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48376 Weaver Thumbnut Tactical Mounts SPR 1" web lookup says: 6-48 screws: 15 in/lbs 8-40 screws: 18 in/lbs

I'm identifying these as the cap screws so, first question is, how do I know what screws I have? understanding that there isn't much difference in the spec but was wondering if there was a difference - deforming the tube would not be cool.

Also, any guidance on the thumbscrew mounting to the receiver.

Where should I be applying thread locker, if at all.

You won't crush the tube, but might strip the screw. You can use a thread checker to make sure, but go with the lower torque if in doubt.

Cross bolts are sometimes as high as 65 in lbs. Pretty dang tight.

I put loctite on base-receiver screws, but not on cap screws.

yukonjasper wrote:48376 Weaver Thumbnut Tactical Mounts SPR 1" web lookup says: 6-48 screws: 15 in/lbs 8-40 screws: 18 in/lbs

I'm identifying these as the cap screws so, first question is, how do I know what screws I have? understanding that there isn't much difference in the spec but was wondering if there was a difference - deforming the tube would not be cool.

Also, any guidance on the thumbscrew mounting to the receiver.

Where should I be applying thread locker, if at all.

Use Blue Loctite for the mount screws (make sure all oils are removed before applying loctite). If you have 2 different set of screws, the 6-48 will be smaller than the 8-40. A #6 screw is .130" in diameter the #8 is .160" in diameter. Take the measurement, if needed, at the threaded portion. A caliper or micrometer will help. You might also be able to determine using a scale (ruler) if it goes down to 1/64th of an inch. The #6 is 9/64 and the #8 is 5/32

Once determined, you can apply the proper torque. Make sure to follow "cross-torque" pattern. If in doubt, youtube can be your friend. Just search Scope Mounting

would they send two different size screws? I'm assuming that, depending on the mount you have that they could ship with either but how do you know which? The table is here:
http://www.weaveroptics.com/resources/ring_charts/weaver_torque_specs.pdf

So I'll crank down the cross bolts and hit the cap screws with 15 in/lbs.

Found a level for the top of the receiver to help with the final scope mount and the bore sighting. I only have my lead sled and it doesn't look like the Upper will sit in that solo very well for sighting so I'll wait for my bags.

You are way over thinking things. Just snug them down till they feel good. Everything has a torque spec, do you use a torque wrench on everything? I think very few things are critical, especially on guns. Snug it up and call it a day. You aren't putting together a space shuttle. They just put torque specs on things so when you snap a bolt they can say "told you so".

Sigfan220 wrote:You are way over thinking things. Just snug them down till they feel good. Everything has a torque spec, do you use a torque wrench on everything? I think very few things are critical, especially on guns. Snug it up and call it a day. You aren't putting together a space shuttle. They just put torque specs on things so when you snap a bolt they can say "told you so".

My understanding is that scopes are one thing you do want to torque correctly.
http://www.shootingtimes.com/optics/optics_st_mountingmistakes_200812/

Ghost wrote:

Sigfan220 wrote:You are way over thinking things. Just snug them down till they feel good. Everything has a torque spec, do you use a torque wrench on everything? I think very few things are critical, especially on guns. Snug it up and call it a day. You aren't putting together a space shuttle. They just put torque specs on things so when you snap a bolt they can say "told you so".

My understanding is that scopes are one thing you do want to torque correctly.
http://www.shootingtimes.com/optics/optics_st_mountingmistakes_200812/

I could go either way. Generally I agree with you. I have a wheeler fat wrench and use it on every scope mounting now but I have guns from my pre-fat wrench days where I used the package provided allen wrench and I don't know that I can tell the difference between them accuracy wise. Some of them have been mounted for 20 years or more.

That said, any possible point of error I can take out of the process I will. Just not convinced it is absolutely necessary.