Scope Ring's

[rickdavis81]

I picked up an Alexander Arms GSR 6.5 grendel the other day. I'm going to order a Vortex Viper PST 4-16x50 to sit on top of it. Anyone know how tall of a ring I'll need? I'd prefer it to sit as low as possible. Has a quad rail on it now but I'm going to install a standard aluminum free float tube.
THanks

 

[threejones]

Grendel and a Viper... Sounds like the prefect match. The Burris PEPR is a great mount, gets the scope up and forward to clear the charging handle and puts the eye in propper alignment. The LaRue line of one peice mounts are even better quality (plus they're US made), but they're quite a bit more spendy. I run the Burris PEPR on my fun guns/hunting rigs, and the LaRue on the guns my life might depend on. Both are quality bits of kit.

 

[rickdavis81]

I'll take a serious look into the PEPR mounts. Hadn't thought of using those yet. It's a side charging upper so clearing the charging handle isn't an issue. Thanks

 

[blksno]

... and puts the eye in propper alignment.

Watch out for that opinion. It's not a "proper" alignment unless the user has their rifle set up like your rifle.

If you're running a collapsible stock, short carbine or prefer your shooting form to have your face right next to the charge handle...then yes, you may need a cantilever optic mount.
This is not the case for all users so it depends how you prefer to have your optics on AR platforms.

Also, with a 50mm, getting it as low as possible is not always an option. The AR's are not designed like bolt actions, in that getting your objective as low as possible will greatly reduce you're ability to get your face low enough on the stock.

Your best bet would be to go into a gun store and have them mount something on an AR of similar design to yours, or simply bring yours in.

The PEPR is a fine mount, but just make sure you're getting it for the right reasons. It may or may not be needed.

I'm going to use Leupold Mark IV rings as a reference, so take that for what it's worth. I use a 56mm objective with EXTRA High rings and they barely clear a quad rail.
You should be fine with Medium if you're switching to a float tube.

 

[LouBoyd]

Asking what scope height to use makes as much sense as asking what trouser size you should buy. The answer is the same. Use what fits YOU. The proper scope height will be the height which puts the scope comfortably centered on YOUR eye when you shoulder YOUR rifle with a comfortable and solid hold. I keep several cheap aluminum rings so whey I assemble a rifle I can test the fit at various heights then buy the proper height rings. Most of my ARs have Warne "Ultra High" rings, but I the spacing from my eye to my cheek is fairly long. I also like to keep my head reasonably erect when shooting. There is also the option of using adjustable cheek rests or fully adjustable stocks to re-position the shooters head.

If you have to strain to get your eye comfortably behind the scope your accuracy will suffer. It might seem that mounting a scope close to the barrel has accuracy advantages, but study the effects on accuracy of a high or low scope with respect to canting and thermal effects and you'll see that a low scope has little if any advantage. It may make dragging your rifle though brush easier.