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Pete Wass
08-05-2009, 05:36 PM
I had the good fortune today of witnessing the culmination of two years of gun trouble a friend has been having. He has been chasing flyers for two years with the rifle in question, sent two scopes back for repair, gone through every powder and bullet known to our community and still eratic performance.

We huddled today and decided that it had to be his scope. Since his Benchmate was using the same brand scope rings and had a rifle that was drilling little ones, they decided to switch scopes and try that.

The Bug Hole rifleman began shooting the "Bad Scope" and after getting on paper, shot a group of three at which point the scope came flying off the rifle. he had leaned on the allen wrench when he installed the scope to his rifle.

The "Flyer" rifle proceeded to shoot an acceptable group when using the scope off the "bug Hole" rifle with the scope and mounts remaining on the rifle without a hint of movement. I guess there isn't any mystery at this point as to where the problem lies, is there?

Question for the day: What brand scope rings?

tenring
08-05-2009, 06:40 PM
Probably those durn Redburleu rings

alinwa
08-05-2009, 08:10 PM
This could illustrate why it's best to bed both the BASES and the RINGS as Harold Vaughn's (Ohhh NOOO not HIM again!) research showed.

Harold showed by tapping with a mallet how typical base setups are weak against lateral forces. Picture a 10lb 30 cal and high rings and now start twisting and turning with sharp impulses....... :eek:

I bed my bases, then grease the screws and glue the bases down.

then align the scope using Kokopelli alignment bars (The ONLY ones that work!) and lapping/tweaking/bedding as necessary.

Many deficient scopes can be fixed this way. :D

al

Big Al
08-05-2009, 09:15 PM
This could illustrate why it's best to bed both the BASES and the RINGS as Harold Vaughn's (Ohhh NOOO not HIM again!) research showed.

Harold showed by tapping with a mallet how typical base setups are weak against lateral forces. Picture a 10lb 30 cal and high rings and now start twisting and turning with sharp impulses....... :eek:

I bed my bases, then grease the screws and glue the bases down.

then align the scope using Kokopelli alignment bars (The ONLY ones that work!) and lapping/tweaking/bedding as necessary.

Many deficient scopes can be fixed this way. :D

al


Listen to what al said. Just keep in mind that a scope is just about the weakest link on the rifle, when they go south they seem to do it all at once.

Pete Wass
08-05-2009, 10:56 PM
nothing is ever as simple as one may think. There is a definate flaw in the manufactur of the rings. Gopping them up will not cure the problem. Tack Welding them May !

I have several sets of these rings in various configurations. most of them work fine, even on HBR rifles but the particular set in question, along with an identical set I had on my spare scope were the same and would not go on the rail of the action made by the same maker. I have also experienced rings by the same maker that were too big to effectively clamp to the rail of the same maker. Pickatinny hardware would cure the whole danged thing ;).

hulk
08-06-2009, 04:54 AM
Pete,

Try a set of rings from John Morrison. Gorgeous quality and very solid. Obviously, not for those times when every ounce counts.

Greg Culpepper
08-06-2009, 05:32 AM
Pete,

I've got one set of rings that allowed a Nightforce to slide forward on a Davison rail under recoil (6-250 imp.). The problem showed itself only after I removed and replaced the scope and rings as a unit. No amount of tightening the ring to base clamping screws would solve the problem until I loosened the scope clamping screws and then torqued the base clamping screws first before re-tightening the scope clamping screws.

This particular ring design (the scope clamping screws are reversed and point up, passing through the bottom half of the ring and thread into the ring top) invites the installer to align the rings on the scope tube and tighten with the scope off the rifle and upside-down to allow easier tool access. But this will spread (spring open) the the base clamping dovetail socket and reduce the amount of grip available on the rail.

Just tightening the base clamping screws first before the scope clamping ring screws solved the problem with these rings for me. Seems to me that it might be a good policy for all rings that clamp to Davison style rails to tighten first to the rail and then to the scope to prevent these opositional effects from leading to potential slippage.

Greg

Al Nyhus
08-06-2009, 07:02 AM
With this type of mounting setup, overtightening everything you can get a wrench on just makes the situation worse.

On the BR style dovetail mounting systems (Davidson type base/rail), I roughen up the ring/rail interfaces (incl. the top of the rail and the bottom of the rings) with a bit of 320 grit paper...just a couple of light swipes. If the fit is loose, I've lightly dimpled rings with a small punch. Then clean both surfaces with acetone, slide the rings on with some JB Weld on all mating surfaces and tighten lightly with a bit of oil on the threads. If the action has seperate bases and no integral rail, I bed the bases to the action and use light oil on the screws.

Once the rings are mounted to the rail, I lap and bed the ring bottoms and tops with a polished 1.00" steel bar mounted like a scope. If you check the the tube diameters of most 1" scopes, you'll find they run from .998 to 1.002. Bedding with Brownells AcraGlass Gel works well as it has enough Nylon in it to offer a bit of flexibility. When it's cured, relieve the parting edges with a small file at a 45 degree angle. Mount the scope and secure the ring tops lightly with some oil on the threads.

For actions with an integral rail, you can get a mount that clamps over the existing rail and uses the Weaver-type ring setup.

We're stressing these systems pretty hard, especially with a 10 lb. .30 cal. Hunter rifle or a 10.5 30BR with single width rings. When at all possible, I try to use the double screw rings for additional surface area. On my Hunter barrels, I'll sacrifice a bit of weight to allow the extra 1.5 oz. of these doubles.

