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

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MCMXI

MCMXI

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Has anyone done this? I've noticed that the Zeiss Conquest scope on my Talkeetna is sliding forward ever so slightly (after 100+ rounds). I have Talley rings (lapped) and torqued the screws to 18 in-lb but have thought about copying D'Arcy Echols' approach to this issue by cutting a cone in the rear of the rear scope ring to match the cone of the ocular bell housing. Once done, I'll gently slide the scope forward a fraction until the bell housing makes contact with the ring. The flat of the cone won't damage the scope and it'll prevent the scope from creeping forward any further.

kimber_talkeetna_02.jpg
 
Should not be necessary.

I have never had a scope slip in my life.

1. Either you lapped the rings to large?
(Are the mating surfaces of the rings coming in contact with each other when the screws are tight? If so you lapped them too big for the scope tube.)

2. Or, there was oil or wax left on the scope tube?
(Clean scope & rings with rubbing alcohol before mounting the rings.)

3. Or, 18 in/lb isn't tight enough to clamp the rings on the tube?

You might try cleaning the scope & rings of all oil, then putting some blue Lock-tight, or powdered rosin in the rings and do a do-over.

Then tighten the rings a little tighter.
Those a pretty narrow rings with not much surface area under them.
 
I have never had a scope slide in correctly lapped rings. Take RCs advice and you should be ok, if that does not work, invest in a new set of rings.
 
PS:

Tighten the ring screws top front, bottom rear, top rear, bottom front, a little at a time.
(Or any other out of sequence method you want to use.)

If you torque one screw then the next to full torque, the rings will not tighten square with the tube and will not provide 100% contact with the tube.

rc
 
I have never had a scope slip in my life.
Click to expand...

I don't think I've ever had a scope slip either. I've lapped many, many sets of rings and some one-piece mounts and this is the first time this has happened. I will add that this is my first .375 H&H hunting weight rifle (total weight of 9lb with scope). There's a reason that one of the best rifle builders today saw fit to machine a cone in the rear ring of his custom rings perfectly aligned and matched to every rifle. Regardless, I'll pull the scope off and check the rings this spring.
 
Don't mean to come across as insulting, but why on earth would a person voluntarily choose horizontally clamping rings? Especially the variety that tighten on the mount and tube simultaneously.

I've always gone with plain old Leupold rings, and never had a problem- not enen with a VX-II 4-12 on my lightweight .375 RUM
 
LaRue one-piece mounts are that way and they're among the best available and now copied by many. I have numerous horizontal and vertical types and don't have a problem with either style. Like I said, this is the first problem I've encountered and the scope has only moved a fraction after 100+ full power loads.
 
i'm not a fan of lapping at all, and it does seem like that ring design leaves something to be desired, but to answer your question, i've never thought of milling a cone in the rings. however, i often run my scope forward where the turret housing is touching the front ring. it's never caused a scope to break and definitely keeps them from moving, but then, i'm not shooting small calibers from heavy guns
 
I only thought of it because D'Arcy's $15,000 rifles often have that feature since they commonly go to Africa on expensive hunts.
 
That is a strange situation. Don't get me wrong, I have left 1 set of rings finger tight when I was being rushed while mounting/bore sighting in f.a.c. weather. It was an easy fix, aside from the scuffed scope. :banghead:
 
While that is heavy for a Kimber, it is a lightweight 375. When you combine heavy scopes with lightweight, heavy recoiling rifles you have a recipe for slipping and scope damage. Your proposed fix might work. It might also put the scope under more stress as it hits the ring with every shot.

A lighter scope would be my recommendation.
 
"I only thought of it because D'Arcy's $15,000 rifles often have that feature since they commonly go to Africa on expensive hunts."


A lot of things are done on "best quality" firearms because it can be done (and charged for), rather than because it actually adds any improvement to performance. If 5000 builders do it one way over the years (because it works) and one other maker does it another way, well... just think about it.

TALIV has one answer, which is what I do. But correctly torqued rings, of the correct size, mounted on degreased scopes, hold under any recoil that we practically see. Theres's a lot simpler solution available to you, you simply need to find it. Ring dimensions, torque value, some oil on the rings or scope, etc., etc... solve that and live long and shoot well.

With that all said, "if it were me", I'd dump those rings for aersthetic reasons if nothing else. They ruin the lines of the rifle to my eye.

Nice rifle, BTW. It ought to drive tacks.


Willie

.
 
jmr40 said:
While that is heavy for a Kimber, it is a lightweight 375. When you combine heavy scopes with lightweight, heavy recoiling rifles you have a recipe for slipping and scope damage. Your proposed fix might work. It might also put the scope under more stress as it hits the ring with every shot.

