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Trijicon ACOG

Posted: Mon Mar 02, 2009 11:13 am
by Purplehood
Okay, I bought one for my AR-15 and took it to the range. I opened up the USMC manual that came with it, and realized that despite my MBA and the manual being geared towards 7th-grade readers that I wasn't making sense of it.

My questions:

- Mounting on the rail. I remember alot of marksmanship training regarding the subject of eye-relief (distance from eye to rear sight being constant). What is the proper way to mount the ACOG and ensure constant eye-relief?

- Sighting it in. In all of my years of shooting it has always been with open sights. Whenever I used a scope it belonged to someone else and was simply a cool novelty. I have no clue how to go about doing it. I wasted 30 rounds shooting at a target at 100 yds yesterday (American Shooting Center, NW Houston), and barely hit paper using it.

I had an ACOG overseas but never mounted it. I figured that if anyone got past the security element on a mission, my open sights would work just fine.

Anyone have any constructive advice?

Re: Trijicon ACOG

Posted: Mon Mar 02, 2009 4:20 pm
by JasonH
I'm not sure if this is particularly helpful but I mounted mine with a LaRue LT100 mount which has the quick detach and really love it.

Super simple to yank the optic off and switch to back up sights and if you pop it back on you're still zeroed. Nifty stuff.

I doubt we're doing it the right way, but I have always just had a buddy looking through the spotting scope telling me where I was hitting and after each shot adjusted as necessary. Definitely easier with a buddy watching the impact.

Re: Trijicon ACOG

Posted: Mon Mar 02, 2009 4:34 pm
by wilder
If you don't have anybody handy with a spotting scope then a boresighter is the next best thing. If that isn't an option the get on paper at 25 yards or something before moving to 100.

Re: Trijicon ACOG

Posted: Mon Mar 02, 2009 4:38 pm
by Purplehood
I was thinking along those lines. Maybe using my spotting scope at 50 yds, since I couldn't see the shot placements at 100 yds.

Re: Trijicon ACOG

Posted: Mon Mar 02, 2009 5:57 pm
by WEC
Purplehood wrote: - Mounting on the rail. I remember alot of marksmanship training regarding the subject of eye-relief (distance from eye to rear sight being constant). What is the proper way to mount the ACOG and ensure constant eye-relief?
I would imagine this is based on the shooter. Some like to be a little more forward when resting a cheek on the stock, others a little more back. It depends on arm length, etc. My advice is to find where you are comfortable holding the AR-15, and then mount the ACOG according to that position. That's part of the benefit of having the picatinny rail system. :cool: Also, it would help to know what type of mount you're using, whether it be the thumbscrew one that comes with the ACOG or some sort of throw-lever mount. Of course, make sure it's tight, because any play can throw off the sighting.
Purplehood wrote: - Sighting it in. In all of my years of shooting it has always been with open sights. Whenever I used a scope it belonged to someone else and was simply a cool novelty. I have no clue how to go about doing it. I wasted 30 rounds shooting at a target at 100 yds yesterday (American Shooting Center, NW Houston), and barely hit paper using it.
As others and you've said, try sighting in closer and then moving out to 100. ASC still has the 50 yd section, right?

Hope this helps!

Re: Trijicon ACOG

Posted: Tue Mar 03, 2009 3:24 pm
by Purplehood
The reason I picked up this item (besides there not being an Eotech or Aimpoint in stock at that moment) was that it was the first solar powered one I had ever seen (fiber optic on top). It has 4x resolution and a crystal clear light-amplifying sight that blew away the one I had overseas (sweet red chevron in center with both windage and elevation marks).
The manual did say to keep both eyes open when using unless you were forced to use your non-dominant eye.

Re: Trijicon ACOG

Posted: Tue Mar 03, 2009 10:42 pm
by Moonpie
1.) Mounting the ACOG depends on what type of weapon you're using it on.
If its a typical flat-top AR, put the gun up to your shoulder in a normal firing position. Move the scope back and forth along the rail until you get the eye relief set for you. The ACOG F model has a very short eye relief. I have to put my nose on the charging handle to get full field of viw in the ACOG.
Its really quite simple.

2.) Sight in: First make sure the ACOG is mounted secure. Absolutel no movement of base or scope once you tighten it down.
Easist way to start is to have it bore sighted. My gun shops can do this for a small fee. This will usually get you on paper at 100yds.
Lacking that you must do it by trial and error.
Put up a large paper target at 25yds. Put a 1" spot in the center to have an aiming point. Fire a round at the center dot. If you can't see the bullet hole you may have to move the target closer to you until you can establish where there shot is going. Based on where the bullet hole is, adjust your scope knobs as needed to dial it in. This should not take a bunch of rounds. 10 or so should get you close. Once you get a few rounds consistantly on the dot, move the target out to 100yds and finish fine tuning your adjustment.

