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Barrett Adjustable Rings |
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Graysteel
Optics Apprentice Joined: October/02/2007 Location: United States Status: Offline Points: 200 |
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Posted: October/16/2007 at 10:48 |
I have a set of Barrett adjustable rings that I am thinking about testing out in a couple of weeks. Has anyone had any experience with them? I know they are made by Barrett and are heavy as can be, but I still am not 100% sure about the whole friction fit adjustments. Does anyone have any idea what the coefficient of friction is on parkerized metal surfaces? I figure I could calculate the shear force needed to knock the rings out of adjustment by figuring out how much the pressure the two crossbolts apply to the lower part of the bases. Hmm... or... I can just beat it with a rubber mallet to see if it moves and decide if I am happy with the strength.... Why do I think I am going to end up beating with it the hammer. |
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Graysteel
Optics Apprentice Joined: October/02/2007 Location: United States Status: Offline Points: 200 |
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Ok... No responses... guess it is time to break out that hammer...
On a side note I did call the folks over at Loctite about my habit wiping a thin layer of their product onto shear surfaces such as in-between scope rings / scope body, or friction binding adjustments like the Barrett rings. I was told that the Loctite will form a chemical bond (glue) and provide additional resistance to shearing movement. The other interesting thing they told me is that once the chemical bond is broken and the surfaces start to slide the loctite forms a mechanical interference, sort of like putting grit on the surfaces to increase friction. As such it should not inadvertently act as a lubricant between parkerized/anodized surfaces. The engineer I spoke too seemed to think it was a 'reasonable' thing to do, but lacked any specific advice. I figured that since I was offering as advice not just doing it to my own scopes I ought to do a bit more research. Edited by Graysteel |
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Graysteel
Optics Apprentice Joined: October/02/2007 Location: United States Status: Offline Points: 200 |
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I feel a little odd being the only person adding to this thread, but perhaps the information will be useful to someone at some point in time. Ok, last night I went down to the shop to test out the rings… The test: I made up a non-marring mounting rail out of two layers of ¼ inch thick hardboard and attached the base of the ring to the rail. From there I tightened the adjustments to about 75% of the recommended torque and measured the adjustment gap with calipers. I then cut a bit of thick leather to line the bottom of the ring and placed a section of schedule 40 pipe into the lower half of the ring. I then proceeded to tap (10 taps) on the pipe with a standard claw hammer. The results: The rings held fairly well, but not great. At the point I was tapping the pipe with the force that would approximate driving a 1.5" finishing nail into pine in 8-10 taps the rings began to shift. (about 20 thousandths). The rings were not marked at all, the friction fit simply slipped slightly. The test was repeated a couple of times. To be fair I suspect with that much impact you would likely damage most scopes before the rings themselves shifted and there was a thin film of oil (from the factory) on the shear surfaces. My conclusion: The rings are workable, but I would be careful to disassemble them and remove any oil from the shear surfaces when you get them. Next, I would make sure you tighten the binding bolts to their full specs and use a locking compound to make sure they don't loosen. And lastly, I would definitely put a drop of Loctite on the shear surfaces before tightening them down just to be safe. Oh.. and don’t beat your scope with a hammer. Hope that is useful to someone. Edited by Graysteel |
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cheaptrick
MODERATOR Joined: September/27/2004 Location: South Carolina Status: Offline Points: 20844 |
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Thanks for the write up!! I'm sure someone browsing this forum will appreciate that info. These write ups like yours are very useful to the forum members and guests.
Nicely done, Sir!!
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Chris Farris
TEAM SWFA - Admin swfa.com Joined: October/01/2003 Location: Texas Status: Offline Points: 8024 |
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We tested a pair on one of our Barretts with no issues. We are selling them now on eBay with NO RESERVE.
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mike4764
Optics GrassHopper Joined: November/16/2008 Location: Albany NY Status: Offline Points: 49 |
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I use them with no problems too.
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rifle looney
Optics Master Joined: November/21/2008 Status: Offline Points: 2553 |
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GREAT! now we know ,I will try this on my next install albeit on a smaller scale. firearm that is.
p.s--- because nobody answered we got a lot of info,thanx. |
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