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Posted: 11/29/2010 5:45:10 PM EDT
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I finished assembling my Mid West Ind 15" free float quad rail handguard and I'm not sure what possessed me to do this, but I put a level on top of the rifle and it seems to not run true. The level touches the upper receiver where the rear sight should be, and touches out near the end of the rail, where the front sight should be, but in between there is about a 1/16"-1/8" gap along the whole rail.
Is this normal or should the upper receiver and the rail run completely flat? |
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I finished assembling my Mid West Ind 15" free float quad rail handguard and I'm not sure what possessed me to do this, but I put a level on top of the rifle and it seems to not run true. The level touches the upper receiver where the rear sight should be, and touches out near the end of the rail, where the front sight should be, but in between there is about a 1/16"-1/8" gap along the whole rail. Is this normal or should the upper receiver and the rail run completely flat? My Troy rail does the same thing, I think that's just how some of these rails are. I tried to make mine straight but always ends up the same way no matter what I do. I just left if be and it works fine, sights line up perfectly. |
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Probably how it's installed. The rail itself is very likely to be straight as can be, but the barrel nut / mounting interface might not be. Good thing you have adjustment on your front sight post. Agreed, rail is probably fine it's those other things thay may knock it off a bit. |
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That is the whole idea behind a free float rail. It is independent from the upper receiver rail. Which means stress won't effect the barrel, but you run the risk of throwing off your BUIS as it flexes.
Even if everything were perfectly level, the second you load up your bipod, or sling it up real tight, the rail will flex and it won't be level anymore This is why it isn't a good idea to "bridge the gap" with a scope. |
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That is the whole idea behind a free float rail. It is independent from the upper receiver rail. Which means stress won't effect the barrel, but you run the risk of throwing off your BUIS as it flexes. Even if everything were perfectly level, the second you load up your bipod, or sling it up real tight, the rail will flex and it won't be level anymore This is why it isn't a good idea to "bridge the gap" with a scope. whats the point of a monolithic rail/ upper then? |
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http://i188.photobucket.com/albums/z6/Weezerglock/ar1.jpg
http://i188.photobucket.com/albums/z6/Weezerglock/ar3.jpg Here are some pictures. Should I replace the rail? |
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This is why it isn't a good idea to "bridge the gap" with a scope. You're telling me that its a GOOD idea to rely on the rigidity of your optics to resist stress on the rail for the preservation of accuracy? Wouldn't the better policy be to just let the rail flex and mount the optics on the receiver? |
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This is why it isn't a good idea to "bridge the gap" with a scope. You're telling me that its a GOOD idea to rely on the rigidity of your optics to resist stress on the rail for the preservation of accuracy? Wouldn't the better policy be to just let the rail flex and mount the optics on the receiver? I think he's saying its not good to mount one ring on the reciever and one ring on the handguard in the case of using a two piece ring setup. |
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Quoted: Quoted: This is why it isn't a good idea to "bridge the gap" with a scope. You're telling me that its a GOOD idea to rely on the rigidity of your optics to resist stress on the rail for the preservation of accuracy? Wouldn't the better policy be to just let the rail flex and mount the optics on the receiver? Read hellbound's reply slowly. And I'll add that all free float rails are not the same. Some have very little flex and are very solid. The DD Lite Rail is one. |
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This is why it isn't a good idea to "bridge the gap" with a scope. You're telling me that its a GOOD idea to rely on the rigidity of your optics to resist stress on the rail for the preservation of accuracy? Wouldn't the better policy be to just let the rail flex and mount the optics on the receiver? Read hellbound's reply slowly. And I'll add that all free float rails are not the same. Some have very little flex and are very solid. The DD Lite Rail is one. my vltor has no flex but its mounted with the delta ring and the upper receiver |
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if thats a plastic level then start over with a good aluminum one. . . those things are pieces of shit, and i should know, i use a number of levels every day at work. you'd really be better off with a machinists straight edge instead of a level anyways. It is aluminum. and its true. |
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This is why it isn't a good idea to "bridge the gap" with a scope. You're telling me that its a GOOD idea to rely on the rigidity of your optics to resist stress on the rail for the preservation of accuracy? Wouldn't the better policy be to just let the rail flex and mount the optics on the receiver? I think he's saying its not good to mount one ring on the reciever and one ring on the handguard in the case of using a two piece ring setup. Then will someone define "bridge the gap"? Because I'm reading that putting one ring on the receiver and one on the flexing hand guard is "bridging the gap". |
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This is why it isn't a good idea to "bridge the gap" with a scope. You're telling me that its a GOOD idea to rely on the rigidity of your optics to resist stress on the rail for the preservation of accuracy? Wouldn't the better policy be to just let the rail flex and mount the optics on the receiver? I think he's saying its not good to mount one ring on the reciever and one ring on the handguard in the case of using a two piece ring setup. Then will someone define "bridge the gap"? Because I'm reading that putting one ring on the receiver and one on the flexing hand guard is "bridging the gap". That is exactly what he is saying and he is saying it isnt a good idea |
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http://i188.photobucket.com/albums/z6/Weezerglock/ar1.jpg http://i188.photobucket.com/albums/z6/Weezerglock/ar3.jpg Here are some pictures. Should I replace the rail? I don't see any problem. |
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One thing to take into consideration also is the face of the barrel extension on the upper may not be true causing it to make the rail run crooked. They do make a tool to true it up.
TOOL |
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One thing to take into consideration also is the face of the barrel extension on the upper may not be true causing it to make the rail run crooked. They do make a tool to true it up. TOOL Does that mean my barrel is angled upwards as well?? |
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Quoted: Quoted: One thing to take into consideration also is the face of the barrel extension on the upper may not be true causing it to make the rail run crooked. They do make a tool to true it up. TOOL Does that mean my barrel is angled upwards as well?? Is the barrel centered in the forearm? If so, yes it is. |
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Not something to worry about, either. I wouldn't take my shit off and lap my receiver face just because my rail is slightly out of line with my upper.
No matter how you cut it, you're mounting a tube up to 14" long on about 2" worth of threading that is mounted itself on about 1" of threading. There's going to be slop, and when it gets all tightened down you can expect it to be off-set to a certain degree. What's more is that any pressure put on that tube forward of the barrel nut is going to shift it. I don't care what company makes it, they're not 100.0000% rigid, it's going to bend to some degree. That said, it's better for your FF tube to bend than your barrel–– which is the whole purpose of the FF tube. So if you want your sights to be (near to) perfectly aligned at all times regardless of pressure on the FF tube, mount the front sight to the barrel or gas block. |
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