TKCastle Posted January 29, 2014 Share Posted January 29, 2014 I did a search and came up empty which baffles me since I know it has been asked but here goes. Have an old 20hbar 1/9 that I want to cut down to 18 or preferably 17 inches and still keep the rifle length gas system. Anyone try? What were the problems? Was finding out a buffer and spring combo a pain? What the hell is dwell time? Can a gas port be enlarged enough and regulated with a adjustable gas block to run reliably? Am I making an ass of myself? Thanks Brothers. Mike. Link to comment Share on other sites More sharing options...
Mberry Posted January 29, 2014 Share Posted January 29, 2014 (edited) I'm running a 17" Krieger barrel on a Lancer rifle. No issues. Also using the SLR adjustable gas block, JP LMOS and silent captured buffer system with the second lightest spring. I'd say you're overthinking it, but if you enjoy the details, then read all you can and make your decision from there. You can find lots of info on dwell time, barrel length and gas tube lengths with a little searching. SBR sites have lots of info. Edited January 30, 2014 by Mberry Link to comment Share on other sites More sharing options...
GreenDragon64 Posted January 30, 2014 Share Posted January 30, 2014 I'm running an 18" barrel with rifle length gas system. No flaws related to gas system. Using carbine buffer and spring in a carbine buffer tube. Link to comment Share on other sites More sharing options...
Steve RA Posted January 30, 2014 Share Posted January 30, 2014 I don't quite grasp the difference in a barrel mfd as an 18" with a rifle length system and a 20" barrel cut to 18" with a rifle length gas system ??? Link to comment Share on other sites More sharing options...
TKCastle Posted January 30, 2014 Author Share Posted January 30, 2014 Thanks for taking the time to answer my questions guys. Link to comment Share on other sites More sharing options...
Stlhead Posted January 30, 2014 Share Posted January 30, 2014 It would work fine, but just because you can do it does not mean that you should. Why not just get a new 18" barrel that is of the contour you want? It will most likeley be cheaper and less hassle than modifying your old one. Link to comment Share on other sites More sharing options...
gondo Posted January 30, 2014 Share Posted January 30, 2014 I have read 17 is pushing it on rifle length gas... I have an 18 Nordic that had to be cut to 17.6 because I did an oh frick on it... I'll let you know how that works next Thursday I'll know caz I have time to go run a few hunge rnds through it then Link to comment Share on other sites More sharing options...
fastshooter03 Posted January 31, 2014 Share Posted January 31, 2014 Just cut it down to whatever you want. Whoever is doing the work should be able to open up the gas port if it doesn't cycle how you like. I've gone down to 16" without issues. Depends on your ammo, barrel gas port, and the bore. Nick Link to comment Share on other sites More sharing options...
HRider Posted January 31, 2014 Share Posted January 31, 2014 I have a rifle with an 18" rifle gas barrel, LMOS bolt carrier and LMOS buffer, rifle buffer tube and spring. I have had zero reliability issues. I have seen one man at my local club have issues with a 16" rifle length gas gun. I don't know all of the particulars on that setup though. I would think that a 17" rifle length gas should be able to be reliable. Hurley Link to comment Share on other sites More sharing options...
jaredr Posted February 1, 2014 Share Posted February 1, 2014 I'm running an 18" barrel with rifle length gas system. No flaws related to gas system. Using carbine buffer and spring in a carbine buffer tube. Same here. No problems. Using adjustable gas block but that's just to tune gas for running the rifle suppressed. Link to comment Share on other sites More sharing options...
GreenDragon64 Posted February 1, 2014 Share Posted February 1, 2014 I'm running an 18" barrel with rifle length gas system. No flaws related to gas system. Using carbine buffer and spring in a carbine buffer tube. Same here. No problems. Using adjustable gas block but that's just to tune gas for running the rifle suppressed. I'm using an M16 profile bcg and a standard gas block. Link to comment Share on other sites More sharing options...
CJW Posted February 1, 2014 Share Posted February 1, 2014 I have a Rainier 18" running in my main 3-Gun rifle, standard gas block and JP silent captured spring. Very reliable. I picked an 18" because I had seen mixed reviews of 17"/rifle reliability. Link to comment Share on other sites More sharing options...
openclassterror Posted February 1, 2014 Share Posted February 1, 2014 Sweeney wrote in his AR book that he cut a BUNCH of 20" surplus M-16s down to 16" for the state police so they could get in and out of their squad cars easier and didn't need to change the gas port size. Granted, most Mil-Spec guns are overgassed to start, but I would guess the hbar will shorten up no prob. Lots of shops only charge $50 or $75 to shorten and recrown, so depending who does the work it is a lot less money than a new barrel. Assuming it is in good shape..... Link to comment Share on other sites More sharing options...
