Gotta question for you pistol/sbr pros. I'm interested in a pistol upper that I can nfa later for a sbr lower I've yet to build (dont worry, I already have the pistol lower). I'm interested in a 9.5 or 10.5 barrel but want to know how they stack up against eachother in terms of reliability and recoil impulse. I had assumed that the 10.5 carbine would be better for both but then it dawned on me that the 9.5 with a pistol length gas port would provide more dwell time. So maybe the 9.5 would be more reliable but probably have a greater recoil impulse. And if that's the case then could the recoil be dampened by an adjustable gas block? Also, I thought it might be possible that the polygonal rifling would be more conducive to reliable sbr cycling then traditional land/groove rifling. What do you guys think? I'm sure some of you already have these barrels. Which do you like more and why? Too many questions, I know. But I genuinely appreciate any input. I'm itchin' to get an order in. Size matters, but on this subject less is more.
Post by Brandon Sneed on May 14, 2012 4:32:16 GMT -8
The dwell time would be better in the longer gas system for the length of barrel, ie carbine 10.5".. The thing to keep in mind is that these barrels either one will play havoc on you carrier and extractors.
Personally sbrs/pistols in my safe have an adjustable gas block to reduce the extra stress on the BCG. Just word to the wise. Preference will determine length once you slow the gas into the chamber with the block
If it were me I'd skip 5.56 in that short a gun and go 6.8 or 300blk but you didn't ask me for that info lol.
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Are your sbr/pistol barrels BHW? I ask because I wasn't sure of how much of an attempt BHW makes to tune the gas port. I'm assuming that despite any attempts to do so would STILL warrant the use of an adjustable gas block. I really wanted 5.56 in the hopes that it would run a 22lr conversion kit. Also, I'm not into reloading yet and would like to keep the ammo cheap for now (at least for a range gun like this that I want to dump a ton of rounds through). Is there any reason a 22lr conversion wouldnt operate through a sbr/pistol upper? I hear what you're saying about calibers though. I WILL own a 300blk some day. Still waiting for Spikes to deliver a billet upper so I can complete my 6.5 build.