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Page AR-15 » Troubleshooting
AR Sponsor: bravocompany
Posted: 2/25/2006 5:38:47 PM EDT
OK guys, I read the thread here about the rifle shooting about a foot to the right at 50 yards and I have a similar situation. Now mind you I have never taken one of these things completely down nor built one from scratch so some of the stuff mentioned has me a tad confused.

I have a Bushmaster 20" A2 preban and while I can get it sighted in, my rear sight is VERY far, though not completely, to the left. (Rifle shooting far right). Theres a few clicks before it is as far over as it goes but it bugs me. Is this anything to worry about since it WILL zero in or do you think its probably an overtorqued barrel or something?

Ive had this particular rifle for about a year and when I read that other thread it just got me to thinking about it...............

I have 4 other Bushys and they all zeroed in a few clicks from center.

Leave it alone or make some adjustments? What yall think?
Link Posted: 2/25/2006 5:50:17 PM EDT
[#1]
Ahhh yes, the ol Bushmaster canted FSB syndrome... If its zeroed, you could leave it alone... If the aperture not being centered is bothering you, whack the front sight base into alignment using a mallet...
Link Posted: 2/25/2006 5:53:49 PM EDT
[#2]
I agree with shootersden,  it sounds like a canted FSB.
Link Posted: 2/25/2006 5:56:27 PM EDT
[#3]
Truth is............ it bothers the hell out of me........LOL!
Yall serious about whackin it with a mallet??
Link Posted: 2/25/2006 6:11:19 PM EDT
[#4]

Quoted:
Yall serious about whackin it with a mallet??



Yup... Just be sure to move it in the right direction the first time so you don't end up having to move it back and forth... Another note, don't smack the winged/ears area of the FSB, whack it below the ears...

ETA: Im with you, it would bother the hell out of me too...

The heavy hard rubber mallets with the lead shot in them works great...
Link Posted: 2/25/2006 6:19:05 PM EDT
[#5]
Well, I'll take yalls advice and smack it. I have some "dead-blow" mallets to use so there wont be any marring.
Link Posted: 2/25/2006 6:19:06 PM EDT
[#6]
Link Posted: 2/25/2006 6:22:35 PM EDT
[#7]

Quoted:
Yes, you can use a leather mallet to drift the barrel in the upper socket.  This rotates the whole barrel in the upper receiver, and correctly indexes the front sight to where it should be, i.e. the barrel is always going to shoot the same place, but by re-indexing the barrel (front sight index plain), you now make the sights look where the barrel is shooting.

But, since we have been seeing this coming out of Bushmaster way to frequently, here is a better idea.  Get Bushmaster on the phone and have them issue you a call tag to send the rifle back to them for correction. Somehow who every from Bushmaster monitors the posts here, has been a sleep at the wheel, and it going to take the accounting department a few hits on shipping charges until they go out to the shop and straighten out the tech how is installing the barrels canted.



I wonder if since Ive had this particular rifle for a little over a year if they would take care of it as warranty? Truthfully I shoulda done something about it when I got it but I was a dumbass and didnt.........
Link Posted: 2/25/2006 10:02:04 PM EDT
[#8]
Link Posted: 2/26/2006 7:22:30 AM EDT
[#9]
Ok guys............... (Laugh!)..........
I got up this morning with this still on my mind so I did the mallet-whack thing.
First I marked the sight base and barrel just to see exactly what the heck (if anything) I would be moving. I had a no-mar mallet handy and went ahead and gave it 3 or 4 whacks.
I went down to the range (I have one here handy on my property) and set up my targets and sandbags on the bench. Fired 2 rounds and walked down to inspect. (50 yards) and it was completely off the target. I though OH SH!T!......... Then I realized I hadnt centered the rear back up, so I did that and fired another couple rounds. This brought it back to the paper and I realized I had miscalculated my whacks...LOL!
I adjusted the rear farther, which put it farther to the right than it needed to be and test fired again.
Long story short, I wound up whackin it once back in the opposite direction and everything fell in place with the rear being pretty close to center.
There was no movement between sight base and barrel according to my marks so I guess the barrel assembly moved entirely. At any rate it worked and everything seems fine.
Thanks for the lesson. Maybe i can sleep tonight...........      
Link Posted: 2/26/2006 2:26:09 PM EDT
[#10]
LOL... It sounds like it was a good learning experience...  

