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Posted: 9/10/2003 7:58:43 PM EDT
It seems I have an overtorqued barrel on my new BM. Although the reat sight is adjusted far to the right, the gun is sighted in. Should I send the upper back to BM? Will the overtorqued barrel cause accuracy or safety problems down the road? Thanks, Jim
Link Posted: 9/11/2003 1:24:55 AM EDT
Originally Posted By jeh: Should I send the upper back to BM?
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Yes.
Link Posted: 9/14/2003 7:41:50 AM EDT
[Last Edit: 9/14/2003 8:10:10 AM EDT by James_Gang]
Originally Posted By jeh: It seems I have an overtorqued barrel on my new BM. Although the reat sight is adjusted far to the right, the gun is sighted in. Should I send the upper back to BM? Will the overtorqued barrel cause accuracy or safety problems down the road? Thanks, Jim
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------- How much right windage are you talking about? I have a new Bushmaster M-4. To zero the rifle takes 9 clicks right windage. This appears to be about standard and normal for this rifle/sight combination. The A-2 sight is slightly cocked to the left due to its design and seems to be the major culprit. [img]http://www.thewilderness.com/Media/singlepoint_cuqd.jpg[/img] My understanding is that Bushmaster is laser bore sighting all A-2 sight/barrel combinations to ensure they will zero. Not to ensure they will zero at mechanical zero, or require no adjustment. As well I spoke to Bushmaster who stated that the overtorqued barrel problem only occured on approximately 400 rifles or so a couple of years ago. But like Tweak says, if it bothers you send it back, they can retorque and remount your barrel. How much windage is too much? I don't know. But, I'm keeping mine as is. If it aint broke I aint fixing it. And I still have plenty of right windage left. Further, as the rear sight is cranked up in elevation requires one to crank a couple of clicks of left elevation(back towards mechanical zero). This is also necessary when one switches to the ghost ring. Which leads me to believe this adjustment is due to the built in tolerances of the sight, not necessarily the barrel. It also pays to remember that thread pressure on the barrel itself can also cause a slight off center response. This is not defective or a case of barrel overtorquing. Just an inherent part of mechanical design and current machine tolerance technology itself. I'm very impressed with the excellent accuracy, and 100% reliability of my Bushmaster. Here is a target from a recent shoot at 100 yards with the A-2 'iron sights' and Q-3131A ammo off a sandbag. The bullseye is 8" across. I made a number of sight adjustments up, down and back and forth which opened the group up larger than it would have been otherwise, as well some of these shots were taken with the ghost ring. Look carefully at my first 10 round string above the bullseye. When corrected for elevation this string could have easily come in at sub MOA off a bench with a good scope, a good rest and a calm wind. The groups were very consistent through 50 rounds. Yes this is out of my new 14.5" chrome lined barrel(79 total rounds fired) and with Israeli Q3131A mil spec ammo on a breezy day. I think I'll leave mine as is. No sense in messing up a good thing. [img]http://img.villagephotos.com/p/2003-8/325392/Bushmasteraccuracy2.JPG[/img]
Link Posted: 9/14/2003 11:04:53 PM EDT
Originally Posted By James_Gang: How much windage is too much?
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The spec calls for rounds to impact within a 16" wide target for the carbine and 11.6" wide target for the rifle set at 100 yards when the rear sight is within 5 clicks of center. So, for a proper 100 yard zero the rear sight must be within 12 clicks for the A2 sights, or within 6 clicks for the A1 sights, +/- 5 clicks.
Link Posted: 9/15/2003 5:46:09 AM EDT
Originally Posted By Tweak:
Originally Posted By James_Gang: How much windage is too much?
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The spec calls for rounds to impact within a 16" wide target for the carbine and 11.6" wide target for the rifle set at 100 yards when the rear sight is within 5 clicks of center. So, for a proper 100 yard zero the rear sight must be within 12 clicks for the A2 sights, or within 6 clicks for the A1 sights, +/- 5 clicks.
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------ Thanks Tweak. That's exactly what I needed to know.
Link Posted: 9/15/2003 6:03:03 AM EDT
Thanks guys for the advice/help. I took my rifle into my dept's armorer and he agreed with everyone here. I still have enough adjustment to the right, and the rifle is fine. I'm just leaving it as it is. Thanks again all.
Link Posted: 9/20/2003 3:30:07 AM EDT
Send it back...although it is an esthetic thing... they have an excellent costumer service department
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