Lapping and Loctite

[darmento]

I have a couple of good scopes that I recently purchased - One is a Zeiss 4x24 50mm and one is an Athlon with a 34mm tube and a 56mm objective. So these are both pretty big and heavy - more than I have dealt with in the past. These are going on a 6.5 Creedmoor and a .308

My question is this.....in mounting these scopes, do I need to use Loctite on the screws, and do I also need to lap them? I have seen some videos on Youtube that suggested you do not need to do either of these things, and long as you tighten the mount and rings according to the manufactures suggested limit. I would prefer NOT to use Loctite (for fear of having the screws becoming "stuck", and me stripping the screw when I try to remove it), and I would prefer NOT to lap the scopes (due to the mess caused by lapping), but if that is really the right way to do it, I will do so. My other cause for not wanting to do these things is that it makes the scope a "fixed system", meaning it is much hard to make scope adjustements when you have used Loctite and lapping.

Would like to hear the thoughts of people who have shot a lot of rounds through their rifles and scopes and have a lot of field experience. Thanks as always in advance for any advice!!!

 

[keystone112]

Agree with the post above, lapping should not be necessary.

I do use blue loctite for the screws that attach the base to the rifle and then torque to the proper spec. 25 inch pounds normally. Make sure the loctite isn't expired.

The only problem I have ever had with a base failing on me was with a muzzleloader. I suspect that the cleaning foam I used somehow got close to the base screws and softened them up a bit. When I had the scope off I went to check the base screws. The first two were loose and when I tried to tighten the third one, it sheared off at 10 inch pounds.

 

[CApighunter]

Never lapped a ring. Tiny dab of blue lock tite and torque to spec. Bedding the base to the action won’t hurt, I’ve done it on my harder kicking rifles.

 

[wapitibob]

Lapping your rings isn’t about making the bores round, it’s making the two halves and the whole set concentric and cylindrical. If you never cut the rings in half yea, they can cnc them right. Or now, many of them are made on horizontals, one side at a time. Once you mount the btm half on a maybe accurate action all bets are off. Use a rail and mount the bases, that way you aren’t dealing with the clearance between the base thru holes and the screw body. Drop in the scope and see how it fits. If you can feel the scope move get better rings. If you lap, don’t go thru the ring finish, just dust it. Get into the metal and the lap compound will oversize the bores.

 

[Bubblehide]

Buy quality rings. Degrease all screws and screw holes and Locktite.

 

[Myronman3]

do you need to lap? no.

i have lapped at least 7 rifles. each time, i shot the tightest group i could off of bags before lapping to see if it made any difference. lapped the rings, then shot another group off bags. each time, i saw an improvement. sometimes major, sometimes minor. but an improvement each time.

i went into it kinda thinking i was wasting my time. i did not expect it to make a difference; but each time it netted positive results.

some say with very high quality rings, you dont need to lap. after what i've witnessed firsthand, i'll continue to lap my rifles' rings.

 

[Sandstrom]

Most ring manufacturers have a recommendation on their rings and lapping. Never hurts to follow the recommendations. As for CNC being “the best”, CNC is great but, it sure as heck doesn’t guarantee two parts that are equal and exactly to spec. All kinds of things from tool wear, tool setup, placing the blank into the machine, to actual slop in the machine can affect how precise the part is. With out exacting quality control practices, CNC should not be a singular gauge of excellence.

As far as loctite I have seen several instances where stuff has come loose without it...

One trick that I have found for helping make sure my rings are in line with each other is to use my lapping bar as a jig for bolting down my bases by moving it forward and back just enough to to keep the bases aligned and allow access to the screws. It seems to help with the slop that is allowed by the clearances for the screws.

Ryan

 

[Pickettpuncher]

I’ve seen loctite cause more issues than it cured, and won’t use it.

 

[Sandstrom]

I’ve seen loctite cause more issues than it cured, and won’t use it.

Out of curiosity, what issues have you seen loctite cause?

Ryan

 

[Pickettpuncher]

Out of curiosity, what issues have you seen loctite cause?

Ryan

Usually it just makes a mess and when you want to change things it can make it a pain to get the screws out. The couple times that stick out at the moment, had a friend send me a rifle to clean up. It was pretty dirty and he wanted a scope mounted. Liked to have never got the base screws out and when I finally did the bases were stuck to the gun. Got those popped off and all the excess loctite has went between the action and bases. I’ve bought several guns thru the years where they used loctite and over toruqued the screws. Pretty easy to strip those out. Also, most base screws are drilled all the way thru the action. I’d rather not have loctite drip down onto the bolt and inside the action.

Quality bases and rings should just need cleaned and torqued properly. Nothing more.