Good to hear it worked out for you in the end... Sleep well...
Link Posted: 2/26/2006 2:30:47 PM EDT
[#11]
Ya know.............. Ive always thought my wife was a little twisted too, but she wont let me whack her in the noggin with the mallet............... may lose sleep again tonight trying to figure that one out.................
Link Posted: 2/26/2006 5:17:12 PM EDT
[#12]
So, to clarify (as I have three uppers from various places with this issue) I want to wack the front sight in the direction of the group correct ?

For example my group is to the right, therefore I will knock the front sight towards the ejection port side of the weapon. Is this right ?

Seems like you move the rear sight in the direction you want the group to go, the front sight moves in the direction of the bullets. Or do I have that backward ?

I have a bench vise, and a DPMS receiver block, was going to fix the upper in to the vise and then whack as mentioned above. If currently hitting 6 inches to the right at 25 yards, should be a few degrees and in business I should think.

Thanks for any input
Link Posted: 2/26/2006 6:02:40 PM EDT
[#13]
Link Posted: 2/26/2006 7:06:35 PM EDT
[#14]
FIRST THING TO DO BEFORE PROCEDING WITH ADJUSTMENT... MAKE SURE THE GUN IS UNLOADED!!!


Quoted:
So, to clarify (as I have three uppers from various places with this issue) I want to wack the front sight in the direction of the group correct ? Correct

For example my group is to the right, therefore I will knock the front sight towards the ejection port side of the weapon. Is this right ? That is right

Seems like you move the rear sight in the direction you want the group to go, the front sight moves in the direction of the bullets. Or do I have that backward ? Its not backwards

I have a bench vise, and a DPMS receiver block, was going to fix the upper in to the vise and then whack as mentioned above. If currently hitting 6 inches to the right at 25 yards, should be a few degrees and in business I should think. No vise needed or recommended... Don't separate the upper from the lower... Lay the rifle across your lap and firmly hold the receivers and then whack the FSB...

Thanks for any input

Link Posted: 2/26/2006 7:16:07 PM EDT
[#15]
Thanks for the advice. Will do. Based on the recommend technique, will be an easy task to do during a range session, get some instant feedback.

Of course being mindful of all safety rules in the process.
Link Posted: 2/27/2006 5:27:35 PM EDT
[#16]

Quoted:
OK guys, I read the thread here about the rifle shooting about a foot to the right at 50 yards and I have a similar situation. Now mind you I have never taken one of these things completely down nor built one from scratch so some of the stuff mentioned has me a tad confused.

I have a Bushmaster 20" A2 preban and while I can get it sighted in, my rear sight is VERY far, though not completely, to the left. (Rifle shooting far right). Theres a few clicks before it is as far over as it goes but it bugs me. Is this anything to worry about since it WILL zero in or do you think its probably an overtorqued barrel or something?

Ive had this particular rifle for about a year and when I read that other thread it just got me to thinking about it...............

I have 4 other Bushys and they all zeroed in a few clicks from center.

Leave it alone or make some adjustments? What yall think?




Why all the HOOPLA here thats why your sight will adjust if it's zero it's zero just because it "doesn't look center is all BS not trying to be a dick here but just think about this!!!!!
Link Posted: 2/27/2006 5:49:18 PM EDT
[#17]
My rationale is that I want to preserve my windage for those times when shooting in hurricane force winds..... applied at 90 degree angles to my shooting direction....

haha

Just seems that it shouldn't take 1/3 of your built in windage to get a mechanical zero. So, if I can adjust to where I am 8 clicks or less from mechanical center than I would be happy , right now I am around 18 or so.
Page AR-15 » Troubleshooting
AR Sponsor: bravocompany
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