Aries144
06-16-11, 01:18
I've tried three red dot mounting solutions so far.
http://i144.photobucket.com/albums/r173/aries14482/DSC00470sm.jpg
I actually really liked this setup using a "mid jaw weld" because it kept your head up high and allowed you to get the stock lower, which I found helped with recoil management. It was also easier on the neck when used for any length of time. My side rail mount didn't allow for a co-witness, but was high enough to look under and see the iron sights.
http://i144.photobucket.com/albums/r173/aries14482/181893_1816252216172_1536111540_1994818_5018212_n.jpg
I got an Aimpoint-R1 and Ultimak when the R1s were on sale. I noticed a definite improvement in handling with this setup over my previous sidemounted CompM2 since it reduced the weight by almost a pound. I didn't mind that the added weight of the mount and optic was forward of the rifle's point of balance, since it was only 5.5 ounces total. This setup did cowitness with my R1.
http://i144.photobucket.com/albums/r173/aries14482/DSC00713.jpg
After adding a Surefire G2 and Vltor mount, which added another 6 oz, and considering the possibility of mounting a suppressor (which would add about 21oz to the most forward part of the rifle), I decided I wanted to try to find a way to move the rifle's point of balance back to improve handling, which led me to the TWS rail.
Moving the Aimpoint micro to the rear of the TWS rail from the Ultimak has moved the point of balance rearward significantly, as I hoped it would. With the light still mounted on the Ultimak, the point of balance is 1/2" in front of the magazine. It is 1/4" behind the front of the magazine with the light removed.
I find having the optic closer to my eye (as was also the case with my siderail mounted Comp M2) also makes it a little easier to avoid having to hunt for the dot while shooting while moving or when bringing the weapon up from low ready or patrol carry positions for the first shot. I've heard some people mention a preference for having the optic mounted forward to clear the field of view, complaining that having it close to the eye blocks their vision. Having tried it both ways I haven't found that to be an issue at all, at least in multi gun competition.
As much as I liked my Krebs aperture replacement rear sight, the aperture I got with the TWS rail is better. Having it close to your eye gives you the full benefit of an aperture sight.
The iron sights do have roughly a 1/3 lower co-witness.
The only things I find with the potential for concern with this setup are durability and zero.
The setup requires replacing the rear section of the recoil guiderod, including the takedown button, with one designed to provide tension to the rear of the top cover. I have read one user report that the special guide rod part broke on his example, whether or not it broke in such a way as to render his rifle inoperable, he didn't say.
I am also somewhat concerned about the durability of the junction between the section that replaces the rear sight and the main part of the cover.
These two sub-assemblies are separate to allow for variations in length between the rear sight pivot hole and the section of the rear trunnion where the rear of the top cover is held. The sub-assemblies are fitted together with a "step", which prevents side to side movement and rotation but allows sliding forward and backward to make the length adjustment, and then held together using two hex screws. I have to wonder if a dovetail instead of the simple "step" might not be stronger, since it would not require the two screws to serve as the only things holding the two sections together.
I have not heard or read of any problems with damage, but I am concerned about whether or not damage to this area would result if the weapon landed upside down after being dropped.
With regard to zero, I am somewhat concerned about the mount holding elevation zero, since the part that prevents movement of the topcover on this axis is the replacement takedown button/recoil spring guiderod. The bolt carrier comes into contact with an attached metal buffer, like that seen on a Saiga rifle, with every shot. I am not yet certain whether or not this can result in significant movement of said part, resulting in changes in the up/down position of the rear of the top cover.
In summary:
The siderail mount
Pros:
Quick to install and remove optics with small zero shift (My example would reliably return to within about 2 MOA of original zero when removed and remounted)
With a high mount, they allow a comfortable "heads up" shooting method that allows your head to remain erect using a "chin weld" while the buttstock is on the upper chest or in the pocket of the shoulder
Depending on the mount, they can mount the optic close to or behind the weapon's point of balance.
