Cutting a cone into the rear of a rear scope ring.

[MCMXI]

dennymac, thanks. Yes, I have access to some talented machinists.

rcmodel in his first post made the comment that maybe I "lapped the rings to large". I've mounted many, many scopes over the last 20 years and have lapped numerous sets of rings (25+) with good success. This is the first time that I've had this issue. I took some photos this morning before I left for work and figured that I'd post them here to show that the rings aren't excessively lapped. You can see in the second photo that the ocular bell is very close to the ring. Eventually it'll make contact which will stop the forward motion but cut into the tube. As mentioned, I'd rather have a conical relief in the back of the rear ring to match the ocular bell so that there's no damage to the tube. I'm a fan of Talley rings and bases and have no intention of looking for any other brand for my hunting rifles. I will check the lapping first though and perhaps more lapping will be all that's needed.

 

[OYE]

As mentioned, I'd rather have a conical relief in the back of the rear ring to match the ocular bell so that there's no damage to the tube.

Yes, but it's still not tight is it. And what keeps the scope from rotating a bit now and then, well nothing because it still isn't tight. Think RC mentioned a little powdered rosin on the inside of the rings. It used to be standard practice on heavy caliber rifles and many of us still use it on all mounts. The grit adds tremendous gripping power provided the rings are tightened sufficiently.
OYE

PS: By the way do you have any heavy duty dents in the front of the magazine well ?

 

[tbotts]

rubber cement will work. It is easy to remove if you change scopes.

 

[rcmodel]

Maybe just the camera angle playing tricks in the last two top view photos.

But, my Calibrated Eyeball is seeing a wider gap at the front of the ring gap then at the rear.

So:
1. It is the camera playing tricks?
2. My Calibrated Eyeball is off?
3. You lapped the rings crooked into a cone shape?
4. The screws are not torqued equally to close the rings in full contact around the scope tube.

That's all I got from the photo's.

PS: I truly beleive if you hadn't of lapped the rings, and torqued the screws for an equal front & rear gap at the split?

Your scope wouldn't be slipping.

rc

 

[MCMXI]

I finally got two rear rings machined with a 30 degree chamfer to match the ocular bell on the Zeiss scopes that I have. A coworker did two rear rings since I'm planning on a. 458 Lott at some point. He tightened the rings around a 1"bar to maintain the proper geometry while machining.

 

[kwg020]

18 in. of torque on the ring screws isn't much. What size are the screws and check for torque values on the screw size. Without seeing the screw size it's my thought any good quality screws should go 25 in lbs without stretching or destroying the threads of the rings.
kwg

 

[Walkalong]

I am a bit late to the party, but along the line of physics, which you are challenging with that setup, my first suggestion would have been rings with more surface area.

 

[2dswamp]

Small piece of rubber inner tubing wrapped around the scope tube before attaching the rings.

 

[MCMXI]

Thanks for all the good suggestions. I'm going to stay with my current plan of a cone (inside chamfer) on the rear ring since it's elegant and functional. I don't post any fake test results, falsified targets, made up stories or intentionally misleading information. I make mistakes and try to learn from them. In that light, I have a confession to make. When I got the rings back from the machinist I was really pleased with the quality of the work. However, I asked him twice about the angle because it didn't look right to me. I was expecting less of a bearing surface given that the ring thickness isn't substantial. The machinist reassured me that the chamfer was 30° from horizontal but sent me a text a day later with the realization that the included angle was 30° rather than 60°. He's very busy so had another machinist do the work and one of them messed up. Anyway, I'll be giving him two more rings to machine this week.

 

[MCMXI]

UPDATE 2:

I now have rear rings for two scopes that have been cut with a 60° included angle to give a chamfered surface to engage the ocular bell on my Zeiss scopes. This is how I imagined they would look. I will post another update once I have both rifles/scopes dipped and scopes mounted.

 

[Walkalong]

Looks nice, and you don't lose as much surface area.