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Posted: 3/2/2005 8:54:06 AM EDT
| I seem to recall reading that the M4's have a higher front sight base (marked a certain way?) than the regular M16A2 and if you don't have the higher base, you need to use a higher front sight post in order to sight in using a BUIS. Is this true or did I just dream this up? Do you need a higher front sight / front sight post with all BUIS's? |
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Colt and ONLY Colt M4 barrels have a sight base with the ledge, where the front sight post sits, is machined 0.40" higher than any other FSBs - other companies have since been building their barrels with the correct "F" stamped FSBs, but the Colt M4 barrel is the only factory barrel with the "F" stamped FSB (I think). OThe are stamped with an "F" on the left side of the FSB (non-ejecting side for standard ARs/M16s/M4s). Nearly all of the aftermarket BUIS are set up for this "F" type FSB, so if you have a non-"F" stamped FSB, you may need a taller front sight post to make up the height difference. Bushmaster sells them for around $5. |
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