I have been consodering those to use on my set up. You have been pleased with them?
Yes. Before I put thermal scopes on my AirForce air rifles, I used the dovetailed version. They get the scope up high because AirForce is notorious for having the bottle too high and you have to be a contortionist to get a decent cheek-weld.
It's hard to describe in writing but the bases are clamped on with the allen screws. I torque them to about 45 inch-lbs. Those are the very bottom screws on the base as everyone knows. Sorry, I'm not trying to insult anyone's intelligence but like I said; it's difficult to describe in writing.
Look at the allen screws that the arrows are pointing to in the photo below. Those are the screws that, when tight, keep the rings from moving up and down. When loose, they allow you to adjust the elevation of the entire scope, instead of the reticle.
When you attach the base to the rifle, keep those screws loose enough to permit the mounting of the scope.
After you have tightened the base (bottom) screws, put the scope in the rings. Note this is my method and others may choose to do it differently. When placing the scope in the rings get a good idea of how far forward you want it mounted for proper eye relief but keep all of the screws loose to permit movement and prevent any binding on the scope tube.
At this point the only screws that should be tight are the base screws.
Before leveling the scope and tightening the ring halves. you will need to tighten the screws that the red arrows are pointing to. Don't worry about an elevation point for now. You will do that at the range. Make sure that they are bottomed out in the assembly. Then torque those screws to about 35 inch pounds.
Now you level the scope and tighten the ring halves down to the specs the scope manufacturer recommends. I use 15 inch pounds.
Now take the rifle to the range. When zeroing I put up a large section of butcher paper on the back stop to see where the projectiles are going. A 2' X 3' section should do.
For me, I adjust the elevation knob so I have 2-3 mils to play with from the bottom. So adjust the elevation so it bottoms out, then bring it back up about 2-3 mils.
Now fire a round or two and see where it is hitting. It should be extremely low. If it's so far off paper, just loosen both those screws indicated by the red arrows. You will feel a lot of vertical movement. It will feel so sloppy that you might think you have junk on your rifle. That's okay.
I take a couple of credit cards and place them, like a feeler gauge, in the gap indicated by the red oval in the photo. Don't worry about the front gap. Remember that you are only trying to raise the point of impact to get a close zero. The back ring assembly is the only one getting raised but remember to loosen front screw also to prevent any binding force on the scope tube.
Leave the credit cards in the gap and push the ring down so it just kisses the credit card feeler gauge. Make sure that the front ring assembly is bottomed out. With the cards in place, alternate tightening the screws and torque to 35 inch pounds.
Shoot a another round or two. If you didn't see any bullet holes with the first rounds, you should see something now. If it's still too low, you might have to use three credit cards as your feeler gauge.
You can also use a real feeler gauge but I mentioned the credit cards as they have always seemed to work for me. IIRC, I don't think I used no more than three credit cards and it got everything close for me to fine tune my zero. I think I may have come up a couple more mils with the elevation know to get the proper POI for elevation purposes.
In the end my elevation knob was around 5 mils from the bottom. That left me a lot of elevation adjustment for holdover at long distances.
If none of that made sense, PM me for a phone number and I'll be glad to talk you through it.
Here's a photo of my AirForce Talon SS, using the FX rings, before I put a Talon Tunes moderator on it and added the Thermal scope. I read a lot of complaints on the forums about the extra effort people go through the add picatinny mounts to the receiver of the AirForce airguns to get the proper height but nobody seems to take my recommendations for the No-Limit rings seriously.