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Rifles, Reloading, Optics, Equipment
AR15/10 Rifles
+ length gas systems
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<blockquote data-quote="Munch" data-source="post: 2903518" data-attributes="member: 36823"><p>When it comes to direct impingement rifles (AR10/15) getting the dwell time correct is critical to reliable performance.</p><p></p><p>Dwell time is the variable based on the distance from the gas port to the muzzle end of the barrel, not including any vented muzzle brakes or flash hiders. Not a distance from the gas port aft to an indeterminate reference point.</p><p></p><p>Generally, a 7 - 9" dwell time is desirable in an AR10. Thus, the gas tube length will be determined by the distance from the gas port to the crowned muzzle.</p><p></p><p>Proof Research uses a Rfile length gas tube in their 308 20" AR barrels which achieves a 7" dwell time. PR uses a Rifle+2 in the 6.5CM 20" barrel for a 5" dwell time. While I have no doubt the PR engineers are confident with their decision regarding a 5" dwell time, I have read too many technical papers stating a 5" dwell time is on the short side. So I went with the PR 22" 6.5CM barrel with Rifle+2 to achieve a 7" dwell time. My rifle does not have any dwell time issues; or any other issues for that matter.</p><p></p><p>Too little or too much dwell times will adversely effect reliability causing feeding and extraction problems. And not the same feeding/extraction problems if over or under optimum dwell time.</p></blockquote><p></p>
[QUOTE="Munch, post: 2903518, member: 36823"] When it comes to direct impingement rifles (AR10/15) getting the dwell time correct is critical to reliable performance. Dwell time is the variable based on the distance from the gas port to the muzzle end of the barrel, not including any vented muzzle brakes or flash hiders. Not a distance from the gas port aft to an indeterminate reference point. Generally, a 7 - 9" dwell time is desirable in an AR10. Thus, the gas tube length will be determined by the distance from the gas port to the crowned muzzle. Proof Research uses a Rfile length gas tube in their 308 20" AR barrels which achieves a 7" dwell time. PR uses a Rifle+2 in the 6.5CM 20" barrel for a 5" dwell time. While I have no doubt the PR engineers are confident with their decision regarding a 5" dwell time, I have read too many technical papers stating a 5" dwell time is on the short side. So I went with the PR 22" 6.5CM barrel with Rifle+2 to achieve a 7" dwell time. My rifle does not have any dwell time issues; or any other issues for that matter. Too little or too much dwell times will adversely effect reliability causing feeding and extraction problems. And not the same feeding/extraction problems if over or under optimum dwell time. [/QUOTE]
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Rifles, Reloading, Optics, Equipment
AR15/10 Rifles
+ length gas systems
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