Revopop Posted October 20, 2009 Share Posted October 20, 2009 Ran across a deal on a DPMS Tactical upper. It's a 16" with a rifle length gas system. I've read much about how this setup is less than reliable, but then while searching here I've found several posts where Bruce Piatt says he uses one at work and it runs great. Has anyone else had success with this setup? Link to comment Share on other sites More sharing options...
sheik_djibouti Posted October 21, 2009 Share Posted October 21, 2009 i've had a 20" cut down to 16" and run great. i've also had factory 16" and shorter guns run horribly. there can be other variables besides the barrel- but most of the time when you are getting short in front of the gas port, if you have problems, opening the gas port a bit can help. is there any way you can run the upper through its paces before buying it? Link to comment Share on other sites More sharing options...
Canuck223 Posted October 21, 2009 Share Posted October 21, 2009 The AR-15 gas sytem relys on pressure, volume, and duration to cycle properly. Simply drilling a larger port hole may increase the volume, but it also adversely affects the pressure and duration. It's the last step I would consider taking to get a malfunctioning AR to run. Assuming that it's not illegal in your corner of the universe, the first thing I'd check if my AR-15 was malfunctioning is the weight of te bolt carrier and buffer. It's counter-intuitive, but the answer to many malfunctions isn't a faster cycle speed, but a slower one. If you are running a Colt lightweight/cut carrier, try a M-16 version. Same goes for the buffer. Try the H buffer if it's not already installed. Link to comment Share on other sites More sharing options...
dmshozer1 Posted October 21, 2009 Share Posted October 21, 2009 Ran across a deal on a DPMS Tactical upper. It's a 16" with a rifle length gas system. I've read much about how this setup is less than reliable, but then while searching here I've found several posts where Bruce Piatt says he uses one at work and it runs great. Has anyone else had success with this setup? Revopop I have been running two 16 inch rifle length gas system guns in 3gun events for the past five years. One is a DPMS heavy barrel, the other light. I have had no ammo related problems including shooting lots of Wolf and other so called junk ammo! The heavy barrel is a tack driver, the light is ok. Both guns are stock except for a Benny Hill Rolling Thunder Comp,carbine spring,and buffer. Everyone that shoots either gun, comments on how soft they shoot. Oh yeah, both gas ports are .113. There is 3and1/2 inches from the gas port to the end of the barrel, not to the end of the comp. Hope this helped. Take care Link to comment Share on other sites More sharing options...
Xfactor Posted October 21, 2009 Share Posted October 21, 2009 Ran across a deal on a DPMS Tactical upper. It's a 16" with a rifle length gas system. I've read much about how this setup is less than reliable, but then while searching here I've found several posts where Bruce Piatt says he uses one at work and it runs great. Has anyone else had success with this setup? Revopop I have been running two 16 inch rifle length gas system guns in 3gun events for the past five years. One is a DPMS heavy barrel, the other light. I have had no ammo related problems including shooting lots of Wolf and other so called junk ammo! The heavy barrel is a tack driver, the light is ok. Both guns are stock except for a Benny Hill Rolling Thunder Comp,carbine spring,and buffer. Everyone that shoots either gun, comments on how soft they shoot. Oh yeah, both gas ports are .113. There is 3and1/2 inches from the gas port to the end of the barrel, not to the end of the comp. Hope this helped. Take care Did they start out as longer barrels that you had cut down, or were they DPMS factory 16" rifle gas barrels? Link to comment Share on other sites More sharing options...
dmshozer1 Posted October 22, 2009 Share Posted October 22, 2009 The heavy barrel is a over the counter DPMS,the light is a TTI international ss. Both are original 16 inch. Link to comment Share on other sites More sharing options...
Xfactor Posted October 22, 2009 Share Posted October 22, 2009 The heavy barrel is a over the counter DPMS,the light is a TTI international ss.Both are original 16 inch. Interesting... I've been looking around for a nice light 16" barrel, and I've been seriously considering going with rifle gas over middy. Does the TTI shoot pretty well? (MOA, or close?) How much softer do you think the rifle gas is than middy gas? Link to comment Share on other sites More sharing options...
sheik_djibouti Posted October 22, 2009 Share Posted October 22, 2009 canuck223, well put. with regards to opening the gas port, it is indeed the last option, but i was speaking mainly to the issues unique to shorter than normal bbl length in front of the gas block, in this case 16" bbl/12" gas system. while extractor upgrades, heavier buffers and carriers will help increase the necessary duration to allow for proper extraction with a good gas sample (fixing double feeds), with the 16"/rifle-length gas systems, the gas sample may not be sufficient and cause a short-stroke malfunction. all those problems were the basis for the famed bm dissipator model back in the day. based on comments here, it looks like the dpms factory configuration seems to be working just fine. revopop- let us know how it works out if you go for it! Link to comment Share on other sites More sharing options...
dmshozer1 Posted October 22, 2009 Share Posted October 22, 2009 The heavy barrel is a over the counter DPMS,the light is a TTI international ss.Both are original 16 inch. Interesting... I've been looking around for a nice light 16" barrel, and I've been seriously considering going with rifle gas over middy. Does the TTI shoot pretty well? (MOA, or close?) How much softer do you think the rifle gas is than middy gas? Xfactor, When new,the TTI gave me 3 to 4 inch groups at 300 yds. Now after 10,000 rds. or so, it gives me 4 to 5 inches. This is pretty much with any ammo except Wolf. The difference between rifle and middy is not night and day but after shooting both, I would not even think about building a middy for myself. People that own a middy that have shot my guns say there next gun will be a rifle gas system. Do it! You will thank me! Take care Link to comment Share on other sites More sharing options...
