
Thanks for the update, good to see a happy result.

Strewth
04-20-2017, 12:35 PM
Great to see the update, thanks!
I've always kinda wondered about this (RDS elevation on pistols), the dot is a fair bit higher than the iron sights.