JRoss Posted February 28, 2016 Author Report Share Posted February 28, 2016 Longer screws means more clamping force. Looking closely at the original screws there was only 4 threads into the block, that is not much for an 8/32 screw to grip into aluminum. The new longer screws will double the clamping force. I also noticed that the area where the block deformed was at the thinnest area of the block and closest to the gas port hole, not the greatest design on the engineers part Quote Link to comment Share on other sites More sharing options...
survivalshop Posted February 29, 2016 Report Share Posted February 29, 2016 (edited) " The Aluminum that they are using looks awfully soft to flex like that , but the 308 does have some power & it showed it on the Gas Block"Survival...but of course it looks cheesy/soft...its Chinese aluminum....no insult to anyone but most of our stuff comes from there....I used to deal with a Chinese dist. that had gas blocks that looked just like this one... its most always the Chinese threads and screws that suk....... its sad but true Wash I agree , a good area not skimp with sub standard components , as demonstrated . Four threads aren't much of a hold . Edited February 29, 2016 by survivalshop Quote Link to comment Share on other sites More sharing options...
JRoss Posted March 2, 2016 Author Report Share Posted March 2, 2016 Transfer hole in barrel to measures .155". Transfer hole in gas block measures .150". Transfer hole in gas tube measures .125". Very different from a standard AR15 configuration. Quote Link to comment Share on other sites More sharing options...
Robocop1051 Posted March 2, 2016 Report Share Posted March 2, 2016 Your barrel hole is .155!?!?! Quote Link to comment Share on other sites More sharing options...
washguy Posted March 2, 2016 Report Share Posted March 2, 2016 Your barrel hole is .155!?!?! Robo.....no wonder the gb split open...I missed that in his post.....Yikes. Wash Quote Link to comment Share on other sites More sharing options...
survivalshop Posted March 2, 2016 Report Share Posted March 2, 2016 Transfer hole in barrel to measures .155". Transfer hole in gas block measures .150". Transfer hole in gas tube measures .125". Very different from a standard AR15 configuration. That's a BIG Gas Port in the Barrel . Are you sure of your measurements ? How did you measure them ? Quote Link to comment Share on other sites More sharing options...
JRoss Posted March 2, 2016 Author Report Share Posted March 2, 2016 Measured them with drill bit then measured the drill bit with a 0"to 1" outside micrometer. Quote Link to comment Share on other sites More sharing options...
survivalshop Posted March 2, 2016 Report Share Posted March 2, 2016 (edited) Any idea who made the Barrel ? That's also different then a 308AR should be also. Edited March 2, 2016 by survivalshop Quote Link to comment Share on other sites More sharing options...
JRoss Posted March 2, 2016 Author Report Share Posted March 2, 2016 No Idea Quote Link to comment Share on other sites More sharing options...
JRoss Posted March 2, 2016 Author Report Share Posted March 2, 2016 I have never played with gas port sizes on a .308 ar It will be an interesting opportunity to repair and experiment with different combinations of methods. Hope buying a new barrel does not turn into one of the options. Quote Link to comment Share on other sites More sharing options...
shepp Posted March 2, 2016 Report Share Posted March 2, 2016 Did you buy this gun as a complete build? If so I'd contact the company you bought it from and have them make nice Quote Link to comment Share on other sites More sharing options...
Robocop1051 Posted March 2, 2016 Report Share Posted March 2, 2016 I've never seen a gas port bigger than .11 diameter. My biggest port is .099 on my rifle length 17" bbl. I see an adjustable gb in somebody's future... a steel one! Quote Link to comment Share on other sites More sharing options...
survivalshop Posted March 2, 2016 Report Share Posted March 2, 2016 I have never played with gas port sizes on a .308 ar It will be an interesting opportunity to repair and experiment with different combinations of methods. Hope buying a new barrel does not turn into one of the options. What length gas system is the Barrel. Also as said above , talk to the Manufacturer . The issue I see is , if the Gas Port in the Barrel is larger then the Gas Blocks Port , its putting High Pressure Gas impulse under the Gas Block & that may be why the Gas Block blew out or helped it blow out like that .Weak or soft Gas Block Material /short screw, probably didn't help ether . I would recommend an adjustable Gas Block , but the size of your Barrels Gas Port may be an issue . Steel may help & if it gets a chance to seal up , it may be ok , I just would not like that much gas impulse directed under the Gas Block . The Gas Tube ID is only so big ( 0.120" ), so it gets throttled down . Depending on the length of you gas system , it may cause Cycling issues also & you will definitely feel it in recoil . My 16" Rifle length gas system , has a Port size of 0.1095"& is more then enough to operate the Action . Quote Link to comment Share on other sites More sharing options...
Robocop1051 Posted March 2, 2016 Report Share Posted March 2, 2016 My 16" Rifle length gas system , has a Port size of 0.1095"& is more then enough to operate the Action .this was the .11 I was referring too. I can't imagine a barrel configuration that would require a bigger hole, without going to an extended/custom length gas tube on a VERY long bbl. Quote Link to comment Share on other sites More sharing options...
