Gunsmithing Slippery scope on 338 Lapua Magnum

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Khaos11378

Private
Minuteman
Nov 24, 2011
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#1
Hello all, I'm having trouble with my optics set up. I have a Millett LRS-1 scope in Millett 35mm high rings mounted on a Mccann Industries MIRS rail for a scope base. I used loctite blue on all my screws except the screws on the rings, went out to shoot once and the MIRS mount was loose after 30 rds, and though the ring screws were still tight, the scope had drifted forwarduntil the zoom ring was touching the rear scope ring. What am I doing wrong?

P.S. If it helps, here is my setup... Remington 700P chambered to .338 Lapua Magnum, APA Fat Bastard muzzle brake, 24 in heavy barrel. Scope is a Millett LRS-1. Rings are 35mm Millett high rings, and mount is Mccann industries MIRS mount. Trigger is Jewell set to 8 oz.

Thank you for your help.
 
#2
Re: Slippery scope on 338 Lapua Magnum

Loc Tite everything! 25 in/lbs on ring halves, 65 in/lbs on cross screws. Also if your rings aren't perfectly machine inside, they may need to be lapped.
 
#3
Re: Slippery scope on 338 Lapua Magnum

Did you use a torque wrench when tightening the screws?
I would lap the rings, add some locktite, and use a torque wrench to tighten all the screws to the manufacturers recommendation.
If you still have problems it may be time to drop some cash on a set high quality rings that will stand up to the repeated heavy recoil of the 338 Lapua.
 
#4
Re: Slippery scope on 338 Lapua Magnum

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Special Delivery</div><div class="ubbcode-body">Loc Tite everything! 25 in/lbs on ring halves, 65 in/lbs on cross screws. Also if your rings aren't perfectly machine inside, they may need to be lapped. </div></div>

You should be specific about the screw sizes before you recommend torque values.
He could have #8 or #10 scross screws and 65 in-lbs would not be good on those...
 
#5
Re: Slippery scope on 338 Lapua Magnum

I think the rings and bases are aluminum and the scope is too heavy under recoil for the rings to hold. Upgrade to all steel rings and mounts...I use Leupold
 
#6
Re: Slippery scope on 338 Lapua Magnum

Gotta ask, had a couple of references to aluminum rings not holding a heavy scope? What is the logic behind this, I use nothing but aluminum with seekins and no problems. Isn't the contact area more important than material? Many really good aluminum ring makers out there.
 
#7
Re: Slippery scope on 338 Lapua Magnum

Aluminum rings and mounts are great as long as you mount them to no larger than 308 win and your optic weighs less than 1.5 pounds...introduce a heavier scope to a rifle with more recoil and the aluminum WILL flex and the scope WILL shift.
 
#8
Re: Slippery scope on 338 Lapua Magnum

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: insight3b</div><div class="ubbcode-body">Aluminum rings and mounts are great as long as you mount them to no larger than 308 win and your optic weighs less than 1.5 pounds...introduce a heavier scope to a rifle with more recoil and the aluminum WILL flex and the scope WILL shift. </div></div>

This is really poor advice and just fundamentally wrong. There are so many other factors involved that such a blanket statement is worse than worthless.


ETA: I'm going to skip the long winded technical explanation as I've hashed it before with folks who don't understand Steel vs. AL vs. Titanium on here.




Good AL rings have no issues with that setup, my personal choice is the stuff that American Rifle makes, but many others have proven success with AL rings from different QUALITY MADE brands such as Seekins, Badger, USO.

The Millet rings are junk grade production.
 
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#9
Re: Slippery scope on 338 Lapua Magnum

+1 on what bohem stated!!

I run Seekins and Nightforce Ultralight rings on my big .30 calibers without any problems WHAT-SO-EVER.

Purchase top-quality rings & torque them to spec and you'll have no issues.
 
#10
Re: Slippery scope on 338 Lapua Magnum

I've seen too many scopes mounted in aluminum to believe anyhting other than heavy scopes WILL shift when mounted with aluminum. I'm not talking 'I heard about' I'm talking I have actually seen a half dozen scopes shift in their rings and every time those scopes were mounted in aluminum rings. Even saw one scope ring combo that sheared the screws mounting the aluminum combo to the rifle. Several will tell folks not to worry about it those folks scopes haven't shifted...yet
 
#12
Re: Slippery scope on 338 Lapua Magnum

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: bohem</div><div class="ubbcode-body">The problem doesn't exist with quality manufactured rings, I've seen shifting too and it happens when trash is trusted, including steel trash.

Buy once, cry once and then the issue disappears. </div></div>

WHAMMY!!
 
#13
Re: Slippery scope on 338 Lapua Magnum

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: bohem</div><div class="ubbcode-body">The problem doesn't exist with quality manufactured rings, I've seen shifting too and it happens when trash is trusted, including steel trash.

Buy once, cry once and then the issue disappears.</div></div>

Exactly! There are good aluminum rings and bad aluminum rings. I had those shit aluminum millet rings. Cross bolt stripped before I could get it close to the torque setting. They also flexed like a rubberband. All the issues I had, I never hear about from the Badger, Seekins, USO, and even Burris guys. Thats a clue right there. Because I was not quite willing to spend a lot on aluminum rings, I went with steel Leupold PRWs. Not as tacticool looking as the others, but they do the job, and do it well. All while mounted to an aluminum EGW base. (Wonder if that will recreate the "Dont use steel on aluminum" argument.)
 
#14
Re: Slippery scope on 338 Lapua Magnum

Thanks for the advice. After loc-titeing the screws and putting liquid electrical tape on the inside of the rings, the scope is not moving, but the MIRS base will still come loose every 40 rds or so. I just cleaned out the holes and screws and put probably an excessive amoount of loc-tite on everything so I'll see if that helps.
 
#15
Re: Slippery scope on 338 Lapua Magnum

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: insight3b</div><div class="ubbcode-body">I've seen too many scopes mounted in aluminum to believe anyhting other than heavy scopes WILL shift when mounted with aluminum. I'm not talking 'I heard about' I'm talking I have actually seen a half dozen scopes shift in their rings and every time those scopes were mounted in aluminum rings. Even saw one scope ring combo that sheared the screws mounting the aluminum combo to the rifle. Several will tell folks not to worry about it those folks scopes haven't shifted...yet </div></div>

what brand were they?

aluminum rings are going to have a higher coefficient of friction against the anodized scope body than steel will. same would be true between an aluminum base and steel receiver. if you sheared the mounting screws to the receiver, there was an installation problem, not a material problem.

also, don't forget there are different alloys and tempers of aluminum and different grades/hardness of steel. just assuming "steel" is better than "aluminum" is ignorant. i am assuming the problems you have had with aluminum rings and bases had more to do with the quality of the manufacture or the installation.
 
#16
Re: Slippery scope on 338 Lapua Magnum

I have the aluminum Nightforce Ultralight rings on my .338LM and have not had any problems with movement. Yeah, those were $150, but that's a solid investment considering the cost of pulling the trigger on this rifle.
 
#17
#18
Re: Slippery scope on 338 Lapua Magnum

Buy a good quality set on rings and bases. Lap the rings in and torq everything down with blue loctight. Never had a problem, I know rings a bases can get a little spendy but as Eric said look at what your spending when you pull the trigger. It can save you a lot of headache and money down the road...

Kc
 
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