Warning

 

Close

Confirm Action

Are you sure you wish to do this?

Confirm Cancel
Member Login
Posted: 10/13/2005 1:38:39 PM EDT
I tried to do a search on this but was unable to find anything. I called Bushmaster about this, and they said that the rear sight on my Patrolman M4A2 is meant to be slightly crooked in a counterclockwise (left) position. Something about a ball detent and the need for adjustment clearance. Is this correct? I'm more of a pistol guy who's just getting into AR-15's, so please have patience with me if I asked a stupid question.
Link Posted: 10/13/2005 1:41:06 PM EDT
Are you talking about the rear sight aperture moved slightly off center when the rifle is zeroed or are you talking about the rear sight assembly being slightly twisted off axis from the rifle?
Link Posted: 10/13/2005 1:42:03 PM EDT
Yes it's perfectly normal.
Link Posted: 10/13/2005 1:56:50 PM EDT
Like this............?



we had a healthy discussion on this and it was overwhemingly determined to be "normal"

Precision or CMP shooters go with 'fixes" or replacements that are pinned and square, otherwise good to go.
Link Posted: 10/13/2005 1:57:25 PM EDT
Link Posted: 10/13/2005 1:59:28 PM EDT
Redfisher, we posted almost simultaneously. Thanks for the help. I just wanted to make sure Bushmaster wasn't giving me some BS.
Link Posted: 10/13/2005 2:01:56 PM EDT
I have a Bushmaster carry handle and mine looks just like that. I assumed it was normal and I wasn't really worried about it too much. I'm glad that's the general consensus.
Link Posted: 10/13/2005 2:04:15 PM EDT
now thats what i expect from a 100+ dollar carry handle. guess it would cost too much to make the sight fit right...
Link Posted: 10/13/2005 2:25:06 PM EDT
Normal....My Bushmaster and my Colt are both like that.
Link Posted: 10/13/2005 2:43:46 PM EDT
It is a bit disconcerting to see that these manufacturers have that engineered into the design. It give the rifle a somewhat cheap appearance IMO.
Link Posted: 10/13/2005 2:44:15 PM EDT
[Last Edit: 10/13/2005 2:47:23 PM EDT by 200-10x]
YES, perfectly normal... the site base is spring loaded (twist it straight and see, it will return to the slightly "canted" position. It does not cause accuracy issues at all. I shoot High Power matches at 600 yards and it's not an issue.

SOME people believe that at that distance, reproducibility is an issue as you can put 10-20 minutes on going from 100 to 600 yards. WOP, Compass Lake, Accuracy Speaks and some other competitive smiths offer site bases with 2 or 3 "pins" that hold it straight, if you're so inclined. Obviously, you'd have to ship your upper to them, so that it can be drilled for the pins.

There is a company in WI, I forget who at the moment, that sells A2 site bases with a little "bump" welded on the forward side of the base to hold it straight, but I think that's just a single point that rubs up and down. At least with the whole thing sliding as you add elevation, it won't also torque vertically around that little "bump"
Link Posted: 1/2/2006 1:22:10 AM EDT
Link Posted: 1/2/2006 4:09:18 AM EDT
One more reason A1's rule!

Link Posted: 1/2/2006 4:42:15 AM EDT
[Last Edit: 1/2/2006 4:44:53 AM EDT by pun]
I just posted a question with a similar problem,wich Tweak helped me a great deal.I have an A2 upper that does this but my others dont..they move but line up straight with no cant..I think its just like Tweak said ..sloppy fit..it should not stay that way.I think its a poorly machined handle.It should have more meat on the right to prevent it from canting that far.And although the eacuracy is fine I had to compensate with windage adjustments 5 clicks right.
Link Posted: 1/2/2006 4:54:08 AM EDT
my DPMS is like that as well.
Link Posted: 1/3/2006 11:35:46 AM EDT
Fulton Armory provides a nifty handbook when you purchase an AR from them. By coincidence I jusread last night that this is normal, and they even explain why. I've never noticed. I don't even think I've ever used the carrying handle on mu issue M4.
Link Posted: 1/3/2006 12:00:13 PM EDT
It seems to have to do with how the sight assembly fits into the cutout in the handle. If the assembly body is snug against the front of the cutout, it won't turn, but if there's room for it to move, it will. I don't have the detailed specs (or the know-how to properly read them) but I'll bet this is a case of the tolerance for the cutout and the tolerance for the body not "playing nice." A small body in a large cutout will turn, and a large body in a small cutout will bind.
Link Posted: 1/3/2006 3:06:50 PM EDT
Link Posted: 1/3/2006 6:07:54 PM EDT
My Colt 6721's handle is the same way, and yes tweak, if I raise the elevation all the way up, it straightens at about the last two clicks.
Link Posted: 1/3/2006 6:23:46 PM EDT
Link Posted: 1/4/2006 5:00:26 AM EDT
Interesting!

I sent my M4A2 back to Bushmaster because rear sight was way off center. They replaced upper receiver and sight is now perfectly aligned. I was surprized they replaced upper receiver but was glad they did so....New upper has an excellent finish and is matches and fits to lower perfectly.

Side note - Wanting to scope my A2 on a budget I purchased AR/M16 scope manufactured by Hakko in Japan....looks just like original Colt scope and appears to be excellent quality. First time out is shoots dead on at 50 yards(thats all the distance I have to shoot) and required no adjustment - I was impressed...downside, eye relief is is insufficient. Next time out I'm shooting 12 inches to the left and can't get is dialed back in....weird...it appears that what I read in other forums about this scope is true...they don't hold zero.....I would expect that from a China copy but thought a Japan made unit would be excellent.

Dill

Link Posted: 1/4/2006 6:23:45 AM EDT
Normal!
Link Posted: 1/4/2006 11:09:23 AM EDT
Normal but fairly easy to repair.

Drill a blind hole on the side of the moveable sight base opposite where the spring and plunger are located. This hole should be parallel to the existing plunger hole. Insert a short piece of aluminum or steel rod into the hole so that it protrudes slightly. It now becomes a new "stop" for the sight. File the exposed part of the rod down until it causes the sight base to be properly aligned with the carry handle.

Reassemble the whole thing and you are good to go.
Top Top