Proper way of mounting a scope on an AR, is there?

[5.56Geo]

Yesterday a friend came over and assisted me in mounting my Vortex HST to my 20" AR. We placed the rifle in a rifle vise/sled and leveled it using two bubble level vials set on gaps in the top rail of the receiver. Once it was level I looked through the scope at a 4' level we had clamped vertically on the fence post 30 yards away and lined up the vertical crosshair with the level on the fence then verified with another bubble level on the top turret of the scope. It was dead nuts on! I had never done it that way. Everything was torqued to specs, 20 inch/pounds. At first I thought it was overkill but now not so much.

What are your thoughts...? How have you mounted scopes on AR's?

[tpe187]

I have found a feeler gage set to work best. Others use a deck of cards. Place between the bottom of the turrets and the rail or your mount if using a one piece. Just slide in the whole stack and wiggle back and forth until there is no play. Rings need to be barely loose before you start. Make sure to final torque again after you pull the feeler gage out. It should be kind of difficult and you will have to pull side to side.

[sasquatchoslav]

As far as reticle to rifle aspects I shine a flashlight back through the objective onto the wall against a plumb bob hanging on the wall. once the rifle is perfectly level.

[Toyoland66]

Feeler gauges if you have a scope with a flat on the bottom of the turret. Arisaka sells a tool that does the same thing.

[Colnago]

Have mounted a few different scopes on different ARs my perspective is that the amount of rigour in your scope mounting needs to be consistent with that you are looking to accomplish with the rifle. If you are going to shoot paper a few times a year at 100 yards or less, then you are not going to see a big benefit from all the work the OP describes. If you are going to shoot at longer ranges 300-500+, then these activities are key to being accurate at longer range. The other key to getting a scope mounted well from my perspective is playing with the eye box and finding that comfortable point where your cheek weld fits perfectly with the eye box.

[hk_shootr]

Spuhr has a pic eve that is inserted into the reveiver's picatinny tail. A wedge is then placed between it and the flat of the turret boss. This aligns the windage line with the receiver. I've used the Spuhr tool a few times, it has yet to align a scope improperly

[Zim]

The Arisaka tool is really nice and easy to use.

[Alex V]

I usually use two small levels or a deck of playing cards. The Arisaka tool makes life much easier.

They way I understand it, the scope doesn't "have to" be level to the gun. As long as the scope is level to the world at the time the round is fired, you will have repeatable results.

[TAZ]

I usually use two small levels or a deck of playing cards. The Arisaka tool makes life much easier.

They way I understand it, the scope doesn't "have to" be level to the gun. As long as the scope is level to the world at the time the round is fired, you will have repeatable results.

I use feeler gauges and then verify that the reticle is level to the gun as well. On well made scopes this is more of a redundant check.

It's wise to have the scope level to the gun, especially if you're mounting it relatively high above the bore like an AR. You will subconsciously level the reticle by canting the rifle. As you do so you create an offset between the bore and scope. Practically will this make the difference between a hit or a miss????

[Alex V]

I use feeler gauges and then verify that the reticle is level to the gun as well. On well made scopes this is more of a redundant check.

It's wise to have the scope level to the gun, especially if you're mounting it relatively high above the bore like an AR. You will subconsciously level the reticle by canting the rifle. As you do so you create an offset between the bore and scope. Practically will this make the difference between a hit or a miss????

I run bubble levels on all my scopes. I am no expert, but people who are, Todd Hodnett for one, emphasizes the importance of the scope being level with the world over being level with the gun. Personally, the longest I have ever shot was 700y and the scope was level to the gun... well... as level as a cheap Home Depot line level can gauge. I am sure if the scope is off by 30* to the bore it would become a problem, but a few degrees here and there? I don't think it would become a problem. Just my uneducated $0.02