STIGUY Posted October 22, 2009 Share Posted October 22, 2009 canuck223, well put. with regards to opening the gas port, it is indeed the last option, but i was speaking mainly to the issues unique to shorter than normal bbl length in front of the gas block, in this case 16" bbl/12" gas system. while extractor upgrades, heavier buffers and carriers will help increase the necessary duration to allow for proper extraction with a good gas sample (fixing double feeds), with the 16"/rifle-length gas systems, the gas sample may not be sufficient and cause a short-stroke malfunction. all those problems were the basis for the famed bm dissipator model back in the day. based on comments here, it looks like the dpms factory configuration seems to be working just fine. revopop- let us know how it works out if you go for it! WTF.....I have a 16" w/rifle length gas system and JP lightened carrier and the only problem I have is with the steel and lanquered Monarch ammo when the gun "heats" up. All that is total BS in my experience. I have a stainless steel barrel (from a no-name maker) because I could not get a Wilson from RockRiver when I was building the upper and have had NO funtioning problems like your describing with the system. Link to comment Share on other sites More sharing options...
Revopop Posted October 22, 2009 Author Share Posted October 22, 2009 canuck223, well put. with regards to opening the gas port, it is indeed the last option, but i was speaking mainly to the issues unique to shorter than normal bbl length in front of the gas block, in this case 16" bbl/12" gas system. while extractor upgrades, heavier buffers and carriers will help increase the necessary duration to allow for proper extraction with a good gas sample (fixing double feeds), with the 16"/rifle-length gas systems, the gas sample may not be sufficient and cause a short-stroke malfunction. all those problems were the basis for the famed bm dissipator model back in the day. based on comments here, it looks like the dpms factory configuration seems to be working just fine. revopop- let us know how it works out if you go for it! WTF.....I have a 16" w/rifle length gas system and JP lightened carrier and the only problem I have is with the steel and lanquered Monarch ammo when the gun "heats" up. All that is total BS in my experience. I have a stainless steel barrel (from a no-name maker) because I could not get a Wilson from RockRiver when I was building the upper and have had NO funtioning problems like your describing with the system. This is exactly why I asked this question in the first place. There are plenty of theoretical reasons why this shouldn't work, yet all the anecdotal evidence I've seen from actual owners indicates that the theory has no basis in reality. Link to comment Share on other sites More sharing options...
Revopop Posted October 22, 2009 Author Share Posted October 22, 2009 I'll definitely keep y'all posted if I decide to go this route. I just finished my first build, it's a Cav lower with a 20" heavy barrel, and I don't like how it balances. I'm going to get a standard lower for the 20" upper, and I was going to get a 16" lightweight upper for the Cav lower but I ran across this one for $20 more than the one I was looking at. My AR experience has been very limited, but I definitely remember that I liked the softer recoil impulse of rifle length gas over carbine length. Link to comment Share on other sites More sharing options...
Xfactor Posted October 22, 2009 Share Posted October 22, 2009 When new,the TTI gave me 3 to 4 inch groups at 300 yds. Now after 10,000 rds. or so, it gives me 4 to 5 inches.... The difference between rifle and middy is not night and day but after shooting both, I would not even think about building a middy for myself. People that own a middy that have shot my guns say there next gun will be a rifle gas system. Do it! You will thank me! Thanks, DMS. You've got me really interested in getting this project going again... any other nice, accurate, light- to mid-weight 16"/rifle gas barrels that you recommend? (I was also wondering if it would be wise to consider chrome-lined options, if there are any. Not sure how much that would affect accuracy, though.) I'll definitely keep y'all posted if I decide to go this route. I just finished my first build, it's a Cav lower with a 20" heavy barrel, and I don't like how it balances. I'm going to get a standard lower for the 20" upper, and I was going to get a 16" lightweight upper for the Cav lower but I ran across this one for $20 more than the one I was looking at. My AR experience has been very limited, but I definitely remember that I liked the softer recoil impulse of rifle length gas over carbine length. Good luck with your new build, Revo... keep us posted! Link to comment Share on other sites More sharing options...
