Advice on scope mount

[ditcherman]

I am wondering if I could get some advice on the differences between a basic $89, a higher end (Midwest Industries QD or Kinetic Development) $200ish and high end (Spuhr) $400 scope mount. I have a nice Trijicon Accupoint 1-6 in a 'cheap' mount, but would really like to know the practical difference between them, besides the fact that the ridiculously huge mounting nuts on the one I have drive me nuts aesthetically speaking. Going to get another Trijicon or Vortex and kind of balk at 400, but not afraid to spend 200 with QD but really wondering where the right price point is?
We're talking AR15 here.
I did search the forum before posting as well.
Thanks in advance!

 

[Sling10mm]

I have a few American Defense QD mounts that seem to be well made. I'm not sure which model would be needed for your scope(s), but would come in under the $200 mark.

 

[MontereyC6]

I'm by no means a scope mount expert, but what I know from my own usage, is that some scope mounts(larue and bobro from my experience ) allow a user to take off a scope, and remount with zero POI shift.

 

[mammynun]

LaRue is my "go to" for mounts, though I'd like to try a Bobro. In practical terms I'll use a less expensive mount (with the huge nuts sticking out the left side) till I have a "reason" not to... and I've come to the conclusion that for a gently used range gun a LaRue/Bobro/Spuhr isn't necessary. I've not had an Aero or Primary Arms mount fail, or even shift on a lightly used rifle.

Unlike MontereyC6, all my LaRue mounts exhibit some small degree of POI shift when removed and then reattached... and I take great care to make sure the mount is seated fully forward in the same location. I stopped getting the QD LaRue's and save a few buck by deleting the levers, and I leave the optics on the even if the mount has a QD; "problem" solved.

For me, it comes down to this... a "serious" weapon system should consist of "quality" parts and accessories that will help accomplish the goal the weapon is meant to fulfill. The more serious the nature of the intended use, the greater the need for bombproof reliability.

 

[ditcherman]

Thanks for the advice all, I will look into these.
I did look up what I have, it is a Rock River $70 mount, and I also remembered the spill I took on some ice this winter, pretty hard fall with the gun banging around and it held zero. It was probably those big huge ugly nuts on the side.

 

[JeepHammer]

AR is an aluminum top end, so an aluminum mount is fine, it will expand & contract with temp changes just like the top end does.
On a steel action, like a bolt rifle, you would want a full length, one piece steel mount to stiffen up the receiver, the stiffer the more accurate.

Look for a LONG rail mount, not only the mount itself, but the 'Claw' the screws hold down.
The longer the load bearing surface, the more accurately it will zero when removed/replaced,
AND, the longer the clamps the more protection for the upper rails on the receiver.
When faced with a choice between the mount or upper being damaged, sacrifice the mount every time.

Bigger/thicker may be 'Ugly', but more material is stronger and more likely to survive rough service.
Form should follow function, the problem is people want 'Swoopy' & 'Cool' rather than functional, and things can go sideways real quick when too much material gets cut away, or mounts are cantilevered and not directly supported, mounting 'Claws' are short and can dig into/damage the upper receiver.

 

[ditcherman]

AR is an aluminum top end, so an aluminum mount is fine, it will expand & contract with temp changes just like the top end does.
On a steel action, like a bolt rifle, you would want a full length, one piece steel mount to stiffen up the receiver, the stiffer the more accurate.

Look for a LONG rail mount, not only the mount itself, but the 'Claw' the screws hold down.
The longer the load bearing surface, the more accurately it will zero when removed/replaced,
AND, the longer the clamps the more protection for the upper rails on the receiver.
When faced with a choice between the mount or upper being damaged, sacrifice the mount every time.

Bigger/thicker may be 'Ugly', but more material is stronger and more likely to survive rough service.
Form should follow function, the problem is people want 'Swoopy' & 'Cool' rather than functional, and things can go sideways real quick when too much material gets cut away, or mounts are cantilevered and not directly supported, mounting 'Claws' are short and can dig into/damage the upper receiver.

Thanks for the input, hadn't thought about the load bearing surface like that.
The more I look at them the more I see that you can pay a lot for a beautifully machined very thin piece of Al. I think some of these would not have survived my fall and would have sacrificed my scope in the process. I am leaning toward the bulkier ones, I need to figure out what the eye relief/measurments are to see if I really need the cantilevered, I believe I do even though that Trijicon has awesome eye relief.