Hope this helps.

p.s. ACOG's are super cool!

Re: Trijicon ACOG

Posted: Wed Mar 04, 2009 7:30 am
by Purplehood
Moonpie wrote:1.) Mounting the ACOG depends on what type of weapon you're using it on.
If its a typical flat-top AR, put the gun up to your shoulder in a normal firing position. Move the scope back and forth along the rail until you get the eye relief set for you. The ACOG F model has a very short eye relief. I have to put my nose on the charging handle to get full field of viw in the ACOG.
Its really quite simple.

2.) Sight in: First make sure the ACOG is mounted secure. Absolutel no movement of base or scope once you tighten it down.
Easist way to start is to have it bore sighted. My gun shops can do this for a small fee. This will usually get you on paper at 100yds.
Lacking that you must do it by trial and error.
Put up a large paper target at 25yds. Put a 1" spot in the center to have an aiming point. Fire a round at the center dot. If you can't see the bullet hole you may have to move the target closer to you until you can establish where there shot is going. Based on where the bullet hole is, adjust your scope knobs as needed to dial it in. This should not take a bunch of rounds. 10 or so should get you close. Once you get a few rounds consistantly on the dot, move the target out to 100yds and finish fine tuning your adjustment.

Hope this helps.

p.s. ACOG's are super cool!
Ah, thanks for that advice. I will take it to a shop and do the bore-sighting thingie and then to a range. Thanks again.

Re: Trijicon ACOG

Posted: Wed Mar 04, 2009 8:48 am
by RECIT
If you buy a laser bore sight tool you can do it yourself over and over again instead of paying a one time fee. If you change optics or weapons you can set it up without a trip to the smith.

Re: Trijicon ACOG

Posted: Wed Mar 04, 2009 8:50 am
by Purplehood
RECIT wrote:If you buy a laser bore sight tool you can do it yourself over and over again instead of paying a one time fee. If you change optics or weapons you can set it up without a trip to the smith.
LOL, something else to buy. These available at normal gunshops or are they a more specialized item? I ask because I cannot access weapons-related sites while at work.

Re: Trijicon ACOG

Posted: Wed Mar 04, 2009 9:18 am
by Backslider
Purplehood wrote:
RECIT wrote:If you buy a laser bore sight tool you can do it yourself over and over again instead of paying a one time fee. If you change optics or weapons you can set it up without a trip to the smith.
LOL, something else to buy. These available at normal gunshops or are they a more specialized item? I ask because I cannot access weapons-related sites while at work.
I saw them on the rack at Cabela's last week, and you can even get them from Amazon.

I like the style of the cartridge-based ones, but the magnetic or arbor style models seem much more flexible.

Re: Trijicon ACOG

Posted: Wed Mar 04, 2009 9:44 am
by Purplehood
Backslider wrote:
Purplehood wrote:
RECIT wrote:If you buy a laser bore sight tool you can do it yourself over and over again instead of paying a one time fee. If you change optics or weapons you can set it up without a trip to the smith.
LOL, something else to buy. These available at normal gunshops or are they a more specialized item? I ask because I cannot access weapons-related sites while at work.
I saw them on the rack at Cabela's last week, and you can even get them from Amazon.

I like the style of the cartridge-based ones, but the magnetic or arbor style models seem much more flexible.
Just ordered a Leupold Zero Point Magnetic Illuminated Boresighter - 59012 from OpticsPlanet. It says that I do not need to shoot rounds to sight in the scope.

The accompanying photo on the website showed the boresighter magnetically stuck to the muzzle of an AR-15. It looked to me like it would actually block whatever optic you are trying to use, so I am really hoping that it comes with clear, concise and above all, elementary directions in its proper usage.

Re: Trijicon ACOG

Posted: Wed Mar 04, 2009 3:10 pm
by Backslider
You'd better hope that it extends in front of the optic - it looks like that's how it's supposed to work.

real-world instructions

Re: Trijicon ACOG

Posted: Wed Mar 04, 2009 3:14 pm
by Purplehood
Backslider wrote:You'd better hope that it extends in front of the optic - it looks like that's how it's supposed to work.

real-world instructions
Thanks for the link. I think that even I understood that.