sheik_djibouti Posted October 23, 2009 Share Posted October 23, 2009 stiguy, take it easy bro- you dont have to react as if i'm making fun of your mom or something. im just sharing what i know from my experience, which is my upper happened to work, but back in the day folks were reporting problems with those configurations. it seems that much of that came from simply cutting 20" barrels down and having a go. even today gas port sizes for same-length barrels vary from manufacturer to manufacturer, and they knew much less about this stuff back when the first 16"/rifle-length-gas-systems came out than they do now. as a comparison, i also mentioned that i've had ar's in more traditional configurations not work from the factory, be it 16", 14.5", 11.5" or 10.5", so i'm not singling out this configuration as condemned. i'll say it again, but it seems like dpms's are running fine from the looks of it. i'm glad your system works great with certain ammo. i know that bruce's duty rifle works well. i hope revopop's project works out and want to hear about his success. lets all relax and help each other have guns that work. Link to comment Share on other sites More sharing options...
dmshozer1 Posted October 23, 2009 Share Posted October 23, 2009 When new,the TTI gave me 3 to 4 inch groups at 300 yds. Now after 10,000 rds. or so, it gives me 4 to 5 inches.... The difference between rifle and middy is not night and day but after shooting both, I would not even think about building a middy for myself. People that own a middy that have shot my guns say there next gun will be a rifle gas system. Do it! You will thank me! Thanks, DMS. You've got me really interested in getting this project going again... any other nice, accurate, light- to mid-weight 16"/rifle gas barrels that you recommend? (I was also wondering if it would be wise to consider chrome-lined options, if there are any. Not sure how much that would affect accuracy, though.) I'll definitely keep y'all posted if I decide to go this route. I just finished my first build, it's a Cav lower with a 20" heavy barrel, and I don't like how it balances. I'm going to get a standard lower for the 20" upper, and I was going to get a 16" lightweight upper for the Cav lower but I ran across this one for $20 more than the one I was looking at. My AR experience has been very limited, but I definitely remember that I liked the softer recoil impulse of rifle length gas over carbine length. Good luck with your new build, Revo... keep us posted! Xfactor, I have no experience with chrome lined barrels.I wonder about them myself. I got my light TTI barrel from the Yellow Tavern Custom Shoppe. Back then they were building guns for Eric Lund and other top guys. Trapper John is the guy to talk to. 1-877-884-4685. Take care Link to comment Share on other sites More sharing options...
Jon Merricks Posted October 23, 2009 Share Posted October 23, 2009 I had a DPMS 20" and I had it cut down to 17" it ran fine but the accuracy was not that great with 55's but was better with 62's but still not worth measuring. Link to comment Share on other sites More sharing options...
Xfactor Posted October 24, 2009 Share Posted October 24, 2009 ...I got my light TTI barrel from the Yellow Tavern Custom Shoppe. Back then they were building guns for Eric Lund and other top guys. Trapper John is the guy to talk to. 1-877-884-4685. Is Yellow Tavern Custom now called TTI Intl? Link to comment Share on other sites More sharing options...
dmshozer1 Posted October 24, 2009 Share Posted October 24, 2009 Sorry,I don't know, its been about five years since I bought the barrel. Take care Link to comment Share on other sites More sharing options...
sheik_djibouti Posted October 24, 2009 Share Posted October 24, 2009 i'm pretty certain that yellow tavern is the name on the ffl that is used to do transfers for "tti"- i had an item duracoated at tti years ago and that was the ffl used. Link to comment Share on other sites More sharing options...
Sako92S Posted October 25, 2009 Share Posted October 25, 2009 I had 20" Colt Gov't profile barrel cut down to 17" and it ran very well. My wife liked it a lot because it was light weight system. Link to comment Share on other sites More sharing options...
lefty556 Posted October 28, 2009 Share Posted October 28, 2009 I've had a DPMS Tactical 16 for about two years now. Mine runs like a demon, and shoots pretty dang good, too-even after I turned the barrel to .675" under the handguard. Link to comment Share on other sites More sharing options...
peabody Posted August 13, 2010 Share Posted August 13, 2010 anything more ? you guys can add ? about the DPMS tactical ? im wanting one pretty bad, and yes... in my limited time, i've learn'd to love rifle gas. seem's like the dissy, is the way to go. peabody Link to comment Share on other sites More sharing options...
wannabe Posted August 13, 2010 Share Posted August 13, 2010 I have a silly question. I am really considering making a 16" DPMS into a full length gas system since it will work. However, what do you do with the original gas port hole? Link to comment Share on other sites More sharing options...
peabody Posted August 13, 2010 Share Posted August 13, 2010 I have a silly question. I am really considering making a 16" DPMS into a full length gas system since it will work. However, what do you do with the original gas port hole? hi wannabe... i sent my barrel to steve at ADCO, he moved mine to the mid-length position, and welded the carbine gas port shutt. ..................................................................................... this time around, i'll send him a 20'' pencil barrel, have him cut/recrown/thread to 17 inches. i gotta try this short barrel, with rifle gas. peabody Link to comment Share on other sites More sharing options...
wannabe Posted August 13, 2010 Share Posted August 13, 2010 Thanks for the feedback. Link to comment Share on other sites More sharing options...
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