About Trijicon ACOGs carry handle mounts and range compensating

[Snaps]

First off the most important thing.. The carry handle mounts.. I'm wonder if anybody's got any experience with these? I saw Bushmaster's site that they're a 1 or 2 (second optional) screw mount. I'm wondering if those will hold tight and not come loose? My ARMS mount I've had to loc tite in there.

Also those range compensating recticles..... How accurate are those things? The longest rifle range around me is 100 yrd. So the way I'm thinking is if I get it dialed in at 100yrd it should be accurate at 200, 300 etc. Is that right?

 

[Double Naught Spy]

The ACOG can come loose. Either keep checking the tightness or use something like loctite or paint the threads of the screw such that there is enough friction to help keep it from vibrating loose.

How accurate are the range compensating reticles? They are supposed to be right on, but only for what they were intended. I don't recall the specifics and don't quote me, but from memory, I think they are set for use with a M4, 14" barrel, shooting SS109 (US manufacture military ball, not anyone else's).

Of course, the reality is that outside of the range, you won't get the benefit of always shooting at intervals of 100 yards. What if your target is 341 yards? There is no crosshair there.

 

[Jeff White]

The reticle on the TAO-1 is set up for M855 from a 20" barrel mounted on the carry handle. The TAO-1 NSN is set up for M855 from a 14.5" barrel mounted on the receiver.

I have a TAO-1 mounted on and A.R.M.S. Swan Sleeve in a TA51 mount on a 20" 1/7 twist AR. The reticle is fairly close out to 400 yards with IMI M855. I haven't had the opportunity to shoot it farther then that. I don't normally shoot M855 so the ranging part of the reticle is not that important to me personally.

HTH

Jeff

 

[El Tejon]

Hi, Snaps, I have a couple different models. I mounted my first one on the "carry handle", big mistake, especially up close and was hard for me to get a good weld. Never had a problem with it coming loose but I think I clamped it down with Loctite.

Don't use the range finder clutter as I don't shoot 62 grers. and mount it to the upper receiver. Being of the Old Skul, I don't trust them.

For my experiences with an ACOG, e.g., you can check out my report on YFA's HITT class in the SundT forum thingy.

 

[Bartholomew Roberts]

The reticle on the TAO-1 is set up for M855 from a 20" barrel mounted on the carry handle.

Actually, I believe the TA01 is set up for M193 (55gr) from a 20" barrel mounted to the carry handle and TA01NSN (and all other flattop mounted ACOGs) are set up for a 14.5" 62gr M855 from a TA51 flattop mount.

I'm wondering if those will hold tight and not come loose?

As noted, you'll need to use loctite or vibration from shooting will cause them to work loose. Also, the second screw mount is only available if you drill a second hole in your carry handle; but I have found that as long as you use a dab of blue loctite, the single screw will do just fine.

Also as El Tejon noted, you'll increase height over bore issues in close and for some people the height of a carry handle mount is an uncomfortable cheekweld. I used mine in an A2 for some time but got tired of having to rezero every time I removed the ACOG and the rifle didn't fit in several racks/cases well with the ACOG mounted on the carry handle.

I eventually went to a flattop receiver and an ARMS #19S mount.

So the way I'm thinking is if I get it dialed in at 100yrd it should be accurate at 200, 300 etc. Is that right?

A couple of things to remember - first is that the ACOG is set up for specific barrel lengths, ammunition and mounting locations. If you change just one of these, it won't affect the reticle that much for 99% of your shooting. If you change several of these, you may need to tweak your sight-in procedure in order to better match the reticle. There is a very long post in the optics forum at AR15.com that deals with this; but that site is down at the moment and it is too much information to duplicate here.

Second thing - the ACOG is set up in meters, not yards. You can still zero the ACOG at 100yds; but at longer ranges you need to remember that since 109yds = 100m, you will see some misses if you shoot at a 600yd target (550m) using the 600m hashmark.

Finally, at less than 300yds, there won't be a lot of difference. At 100, there will be even less.

 

[Jeff White]

Bartholomew,
The instruction sheet that came with my TAO-1 (purchased in 1989, still glows brightly BTW) says M855. That matches a Trijicon Spec sheet I picked up in Building 4 at Ft Benning in either 86 or 87 at a conference. I don't know if they've changed that on newer production models. Mine has the original reticule with a dot at the center of the cross hair. This was supposed to be for fast aquisition at close ranges, but in practice the 4X optics makes the scope slow for close in work.

