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Posted: 2/19/2006 4:42:17 PM EDT
[Last Edit: 2/19/2006 4:49:11 PM EDT by ALPHAGHOST]
ok, it was a 16in banned Bushmaster A2, but then i replaced the bbl with a 1-7 Bushmaster 20in bbl assembly

i tried to sight it in, and i was not getting anything on paper--turns out i was shooting WAY to the right....

i maxed out and put the windage all the way to the left...and i still barely hit the center of what i am aiming at

distance was 50yrds

now i have done some searches and some reading and some bbl checking--i hear that bushmaster has been having problems w/ canted front sight bases....but i dont see the cant ( to test, i placed the complete upper upside down on a level table and all the wings and sights were on the table)

the only ways i can supposidly fix it is to:
1:) hit the FSB hard (to the left?) w/ a mallet.....
2:) take off my bbl nut, and check the alignment of the bbl notch and make sure its lined up w/ the FSB--if its not, get a punch and smack the edge of the bbl notch to make it fit (in my case, smack the right side so it will alighn left) and make sure it fits into the reciver notch

so, any other ideas or advise?

thanks all
Link Posted: 2/19/2006 6:40:53 PM EDT
Link Posted: 2/19/2006 6:44:04 PM EDT
[Last Edit: 2/19/2006 6:45:57 PM EDT by chewbacca]
Sorry man, you got the patent pending canted Bushmaster FSB. They engineered it for a 20mph cross wind.

All kidding aside, you could have over torqued the barrel nut and therefore bent the indexing pin.
Link Posted: 2/19/2006 7:11:12 PM EDT
[Last Edit: 2/19/2006 8:27:31 PM EDT by Dano523]

--------------------------------------------------------------------------------
Originally Posted By chewbacca:
Sorry man, you got the patent pending canted Bushmaster FSB. They engineered it for a 20mph cross wind.

All kidding aside, you could have over torqued the barrel nut and therefore bent the indexing pin.
--------------------------------------------------------------------------------



--must be for hurrican weather

maybe...i forgot to mention: when i first installed it, i thought that the next notch was too far, so i went one below then added on the gas tube

h/w, i noticed that there was some rattle near the delta ring area

i took off my HGs and i noticed that my bbl nut was loose, loose enough that i could manually move it--so i re-torqued it to the next notch (the one where i initially thought was too much....)

its on tight now (maybe a little too much?)......if so, i dont think that i twisted the bbl--but if i did bent the indexing pin, what happens/what can i do?


thanks all


--------------------------------------------------------------------------------
"I'm not stupid; y'all just retarded."
--CJ
"Praise the Lord and pass the ammunition!"
EAT THIS!
Oh, Yeah!
Link Posted: 2/19/2006 7:56:34 PM EDT

Originally Posted By chewbacca:
Sorry man, you got the patent pending canted Bushmaster FSB. They engineered it for a 20mph cross wind.

All kidding aside, you could have over torqued the barrel nut and therefore bent the indexing pin.




im guessing patent breached then, cause colt,model1, rra, dpms, there are cases of all of them.
Link Posted: 2/19/2006 8:28:04 PM EDT
[Last Edit: 2/19/2006 8:28:38 PM EDT by Dano523]
Link Posted: 2/19/2006 9:24:15 PM EDT

Originally Posted By eklikwhoa:

Originally Posted By chewbacca:
Sorry man, you got the patent pending canted Bushmaster FSB. They engineered it for a 20mph cross wind.

All kidding aside, you could have over torqued the barrel nut and therefore bent the indexing pin.




im guessing patent breached then, cause colt,model1, rra, dpms, there are cases of all of them.



I was joking .
Link Posted: 2/20/2006 10:38:53 AM EDT

Originally Posted By Dano523:

Originally Posted By chewbacca:

i took off my HGs and i noticed that my bbl nut was loose, loose enough that i could manually move it--so i re-torqued it to the next notch (the one where i initially thought was too much....)

what happens





Upper receiver barrel socket threads, barrel nut threads, and inner contact edge of barrel nut, and front face of the barrel extension all greased with moly.

Torque the barrel nut to 35 lbs, then the back the nut off, for a total count of three times (this mates the threads). On the third tightening, take the nut the needed amount more to line up the barrel nut spines to allow the barrel nut to pass threw cleanly. If you hit 80 LB of torque, you need to stop, back off the barrel nut and try again.

