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Posted: 11/8/2012 9:13:45 AM EDT
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I am installing a MI Gen2 SS free float tube on my rifle and when I torque the barrel nut to 30 the gas tube is not lined up and it says not to exceed 60 and it is not even close to linning up at 60. It will line up up if i back it off 30 a little to mabe 25-26ftlbs. Is this ok or not. When i get to 60 one of the points on the nut is dead center of the gas tube hole so it would have to go way above 60 to line up. I tried it on a PSA upper and a SAA upper and the same thing on both. Could I have a bad barrel nut from MI?
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Quoted: I am installing a MI Gen2 SS free float tube on my rifle and when I torque the barrel nut to 30 the gas tube is not lined up and it says not to exceed 60 and it is not even close to linning up at 60. It will line up up if i back it off 30 a little to mabe 25-26ftlbs. Is this ok or not. When i get to 60 one of the points on the nut is dead center of the gas tube hole so it would have to go way above 60 to line up. I tried it on a PSA upper and a SAA upper and the same thing on both. Could I have a bad barrel nut from MI? How many times have you tightened and loosened the nut? Spike's sells a shim kit for ~$12.00. |
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Quoted:
I am installing a MI Gen2 SS free float tube on my rifle and when I torque the barrel nut to 30 the gas tube is not lined up and it says not to exceed 60 and it is not even close to linning up at 60. It will line up up if i back it off 30 a little to mabe 25-26ftlbs. Is this ok or not. When i get to 60 one of the points on the nut is dead center of the gas tube hole so it would have to go way above 60 to line up. I tried it on a PSA upper and a SAA upper and the same thing on both. Could I have a bad barrel nut from MI? I am getting my MI Gen 2 SS handguards tonight, I will let you know if I have the same issue. I found this on youtube, may be of some help. https://www.youtube.com/watch?v=PT6PN8sdGsw |
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Quoted:
Quoted:
I am installing a MI Gen2 SS free float tube on my rifle and when I torque the barrel nut to 30 the gas tube is not lined up and it says not to exceed 60 and it is not even close to linning up at 60. It will line up up if i back it off 30 a little to mabe 25-26ftlbs. Is this ok or not. When i get to 60 one of the points on the nut is dead center of the gas tube hole so it would have to go way above 60 to line up. I tried it on a PSA upper and a SAA upper and the same thing on both. Could I have a bad barrel nut from MI? How many times have you tightened and loosened the nut? Spike's sells a shim kit for ~$12.00. I have done it about 6 times each on two recievers |
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Quoted:
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Quoted:
I am installing a MI Gen2 SS free float tube on my rifle and when I torque the barrel nut to 30 the gas tube is not lined up and it says not to exceed 60 and it is not even close to linning up at 60. It will line up up if i back it off 30 a little to mabe 25-26ftlbs. Is this ok or not. When i get to 60 one of the points on the nut is dead center of the gas tube hole so it would have to go way above 60 to line up. I tried it on a PSA upper and a SAA upper and the same thing on both. Could I have a bad barrel nut from MI? How many times have you tightened and loosened the nut? Spike's sells a shim kit for ~$12.00. I have done it about 6 times each on two recievers Does that FF forend use a propriatary barrel nut? If not, I'd try another nut. |
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Read this thread. It addresses the solution to your problem.
Free Float Installation |
| I think this is a common problem with the Gen II SS. I just installed one a month or so ago and had the same problem (not lined up at any point between 30 and 80 ft/lbs). I lapped the the front of the receiver just slightly to get it lined up, and got it right around 45 ft/lbs. They also make shim kits as was said before. I didnt take the time to look at the other links posted, but i'm sure those will help as well. good luck! |
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Quoted:
I am installing a MI Gen2 SS free float tube on my rifle and when I torque the barrel nut to 30 the gas tube is not lined up and it says not to exceed 60 and it is not even close to linning up at 60. It will line up up if i back it off 30 a little to mabe 25-26ftlbs. Is this ok or not. When i get to 60 one of the points on the nut is dead center of the gas tube hole so it would have to go way above 60 to line up. I tried it on a PSA upper and a SAA upper and the same thing on both. Could I have a bad barrel nut from MI? 1) Using moly-fortified grease ?? 2) Can the nut be flipped around ? 3) Barrel nut shims can be your friend. |
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I have read complaints in the past that MI barrel nuts for the Gen 2's were soft, and that might explain the 30-60 range on the packaging. It is also possible that MI has corrected that problem with them, if it was even a real problem at all. Just trying to give you all the data I have read to plug into your decision-making process.
Personally, I would be tempted to get with MI and try a different barrel nut or two. I just installed my SS15 Gen 2 and the nut lined up perfectly with the gas tube hole when I torqued to 30 for the third time. I couldn't believe it! I was like "Well, that's a wrap..." with a big smile on my face. |
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Quoted:
I think this is a common problem with the Gen II SS. I just installed one a month or so ago and had the same problem (not lined up at any point between 30 and 80 ft/lbs). I lapped the the front of the receiver just slightly to get it lined up, and got it right around 45 ft/lbs. They also make shim kits as was said before. I didnt take the time to look at the other links posted, but i'm sure those will help as well. good luck! Look into Lapping the receiver. MAHA |
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If MI can’t help you resolve this situation it seems to me there are too many good forearms out there to live with one that has this limitation.
