20 MOA scope mount on an AR?

[BoulderE89]

Question for you more experienced shooters out there. I am going to get the new Arken 4-16 and split time with it between a 6.5 Grendel upper and 556 SPR upper. Because of moving between uppers I want my mount to be QD, but I'm wondering if I'll also need it to be a 20 MOA mount too? From what I understand the Arken has 36 mils of travel, is that enough travel to justify 20 moa? I will for sure be shooting from 100-600 yards with both, but may occasionally try and go beyond 600 with the Grendel. What do you guys think? Worth the extra money getting a 20 moa mount or not worth my time?

 

[plt228]

I would say always go for a 20 moa mount, no reason not to. And as far as a QD mount, I'd pass and go with a regualr unimount even if the scope might be moved between rifles. Get a good mount, Nightforce, Seekins, Geissele, etc and a good torque wrench. You can move it and have it remounted in no time. But I would think moving and rezeroing would get old in a hurry.

 

[RifleBlog]

Assuming you’re running the 22” barrel Grendel from your post history, my JP 22” Grendel runs about 12 mils out to 1000yards assuming ~2560fps shooting Hornady American Gunner 123gr.

Your Arken has more than enough mechanical elevation to get it done without a 20moa mount assuming your zero is roughly in the middle of its travel.

All things considered, I would just get the 20moa mount regardless so that your 556 can stretch it’s legs with no issues.

Regarding the mount, I personally moved away from QD as I could never find a high quality one that (truly) held zero without having to torque it down so hard that it nearly required tools and damaging the upper. After having a few uppers get LaRu-ined, I converted over to Warne non-QD on all my guns.

Carrying a Wheeler FAT wrench and the relevant socket isn’t overly cumbersome and it holds zero no issues, and they’re inexpensive, high-quality mounts.

 

[theLBC]

Bobro Engineering QD mounts are very repeatable on a rail that is to spec. (IME) they have a patented system that is like a press fit.
they are unfortunately expensive, but they do offer discounts for LE/MIL.
while your zero may not be the same for both uppers, at least you should be able to make the same adjustments back and forth, which might make it worth the extra cost.
they don't "get loose" they cannot be adjusted or tightened. they are designed specifically to eliminate that.

i have no connection to the company (an ex military guy), but i have one of their scar mounts and i have tested zero hold half a dozen times at least, moving it back for my daughter.

Scope Mounts/Rings

The Precision Optic Mount features the Patented [US Patent 8,567,105] BLAC™ lever system which was designed around the following parameters:

• Must be compatible with any 1913 Specification Rail, to include systems that are out of specification (within reason) and this includes Weaver rails.
• Must be completely tool and user adjustable free. It needs to be 100% self contained and mate securely to any rail without the user having to tailor the pressure/engagement position.
• Must lock with enough pressure to positively attach any device or optical instrument to a rail without movement, static or dynamic forces not withstanding.
• The rail must not experience any deformation due to user error. This must include synthetic (plastic/polymer/composite) rail systems.
• Auto Index capability. The device must also index parallel to the bore. The unit must always repeat the forward shift (recoil forces direction of influence) not only to maximize zero repeatability, but to take this step of installation out of the users initial mounting sequence. Index must be redundant.
• Unit must not shoot loose due to improper mounting or a mechanical bottoming out.
• The system must incorprate a safety that prevents the lever from being accidentally opened. The safety must be able to be manipulated in conjunction with the lever rotation, so that only one hand is required to open it.
• The unit will utilize constant force to ensure required pressure in all conditions. The force must be substantial to prevent any shift forward/aft left/right.
• The pressure must be applied in a linear direction centered in the main body to prevent cocking of the mount.
• It must be easy to manipulate by gloved or fatigued hands.
• It must be extremely robust, and withstand shock and impact to the system housing.
• There were others, but by listing them we would compromise our trade secrets

 

[Matches Malone]

Question for you more experienced shooters out there. I am going to get the new Arken 4-16 and split time with it between a 6.5 Grendel upper and 556 SPR upper. Because of moving between uppers I want my mount to be QD, but I'm wondering if I'll also need it to be a 20 MOA mount too? From what I understand the Arken has 36 mils of travel, is that enough travel to justify 20 moa? I will for sure be shooting from 100-600 yards with both, but may occasionally try and go beyond 600 with the Grendel. What do you guys think? Worth the extra money getting a 20 moa mount or not worth my time?

