My project of the week… Drooped scope riser
Waiting for my TRS-1 to show up so I figured I’d get rid of my Tri-Rail and made a new scope riser. Add’s 3/4″ height, fit’s Condor rail length, clamps evenly from both sides to maintain windage alignment and provides 30 MOA droop compensation. I plan on painting it black and getting some BKL mounts when they become available again.
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What you can do is this. Place a target a 35 yard shoot a 3 shot group.
Loosen the barrel and rotate it 30 degrees(you won’t be able to use the holes for the set screws, but as long as you not shooting 100ft.llbs+ gun you should be fine for those few shots. And shoot another 3 shot group. Repeat this until your covered all 360 degrees.
Now you should be left with a circular pattern on your target. Pick the top or bottem group and turn your barrel the way as it was pointing when you shot the group. and shoot a group once more. If it wasn’t the completely high or low group you can take some smaller degree intervals to finetune.
Once you’ve got it troud up to your scope you can mark where your new holes should be for the setscrews and drill new once.
This way you should be left with a nice setup for all distances.
Cheers,
Marc
Good old fashion horse sense! This one should be a sticky!
May be you want to point it out to WOK or Tron.
Mike
Very nice work Metal Head! I think 30 MOA was a good choice. I’ve got a set of Barrett (yes the guys that make the .50) 40 MOA droop rings on one of my guns and even at low power (about 100 fpe) I can barely dial the scope down on target at 43 yards. At high power, I’m still below the center of adjustment at 175 yards. I might move the back ring one slot (Weaver mount) to reduce the droop just a bit.
Very nice job, Metal Head 😉
And it will be better if the two ends were cut in angle. Not only one.
Thank you 😉
Same here, i’d pay the price of the trirail plus 25-30%!!!!
I like that idea a lot!!! 😯
I would not need rails on the sides…
Probably your bore isn’t lined up with the bushings(scoperail)
What you can do is this. Place a target a 35 yard shoot a 3 shot group.
Loosen the barrel and rotate it 30 degrees(you won’t be able to use the holes for the set screws, but as long as you not shooting 100ft.llbs+ gun you should be fine for those few shots. And shoot another 3 shot group. Repeat this until your covered all 360 degrees.
Now you should be left with a circular pattern on your target. Pick the top or bottem group and turn your barrel the way as it was pointing when you shot the group. and shoot a group once more. If it wasn’t the completely high or low group you can take some smaller degree intervals to finetune.
Once you’ve got it troud up to your scope you can mark where your new holes should be for the setscrews and drill new once.
This way you should be left with a nice setup for all distances.
Cheers,
Marc
MH, the bushings are aluminum bushings from TT. They were undersized so I painted them. They are pretty snug fit to the barrel OD. I have not tried the test without the trirail yet. That will be my next step.
To get this to work as a “Tri-Rail” I’d have to use more & smaller screws to get the same pinch I do with the screws that are in there now. With the ones I have now the screw heads would interfere with any dovetails cut on the side. I only needed a riser so not having the side mounts wasn’t a concern for me.
Windage “shouldn’t” change at differing distances as long as Airforce made the scope rail on the frame straight; at least once I get a better set of rings. I machined nice fitting barrel bushings a while back and I checked my vise for square in the mill before machining this riser. It was within .0005″ over 6″ so I left it alone figuring for a pellet gun this would be plenty good enough as it equates to .3″ @ 100 yards. I want to get the BKL rings since they clamp evenly. Since most rings are made to fit anywhere between 3/8″ and 11mm the side clamp rings can kick you off to the side some.
ATP, are you using the factory barrel bushings, or a set that has been turned true to the bore? Also did you try removing the tri-rail to see how it was effecting your shots?
I just figured droop for my setup.
At 10 yards, using an optically centered scope, I want it to be hitting 1.8″ low of POA. That should set up for a good 60 yard zero which will be optimal for my setup given a 2″ KZ. POI is 3.0″ low and 3.35″ right of that mark that is 1.8″ below POA. Distance between mount centers is 5.0″
This equates to 0.0417″ of shim under the rear mount, or 28.6479 MOA. Your assessment of 30 MOA will work out great.
Now, about that windage correction… it seems like a long ways off and I don’t want to have the mount machined for windage also in case I decide to swap it down the road. I’m using BKL 263s on a trirail. The barrel bushings have been evenly spray painted and are snug in the frame. Nothing ever works out just right with me and optics. 🙄
Nice rail…Just like the BKL split mounts..Cool….I’d like to see the
targets at long and close range to see if there is any POI change on
the windage at different distances….Just interested…Not questioning…
Ditto here
I wouldn’t want any drop in mine, just a real tri rail with the clamping action you have milled in.
Thanks, I think lol. ❓
I dunno, these are a bit of a pain to make, lots of measuring and setup work to make sure everything stays at the angles you want. I wouldn’t want to make a production run of 30moa droopers as everyone would ask for 20 then if you know what I mean.
Wife just called and said the Millett showed up today so once I see how the 30 works out for me I’ll talk about making them on a custom basis but I’ll tell you they be at least 2-3 times the cost of a tri-rail.
For me to figure out what droop would be best for you I’d need to know what your optimum target zero range would be and how far off your POI is at that range when your scope is optically centered.
Thanks Marc, I double checked your math out of curiousity and I come up with 25 MOA on your mount, which is cool as I’m not that far off. I basically arrived at 30 for shooting at short backyard distances and it will also help out on the long end as you said.
Dwalk, Like Marc said your .308 is going to shoot like a straightedge compared to my pellet gun. I’d guess your bullets are dropping at 1000 yards about the same as our pellets at 100 lol. Plus with the Scope height on the Airforce guns I about max out my elevation when shooting at shorter distances in the backyard.
If it’s too much I can always make another!
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Thanks jkaleido & Jerry!
I’ve actually got a couple feet of Picatinny blank extrude waiting for me to re-do this project. I got tired of waiting on BKL to get their scope rings back in production so I’m going to make the Picatinny riser so I can use some real rings. I don’t like how dovetail sizes are all over the place and besides the BKL’s all other rings clamp from one side. At least with the Picatinny rings that clamp from one side, there are set standards for the rail dimensions so the rings can be made to fit accurately.
Once I finally get around to doing it, I’m sure BKL will be stocked up 😡