 

[Sandstrom]

With all due respect, all of the examples that you gave of loctite causing problems sound like they were from excessive amounts applied to the bolts. All you need is a tiny amount in the threads, it shouldn’t migrate to any other area except the threads. Also, if it is hard to remove the bolts, that means it is doing exactly what it was designed to do.

Ryan

 

[Wrench]

Lapping isn't just to cure the manufacturing tolerance in the rings. When you mount a ring there's some play before it's locked down. The screw holes have clearance. The screws on some bases are tapered which aids in hitting center....assuming that the radius on the bottom and the holes are on the money....usually a pretty safe bet.

Now add the action in to the mix. If you are running a factory action the scope base holes were drilled/milled with a tool that did a bunch of other actions. If the drill/endmill didn't follow center 100%, and it happens a lot, you end up with a base hole that isn't parallel to the bore.

Lapping takes ALL of those variables and proves them to the end user. I don't shoot for 100% contact, but close.

Quality rings with enough meat to eliminate springback help. Custom or proven base holes help. Bedded bases rule.

As for locktite, it does modify the measured torque by lubricating the threads....so keep that in mind. It certainly does what it's supposed to do.

Even red or green can be neutralized by heating with a soldering iron on the screw head to 400*F.

 

[SDHNTR]

I’m not going to comment any more on lapping or not as it’s been well covered, except to say it’s not a one size fits all approach. Some rings need it and some don’t. Sometimes some rings need it and sometimes not. Learn when to and when not too. Precise alignment is key.

Loctite always. On degreased threads. In small amounts. With blue removable compound. I like #243 for it’s oil resistance. As mentioned it can increase torque settings so err on the low end of recommended range.

 

[WRM]

I always check my rings with a lapping kit to ensure there is proper alignment. I've not run into a situation (yet) where actual lapping was warranted. Using quality rings helps a lot, of course, as noted prior. You always hope the receiver was drilled accurately, but you get what you got. Better to know, as it doesn't take a whole lot of torque applied poorly to start busting scope internals.

Any rifle intended to shoot at anything much beyond 200 yards, I bed the base to the receiver. On super recoilers I'd probably just do it anyway. I like Acraglass. Plenty of online vids for process.

I don't use any loctite, but I'm also not shooting giant scopes on a 50 BMG. Maybe someone mentioned purple--I didn't read every post. If you are concerned, use a drop of purple. Easily broken by you, but the screw will not back out (if it ever was). It's like a belt and suspenders--your pants sure won't fall down. I read a technical article once on why loctite is not needed on ring screws due to how the forces work in recoil. I didn't keep it, but it made perfect sense. In over 40 years, I've never had a screw loosen in a ring.

I don't use a spring style torque device. They have variability and technically need to be re-adjusted and verified by the factory (which is not happening with the "generic" ones offered as "for guns"). I use a device made by CDI which does not use a spring and is made to not have to be re-certified. I have other uses for it, so takes some of the sting out of the price. Of course, inch pounds are the rule--no foot pounds involved. I've watched a scope destroyed by an installer who clearly did not know any better.

 

[freddyG]

Set your scope in the rings, and you will know what to do. Most of the time, you will have to lap in order to get a stress-free installation. This is important, especially for thin-walled scopes.

The posters on here that say no to lapping, either haven’t paid much attention when installing scopes, or haven’t done many. Ring tolerance is all over the place, even from the same manufacturer. Seekins are one of the best, on the other hand Talleys HAVE to be lapped. Stevie Wonder must make those.

 

[WRM]

Talleys HAVE to be lapped. Stevie Wonder must make those

HA--they sure need to have the threads chased. I've not had to lap a Talley (yet), but man the thread cutter must be asleep at the wheel sometimes!

 

[freddyG]

Talleys must be made for those super common egg shaped tube scopes. Add in any other out of spec tolerance in the mounting system, and it’s a disaster.

 

[WRM]

Talleys must be made for those super common egg shaped tube scopes. Add in any other out of spec tolerance in the mounting system, and it’s a disaster.

May help that I've only used their QD ring line which is "side mounted". Probably made on different machining.

 

[SDHNTR]

HA--they sure need to have the threads chased. I've not had to lap a Talley (yet), but man the thread cutter must be asleep at the wheel sometimes!

Talley lightweights, yes. Vertically split steel rings, not in my experience.

 

[WRM]

Talley lightweights, yes. Vertically split steel rings, not in my experience.

What a misnomer though--lightweight. I'm using them on a Marlin .45-70 with a Leupold scope on a rail that is "dovetail" spec. Had to use an adapter to get me from Picatinny mount down to dovetail. Have had no issues. Scope returns to good zero and have never had the QD loosen under recoil.