Depends on the where your zero lands, and the worst condition of you’re max range you plan on shooting if you will have enough drop in the scope.
I have a 20 moa riser on a SPR type build. Works for
me.

 

[BoulderE89]

Bobro Engineering QD mounts are very repeatable on a rail that is to spec. (IME) they have a patented system that is like a press fit.
they are unfortunately expensive, but they do offer discounts for LE/MIL.
while your zero may not be the same for both uppers, at least you should be able to make the same adjustments back and forth, which might make it worth the extra cost.
they don't "get loose" they cannot be adjusted or tightened. they are designed specifically to eliminate that.

i have no connection to the company (an ex military guy), but i have one of their scar mounts and i have tested zero hold half a dozen times at least, moving it back for my daughter.

Scope Mounts/Rings

The Precision Optic Mount features the Patented [US Patent 8,567,105] BLAC™ lever system which was designed around the following parameters:

• Must be compatible with any 1913 Specification Rail, to include systems that are out of specification (within reason) and this includes Weaver rails.
• Must be completely tool and user adjustable free. It needs to be 100% self contained and mate securely to any rail without the user having to tailor the pressure/engagement position.
• Must lock with enough pressure to positively attach any device or optical instrument to a rail without movement, static or dynamic forces not withstanding.
• The rail must not experience any deformation due to user error. This must include synthetic (plastic/polymer/composite) rail systems.
• Auto Index capability. The device must also index parallel to the bore. The unit must always repeat the forward shift (recoil forces direction of influence) not only to maximize zero repeatability, but to take this step of installation out of the users initial mounting sequence. Index must be redundant.
• Unit must not shoot loose due to improper mounting or a mechanical bottoming out.
• The system must incorprate a safety that prevents the lever from being accidentally opened. The safety must be able to be manipulated in conjunction with the lever rotation, so that only one hand is required to open it.
• The unit will utilize constant force to ensure required pressure in all conditions. The force must be substantial to prevent any shift forward/aft left/right.
• The pressure must be applied in a linear direction centered in the main body to prevent cocking of the mount.
• It must be easy to manipulate by gloved or fatigued hands.
• It must be extremely robust, and withstand shock and impact to the system housing.
• There were others, but by listing them we would compromise our trade secrets

I saw these and was interested. But the price is steep. Approaching what the optic itself cost. Do you think an ADM QD recon mount would be repeatable? They offer them in 34mm and 20 moa, which is a hard combo to find

 

[RifleBlog]

I have that exact mount and took it off because it had issues.

Don’t buy a vertically split mount, especially with heavy 34mm precision-oriented scopes.

 

[theLBC]

I saw these and was interested. But the price is steep. Approaching what the optic itself cost. Do you think an ADM QD recon mount would be repeatable? They offer them in 34mm and 20 moa, which is a hard combo to find

this website (recoil) did a repeatability test, and ADM was not among the best.
of course, there may be many models that perform differently and of course i cannot vouch for anything beyond my own experience.

A Guide to Quick-Detach Scope Mounts

Mount ’Em Up

www.recoilweb.com

 

[BoulderE89]

Maybe the larue Mount is my best bet then

 

[theLBC]

Maybe the larue Mount is my best bet then

i might have seen some people complain about larue QDs, but that might apply to their bipod mounts only?
i actually have a harris/larue bipod, and the Larue QD is a cheap cam design that can cut into your rail and get loose over time.
for a bipod, this is not a huge deal, for a scope mount, i would consider it shit.
but the QD for the scope might be different.

i would suggest waiting for feedback before pulling the trigger.

 

[BoulderE89]

i might have seen some people complain about larue QDs, but that might apply to their bipod mounts only?
i actually have a harris/larue bipod, and the Larue QD is a cheap cam design that can cut into your rail and get loose over time.
for a bipod, this is not a huge deal, for a scope mount, i would consider it shit.
but the QD for the scope might be different.

i would suggest waiting for feedback before pulling the trigger.