There was a post a while back where a guy with this setup broke something going above 60 ft/lbs. With shim kits available and since lapping removes the anodizing I do not lap unless the upper needs it. YMMV |
| First, follow the instructions that came with any free-float setup that uses its own barrel nut, since these aren't at all the same as a GI barrel nut. Second, use an appropriate grease on the threads (some people like to put some on the barrel flange too); ALL barrel nuts are spec'd for torque WITH grease. And keep in mind that it sometimes takes several attempts to tighten to the right torque - it is often necessary to tighten/loosen many times to get the grease properly distributed, high spots on the hard coat knocked off, etc. I've read people's reports of repeating the "try/back off" cycle 10 or more times before the nut "all of a sudden" lined up a notch at 40 or so ft/lb. |
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I've heard that torque at the lower end of the range is better for accuracy. Not sure if that's true, I think it was in a brownell's video I have.
All good suggestions, I wouldn't be concerned with a barrel torqued at 28. If it bothers you grind off the tooth that's in your way on the barrel nut and be done with it. |
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Going over 80lbs is not that big a deal. Just loosen and tighten until you get to the next lineup. People overcomplicate this. +1000 This, you don't even need a torque wrench, once you loosen and tighten the barrel nut at least three tiimes to seat the barrel square, all you do it tighten the barrel nut until "firm" and then go to the next "scallop". If you have a torque wrench you can go to at least 90 ft/lbs to get to the next scallop assuming you have a good upper vice block with a support insert. The bottom lne is that I know I've gone to at least 90 ft/lbs and probably even more to get alignment with no issues. When installing free float barrel nuts sometimes you have to use a lot of moly grease and keep loosening and tightening the barrel nut until it aligns. Generally its a bad idea to tighten a barrel and then loosen the nut to get back to a scallop. |
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Something that bears mentioning about torque wrenches. To torque to the value selected or indicated on the wrench, the adapter must be 90* offset. If the adapter is in line with the handle of the torque wrench you have increased the wrench's leverage and the torque value is HIGHER than indicated by the wrench. In other words looking like an "L" with the adapter either pointing left or right.
I just installed a 10" MI SS gen 2 on a WMD upper over a centurion barrel and she went into perfect alignment at about 45 ft/lbs using well cleaned threads and moly grease. |
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Something that bears mentioning about torque wrenches. To torque to the value selected or indicated on the wrench, the adapter must be 90* offset. If the adapter is in line with the handle of the torque wrench you have increased the wrench's leverage and the torque value is HIGHER than indicated by the wrench. In other words looking like an "L" with the adapter either pointing left or right. I just installed a 10" MI SS gen 2 on a WMD upper over a centurion barrel and she went into perfect alignment at about 45 ft/lbs using well cleaned threads and moly grease. That is incorrect. All barrel nut wrenches, whether GI or aftermarket, standard of specialized, must be IN LINE with the wrench. This is the configuratn the specs are based on. Each procedure in the TM, for example, takes the added length of the wrench and adapter into consideration when specifying torque. Unless some third-party, specialized barrel nut requires something different in the written instructions for that particular nut, then use the adapter in line with the torque wrench. Using an adapter at 90 degrees to the torque wrench changes the effective torque arm length to the hypotenuse of the triangle formed by the length of the torque wrench on one side and the adapter on the other side. If the torque spec was based on the wrench in line with the adapter instead, your torque arm is now noticeably shorter than what is needs to be, and the wrench will show a LOWER value than you are actually applying. Probably not by a whole lot, but if you are anywhere near the top or bottom values, this could be a problem. For what it's worth, MI's instructions, and even the video on their page for the SS rail, call for using the adapter IN LINEwith the torque wrench. |
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When you use the adapter inline you change the length and must mathematically adjust the wrench setting to get x ft/lbs. TMs are written with the torque required on the fastener in them, they have no way to know what adapter you may or may not have. Having used military TMs and TOs since 1985 I can say this with some certainty.. The MI directions DO NOT say anything other than tq. to 30-60 ft/lbs, I have them right here. Nor does the video on the Gen2 SS free float handguard mention orientation of the barrel nut wrench.
FAA advisory circular 43-13.1a/2b and many other places explain this but, here's a page on the formula for use of adapters, extensions and crowsfeet with a torque wrench and actual torque applied: http://www.engineersedge.com/manufacturing_spec/torque_wrench_1.htm |
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When you use the adapter inline you change the length and must mathematically adjust the wrench setting to get x ft/lbs. TMs are written with the torque required on the fastener in them, they have no way to know what adapter you may or may not have. Having used military TMs and TOs since 1985 I can say this with some certainty.. The MI directions DO NOT say anything other than tq. to 30-60 ft/lbs, I have them right here. Nor does the video on the Gen2 SS free float handguard mention orientation of the barrel nut wrench. FAA advisory circular 43-13.1a/2b and many other places explain this but, here's a page on the formula for use of adapters, extensions and crowsfeet with a torque wrench and actual torque applied: http://www.engineersedge.com/manufacturing_spec/torque_wrench_1.htm In the TM the math is already done. Most commercial and USGI wrenches have the drive slot in the same position away from the center of the nut. This why you set the wrench inline and not perpendicular. |
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When you use the adapter inline you change the length and must mathematically adjust the wrench setting to get x ft/lbs. TMs are written with the torque required on the fastener in them, they have no way to know what adapter you may or may not have. Having used military TMs and TOs since 1985 I can say this with some certainty.. The MI directions DO NOT say anything other than tq. to 30-60 ft/lbs, I have them right here. Nor does the video on the Gen2 SS free float handguard mention orientation of the barrel nut wrench. FAA advisory circular 43-13.1a/2b and many other places explain this but, here's a page on the formula for use of adapters, extensions and crowsfeet with a torque wrench and actual torque applied: http://www.engineersedge.com/manufacturing_spec/torque_wrench_1.htm If you dig deeper into the TM"s you well find that torque numbers are based on using the tools specified in the TM. The 23&P specifies barrel nut torque to be 30-50lbsft, not to exceed 80lbsft. If to OP can not get alignment he could mill the metal out between the two gas tube holes in question. Face the upper, shim kit would be a last resource. |
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