For what it's worth.....

jackie schmidt
08-06-2009, 08:12 AM
I feel safe in saying that the most popular scope mounting system in 100-200 yard Benchrest is the 1/2 inch dovetail with a matching set of lightweight rings.

There in is the problem. These rings are designed to sit atop a point blank Benchrest Rifle, chambered in a round that produces a minimum amount of recoil, even in a 10.5 pound Rifle.

A 10 pound HBR Rifle chambered in a legal HBR case can produce enough recoil to compromise this system. Place it atop any Rifle with more than that, and it is an open invitation to problems.

Many of the items we use in 100-200 yard Benchrest are designed for a specific apllication, that being to get the job done without adding undue weight to the Rifle.

I have a Sporter-LV weight 30 BR that I use double Kebly Rings on. The dovetail is a one piece 1/2 inch that I made to mount atop the Stiller Diamond Back Action. I added two extra screws to the mount, as the four 6-32 screws looked a little puny. I have never had a problem.

But that does not have near the recoil as a legal HBR Rifle. I would think that when using the typical 1/2 inch dovetail mounts in that, or a more powerful application, double screw rings would be the minimum.........jackie

glp
08-06-2009, 08:49 AM
I feel safe in saying that the most popular scope mounting system in 100-200 yard Benchrest is the 1/2 inch dovetail with a matching set of lightweight rings.

There in is the problem. These rings are designed to sit atop a point blank Benchrest Rifle, chambered in a round that produces a minimum amount of recoil, even in a 10.5 pound Rifle.

A 10 pound HBR Rifle chambered in a legal HBR case can produce enough recoil to compromise this system. Place it atop any Rifle with more than that, and it is an open invitation to problems.

Many of the items we use in 100-200 yard Benchrest are designed for a specific apllication, that being to get the job done without adding undue weight to the Rifle.

I have a Sporter-LV weight 30 BR that I use double Kebly Rings on. The dovetail is a one piece 1/2 inch that I made to mount atop the Stiller Diamond Back Action. I added two extra screws to the mount, as the four 6-32 screws looked a little puny. I have never had a problem.

But that does not have near the recoil as a legal HBR Rifle. I would think that when using the typical 1/2 inch dovetail mounts in that, or a more powerful application, double screw rings would be the minimum.........jackie

you comments address the issue of scope sliding in rings...double screw vs. single, etc. What are your thoughts on what I hear others saying...that is, that some individual units of this style ring may be out of mfg. spec and don't really clamp and hold well to the dovetail? Your thoughts, see Al's post above, regarding mounting the rings to the dovetail i.e. anything more than just tightening the base screws? Tks

Al Nyhus
08-06-2009, 08:49 AM
An extra bit of insurance can be a recoil lug ahead of one or both of the rings. On my Sporter 30BR, I couldn't use the double rings because of weight...so I used a steel dowel pin ahead of the rear ring. You could also drill and tap for an 8-32 or do the dowel pin in an action with an integral rail. If you look closely at this picture of my lash up, you can see the bedding compound under the base and between the ring and base.
http://img.photobucket.com/albums/v467/tenxal/pin1.jpg

alinwa
08-06-2009, 11:16 AM
I personally think that the one most missed by the inspectors is the BASE to ACTION fit...... those couple little 6-48's connecting the two masses which are trying hard to fly apart.

IMO this is the most important interface to fix.

al

Pete Wass
08-06-2009, 11:37 AM
are a set of double screw 1" rings which had to be "Driven" on the the rail of a Teddy which is a HV 6 PPC. The rings, I suspect, don't hold because they have to be "Driven On". There is no oportunity for the dovetails to clamp much. And that is the rest of the story, as Paul Harvey use to say. The rings clearly are out of spec. I thought it interesting that I have a set that are exactly the same and have had others in the past that were like these two sets.

I personally think Stiller's rings, for dovetail rings are as good as it gets design wise. I have had several (4) pair of them on rifles made on his actions and Even on HBR Boomers they do not move, ever. They also don't have to be "Driven On"AND he used Torks screws :); something to be learnred there.

I once had a BAT HBR rifle that came with a set of Marvin Pearson's rings on it. Now, there is a work of art, the rings he makes. Greg is the proud owner of that rifle now, dang it !

Al Nyhus
08-07-2009, 07:03 AM
are a set of double screw 1" rings which had to be "Driven" on the the rail of a Teddy which is a HV 6 PPC. The rings, I suspect, don't hold because they have to be "Driven On". There is no oportunity for the dovetails to clamp much. And that is the rest of the story, as Paul Harvey use to say. The rings clearly are out of spec. I thought it interesting that I have a set that are exactly the same and have had others in the past that were like these two sets.

Pete, TRS (Tight Ring Syndrome :D) can happen also because of interference between the top of the rail and the cooresponding surface on the ring. If this is an interference fit, the sides of the rings will resist tightening as nicely as they should. You can check this by putting the rings on and inserting a feeler guage in the vertical cut of the rings above the dovetail. When you tighten the rings to the rail, the gap will close....which you can confirm with your feeler guage.

I give my rings a bit of clearance on all the mating surfaces (sides and top) to allow some room for the JB Weld. If the fit is too tight, you push the JB off when you slide the rings on and defeat the purpose of using JB or whatever epoxy you're using. Loctite's Stud and Bearing Mount (red) works on tighter rings pretty well as it's a thinner consistency.

I've seen people have troubles with almost every setup out there, the one piece base/rings included. And I shoot with people that give z-e-r-o consideration to any of this. They just tighten things up, forget about it and go shooting. ;) Nothing wrong with that approach, either if it works for 'ya.

Now to the Bat Cave to point up five hundred 118's before my day job.....