survivalshop Posted November 19, 2016 Report Share Posted November 19, 2016 (edited) Here is the Faxon Carbine gas system Port size . Pistol Gas Port size may be smaller because of the placement of the Port in the gas pressure curve , doesn't hurt to ask around . Here's an article with some interesting info .http://micromoa.com/300-blk-port-size-testing/ Here is a Thread on the 300BLK sight . http://www.300blktalk.com/forum/viewtopic.php?f=136&t=79484 Barrel Material: 416-R Stainless Barrel Type: Button Rifled Barrel Caliber: 300 BLK Barrel Twist: 1:8 Barrel Length: 16" Barrel Profile: Variable Depth Heavy "Flame" Fluted Barrel Gas System: Carbine Inside Finish: QPQ Black Nitride Outside Finish: QPQ Black Nitride Muzzle Thread: 5/8 x 24 TPI (Threads Per Inch) Gas Block Diameter: .750" Gas Port Diameter: .110" Gas Block Journal Length: 1.1" Barrel Extension: M4 Barrel Weight: ~1.53 Lbs Magnetic Particle Inspected! 11-degree Target Crown Gas Block Journal Length: 1.9" This is a Andersonn 10.5" bbl. with Carbine gas system, just for comparison. Product Description AR-15 Barrel, 10.5″ Heavy Barrel with 1:7 Twist, .300 Blackout Caliber, Parkerized Finish, Carbine Gas System, 5/8 x 24 threaded barrel Length 10.5 Profile Heavy Barrel Twist 1-7 Finish Parkerized Material 4150 Caliber .300 Blackout Flutes Non Gas System Carbine Gas Block System 0.750 Gas Hole Diameter 0.125 Edited November 19, 2016 by survivalshop Quote Link to comment Share on other sites More sharing options...
jtallen83 Posted November 19, 2016 Author Report Share Posted November 19, 2016 It appears the anecdotal evidence says I would need to open it up a bit if it is the specified .075. It will be chilly out when I get home to do the testing in December, I would assume that colder conditions would require more gas than warm conditions? I want the "pistol" to function at -30F so being able to add some gas with the adjustable block when needed is a goal. Quote Link to comment Share on other sites More sharing options...
jtallen83 Posted December 20, 2016 Author Report Share Posted December 20, 2016 The TWEAKING has commenced. Installed the d. wilson standard BCG and the Tubbs flat wire 300 BO buffer spring. The original port size was the .075 stated by Faxon. I drilled twice today with a trip to the range for testing after the new spring, BCG, and checking the gas system, then after drilling to .078, and again at .081. The last trip showed evidence of progress. Still no lock back on the last round in the mag but the heavier 220 subs are now being fed after each firing. The lighter subs are not feeding a new round but they are not stovepiping and the hammer is being cocked, getting close! I'll open it up a couple sizes too near .085 tonight and get out for another test in the morning. Does anyone have an idea why Faxon would be putting such an undersized port in the barrel, is it actually undersized, maybe meant to be used for just supersonics? I've double and triple checked for gas leaks and found no signs. No burrs in the BCG or anywhere else I can see. No signs of any gas blockage anywhere, I've run my little gas tube cleaner brush through it and disassembled the SLR gas block with nothing unusual found. Buffer weighs 3+ oz. on my chinese kitchen scale. Pretty confident this pistol will end up running whatever I feed it and however I want to run it but feel the need to make sure I understand the hows and whys that get me there. Quote Link to comment Share on other sites More sharing options...
392heminut Posted December 20, 2016 Report Share Posted December 20, 2016 I'm guessing you'll hit .090 before it starts working good. Quote Link to comment Share on other sites More sharing options...
survivalshop Posted December 20, 2016 Report Share Posted December 20, 2016 You have a "Can" for this Pistol ? I also agree with 392heminut , but just about every build can be different & I would go slow & test as you have been , especially if you plan on using it suppressed . Quote Link to comment Share on other sites More sharing options...
jtallen83 Posted December 20, 2016 Author Report Share Posted December 20, 2016 Got it! .0935 #42 bit finally got it to function with the 200 grain subs. It ran on the UMC 220 grain subs at .089 but still wouldn't lock back or load the next round with the 200's or the 208's so I went another size up. This is with the SLR gas block wide open so now I can tune the block down for everything else I need it to do. The NFA tracker website predicts I will have my first stamp show up mid January, hope congress will drop silencers from the NFA about then, and give me a tax credit for the three stamps I applied for! Quote Link to comment Share on other sites More sharing options...