A lighter scope would be my recommendation.
Click to expand...

Yes, you're absolutely right and I've thought about this. The rifle weighs around 7lb-12oz and the Conquest is about 15oz and probably 16oz with the Butler Creek caps. The scope works so well on that rifle and the RZ600 reticle is by far my favorite hunting reticle that I would hate to move it. I have a silver dot at 7.5X since on that magnification the stadia are accurate out to 650 yards with the Barnes handload I use. Changing to a lighter scope would most likely help but it's a last resort.


Willie Suttoni said:
I'd dump those rings for aersthetic reasons if nothing else. They ruin the lines of the rifle to my eye.
Click to expand...

Damn! I really like Talley stainless QD rings both for aesthetic and functional reasons. This particular set has throw levers on the port side since the rifle has iron sights.


Willie Sutton said:
Nice rifle, BTW. It ought to drive tacks.
Click to expand...

Yep. Here's a three-shot group at 100 yards last October using a Barnes 250gr handload from a cold, clean bore the day before a mule deer hunt. The RZ600 reticle requires a 200 yard zero and I made a small correction after shooting the group shown.

250gr_ttsx_3shot_grp.jpg

Since no one has cut a cone in the rear ring I'll have to venture into uncharted waters ... maybe.
 
taliv said:
i often run my scope forward where the turret housing is touching the front ring. it's never caused a scope to break and definitely keeps them from moving, but then, i'm not shooting small calibers from heavy guns
Click to expand...

You can see from the photo that moving the scope forward isn't an option but the concept is the same. After talking with someone who is very familiar with D'Arcy Echols rifles and who knows a great deal about shooting heavy recoiling rifles in Africa it seems that the rear cone is a popular option to prevent scope slip. Many in Africa prefer heavy S&B, Swarovski and similar optics so scope slip isn't uncommon. D'Arcy solved that problem for his discerning customers.
 
i meant to say "i AM shooting small calibers from heavy rifles"....


if i understand what you're proposing, it seems like it would screw up your eye relief. as an alternative, why not create a shim? i.e. take a piece of aluminum stock, drill and bevel it, then trim to length
 
The scope would only move forward about 3/16" which would be fine. Those Conquest scopes have 4" of eye relief (on 3x) so they need to go as far forward as possible.

When you refer to a shim do you mean a spacer between the rear ring and the ocular bell housing?
 
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I think I would try another set of rings, that seems to be the fastest and easiest way to determine where the issue lies.

I don't think it could hurt anything to contact Talley and get their opinion (and they might hook you up - you never know).

803.854.5700 or e-mail at [email protected]

Mark H.
 
Mark, thanks for the suggestion. I think the problem is the laws of physics. I have a fairly heavy scope on a fairly light rifle shooting a fairly powerful load with rings that have a minimal contact area with the tube. I have the same Talley rings on three other rifles without any issues but will check the lapping on this set.

It did occur to me that 30mm, 34mm or 35mm tubes offer more contact area between the tube and rings if the rings are the same width. A 30mm tube would have 18% more contact area than the 1" tube shown above with rings of the same width. I do have a set of 30mm Talley QD stainless rings and two nice Mark 4 3.5-10x scopes that I could use, but like I said, I really like the simple and quick RZ600 reticle and don't want bulky turrets and parallax adjustments on a hunting rifle.

Thanks for all the feedback.
 
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Only scope I have ever had that moved was with a spring air rifle, bought their mount and it stopped.
 
When you refer to a shim do you mean a spacer between the rear ring and the ocular bell housing?
Click to expand...
that is what I thought he meant?

But there is no possible way to put it on the scope without losing the inert gas and water
Roof seals.

Question I have is, what part turned to change the power setting?

If the tapered part of the power ring turns, you sure don't want it tapered seated into the rear scope ring.

rc
 
Rubber cement, naw that's too silly. It could never work. I still don't know if the rings are bottomed out or did I miss something. If the rings are lapped super smooth they are more likely to allow the tube to slip. Surface texture has alot to do with friction sometimes more than contact force.
 
rc, a spacer would have to be some clever two-piece deal. As for the power ring, it's separate from the ocular cone so that wouldn't be an issue.
 
the spacer i was talking about would be a two piece deal. dunno how clever it needs to be. basically, it would be another ring. no disassembly required
 
Use a Spacer

Howdy. If you are considering cutting a taper in the rear of the rings to match the scope, I am assuming that you have access to machines and have some talent. However, an easier solution would be to measure the gap between the front ring and the turrets. Make a split spacer ring that fits there that looks just like your scope rings. I had one on a Desert Eagle and the scope didn't move on it. I own a machine shop and make special stuff like this all of the time. This would be no problem. Best of luck. DennyMac.
 
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