Maybe I scrap the QD idea haha these all sounds like bad options

 

[theLBC]

in fact, look at the bottom of this LaRue mount.

now look at a bobro mount (and my Larue Harris bipod). huge difference.
the bobro isn't that much more (for a single lever mount).
if you don't want to rezero, and you want to make it easy to swap, i think it is worth the extra money.
the bobro clamps push straight in, and they don't rely on the clamp tension to hold in place, and they don't cut into your rail.
they don't have to be adjusted to fit, and never get loose.
instead if the fixed width indexing bars (that will probably not be tight) in the larue, the bobro uses a spring loaded (patented) index bar for that press fit. it also forces the mount forward against the rail, so you don't have to do that when you install it each time.
there is a second roll pin looking thing that is probably redundant.

 

[BoulderE89]

in fact, look at the bottom of this LaRue mount.

now look at a bobro mount (and my Larue Harris bipod). huge difference.
the bobro isn't that much more (for a single lever mount).
if you don't want to rezero, and you want to make it easy to swap, i think it is worth the extra money.
the bobro clamps push straight in, and they don't rely on the clamp tension to hold in place, and they don't cut into your rail.
they don't have to be adjusted to fit, and never get loose.
instead if the fixed width indexing bars (that will probably not be tight) in the larue, the bobro uses a spring loaded (patented) index bar for that press fit. it also forces the mount forward against the rail, so you don't have to do that when you install it each time.
there is a second roll pin looking thing that is probably redundant.

I Agree with you, their engineering is superior and very well made. The more I look into them the more clear that is. But if I get a 20 moa 34mm QD the price jumps up significantly...well out of what I could spend on a mount. If that’s my only reliable option is to spend that much money, my best bet is to just get a normal 20 moa Mount

 

[theLBC]

I Agree with you, their engineering is superior and very well made. The more I look into them the more clear that is. But if I get a 20 moa 34mm QD the price jumps up significantly...well out of what I could spend on a mount. If that’s my only reliable option is to spend that much money, my best bet is to just get a normal 20 moa Mount

yeah, i can see how spending $250 seems nuts. i think if it saves you from having to buy another scope it might be worth it, especially if the scope you are sharing among rifles is really expensive. if you don't shoot one of the uppers, because it is a pain to swap your scope, that is a waste too, but it isn't that hard to turn two bolts.

 

[BoulderE89]

yeah, i can see how spending $250 seems nuts. i think if it saves you from having to buy another scope it might be worth it, especially if the scope you are sharing among rifles is really expensive. if you don't shoot one of the uppers, because it is a pain to swap your scope, that is a waste too, but it isn't that hard to turn two bolts.

Yeah, at this point I can afford to turn a few bolts and save a couple hundred for now. Maybe down the line I’ll switch it out for a bobro, cause I definitely think it’s superior.

 

[theLBC]

Yeah, at this point I can afford to turn a few bolts and save a couple hundred for now. Maybe down the line I’ll switch it out for a bobro, cause I definitely think it’s superior.

it's easier to stomach when you put a $2000 scope on a $4000 rifle. ?

 

[Two Mikes]

If the question is 0 MOA or 20MOA, the answer depends on your desired target distance.

My theory is based on the concept that the best optical view without distortion through a scope is the center of the travel. The goal is to be close to the center of the scope at the distance we care most about.

Geiselle's National Match mount is a 0 MOA. That makes sense since most of the shooting for Service rifle is at 200 and 300 yards. The drop out of a horizontal barrel with 0 scope height is 4 MOA at 200 yards, and 6 MOA at 300 yards. If you had a 20 MOA mount, you would be at -16 MOA and -14 MOA inside the scope. The O MOA mount is closer to optical center for 200 and 300 yards.

For the 600 yard target, the drop is 18 MOA. A 20 MOA mount would be perfect for that distance as you would be at -2 MOA inside the scope which is close to the optical center.

Since anything beyond 600 yards with an AR will never happen for me, I've moved to 0 MOA mounts.

If you expect to shoot from 600 and beyond, then a 20 MOA mount would be beneficial.