Frankh252 Posted March 2, 2016 Report Share Posted March 2, 2016 Welcome JRoss. Like me, at 308AR.com you've found a great source of professional gunsmithing & shooting information! And just downright good people too. Quote Link to comment Share on other sites More sharing options...
Frankh252 Posted March 2, 2016 Report Share Posted March 2, 2016 Oh yeah, since threadlocker has been mentioned in the thread...what kind is best? I found hi-temp Loctite in 300, 350 & 400 degree formulas at the auto-parts stores and I have some 2000 degree Rocksett Engineering Adhesive (which I am really hesitant to use on a tiny allen set-screw). Quote Link to comment Share on other sites More sharing options...
Robocop1051 Posted March 2, 2016 Report Share Posted March 2, 2016 Oh yeah, since threadlocker has been mentioned in the thread...what kind is best? I found hi-temp Loctite in 300, 350 & 400 degree formulas at the auto-parts stores and I have some 2000 degree Rocksett Engineering Adhesive (which I am really hesitant to use on a tiny allen set-screw).Blue Loctite on most screws. A decent hair dryer will loosen it up just enough to break free.Rockset on gas block's and muzzle devices. It's water soluble. If you need to get it off, just soak it for a few hours. No heat needed. Quote Link to comment Share on other sites More sharing options...
Frankh252 Posted March 2, 2016 Report Share Posted March 2, 2016 Blue Loctite on most screws. A decent hair dryer will loosen it up just enough to break free.Rockset on gas block's and muzzle devices. It's water soluble. If you need to get it off, just soak it for a few hours. No heat needed.Yes, I was only thinking of the high-temp area at the gas-block for this application. Don't know how hot it gets there, just that it's one of the hottest areas on the weapon. Quote Link to comment Share on other sites More sharing options...
Robocop1051 Posted March 2, 2016 Report Share Posted March 2, 2016 The low profile GB's get pretty damned hot. Quote Link to comment Share on other sites More sharing options...
Frankh252 Posted March 2, 2016 Report Share Posted March 2, 2016 The low profile GB's get pretty damned hot. I have the steel SI low block http://www.strikeindustries.com/shop/index.php/products/rifle-accessories/ar/gas-blocks-stubes/si-ar-steel-gas-block.html seems to do ok/no malfunctions so far Quote Link to comment Share on other sites More sharing options...
Dane Armory Posted March 2, 2016 Report Share Posted March 2, 2016 Wow ! Know any good welders ?I would weld that hole shut and start over ! Quote Link to comment Share on other sites More sharing options...
washguy Posted March 2, 2016 Report Share Posted March 2, 2016 Did you buy this gun as a complete build? If so I'd contact the company you bought it from and have them make niceJross...you bought the complete upper.....send it back like Shepp indicates.....thats nutz to have to repair their stuff Wash Quote Link to comment Share on other sites More sharing options...
JRoss Posted March 3, 2016 Author Report Share Posted March 3, 2016 What length gas system is the Barrel. Also as said above , talk to the Manufacturer . The issue I see is , if the Gas Port in the Barrel is larger then the Gas Blocks Port , its putting High Pressure Gas impulse under the Gas Block & that may be why the Gas Block blew out or helped it blow out like that .Weak or soft Gas Block Material /short screw, probably didn't help ether . I would recommend an adjustable Gas Block , but the size of your Barrels Gas Port may be an issue . Steel may help & if it gets a chance to seal up , it may be ok , I just would not like that much gas impulse directed under the Gas Block . The Gas Tube ID is only so big ( 0.120" ), so it gets throttled down . Depending on the length of you gas system , it may cause Cycling issues also & you will definitely feel it in recoil . My 16" Rifle length gas system , has a Port size of 0.1095"& is more then enough to operate the Action .The gas system uses the rifle length 15 1/4" tube on a 24" barrel. The pressure at the large hole in the barrel is not really any higher then a barrel with a smaller hole, the difference is the surface area of the hole is greater with a larger hole. With the larger surface pressure area (.155" compared to say.090) more lifting or spreading power is produced at the contact area of the gas block and barrel. So a more distortion free gas block is going to help seal the gas block to barrel contact area. Of course the original AR10 was designed with a 16" barrel and with optimum hole sizes for proper operation without an adjustable gas system. Here we are 60 years later and people are selling whatever they decide will work. Quote Link to comment Share on other sites More sharing options...
JRoss Posted March 3, 2016 Author Report Share Posted March 3, 2016 Jross...you bought the complete upper.....send it back like Shepp indicates.....thats nutz to have to repair their stuff WashI don't want the morons out there to touch it. And yes it is nutz what I am going to do but I really don't trust them after what they sold me. I will put it back together with the replacement block and longer screws they sent me, if that doesn't fix the problem I will proceed from there. I am going to keep this thread going best I can with the progress of the repair as it goes along. And thanks to everyone for all the help and input! Quote Link to comment Share on other sites More sharing options...
JRoss Posted March 3, 2016 Author Report Share Posted March 3, 2016 Found this link about the AR gas system http://ar15barrels.com/prod/operation.shtmlLots of tech info Quote Link to comment Share on other sites More sharing options...
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