shepp Posted December 21, 2016 Report Share Posted December 21, 2016 4 hours ago, jtallen83 said: Got it! .0935 #42 bit finally got it to function with the 200 grain subs. It ran on the UMC 220 grain subs at .089 but still wouldn't lock back or load the next round with the 200's or the 208's so I went another size up. This is with the SLR gas block wide open so now I can tune the block down for everything else I need it to do. The NFA tracker website predicts I will have my first stamp show up mid January, hope congress will drop silencers from the NFA about then, and give me a tax credit for the three stamps I applied for! Your the king of drilling gas ports lol ???? Quote Link to comment Share on other sites More sharing options...
jtallen83 Posted December 21, 2016 Author Report Share Posted December 21, 2016 50 minutes ago, shepp said: Your the king of drilling gas ports lol ???? Feels more like cursed than kinged...........but as long as it keeps functioning I'll soon forget the ten trips to the range and hours spent assembling and disassembling. Quote Link to comment Share on other sites More sharing options...
survivalshop Posted December 21, 2016 Report Share Posted December 21, 2016 2 minutes ago, jtallen83 said: Feels more like cursed than kinged...........but as long as it keeps functioning I'll soon forget the ten trips to the range and hours spent assembling and disassembling. AH, come on , that was all fun ! Quote Link to comment Share on other sites More sharing options...
jtallen83 Posted December 21, 2016 Author Report Share Posted December 21, 2016 15 minutes ago, survivalshop said: AH, come on , that was all fun ! It was fun doing a twenty round mag dump without a hitch! It's always fun to learn as well. I now know this rifle pistol better than any other I own now. I can only think of a couple things I didn't have apart, the gas key off the carrier and the weights out of the buffer. Even had the detent out of the SI dust cover for cerakote. Now I'm sitting here looking at extra 308 and 5.56 BCG's and wondering what next................. Quote Link to comment Share on other sites More sharing options...
survivalshop Posted December 21, 2016 Report Share Posted December 21, 2016 (edited) 9 hours ago, jtallen83 said: Now I'm sitting here looking at extra 308 and 5.56 BCG's and wondering what next................. Do you really need an answer to that from us ? Edited December 21, 2016 by survivalshop Quote Link to comment Share on other sites More sharing options...
EngrBob Posted December 21, 2016 Report Share Posted December 21, 2016 BCGs get depressed if a rifle is not constructed around them. You wouldn't want to be responsible for depressed BCGs, would you? Quote Link to comment Share on other sites More sharing options...
jtallen83 Posted December 21, 2016 Author Report Share Posted December 21, 2016 22 minutes ago, EngrBob said: BCGs get depressed if a rifle is not constructed around them. You wouldn't want to be responsible for depressed BCGs, would you? As soon as I can un-depress the bank account I'll have to pick one of them to make happy Quote Link to comment Share on other sites More sharing options...
98Z5V Posted December 21, 2016 Report Share Posted December 21, 2016 I was thinking that previous reports on this kinda combo put gas port size right around a hundred thou - 0.100". Looks like you nailed it, and it's damn close to a hundred thou. Quote Link to comment Share on other sites More sharing options...
98Z5V Posted December 21, 2016 Report Share Posted December 21, 2016 1 hour ago, jtallen83 said: Now I'm sitting here looking at extra 308 and 5.56 BCG's and wondering what next................. I'm shocked that you even stated that. I actually cannot believe it... Quote Link to comment Share on other sites More sharing options...
jtallen83 Posted December 21, 2016 Author Report Share Posted December 21, 2016 Just now, 98Z5V said: I'm shocked that you even stated that. I actually cannot believe it... I know in general terms but the specifics are still a bit fuzzy...a lightweight 6.5 creedmoor....maybe a .204 ruger, so many options! Quote Link to comment Share on other sites More sharing options...
jtallen83 Posted March 12, 2017 Author Report Share Posted March 12, 2017 Finally got all the parts on this pistol....... Quote Link to comment Share on other sites More sharing options...
sketch Posted March 12, 2017 Report Share Posted March 12, 2017 Nice pistola brother! Quote Link to comment Share on other sites More sharing options...
unforgiven Posted March 12, 2017 Report Share Posted March 12, 2017 Sweet Quote Link to comment Share on other sites More sharing options...
392heminut Posted March 12, 2017 Report Share Posted March 12, 2017 Nice build JT, you're going to have fun playing with that one! Quote Link to comment Share on other sites More sharing options...
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