 

[JeepHammer]

From field experience,
I don't put rings just forward and behind the reticle adjustment in the middle of the tube, I get rings as close to the objective & ocular bell starts as possible, it's a support for the tube thing.
If the optics take a knock on the bells, the tube can bend, the better supported the tube is the less likely the tube will bend ruining the optic.

It's common sense here, wide bands support better than thin bands,
Two or three screws on each side of the rings fail less than a single screw,
Two or three screws (with a torque wrench) give better clamping power, without increasing crush on the tube, than a single screw does.

When I need eye relief, I add length to the stock.
Since I'm making the rifle fit the owner, and only the owner, I don't worry about 'One Size Fits Everyone'.
I worry about the rifle fitting the owner, and the rifle functioning at its peak.

A well made rifle has the bore aligned with the receiver so the barrel isn't cocked sideways from where the optics mounts.
This gives you a chance the optics align with the bore... But just a chance.
The next step is to get rings that align with the bore AND EACH OTHER,
AND,
The rings are ROUND (not ovaled or misaligned) so the tube isn't ovaled or bent in the middle.
Over-tightening the rings will oval the tube, the reason for a torque wrench...

Now, on an AR clones, there isn't much you can do about a misaligned mount rail since it's integral with the upper,
So I machine on the ring mount to bring the optics into centerline with the bore.
With optics windage & elevation CENTERED, I machine the ring mount to align the optics with the bore.
When your centered reticle/aim point is already aligned with the bore, you have greater adjustment in general, and you are in the optical center of the lenses where best accuracy is found.

This is dirt simple, but a crap load don't understand it and argue against it...
Use a 'Plumb Bob', string & weight, which will ALWAYS give you a perfectly vertical line since gravity works 100% of the time.
You simply center your BORE on the line,
Then you rotate the upper/rifle until the center aim point is on the line.
Then, if it's a cross hair reticle, you rotate the tube until the vertical line in the reticle is aligned with the center of the bore/line.

Now your optic tube is centered over the bore, and your reticle is aligned over the bore vertically.
This excludes all sub-standard machining.
If there is material removal required, I do the mounts/rings to bring everything in line.

Keep in mind with a picatinny rail mount, only one side determines the alignment, the other is just a clamp.
That one groove is pretty easy to move around to get things centered & lined up, and mount/rings are always cheaper/easier to change that receiver or optics tubes...

It goes back to lapping rings for round & true, twisted rings bend the optic tube, oval, undersize or oversize rings put pressure on the tube unevenly.
When the rings are round, and the proper size, they distribute pressure evenly.
It goes back to mounting an optic and having to crank it 6 inches to get a zero, you are now off optical center of the lenses, and you have lost a bunch of adjustment in the event you want to reach further than 100 yards.
An off center optic, the sight line crosses the path of the bullet, but isn't inline with the path of the bullet, you have issues with distance.

The rifle will shoot 'Left' on distances shorter than the zero, and longer it will shoot 'Right' of the target, for instance.
This plays hell with ballistic tables, range compensating optics, etc.
You pay for those options and expect them to work, but a misaligned mount or ring set will screw that all up...

 

[JeepHammer]

Even though I have pretty bad astigmatism, I still like red dot optics.
The trick is to turn the power down so the dot isn't so intense.
Turning the power down also makes the dot smaller, uncovering more of the target.
You can loose 3 MOA or more under the dot, so just turn it down and make the dot smaller...

Astigmatisms make the dot look larger and 'Fuzzy' around the outside edge, sort of like a fog halo...
The correct lenses will fix this issue, but the simple way is simply turn the power down if yours isn't or can't be corrected.
Red dots are stupid fast on target, reasonable priced & pretty tough, so I'm all for them in short or lesser mid range shooting.

The mounts for red dot sights are often fairly sturdy, while common rifle 'Scopes' you can get some pretty useless crap.
If it passes military muster, it's usually pretty study since combat troops beat the hell out of them by definition.