Can mount red dot or magnified optics.
Can co-witness.
Doesn't expose optics to heat (if that's a concern).
Cons:
Adds a significant amount of weight, in some cases, as much as half a pound.
Prevents triangle and 100 series type stocks from locking closed. (The stock can still be "mostly folded" but it swings around freely, adds significant width to the rifle in this position, and greatly increases the likelihood of damage to the stock hinge.)
Currently can only allow cowitness for red dot optics with 30mm tubes. (A micro red dot could be mounted in combination with a piccatinny rail mount, but would sit too high to cowitness.)
The Ultimak
Pros:
Little added weight (since it replaces the gas tube, it effectively adds only 1.75 oz to overall weight)
Is in a perfect spot to mount a light.
Can mount optic and light on one mount.
Can co-witness.
It allows mounting a red dot forward on the weapon to minimize its impact on field of view.
Cons:
Exposes mounted items to fairly high levels of heat. There have been reports of some optics (an RMR sized optic that used fiber optics as a supplementary daylight lighting system, IIRC) failing due to this heat.
Places mounted items and optics forward of the weapon's point of balance, which does make the weapon more muzzle heavy.
Not a good mounting solution for magnified optics, unless intending to use a pistol scope or other long eye relief scope.
The TWS rail
Pros:
It adds very little overall weight- 1.5 oz with rear aperture sight. (closer to 1 oz for the old version of the recoil guiderod/takedown button that omits the hinged steel buffer intended for use on .308 Saigas. This older version part may be available on request.)
Can co-witness.
It adds the possibility of a rear aperture sight.
Can mount red dot or magnified optics.
It allows for optics to be mounted at or behind the weapon's point of balance.
Doesn't expose optics to high heat (if that's a concern).
Cons:
Durability is unproven.
Effect on zero with use over time is unproven.
Would benefit from arriving with some form of installation instructions. My example arrived with no instructions. (I actually used Sturmgewehr's Military Arms Channel youtube review as a guide, since he did a walkthrough of installation.)
http://i144.photobucket.com/albums/r173/aries14482/DSC00470sm.jpg
I actually really liked this setup using a "mid jaw weld" because it kept your head up high and allowed you to get the stock lower, which I found helped with recoil management. It was also easier on the neck when used for any length of time. My side rail mount didn't allow for a co-witness, but was high enough to look under and see the iron sights.
http://i144.photobucket.com/albums/r173/aries14482/181893_1816252216172_1536111540_1994818_5018212_n.jpg
I got an Aimpoint-R1 and Ultimak when the R1s were on sale. I noticed a definite improvement in handling with this setup over my previous sidemounted CompM2 since it reduced the weight by almost a pound. I didn't mind that the added weight of the mount and optic was forward of the rifle's point of balance, since it was only 5.5 ounces total. This setup did cowitness with my R1.
http://i144.photobucket.com/albums/r173/aries14482/DSC00713.jpg
After adding a Surefire G2 and Vltor mount, which added another 6 oz, and considering the possibility of mounting a suppressor (which would add about 21oz to the most forward part of the rifle), I decided I wanted to try to find a way to move the rifle's point of balance back to improve handling, which led me to the TWS rail.
Moving the Aimpoint micro to the rear of the TWS rail from the Ultimak has moved the point of balance rearward significantly, as I hoped it would. With the light still mounted on the Ultimak, the point of balance is 1/2" in front of the magazine. It is 1/4" behind the front of the magazine with the light removed.
I find having the optic closer to my eye (as was also the case with my siderail mounted Comp M2) also makes it a little easier to avoid having to hunt for the dot while shooting while moving or when bringing the weapon up from low ready or patrol carry positions for the first shot. I've heard some people mention a preference for having the optic mounted forward to clear the field of view, complaining that having it close to the eye blocks their vision. Having tried it both ways I haven't found that to be an issue at all, at least in multi gun competition.
