Most of my experience is with M&P pistols, but I have recently shot my new M&P 15 Sport a couple of times and quickly realized that my old eyes just don't work that well, so I got a great deal on an older but never used scope 4.5-14x50. The guy I got it from included some cheap but functional mounting rings and I have it basically mounted but not tightened all the way. My question is how much do I torque it down? Should I use any locktight on the threads? Do I need to re-check the screws every 100 rounds or 1000 rounds? Any advice from you guys with experience in these matters would be greatly appreciated.

That's some scope for a Sport.
Mounting screws should be high quality and hard. Torque it down 1/4 turn from snapping off. If you have cheap soft screws, you're going to break them either in mounting or shooting.
Properly installed, they should never loosen, but...........

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Science plus Art

Thanks. I wasn't looking for that much scope but when I came across it for a good deal, I figured with my aging eyes I might as well. Just looking through it now (not having shot it yet) I can see really well.

I think the screws are quite hard so I will give them a good tightening now.

Torque for scope ring screws is usually 10-20 inch-pounds. Blue (serviceable) loctite is usually recommended. Before and while tightening the screws, keep checking the scope reticle to make sure it stays level with receiver ... sometimes the scope will twist slightly when a scope ring is tightened ... very annoying when you hold a rifle level and the reticle is at a cant. Also, make sure the scope rings are the right size for the scope tube ... 1" diameter scope rings are not compatible with a 30mm diameter scope tube, for instance. Congrats on your scope purchase.

How do you figure out where that point is? Do you torque them down until they snap off, then buy new screws and do it again?

I have mounted hundreds of scopes for customers, and never snapped a screw, nor have I ever used loctite. My method is to do what the manufacturer recommends. If there is no written recommendation, I make the ones on the scope rings 20 inch-pounds, and the ones on the base 35 inch-pounds (if they use 8-40 screws) and 65 inch-pounds (if they are the big, 1/2" nuts on a Picatinny rail base).

The torque on the rings (which hold the scope erector tube itself) are the really important ones to NOT overtighten. I have seen many a scope ruined by overtightening those rings. If you take your scope off, and it has "ring marks" on the erector tube, then you overtightened it. Overtightening these screws can damage a scope to the point that it just won't hold zero.

I don't guess. I use an inch-pound torque screwdriver bit holder, Amazon.com: Wheeler Firearms Accurizing Torque Wrench: Sports & Outdoors@@AMEPARAM@@http://ecx.images-amazon.com/images/I/41Xn-6UMP9L.@@AMEPARAM@@41Xn-6UMP9L.

By the way, my AR-15 has a 6-24x scope on it. You can't ever have enough magnification for those tiny little holes, out past 100 yards.

I, myself, would never mess with scope rings w/o an inch/pound screwdriver in my hand.

Under torque it and it will move, over torque and you stand the risk of snapping the screws, stripping the threads, and distorting the tube and affecting the functions of the optic.

Blue locktite and my cheap Wheeler inch/pound screwdriver($40) , then I have confidence I done right!

EDIT: If you purchase a Wheeler, make sure to store it indexed back to 'zero', or it might loose it's calibration. Instructions cover this aspect.

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AKA: "Strange Tamer"

Thanks everyone for your great advice. I will be following pretty much everything that you recommended.

If I have the proper hard screws, I look up their rated torque capacity in my chart, set the torque and tighten, which after you do a few thousand, including mounting things like electronic SCRs, turns out to be about 1/4 turn from snapping off.

The point I was making is that without knowing what size or rating screws he has for his mount, I can't give him a reliable torque figure, and he has to be cautious about over tightening, and there is a danger of snapping one off. I think he, at least, got the point.

Sometimes I do test a screw to see if it will take rated torque before mounting. I had one person bring me a brand X sets of rings that was so soft the metric screws would snap at about 15 in#. Piece of junk.

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Science plus Art

Mine is torqued to 15 inch pounds for the rings, 35 inch pounds for the base. I also have the wheeler fat wrench. I would suggest a solid one piece mount like a burris PEPR or a nikon M-223. get a few different brands of ammo and find the one that shoots the best out of your sport. I'm having pretty good luck with Hornady 53gr. V-max and 55gr. BTHP match.

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very nice setup////congrats!

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SWCA#2208
KK4EMO

i usually let my GS mount it for $15. He has all the tools you need for the job and will warranty the work. I tend to lean towards higher end glass and would hate to mess something up when i can pay a professional a couple of bucks and he's done in 15min.

That is a good idea, IF your LGS has a real gunsmith who knows what he's doing.

The problem with "gunsmiths" in this country is that a lot of people refer to themselves as such, and aren't. do not go to a big-box retail store (Think Cabelas, Bass Pro Shop, etc. for example) and ask them to mount your scope. Their "gunsmith" is usually some 20-year-old $8/hour kid who wouldn't know what a hollow-ground screwdriver was, if it bit him. These are the same kids who will tell you that a Leupold 4x scope will be perfect for hunting Elk out to 800 yards in Montana with their on-sale .357 lever-action Rossi.