The spec sheet, when they were trying to sell the original to the Army says it was developed specifically for the M16A2 and M855 ammo.

I had a second hole milled into the carry handle of my preban Colt HBAR and used both screws when I had it on that rifle. It came with machinists drawings showing exact placement of the hole. I later mounted it on the carry handle of a different rifle and didn't bother with the second screw. Never had any problem with it coming loose on wither one. It fit very tightly into the carry handle of both the Colt and Bushmaster uppers I had it on. Like everyone else said, a little blue locktite works wonders.

Jeff

 

[Snaps]

The one I was looking at was for the 62gr round and a 16in barrel. Which, I'm geussing is the carry handle mount. I just have a hard time taking the word of the people who sell it i guess

For a short time I had a scope mounted to the carry handle of mine with no problems.

I'm about to start building my new one and I think I'm going with the M-4 style and a trijicon sight.

Thanks for the input all..

BTW: Am I the only one who can't get into AR15com? I keep gettin gpage cannot be displayed. Been that way for 2days now


also I'm not worried about having to remove it. I've got a case that's just perfect for it

IfI do end up going with it it'll be staying there

 

[Jeff White]

Snaps,
For your application, you'll want the TAO-1 NSN. The ballistics will be a bit different out of a civilan legal 16.1 barrel. If you're building your own, you might look at a 14.5" M4 barrel with a vortex FH permanently attached to bring it to length in a pre-ban. If you have to go with a post ban, there are a couple fake flashiders you can permanently attach that will bring you to legal length.

The TAO-1 NSN comes with the TA51 mount that will mount direct to the rail on the upper receiver. You can take the scope out of the mount and mount it on a carry handle. This will change the zero and make the BDC markings in the reticule not as accurate as if it was mounted on the receiver.

Jeff

 

[Snaps]

Dern... i just went and looked at taht one and it sure enough if for a flat top. I've got to find one set up for a carry handle.
The way i was thinking was even on a carry handle mount with one made for a flattop it would just shoot the same once it was aimed in. I'm probably wrong though with my luck.

So now that you've got me wondering what would the difference between a normal 16" barrel and a shorter one with flash hider? I'm planning on going with a preban here. I was kind of thinking of just going with a normal birdcage style flash hider.

any suggestions for the M-4 style on a carry handle?

Oh well, looks like I've got some more checking to do before I start anything.

 

[Jeff White]

Snaps said;

The way i was thinking was even on a carry handle mount with one made for a flattop it would just shoot the same once it was aimed in. I'm probably wrong though with my luck.

It will be close to three inches higher above the bore then it was designed for. You shouldn't have any problem zeroing it, but all bets are off on if the BDC reticule will work right. The TAO-1 NSN can be removed from the flattop mount it comes in and mounted on the carry handle if you choose.

So now that you've got me wondering what would the difference between a normal 16" barrel and a shorter one with flash hider? I'm planning on going with a preban here. I was kind of thinking of just going with a normal birdcage style flash hider.

You will get extra velocity from the 16.1" barrel. This may or may not change the trajectory of the round enough to make the BDC reticule not work as designed. I suspect it will be good at the closer ranges, but I'd want to shoot it at the longer ranges and check before I relied on it.

I suggested the 14.5" M4 barrel with permanently mounted flash hider and a flattop upper as a way of duplicating the rifle the TAO-1 NSN was designed for.

any suggestions for the M-4 style on a carry handle?

You might look at the TA31. You don't get the BDC reticule, but personally I've never used it anyway.

Jeff

 

[Bartholomew Roberts]

Jeff, you may well be right. The Trijicon website lists the following in its FAQ:

http://www.trijicon-inc.com/

The TA01, TA11, & TA31 (.223) was desinged for the 5.56mm, 20 inch barrel, 55 grain bullet, M16/AR15 carry handle mount. The TA01B & TA11C(.308) was desinged for the 7.62mm, 20 inch barrel, 168 grain bullet, M16/AR15 carry handle mount. The TA01NSN was designed specifically for the US Special Operations Command SOPMOD M4 Carbine. To meet their requirements, the reticle bullet drop compensator and range finding stadia lines are based on the trajectory of the 62 grain bullet from a 16 inch barrel, flattop mount (Picatinny rail Mil.Std.1913).

