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Page AR-15 » Optics, Mounts, and Sights
AR Sponsor: bravocompany
Posted: 4/13/2014 9:05:58 AM EDT
First time post. My Trijicon AccuPoint 5-20x50 keeps slipping in my new PEPR mount. I've torqued it way down to no avail. When I remove it I can see the slippage rub points, both rings show twin scuff marks on the scope on the bottom rings. Not sure if previous rings distorted the scope tube or what. I cleaned all surfaces and bedded the scope bottom with Loctite Blue. Currently waiting for the 24 hr cure time. Previous installation was a tack driver but I needed better eye relief. So my question is this. Is lapping in my future or do you think the bedding will do the job? And can I expect the same accuracy from the PEPR one piece scope mount vs the two independent mounts that I had before?
Link Posted: 4/13/2014 9:16:22 AM EDT
[#1]
I'm confused as how you bedded with blue loctite. Also usually when hearing of bedding bases with a steel epoxy. Just don't understand so if you don't care to elaborate. Don't know the answer to your question but would like more info.
Got any other scopes or rings to try to figure out which is out of spec?
Link Posted: 4/13/2014 9:24:33 AM EDT
[#2]
Well I call it bedding but more specifically with scope off I cleaned all surfaces. Applied a small amount of Locktite Blue to both bottom rings. Spread it out with my fingers. Installed scope, added Locktite to the screws.  Waiting for 24 hour air cure before firing. I was reluctant to use friction tape, although I have a mini 30 that I converted to a 6.5 Grendel that has tape that came with the scope mounts and it's spot on.  And I didn't add so much Locktite that I had any oozing upon tightening.  The PEPR is a new install and I can clearly see that the scope is moving even though I'm tightened down tight and still have gaps in my scope rings. So I know the fit is correct.
Link Posted: 4/13/2014 1:09:09 PM EDT
[#3]
If its slipping it sounds like you need more torque on the screws.

Loctite is not meant to be used on the inside of rings, and may be contributing to your problems.  Clean all surfaces, apply loctite to screws only, and get an inch/lbs torque wrench.
Link Posted: 4/13/2014 1:38:02 PM EDT
[#4]
I didn't experience slipping with mine, but I did find that the tolerances were visibly off when I set my lapping bar in there...so I lapped mine(I recently replaced it with a Larue). You might have low surface contact. Sub 10% and you'll slip despite proper torque.

Also, don't use loctite. No glue is necessary, and even if it was, loctite is way too thin.

What in/lb are you torquing your screws to?

I use liquid electrical tape....but its not necessary. However, no way anything can ever slip with that stuff holding it in.....that said, liquid electrical tape will grant you visual evidence of slippage(it will tear) and let you know you have something wrong. Starbrite is the best brand I've found. Thin but dries up hard and comes off clean.

Most people use nothing, and its fine....that said, most people haven't mounted dozens of scopes in crappy 10 dollar rings that need lapping but don't get it. If you have a situation like that, gluing in the scope can help tremendously....in fact a lot of gunsmiths do glue their rings. That's where I found this trick out from with the liquid electrical tape. A local smith. I'd also point out that the spuhr mount has ridges to increase efficiency when gluing, as promoted on their website...and Spuhr is about as good as you can get, mountwise..So while its not common practice to glue in your scope, it is a thing. My savage came with a cheap Bushnell, and they glued it in with regular electrical tape....
Link Posted: 4/13/2014 1:45:33 PM EDT
[#5]
Too late. Will advise the outcome. LaRue is definitely on my radar.
Link Posted: 4/13/2014 1:56:15 PM EDT
[#6]
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Quoted:
Too late. Will advise the outcome. LaRue is definitely on my radar.
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Why did you mount a 1k scope in a 99 dollar mount anyway?
Link Posted: 4/13/2014 1:57:03 PM EDT
[#7]
Loctite should not be used inside the rings in anywhere else besides the threads

Buy a torque wrench and use it to proper specs

What caliber rifle ? Shouldn't matter - I'm just curious that's a pretty large scope
Link Posted: 4/13/2014 5:57:46 PM EDT
[#8]
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Quoted:


Why did you mount a 1k scope in a 99 dollar mount anyway?
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Quoted:
Too late. Will advise the outcome. LaRue is definitely on my radar.


Why did you mount a 1k scope in a 99 dollar mount anyway?


Why not? You think cost of the mount is causing his issue?
Link Posted: 4/14/2014 4:27:47 AM EDT
[#9]
Torqued to 20 lbs. 5.56 NATO rounds.
Link Posted: 4/14/2014 4:39:27 AM EDT
[#10]
I believe green loc-tite would have been the correct type.        
 
Link Posted: 4/14/2014 5:07:40 AM EDT
[#11]
Green sleeve retaining compound would have been better if you're intent on bedding...

I've got the PEPR on my RFB, which is .308 and a lot harsher than an AR, with no bedding, and the scope hasn't budged.

