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Discussion Starter #1
Hello-

I was about to purchase a standard PS90 the other day, but the white sights were a deal breaker. I can't find any USGs or Tri Rails local to look at, but I have found some good deals on Tri Rails online.

I think the Tri Rail is looking like the best option, but without the benefit of actually trying one out, my biggest concern is how comfortable the gun is with different sights on it.

Do optics on the tri rail sit higher than the standard or USG model ring sights?

How does the tri rail work with the following:

1. EOTech
2. Aimpoint Comp M
3. Trij ACOG 4X NSN

Can you get a comfortable cheekweld with any of the above sights, or do they sit too high?

TIA
 

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The Eotech fits well. But I don't cheek-weld with the PS90. I think a head-up body forward style with an Eotech is the fastest way to use a PS90. It allows you to switch POI with a your hands, instead of moving your whole upper body. I know it is counter to everything you ever learned about shooting, but it works. FNH trains police and military to use a heads up style with the P90, and they say to put the butt of the weapon more on the chest than on the shoulder.
 

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I own a Tri-Rail with a Cmore sight. I cheek weld is a little low but you can still get one. If you put the mag clamp on and then you have that extra magazine sitting a bit higher. The cheek weld is better. So basically either way you do it, it is fine. But I do prefer the extra height of the magazine.
 

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This is my head position with the PS90 and an Aimpoint Comp 2x2


This is a better view of the setup.



This is what I was used to with an AR and an EOtech.


TA
 

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Discussion Starter #5
All,

Thanks for the replys.

TX Armadillo,

The pictures really help. It looks like the weld is slightly higher than with an AR/EOTech--Is that a correct assessment? Is your PS90 a standard with the ring sight removed? Any idea how that compares to a trirail? Maybe the ring model is a better buy if they are the same anyway; at least you get a ring sight out of the deal with the standard.

TIA
 

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Yes, mine is a PS90 that came with a white ring optic.

A sight mounted on your tri-rail should sit a little higher. I was just trying to give you an idea of how high yours would be.

TA
 

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Well, realize that the white ringed sight version will be cheaper than a tri rail or a black ringed sight version - just buy it - and then spend a few bucks on an optic rail. U can buy the side rails and optic rails and add them yourself - usually for the same, or even less than a tri-rail.

When I got mine, there were not many options on places to buy the rails. Now, two of our sponsors here (Critical Dimensions and MPF Tech) sell rails for cheaper than the ones I had to buy in Dec 2006.
 

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The rail on a TR sits lower than any rail mounted on in place of the standard sight.

As my SBR paperwork was in process for my TR, I tried out my EOtech 551 and Trijicon ACOG TA31F/LaRue on the gun. In my opinion, both were too high for my taste. I'd charaterize it as a jaw or chin weld vs. a cheek weld.

I was pining for a still-not-available Aimpoint Micro, but also liked the thought of a little magnification. I "settled" on a compact ACOG TA40-R2 - a special ring mount, 2x20 red triangle) with the lowest mount Trijicon makes for it. Optic height (from an engineer at Trijicon) is 0.90" vs. 1.53 for the TA31F. A world of difference - I can get a good cheek weld on the gun. Check out my SBR/cACOG post for a picture, I also posted another thread comparing it to my Colt M16A2 with the TA31F mounted.

The Aimpoint Micro is suppose to be a tad lower at 0.75" and I think that would give a really down-on-it cheek weld.
 

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Whil ethere is a tiny height difference between the triple rail and the standard version with an aftermarket rail - it is negligible.

I am right handed but left eye dominant - so, the height of the eotech doesn't bother me.
 

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ShipWreck said:
While there is a tiny height difference between the triple rail and the standard version with an aftermarket rail - it is negligible.
You are correct sir. I just looked at this at my dealer today. We laid the standard (Ring Sight) model down one on top of a Triple Rail model, and the difference was only about 1/10". It looks like more than that when you view them separately, but if you actually measure, the difference is tiny.
 

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There is a thread on one of these forums comparing a ring sight model with a rail attached vs. a TR. The TR is notably lower - more than a tenth, I'd say at least a quarter inch. Any which way, I went with a TR because I wanted the lowest possible (which is still pretty high) and I wanted flexability with the optic. I knew I didn't like the standard ring sight and at the time the USSS sight was +$600. For +$1000 I got the compact ACOG and am firmly convinced that it is a superior optic.

I've seen the mounts made by TROS for the standard model, and while they mount the cACOG or Aimpoint very low, there is no fore/aft adjustability for eye relief.
 

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Shipwreck, no bashing intended. I mean we all have to buy what's available when we want to by. Some folk had to settle for a green stock! :D

I'm just trying to provide input to the original poster who is trying to decide what to buy now.
 

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ShipWreck said:
Well, when I got mine, there was no tri-rail version out yet. That came later.
Yea, same here. Had I had the choice, I would have definitely went with the TR version. And my only point about the difference in the two models is if you already have the standard model you won't notice a big difference if you replace the Ring Sight with an optics rail.

Time for a group hug?
 

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AverageJoe said:
Yea, same here. Had I had the choice, I would have definitely went with the TR version.
Well, ya know what - I still would get the same version. I like that I can have longer side rails on my regular PS90. The tri rail has tiny side rails. Magazine Parts sells slightly longer side rails for the triple rail PS90 but they are still very short.

Also, if for some strange reason I wanted to take my eotech off and use it for something else - I could at least put the stock sight back and and make use of the gun if I wanted to.

Now, the optic rail and side rails were not cheap when I got mine in Dec - but now that MPF Tech and Critical Dimensions have rails at really good prices, U can buy a standard PS90 and equip it with 3 rails for less than the triple rail version.

Now, if FN added a laser to the tri rail version, then I'd be interested :p
 
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