Of course, the M4 is actually a 14.5" barrel and in the past, Trijicon had the eye relief measurements for the TA31 and TA11 backwards for about 18 months on their website. So no telling for sure; but when I asked them about it via email and phone in 2000, they repeated the above concerning the TA01/TA31/TA11.

You might look at the TA31. You don't get the BDC reticule, but personally I've never used it anyway.

The TA31 does have a BDC reticle; but it is much simpler than the TA01 BDC reticle. Just a single vertical line with hashmarks that equal the width of an E silhouette target at that given range.

Personally, I am not a big fan of the TA01 style reticle. I think the BAC reticles are a lot more versatile; but if you need precision and closer range dynamic shots are less of an issue, then it might be the reticle for you.

Should AR15.com ever return to the Internet, the optics forum there has some good pictures of the various ACOG reticles.

 

[Double Naught Spy]

I appreciate y'all clearing up the less than completely accurate statements I made about the ACOGs, but hopefully my point was still made that the precision of the issue is a little grey unless you conform to all the criteria.

You will please forgive my English/Metric problems. If you note the information on the TAO1NSN ACOG, you will see my confusion. From Trijicon's web site...


The TA01NSN was designed specifically for the US Special Operations
Command SOPMOD M4 Carbine. To meet their requirements, the reticle
bullet drop compensator and range finding stadia lines are based on
the trajectory of the 62 grain bullet from a 16 inch barrel,
flattop mount (Picatinny rail Mil.Std.1913).

Magnification: 4X
Eye Relief: 1.5 in
Exit Pupil: 8 mm
Field of View: 7.0 degrees
Length: 5.8 in
Weight: 9.9 oz
Field of View: 36.8 ft at 100 yds
Adjustment: 3 clicks per inch at 100 yds.

For the TA11, you see...

Details: ACOG 3.5x35 Scope with Red Donut BAC Reticle - Features Dual Illumination (Fiber Optic provides daylight illumination and tritium illuminates reticle at night) and Ranging out to 800 Meters for 5.56
(.223 cal) see Reticle diagram

Magnification: 3.5X
Eye Relief: 60mm (2.4in)
Exit Pupil: 10mm
Field of View: 5.5 degrees
Length: 203mm (8.0 in)
Weight: 397g (14 oz)
Field of View: 9.63m at 100m (28.9 ft at 100 yds)
Adjustment: 15 Seconds of Angle per click
(approx. 4 clicks per inch at 100 yds.)
Reticle: 4 MOA Outside Diameter /
2 MOA Inside Diameter
Tritium Activity: 100 milliCuries in one source

What is left in the end is information showing ranging in meters, and correction in fractions of inches at a set number of yards. So, if you are 4.7 CM off at 100 M, and you have a 4 clicks per inch at 100 yards, or 3 clicks per inch at 100 yards, then just how many clicks do you adjust to ZERO?

Yes, you can convert these things, but Trijicon mixes English and Metric.

 

[Jeff White]

Bartholomew,

It's hard to say what's right. I'll dig out the spec sheet I picked up at Benning and the instructions that came with mine. I do know that Trijicon changed the reticule in the TAO-1 at some point. The current reticule has a duplex type crosshair with no dot like mine has. Perhaps they changed the BDC at that time.

I e-mailed them a few years ago and asked what it would cost to upgrade to the newer reticule, they quoted me a price of $132.50 and suggested I wait until the tritium needed replaced.

I might e-mail Trijicon and ask them when they made the change and if that's when they changed the BDC. Or if the literature I received with mine is wrong. I know they didn't sell very well for the first couple years they were in production. I think they hit the market about 1986. I bought mine direct from Trijicon on a dept. letterhead for $625.00 in the Spring of 1989 and received serial number 818. So in three years less then 1000 units had left the factory. It's speculation on my part, but they may have changed the BDC in order to increase sales. M855 wasn't readily available on the civilian market in those days. You could buy some fairly expensive commercial loadings or take your chances with Canadian surplus NATO ammo of which there were a couple of bad lots in circulation in the US then. (I know, I got some and it scared me that my new HBAR had somehow shot out the barrel in a couple hundred rounds.

My bad about the TA31...I thought it had a different reticule...

Jeff