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Posted: 6/4/2005 2:58:29 PM EDT
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I have a 11.5 barrel with 5.5 FH that has 4 set screws to secure the FSB. There are no flats on the barrel to use pins. No markings that I can find on the barrel. Is this normal on some barrels? Never seen it before. |
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Should be a 16" barrel, with a 5.5 shroud FS if allen screws are being used. The barrel has to be 16" total permanent lenght to be legal. Using a 11.5" barrel without the 5.5" FS welded/silver soldered on makes the barrel a SBR, and would require a tax stamp if used on a Semi rifle. Bottom line is if you can use a tool, such as a allen wrench, to remove the FS, and have a bare 11.5" barrel, it's a SBR/MG barrel only. |
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By FSB, I am guessing that this is a gas block with a weaver style top, and not a standard front sight tower. These do allow the FSB to be correctly indexed/positioned to allow the rear sight to be Dead Center, and the front to be indexed to zero the rifle. Sounds like a custom barrel. The one thing that does set me back though is that there should be 4 flats for the set screw milled into the barrel. This allows the set screws to tension against each other, and not just grab into the barrel round. If the barrel lacks the flats, then look at having them milled (theres enough room to drift the FSB against the FS to make the flats) This will allow a solid tension point for the set screws, and allow the FSB/front sight to take a hit and not drift the base around on the barrel ( lose of zero - FSB/sight index to the rear sight). |
Forgot to add it is legal for AR pistols to have a short barrel. 
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