JavaScript is disabled
Our website requires JavaScript to function properly. For a better experience, please enable JavaScript in your browser settings before proceeding.
Messages
3,560
Reactions
9,380
This involves an 18" JSE upper mated to a PSA lower. A couple of typical extras (B.A.D. lever, BCM charging handle, stuff like that), nothing to effect accuracy.

Two new variables;
1) R&R barrel to replace drop-in handguard with a FF tube (ALG Defense).
2) Added a Vortex Spitfire 3x red/green reticle electronic sight.

Today l took it out and could barely get on paper. Since it was a private "range", l eventually walked myself in until I was about 10 FEET AWAY(!)... at that range l was hitting 8-10 inches low... holy shiite! The optic had no more adjustment left, that's why l started literally walking it in. from 25 yds.

The groups were consistent (such as they were) and function was 100%. No jams, FTE, FTF.

Bad barrel install? Incorrect torque, maybe? Shim the optic mount? I didn't level the optic, just mounted it a hoped for the best. Maybe I should have tried a set of MBUIS but l didn't have em with me today... I thought it was going to be a simple sighting-in.

What say you, AR gurus? Where did l drop the ball (or group... 8-10" at 10 FEET)? I burned up a lot of ammo* to find out l may have F'd up.

*cuz it was still shooting, even if l couldn't hit ANYTHING.
 
Dunno what the issue is, however have laser bore sighters in the range bag in 4 of our most used calibers .

The kind that are just like a cartridge.

Not perfect, still have to dial in. However saves a chunk of ammunition when sighting in a new to us firearm, or an optic swap.

-just an idea to help reduce future time/ammo wasteage-
 
New barrel? Different twist rate for your regular ammo makes bullets shoot much flatter? I'll be quite now and let the AR guys talk ;)
 
The problem sounds like optic or mount for sure. Or something really far out like an out spec receiver (very unlikely). If you are grouping barrel is good.
 
It is either a problem with optic or mount or the barrel installation with the free float tube. Is optic mounted on upper receiver rail. Did you follow proper procedure with barrel install, specifically proper torque? What sighting system was utilized before and was poi/ accuracy reasonable before changes?
 
That is an extraordinary amount of elevation deviance. Personally, I would tear down the handguard, barrel and nut for verification of installation. If your ALG requires timing, make sure the timing shims are on the muzzle side of the barrel flange. Fixed or BUIS would help to determine whether it's an optic or barrel problem.
 
Next time bore sight it at home before wasting all that ammo. You can do this two ways easy enough.

1) use a laser cartridge bore sighter. I have the kind that are momentary. You can use these also for dry fire practice. Measure from bore to centerline of optic, keep that distance in mind, make laser hit a point 20 feet away. Adjust optic so it is that distance high at 20 feet.

2) take the BCG out, set the upper somewhere and look through upper, through barrel at a point 20 feet away. Measure from bore to centerline of optic, keep that distance in mind. Make optic hit that distance higher than the bore is centered on.

These methods accomplish the same thing. For an AR with a 16" barrel at regular velocities. This will be close to a 50/200 yard zero.

I've done this before and (call it dumb luck) was dead on at 50 yards.

I do this to all my guns make adjustments to at home, it makes final zeroing a couple shot affair at the range. It would definitely be good enough for a "battle zero" even if you couldn't verify at the range.
 
What brand of duct tape did you use to attach the optic? The cheap stuff always shifts.


Just kidding, of course. If you try the visual through-the-bore bore sighting at home and let us know how that looks, and post photos of the optics and mounting that will help greatly.
 
Book the odds 90% optics, 10% barrel involvement as to probability. Barrel % maybe lower yet.

On AR design, easy enough to do an actual look through the bore. Take the upper off, bolt carrier out, set it on a table and range it on something off in the distance. See if bore and optics align.
 
Is your gas block making contact with the rail or some attachment? That will definitely throw the accuracy into a tail spin.


This is my guess.

Had a similar issue with my Ruger Precision Rifle after installing an ARCA rail on the free float tube. Didn't realize that the screws for the ARCA rail where too long and making contact with the barrel. Couldn't figure out why I only needed 15 MOA of elevation to get to 1000 yards when it was normally 28 MOA. :oops::rolleyes:
 

Upcoming Events

Tillamook Gun & Knife Show
Tillamook, OR
"The Original" Kalispell Gun Show
Kalispell, MT
Teen Rifle 1 Class
Springfield, OR
Kids Firearm Safety 2 Class
Springfield, OR

New Resource Reviews

New Classified Ads

Back Top