As much as I liked my Krebs aperture replacement rear sight, the aperture I got with the TWS rail is better. Having it close to your eye gives you the full benefit of an aperture sight.
The iron sights do have roughly a 1/3 lower co-witness.
The only things I find with the potential for concern with this setup are durability and zero.
The setup requires replacing the rear section of the recoil guiderod, including the takedown button, with one designed to provide tension to the rear of the top cover. I have read one user report that the special guide rod part broke on his example, whether or not it broke in such a way as to render his rifle inoperable, he didn't say.
I am also somewhat concerned about the durability of the junction between the section that replaces the rear sight and the main part of the cover.
These two sub-assemblies are separate to allow for variations in length between the rear sight pivot hole and the section of the rear trunnion where the rear of the top cover is held. The sub-assemblies are fitted together with a "step", which prevents side to side movement and rotation but allows sliding forward and backward to make the length adjustment, and then held together using two hex screws. I have to wonder if a dovetail instead of the simple "step" might not be stronger, since it would not require the two screws to serve as the only things holding the two sections together.
I have not heard or read of any problems with damage, but I am concerned about whether or not damage to this area would result if the weapon landed upside down after being dropped.
With regard to zero, I am somewhat concerned about the mount holding elevation zero, since the part that prevents movement of the topcover on this axis is the replacement takedown button/recoil spring guiderod. The bolt carrier comes into contact with an attached metal buffer, like that seen on a Saiga rifle, with every shot. I am not yet certain whether or not this can result in significant movement of said part, resulting in changes in the up/down position of the rear of the top cover.
In summary:
The siderail mount
Pros:
Quick to install and remove optics with small zero shift (My example would reliably return to within about 2 MOA of original zero when removed and remounted)
With a high mount, they allow a comfortable "heads up" shooting method that allows your head to remain erect using a "chin weld" while the buttstock is on the upper chest or in the pocket of the shoulder
Depending on the mount, they can mount the optic close to or behind the weapon's point of balance.
Can mount red dot or magnified optics.
Can co-witness.
Doesn't expose optics to heat (if that's a concern).
Cons:
Adds a significant amount of weight, in some cases, as much as half a pound.
Prevents triangle and 100 series type stocks from locking closed. (The stock can still be "mostly folded" but it swings around freely, adds significant width to the rifle in this position, and greatly increases the likelihood of damage to the stock hinge.)
Currently can only allow cowitness for red dot optics with 30mm tubes. (A micro red dot could be mounted in combination with a piccatinny rail mount, but would sit too high to cowitness.)
The Ultimak
Pros:
Little added weight (since it replaces the gas tube, it effectively adds only 1.75 oz to overall weight)
Is in a perfect spot to mount a light.
Can mount optic and light on one mount.
Can co-witness.
It allows mounting a red dot forward on the weapon to minimize its impact on field of view.
Cons:
Exposes mounted items to fairly high levels of heat. There have been reports of some optics (an RMR sized optic that used fiber optics as a supplementary daylight lighting system, IIRC) failing due to this heat.
Places mounted items and optics forward of the weapon's point of balance, which does make the weapon more muzzle heavy.
Not a good mounting solution for magnified optics, unless intending to use a pistol scope or other long eye relief scope.
The TWS rail
Pros:
It adds very little overall weight- 1.5 oz with rear aperture sight. (closer to 1 oz for the old version of the recoil guiderod/takedown button that omits the hinged steel buffer intended for use on .308 Saigas. This older version part may be available on request.)
Can co-witness.
It adds the possibility of a rear aperture sight.
Can mount red dot or magnified optics.
It allows for optics to be mounted at or behind the weapon's point of balance.
Doesn't expose optics to high heat (if that's a concern).
Cons:
Durability is unproven.
Effect on zero with use over time is unproven.
Would benefit from arriving with some form of installation instructions. My example arrived with no instructions. (I actually used Sturmgewehr's Military Arms Channel youtube review as a guide, since he did a walkthrough of installation.)