Jesse Tischauser Posted February 2, 2014 Share Posted February 2, 2014 I've seen barrels get less consistent after they got cut and rethreaded. I'd leave it along and shoot it as is or buy a new 18" if you just gotta lose the 2". Link to comment Share on other sites More sharing options...
fastshooter03 Posted February 3, 2014 Share Posted February 3, 2014 I did a search and came up empty which baffles me since I know it has been asked but here goes. Have an old 20hbar 1/9 that I want to cut down to 18 or preferably 17 inches and still keep the rifle length gas system. Anyone try? YES What were the problems? NONE Was finding out a buffer and spring combo a pain? NO What the hell is dwell time? Don't Worry bout it Can a gas port be enlarged enough and regulated with a adjustable gas block to run reliably? YES Am I making an ass of myself? NOT YET Thanks Brothers. Mike. Any more ??? let me know. The barrel I cut back to 16" was an Olympic Arms ultramatch 20 or 24". Did not touch the gas port. Don't remember what size. Guy wanted it cut back since it wasn't shooting for u know what and needed a 3-gun barrel. He put on an adjustable gas block and had to dial it up and down when he used his reloads and wolf ammo. Wolf ammo he used was really weak. The accuracy improved a lot from the original length. Sometimes the worst part of a barrel is the muzzle due to poor manufacturing. Nick Link to comment Share on other sites More sharing options...
troupe Posted February 4, 2014 Share Posted February 4, 2014 A 16" length barrel with rifle gas system will work. Best to run a adjustable gas block for safety measures. A lot is how serious you want to get and the distances that you are engaging steel. Try to keep the velocities up, many factors to consider. Link to comment Share on other sites More sharing options...
bagdrag Posted February 4, 2014 Share Posted February 4, 2014 Anyone know if cold weather will affect reliability on 16"-17" rifle gas ARs? Link to comment Share on other sites More sharing options...
fastshooter03 Posted February 5, 2014 Share Posted February 5, 2014 Anyone know if cold weather will affect reliability on 16"-17" rifle gas ARs? I think that would affect the type of lube you use which of course may slow things down a bit. I've never looked into cold weather lubes. Not brave enough to try and get stuck downrange and fight the frigid temps here in WI. I'm using fireclean and/or some racing oil with assembly lube added. Straight assembly lube on CH. Nick Link to comment Share on other sites More sharing options...
gondo Posted February 5, 2014 Share Posted February 5, 2014 I have read 17 is pushing it on rifle length gas... I have an 18 Nordic that had to be cut to 17.6 because I did an oh frick on it... I'll let you know how that works next Thursday I'll know caz I have time to go run a few hunge rnds through it then well the verdict is in, it runs everything i can find except wolf and tula... even ran the monarch steel case from academy, here is a 3 shot with some PPU brass case at 100 yards with an eotech... not bad considering it was raining and very windy and 28* Link to comment Share on other sites More sharing options...
gondo Posted February 10, 2014 Share Posted February 10, 2014 I have read 17 is pushing it on rifle length gas... I have an 18 Nordic that had to be cut to 17.6 because I did an oh frick on it... I'll let you know how that works next Thursday I'll know caz I have time to go run a few hunge rnds through it then well the verdict is in, it runs everything i can find except wolf and tula... even ran the monarch steel case from academy, here is a 3 shot with some PPU brass case at 100 yards with an eotech... not bad considering it was raining and very windy and 28* having problems now that it is a little dirty and the weather has changed i guess, may have to make some changes.... im getting short strokes, hopefully i can get it reliable or the barrel will have to go, will be a shame if i have to change barrels caz it shoots and looks great Link to comment Share on other sites More sharing options...
fastshooter03 Posted February 11, 2014 Share Posted February 11, 2014 Ok now what's your buffer system? Nick Link to comment Share on other sites More sharing options...
gondo Posted February 11, 2014 Share Posted February 11, 2014 Rifle buffer and spring Link to comment Share on other sites More sharing options...
fastshooter03 Posted February 11, 2014 Share Posted February 11, 2014 I'm assuming what you have for buffer and bca is "stock" and not lightened in any way. Do you have extra springs? You shouldn't need the full power of a normal rifle length spring. Try putting a carbine length spring in place of the rifle length spring--just the spring of course..... Also make sure nothing is loose like your gas block or no broken carrier key screws(less common). Standard springs are pretty cheap in multipacks from Brownells. You can try experimenting with different spring lengths by cutting them down in 1" increments. You probably want to keep the BCA dirty while you do this. I usually run the Wolff reduced power spring in my setups. Nick Link to comment Share on other sites More sharing options...
gondo Posted February 13, 2014 Share Posted February 13, 2014 I'm assuming what you have for buffer and bca is "stock" and not lightened in any way. Do you have extra springs? You shouldn't need the full power of a normal rifle length spring. Try putting a carbine length spring in place of the rifle length spring--just the spring of course..... Also make sure nothing is loose like your gas block or no broken carrier key screws(less common). Standard springs are pretty cheap in multipacks from Brownells. You can try experimenting with different spring lengths by cutting them down in 1" increments. You probably want to keep the BCA dirty while you do this. I usually run the Wolff reduced power spring in my setups. Nick Just getting back to this problem due to weather and work, is there any chance running the rifle buffer and carbine spring will damage anything ? Link to comment Share on other sites More sharing options...
openclassterror Posted February 14, 2014 Share Posted February 14, 2014 (edited) No, worst case is the rifle buffer bottoms out hard in the end of the tube, but that is why there is a polymer tip on the buffer. Worst case long term is wear on the bolt stop or its roll pin breaks, or buffer pad gets beat up. All are replaceable. Highly unlikely (if it won't even lock back all the time) that it will hit hard enough using the carbine spring to beat stuff up. Ejected brass position will tell you if its running too hard. Edited February 14, 2014 by openclassterror Link to comment Share on other sites More sharing options...
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