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Posted: 4/1/2017 5:18:33 PM EDT
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I’m currently building an AR-15 upper with Aero Precision receiver, Aero Precision BCG, Faxon pencil light 16” barrel, mid-length gas and low profile gas block. Eventually I plan to mate this with a dedicated Aero Precision lower receiver and other components.
Temporarily I plan to shoot the above upper mated with the lower receiver from my Bushmaster that was originally a post ban flat top carry handle HBAR 20” rifle with no terminal device that my gunsmith converted to a heavy carbine by installing a low profile gas block, handguard with more rail than I need, MagPul adjustable buttstock, and replaced the long rifle buffer/spring with a carbine 3.25” buffer/spring. The carbine buffer/spring has no identifying markings on it. Meanwhile I’m wondering whether I can use the carbine buffer/spring currently in the “rifle” with a rifle length gas system that’s working quite well, with my Aero Precision Faxon mid-gas set-up. Or do I need a different buffer for the mid gas barrel? |
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The gas system has NOTHING to do with the buffer system. The "rifle length" gas system only describes how long the gas tube is - you must match the gas tube with the distance to the gas port...
A "rifle" receiver extension and buffer only describe a specific length of receiver extension and the buffer designed to go in that extension. "Carbine" extensions are shorter and have multiple stops for an adjustable stock, and the buffer that goes in these extensions obviously has to be shorter as well. Basically, there's no reason to worry about matching stuff that goes on the upper receiver with stuff that goes on the lower receiver. |
| dan: You could go ahead and try it out with the existing lower assy, it may work just fine. Each upper will produce slightly different gas impulse, especially if the barrel length and/or gas port positions are different. The ideal solution is to install adjustable gas blocks on one or both of the upper assemblies, that way you can tune each to work with the ammo your prefer and the existing lower. I find that rifle length buffer tubes and buffers are more tolerant of these kind of differences than are the lighter carbine parts. - CW |
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