Hate to say it, and pray to the gods it didn't happen, you may have exceeded 80 lbs and either bent the upper barrel socket, or worse cracked the threads of the barrel socket. If this is the case, then the options are either replace the upper receiver, or if you can index the barrel (FSB) to zero and still keep the barrel extension lugs orientated to not bind on the bolt during cycle, you will have a canted front sight on the rifle when zeroed.



thanks for the extra info and help mr Dano523

i'm going to work on it tonight....hopefully it will work
Link Posted: 2/20/2006 10:56:21 AM EDT
You could try replacing the barrel index pin.

www.bushmaster.com/faqnew/content_by_cat.asp?contentid=181&catid=100

Link Posted: 2/20/2006 2:19:33 PM EDT
[Last Edit: 2/20/2006 2:20:13 PM EDT by j3_]
I found that using the blocks on the upper receiver seem to cause this often for me if I have to put much torque on the nut to align it. I started back using the barrel blocks. I come up straight more often or at worst a little to the right with the sight but it ended my all the way to the left days.
Link Posted: 2/20/2006 9:04:10 PM EDT
Update: the front sight did not budge

my bbl is aligned well, the bbl nut/bbl notch is not damaged

i (and 2 others) have verified that the front sight IS massivly mis-aligned--its leaning toward the left

i tried a rubber mallet and a med-weight hammer--~3-4 hard, firm knocks each--nothing (i marked the bbl and sight first to see if they moved)

any other ideas?


thanks all
Link Posted: 2/20/2006 9:25:14 PM EDT
[Last Edit: 2/20/2006 9:27:48 PM EDT by Dano523]
Link Posted: 2/20/2006 9:48:41 PM EDT
gotcha mr dano, thanks

the FSB is attached properly, its just been attached slightly canted to the left.....

i did untorque the bbl, and re-mated it till it went on smoother--the bbl notch did not move this time

i will try it out again when i hit the range, maybe something did move and i just missed it

if not, i will contact bushmaster and send em the bbl and get em to correct the FSB (i really do NOT feel like popping out these PITA pins)

oh well
Link Posted: 2/20/2006 10:25:09 PM EDT
have you tried a 3 pound hand sledge hammer, and a piece of leather to protect the finish?
Link Posted: 2/20/2006 11:24:52 PM EDT

Originally Posted By mcooper:
have you tried a 3 pound hand sledge hammer, and a piece of leather to protect the finish?



no sir--will try that out sometime....
Link Posted: 2/21/2006 5:39:30 AM EDT
Link Posted: 2/21/2006 11:05:31 AM EDT

Originally Posted By Dano523:

Originally Posted By mcooper:
have you tried a 3 pound hand sledge hammer, and a piece of leather to protect the finish?



You might get away with this heavy of a hammer (force) on a forged FSB, but if you try that much force on a casted FSB, you can kiss it good-by.



will do mr dano...thanks

i think that i will try a lighter sledge though...
Link Posted: 2/21/2006 11:07:53 AM EDT
Link Posted: 2/21/2006 12:13:59 PM EDT
[Last Edit: 2/21/2006 12:59:35 PM EDT by Dano523]
Dano,

What are you using for shims in this procedure of yours??

Link Posted: 2/21/2006 12:57:28 PM EDT
Link Posted: 2/21/2006 1:00:06 PM EDT
Link Posted: 2/21/2006 1:12:50 PM EDT
Link Posted: 2/21/2006 5:00:13 PM EDT

Originally Posted By Dano523:

Originally Posted By Boog:
Dano,

What are you using for shims in this procedure of yours??




Pepsi can





seriously??

what is that about , 5 mills thick??


are you just cutting thin strips and laying them on one side or another of the receiver slot (after opening it up a little) where the barrel pin indexes into??

I'll be installing a new 16" M4 profile barrel soon on my old 16" HBar Bushy and I want to make sure all is straight and true before final assy.

quick question if I can:

The old bolt has about 3k rounds on it. Is it a pretty safe bet I'll be ok head space wise with the new barrel??

I've alway heard:

new bolt/new barrel--ok
new bolt/old barrel--ok
old bolt/new barrel--ok
old bolt/different old barrel--not ok.

I don't have HS gauges but I can find someone who has them in a pinch.

(sorry didn't mean to hijack the thread)
Link Posted: 2/21/2006 5:11:20 PM EDT
[Last Edit: 2/21/2006 5:12:25 PM EDT by ar-wrench]
As mentioned above, barrel blocks allow very precise installs.

When using barrel blocks, it is possible to bore sight the sights all throughout the installation. Get everything lined up, bore sight it. Pull half torque, check boresight. Pull final torque, verify boresight is unchanged.

This is not possible using receiver clamps..

ETA...this proceedure is right out of the Army M16 Maintenance Manual.
Link Posted: 2/21/2006 7:40:38 PM EDT
[Last Edit: 2/21/2006 8:00:10 PM EDT by Dano523]
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