I think you should clean all the loctite off and clamp it dry.  There is no reason for a scope to slide in a 12 screw mount...
Link Posted: 4/14/2014 6:04:53 AM EDT
[#12]
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Quoted:
Green sleeve retaining compound would have been better if you're intent on bedding...

I've got the PEPR on my RFB, which is .308 and a lot harsher than an AR, with no bedding, and the scope hasn't budged.

I think you should clean all the loctite off and clamp it dry.  There is no reason for a scope to slide in a 12 screw mount...
View Quote


I would be real careful using pipe-fitting (green) loctite on anything I ever wanted to come back off....just I don't think loctite is a good idea. I would be afraid of both staining the finish on the scope and also with the green, of being able to get it off. In the past, when using the green stuff for pipe fittings, I had to heat it up to get it off...
Link Posted: 4/14/2014 7:28:18 AM EDT
[#13]
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Quoted:


I would be real careful using pipe-fitting (green) loctite on anything I ever wanted to come back off....just I don't think loctite is a good idea. I would be afraid of both staining the finish on the scope and also with the green, of being able to get it off. In the past, when using the green stuff for pipe fittings, I had to heat it up to get it off...
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Quoted:
Quoted:
Green sleeve retaining compound would have been better if you're intent on bedding...

I've got the PEPR on my RFB, which is .308 and a lot harsher than an AR, with no bedding, and the scope hasn't budged.

I think you should clean all the loctite off and clamp it dry.  There is no reason for a scope to slide in a 12 screw mount...


I would be real careful using pipe-fitting (green) loctite on anything I ever wanted to come back off....just I don't think loctite is a good idea. I would be afraid of both staining the finish on the scope and also with the green, of being able to get it off. In the past, when using the green stuff for pipe fittings, I had to heat it up to get it off...


Not all "green loctite" is the same.  There's a difference between the pipe thread sealant and the retaining compound.
The retaining compound is for keeping press fits tight, and has been used for bedding scope rings before, but with a 1 piece mount like the PEPR, I see no need for it.
Link Posted: 4/14/2014 9:59:50 AM EDT
[#14]
Something ain't right.

Get the Loctite off of the rings and limit it to the screw threads only.

If the scope is really, truly slipping, then something is wrong with the scope tube or the mount -- you can't fix that with smearing some kind of "bedding" crap on the inside of the rings.

Back up, start over, clean those rings.  Are each of the caps marked so that they match the lower half?  If so, make sure you have the proper cap on the proper lower half and have it oriented in the correct direction. Start there.  If they are not marked, then try experimenting with swapping the caps and their orientation, if you can do so and have the holes line up.

If that does not work, I'm inclined to believe that you may have bent the scope tube or, more unlikely, an improperly machined mount.

Be sure to put Loctite blue only on the threads of the screws and bring each of the caps slowly down with equal turning of the screws until each is firmly seated.  Then use an inch pound torque wrench to finish it.

I have many scopes on many different rifles with mounts that range from inexpensive to very high dollar return to zero QD and just about everything in between.  I've never had a scope and mount combo that would result in the scope slipping inside the rings after pulling the mounting screws down evenly and correctly.  I'm 63 years old and have a 32 gun safe full of rifles.  Some of them are over 40 years old, bought new, and before Loctite, we simply used a drop of varnish on the screw threads.  Still holding fine.
Link Posted: 4/14/2014 10:27:27 AM EDT
[#15]
I'm reading posts on other sites about slipping problems with PEPRs.  I've also read posts where the Locktite Blue worked very well to solve the prob.  It certainly went on water thin and gave me good working time to get the scope set perfectly. But in retrospect I'm worried that if I ever take it off and use a different mount I will have glossy spots on my scope where the Loctite was. But it's done, and it's cured for 24 hours. Unfortunately it's raining in Houston so I won't be testing it today. But for me the next step is to lock and load and see what happens.  If it's a nail driver all will be fine. But I must say I haven't been too impressed with the PEPR so far. And since I'm not tooled up for lapping I'll be reluctant to outsource it and just get deeper in the money hole with this mount.   Hoping for the best but plan B from here is prolly LaRue.
Link Posted: 4/14/2014 11:07:29 AM EDT
[#16]
If you want a nicer mount the BOBRO 30mm mount is on sale at Palmetto State Armory.  The one they have on sale is Trijicon marked (made by BOBRO for Trijicon).  $200 is a good price for the mount.  I really like my BOBRO mount - even better than some of my Larue mounts.  I wish Larue would come out with a self-adjusting design.        
 
Link Posted: 4/14/2014 12:08:22 PM EDT
[#17]
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Quoted:


Not all "green loctite" is the same.  There's a difference between the pipe thread sealant and the retaining compound.
The retaining compound is for keeping press fits tight, and has been used for bedding scope rings before, but with a 1 piece mount like the PEPR, I see no need for it.
View Quote View All Quotes
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Discussion ForumsJump to Quoted PostQuote History
Quoted:
Quoted:
Quoted:
Green sleeve retaining compound would have been better if you're intent on bedding...