 

[Docsherm]

I have a 20 MOA LaRue mount on my 6.5 Creedmoor AR and a plan no cant LaRue mount on my Noveske 5.56 SPR. I do not go past 600 yards with the 5.56, even though i am sure I could if I tried.

 

[Precision Underground]

I have that exact mount and took it off because it had issues.

Don’t buy a vertically split mount, especially with heavy 34mm precision-oriented scopes.

What issues did you have with this mount? I use 3 of them and have never had a problem.

 

[Darqusoull13]

I'm a huge fan of Bobro mounts as I swap my 1-8 between 3 rifles. The difference in zero is always the same when I swap the optic around and it's always back exactly to zero. I think I'm up to 5 or 6 Bobro mounts and I absolutely recommend them.

 

[BoulderE89]

I'm a huge fan of Bobro mounts as I swap my 1-8 between 3 rifles. The difference in zero is always the same when I swap the optic around and it's always back exactly to zero. I think I'm up to 5 or 6 Bobro mounts and I absolutely recommend them.

got any extra you wanna sell? lol

 

[theLBC]

got any extra you wanna sell? lol

i actually have a dual lever cantilever (0moa) mount, but for 35mm tube. i needed the levers on the other side because i run the charging handle for my scar on the left side. I would sell it cheap (1/2 price) if it would have worked for you.

 

[striped1]

Both Bobro and geissele are outstanding.

 

[mudpig]

This is the one I went with for my Arken EP4:

MXM Scope Mount

https://www.seekinsprecision.com/product/scope-rings/mxm-scope-mount-2.html

www.seekinsprecision.com

 

[BoulderE89]

i actually have a dual lever cantilever (0moa) mount, but for 35mm tube. i needed the levers on the other side because i run the charging handle for my scar on the left side. I would sell it cheap (1/2 price) if it would have worked for you.

So close...yet so far

 

[BoulderE89]

This is the one I went with for my Arken EP4:

MXM Scope Mount

https://www.seekinsprecision.com/product/scope-rings/mxm-scope-mount-2.html

www.seekinsprecision.com

Actually I’ve been eyeing that one too! And a badger ordnance one. But I like the seekins styling a lot. Have you had a chance to run the two together yet?

 

[Merle]

Badger Ordnance is also a good option and they are about $100 less than a Geissele. I have both mounts and they are solid.

 

[Ravenworks]

Yeah, at this point I can afford to turn a few bolts and save a couple hundred for now. Maybe down the line I’ll switch it out for a bobro, cause I definitely think it’s superior.

Or
You could buy a used Spuhr mount from the PX.
Patience
I seen one in there yesterday that would be perfect for you,it was $300
But
New that mount goes for close to $400

 

[BoulderE89]

Or
You could buy a used Spuhr mount from the PX.
Patience
I seen one in there yesterday that would be perfect for you,it was $300
But
New that mount goes for close to $400

PX?

 

[Ravenworks]

PX?

Classifieds
If you're not in a hurry you can score some decent deals.
You need to check often and buy when you see it.

 

[Greg Langelius *]

My LR AR's have 24" barrels, but no slope in the scope mounts. My scopes already have enough elevation travel to shoot as far as I would care to shoot with them. I limit my 223/5.56 shooting to 600yd. For further, I have more appropriate chamberings. Right tool for the right job.

BTW, I've been mounting my AR's with BDC scopes.

FWIW, the 308 BDC scopes are within 1/2in drop for the 6.5 Grendel 123 SST at 300yd, and around 2"-3" low at 500yd. Their drops are figured on the 308 168 FGMM load.

Greg

 

[mudpig]

Actually I’ve been eyeing that one too! And a badger ordnance one. But I like the seekins styling a lot. Have you had a chance to run the two together yet?

I have not been out to shoot with this combo yet. I just got the mount last week and will be out at the range this next weekend, weather permitting.

 

[BoulderE89]

I have not been out to shoot with this combo yet. I just got the mount last week and will be out at the range this next weekend, weather permitting.

I did the math as someone pointed out, and with 0 moa I have enough internal adjustment to still get out to 1K with a 6.5 Grendel and out to 600 with 556.