As for knobs on the side...
Depends on application.
Keep in mind in my day the military had to change from night vision, to day optics, and in some cases long range optics, the knobs with a groove allowed fingers or knife blade to remove/install.
If it's semi-permanent mount, little Allen or torx screws (tools needed) mounts are fine.

 

[ditcherman]

Lotta good info there, JeepHammer.
Ive been fortunate I guess and been pretty close to zero’d on most builds, and have done the plumb bob thing but never thought about how much you could be off at different distances if you had to make a big initial adjustment. It’s all common sense, if you know it.

 

[JeepHammer]

It's simple geometry, but it took the Marines to point it out to me...
There is a reason every M40 built by Marines shoots 1,000 yards (and beyond) using a 7.62x51mm round, and that rifle/optic shoots right on ballistic tables.

When the .223 range compensating optics came out, there were changes to make in the rifle to get it shooting dead on the optic graduations.
The projectile MUST exit the muzzle at a specific velocity, and the projectile MUST have a specific Ballistic Coefficient to maintain velocity and therefore bullet drop to shoot on the graduations at distance.

That was a challenge to get the correct BC, weight of bullet & velocity to make the rifle shoot on the optic graduations.
The way it was done before was to 'Dope' the scope, move the reticle, and pray the adjusters all worked like they were supposed to each & every time, and you don't make a mistake in figuring the 'Dope'.
With a velocity, barrel twist rate, bullet weight & BC matching the optic graduations, you simply use the cross on the reticle that matches the range to target, and figure the 'Spin Drift' and wind, you were pretty much on the target without cranking knobs.

It's like recommending a fixed 4x or 6x for a 'Deer' rifle...
First off, you don't get time to adjust a dozen knobs when hunting, so no point in having those big target knobs.
If you can see much past 100 yards around here, you are hunting an open field somewhere, so 300 is about the limit of where you can be sure of your backstop...

The hunting scopes usually have friction adjustments instead of 'Clicks', so you can stop in the middle between where normal 'Clicks' are to get a very precise zero.
Most of us use point blank zero (rifle version) at about 200 yards.
At 100 yards it shoots an inch high, it shoots dead on at 200 yards, and 2 inches low at 300 yards... Point blank zero since it will blow the heart out of a deer from 100 to 300 yards without adjustments, aim point dead on the heart.
This worked for a century before 'Tactical' scopes, and it still works without lighted reticles, big snagging target knobs, all the crap the 'TACTI-COOL' optics have now...

If you shoot much past 300 yards, everytime you change ammo it's time to hit the range to develope a new ballistic card.
I don't know about what others do, but firing 2,500 rounds in all wind conditions to work up another ballistic table is more than I want to do.
I stick with a 'Standard' round that mimics long range military rounds most times so I know more or less what that projectile is going to do.
There is a crap load of information, ballistic tables & accessories that shoot (more or less) on military standards, and that simplifies things.
I like simple when it's available and works...

Now, this kind of goes out the window on civilian 5.56/223 AR clones because the barrel length, barrel twist rate screw things up.
A crap load of civilian 'Varmint' rifles stick with around 10:1 twist rate, while AR twist rates are anywhere from 6:1 to 14:1 (often depending on age, older rifles usually have slower twist rates).

Spinning any bullet faster will help stabilize that bullet, but will screw with spin drift printed data tables.
Shorter barrels or heavier bullets screw with muzzle velocity,
A change in BC screws up velocity at range changing the drop of the bullet, so back to square one,
Sometimes your 'Favorite' round simply needs a ballistic table/range card made up for it, and that takes a LOT of range time.

Minimize all this by getting the optic square, but more importantly TRUE WITH THE BORE so you have a dead even starting point and your shot print at the target can be trusted.
If you want a second reference, a second variable removed, when you have the optic & bore dead centered on the plumb line, with vertical reticle on the plumb line,
Then, and only then, add a 'Bubble' or 'Spirit' level and use it when working up the ballistic table. (Sometimes called an anti-cant device)
It depends on how high the optic is over the bore line, but on M40 rifles 1 minute cant (1 minute mark on a watch face) is 1/2" miss at 100 yards, and over 55" at 1,000 yards.
The bubble level, when it's in line with bore/reticle (and not rifle receiver or optic adjustment caps) keeps you honest on the bench and gets better results when working up a range card/ballistic table.