I've got the PEPR on my RFB, which is .308 and a lot harsher than an AR, with no bedding, and the scope hasn't budged.

I think you should clean all the loctite off and clamp it dry.  There is no reason for a scope to slide in a 12 screw mount...


I would be real careful using pipe-fitting (green) loctite on anything I ever wanted to come back off....just I don't think loctite is a good idea. I would be afraid of both staining the finish on the scope and also with the green, of being able to get it off. In the past, when using the green stuff for pipe fittings, I had to heat it up to get it off...


Not all "green loctite" is the same.  There's a difference between the pipe thread sealant and the retaining compound.
The retaining compound is for keeping press fits tight, and has been used for bedding scope rings before, but with a 1 piece mount like the PEPR, I see no need for it.


10-4 didn't know there were different types of green.
Link Posted: 4/14/2014 5:27:15 PM EDT
[#18]
I did not have this problem with my PEPR but I dumped it because all those screws are a pain in the ass. Much simpler mounts out there.
Link Posted: 4/14/2014 6:09:35 PM EDT
[#19]
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Quoted:
I did not have this problem with my PEPR but I dumped it because all those screws are a pain in the ass. Much simpler mounts out there.
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Only if you play barbie doll with your rifles and optics and can't leave well enough alone once it's mounted...
Link Posted: 4/14/2014 7:37:52 PM EDT
[#20]
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Quoted:
I did not have this problem with my PEPR but I dumped it because all those screws are a pain in the ass. Much simpler mounts out there.
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"All those screws"?  I tightened them once and haven't touched them since.  You play musical screws or something?
Link Posted: 4/14/2014 7:39:24 PM EDT
[#21]
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Quoted:


Why did you mount a 1k scope in a 99 dollar mount anyway?
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Quoted:
Quoted:
Too late. Will advise the outcome. LaRue is definitely on my radar.


Why did you mount a 1k scope in a 99 dollar mount anyway?



A set of standard Trijicon rings only cost $100.  I have two Trijicon scopes mounted on P.E.P.Rs.  One on a 5.56, the other on a 308 and I haven't had a single problem.
Link Posted: 4/14/2014 7:41:38 PM EDT
[#22]
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Quoted:
If its slipping it sounds like you need more torque on the screws.

Loctite is not meant to be used on the inside of rings, and may be contributing to your problems.  Clean all surfaces, apply loctite to screws only, and get an inch/lbs torque wrench.
View Quote



He already said he torqued them way down.  I only applied 20 in lbs of torque on mine, and they have held just fine.  The answer is not to simply add more torque.  If anything, you will do nothing but damage your scope that way.
Link Posted: 4/15/2014 2:36:50 AM EDT
[#23]
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Quoted:



He already said he torqued them way down.  I only applied 20 in lbs of torque on mine, and they have held just fine.  The answer is not to simply add more torque.  If anything, you will do nothing but damage your scope that way.
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Quoted:
Quoted:
If its slipping it sounds like you need more torque on the screws.

Loctite is not meant to be used on the inside of rings, and may be contributing to your problems.  Clean all surfaces, apply loctite to screws only, and get an inch/lbs torque wrench.



He already said he torqued them way down.  I only applied 20 in lbs of torque on mine, and they have held just fine.  The answer is not to simply add more torque.  If anything, you will do nothing but damage your scope that way.

I think you will strip threads before you damage the scope
Link Posted: 4/15/2014 5:23:35 AM EDT
[#24]
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Quoted:

I think you will strip threads before you damage the scope
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Quoted:
Quoted:
Quoted:
If its slipping it sounds like you need more torque on the screws.

Loctite is not meant to be used on the inside of rings, and may be contributing to your problems.  Clean all surfaces, apply loctite to screws only, and get an inch/lbs torque wrench.



He already said he torqued them way down.  I only applied 20 in lbs of torque on mine, and they have held just fine.  The answer is not to simply add more torque.  If anything, you will do nothing but damage your scope that way.

I think you will strip threads before you damage the scope


I think a lot of people have crushed their scopes before.
Link Posted: 4/16/2014 8:43:45 AM EDT
[#25]
I have used both the 1" and 30mm PEPR mounts on several scope and never had one slip. Of course you may have gotten one out of spec. I'd call Burris and see what they say. Have you measured the inside diameter of the mount without the scope installed and the rings torqed down? IIRC it should be a few thousands less the the stated diameter. Burris will give you the correct ID and you can go from there.
Link Posted: 4/16/2014 10:38:55 AM EDT
[#26]
I seem to remember cutting strips of very fine sandpaper and putting them between the scope and rings
Link Posted: 4/19/2014 6:32:01 AM EDT
[#27]
Years ago I had a Horus scope that was slipping in Burris Xtreme rings on a 308 AR.  I tried more torque with a FAT wrench, and it still slipped.  I put a thin coat of black silicon inside the rings at the suggestion of some folks on Sniper's Hide, and the problem went away.  Same thing later happened with a 10x SS scope in the same rings on the same gun.  A very thin coat of silicon worked for that one as well.
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