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Posted: 3/21/2009 9:28:54 AM EDT
| I recently bought a SW M&P15T that was ban state legal. It has a heavy barrel without a flash hider. I'm going to send the barrel to ADCO for threading soon. I'm wondering if there would be any advantage to having the barrel contoured also? I know it would make it lighter, but are there any other advantages or disadvantages ? |
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Quoted:
I've read that reprofiling after the barrel is bored can affect accuracy in match-grade barrels. Reprofiling a stock AR barrel is only going to make it lighter for you. ADCO does good work, I think you'll like what you see. I've heard that also, but don't see how it makes sense as barrel blanks are already rifled. |
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Quoted:
Quoted:
I've read that reprofiling after the barrel is bored can affect accuracy in match-grade barrels. Reprofiling a stock AR barrel is only going to make it lighter for you. ADCO does good work, I think you'll like what you see. I've heard that also, but don't see how it makes sense as barrel blanks are already rifled. Perhaps blanks that are to be cut-rifled are profiled first? I was under the same impression as you, but I've read that bit of info from more than one source. Who knows? 
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Quoted:
Quoted:
I've read that reprofiling after the barrel is bored can affect accuracy in match-grade barrels. Reprofiling a stock AR barrel is only going to make it lighter for you. ADCO does good work, I think you'll like what you see. I've heard that also, but don't see how it makes sense as barrel blanks are already rifled. What I know about commercial barrels is this; Button rifles inherently have more built in stress from the rifling process than cut rifled barrels. Buttoning is a swaging process which displaces metal to form the land and grooves and cut rifling simply removes metal to form the grooves. As far as I know, high quality commercial barrels made by Krieger, Hart, Shilen, etc. barrels are rifled prior to contouring/profiling. Especially button rifled barrels because there is a need for a uniform od so as the button is passed through the barrel, the bore dims will remain uniform. If one end were skinnier that the other, the skinny end would have less resistance to the button and the bore dims would be different because of this. Reputable barrel makers such as Krieger, Hart, Shilen, etc. stress relieve at some point. The possibility of changing the internal dims. of the bore by contouring, turning down muzzles for flash hiders, etc. are less of a problem when properly stress relieved and although I'm no machinist, I think stress relieving helps keep dimensions uniform all during the manuf. process. I suppose you could cut or broach a barrel after it were contoured if it somehow enhanced the expediency of manuf. Can't speak as to how manufacturers other than the aforementioned operate. Turning down you AR barrel may or may not affect the accuracy. Most likely it was profiled after it was rifled anyway. If it doesn't shoot under an inch now, I wouldn't sweat it. |
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