BigDave Posted January 24, 2003 Share Posted January 24, 2003 What is the disadvantage (if any) of the shorter gas system in the 16" carbines and dissapator type AR rifles (.223, just to be clear)? If someone wanted a shorter OAL AR rifle, what might the problem be with taking a standard 20" gun with the full length gas system and cutting off 2-4" to make a 16" or 17" gun with the full length system? We've discussed here at length the problem some folks have of making minor with 55gr loads and 16" barrels, would the longer gas system decrease that chance (in the situation I mentioned above?). AR newbie has no clue (as if you couldn't tell) Link to comment Share on other sites More sharing options...
benny hill Posted January 25, 2003 Share Posted January 25, 2003 the shorter 16" guns are much harsher .[ recoil felt & sight picture] than the 20". shorting the 20" barrel will result in short stoking of bolt from loss of gas. you can enlarge gas port till it work's, but why. most all really good shooters use 20" because it is better. Link to comment Share on other sites More sharing options...
lynn jones Posted January 25, 2003 Share Posted January 25, 2003 benny, please quit posting and get back to gunsmithing. i don't want you to go hungry and loose weight. now, chop chop back to work. lynn Link to comment Share on other sites More sharing options...
BigDave Posted January 25, 2003 Author Share Posted January 25, 2003 i consider myself educated now, should have visualized the gas system and answered my own question. Thanks Benny!!! feel free to keep posting Benny!!! Lynn, we need all the help we can get here!!! Link to comment Share on other sites More sharing options...
SGDM Posted January 25, 2003 Share Posted January 25, 2003 We have been testing an 18" with full length and medium gas system, no problems. Link to comment Share on other sites More sharing options...
Guest Dick W Holliday Posted January 27, 2003 Share Posted January 27, 2003 i think my dissapator bushy has the same system you're describing and mine has never missed a beat and come to think of it niether have my 16" carbines.....Dick Link to comment Share on other sites More sharing options...
Carlos Posted January 27, 2003 Share Posted January 27, 2003 Dick is correct - the dissipators have full length gas systems which are more reliable/less harsh than the shorties. Check out the add in Small Arms Review (Class III rag) for an ad about the "pigtail" gass system for shorty ARs; itsa corkscrew shaped full length gas tube for shorties to assure reliable cycling in full auto (not that you would want that for 3gun). but it makes the point. Link to comment Share on other sites More sharing options...
Mig Posted January 27, 2003 Share Posted January 27, 2003 The Dissaptor gas system is in the same location as the carbine gas system. What makes the Dissaptor different is the full length iron sights as compared to the carbine. (Edited by Mig at 8:35 am on Jan. 27, 2003) Link to comment Share on other sites More sharing options...
PacMan Posted January 30, 2003 Share Posted January 30, 2003 Gas port location has nothing to do with bullet velocity, therefore it would not affect the 16" barrel's ability to make minor. Each inch of length cutoff from the 20" inch barrel is worth roughly -100 fps, you do the math. Link to comment Share on other sites More sharing options...
skeeter Posted January 30, 2003 Share Posted January 30, 2003 just how hard is it to make minor anyway? i'm quit fond of my 16 inch guns and really like the way they handle. Link to comment Share on other sites More sharing options...
Patrick Sweeney Posted January 30, 2003 Share Posted January 30, 2003 Not very hard, if you load your own. Some factory ammo, however, might come close to getting you dinged and zeroed. Link to comment Share on other sites More sharing options...
kellyn Posted January 30, 2003 Share Posted January 30, 2003 It's easy to make the power factor with heavy bullets but Kurt does no t approve. Link to comment Share on other sites More sharing options...
kurtm Posted January 31, 2003 Share Posted January 31, 2003 Kelly: Heavy shmevy; heavy and .224 bullets should NOT be mentioned in the same sentence. My 45-90 Winchester 86 throws HEAVY bullets...505gr, and the .50s even more. I am NOT opposed to 62s, 69s, 75s, 77s, even 80s and beyond. ALL I AM SAYING is for the distances involved in 3 gun matches it is not a huge difference!! I know Natinal match shooters Love these things but remeber they don't move, the target doesn't move, they are allowed spoters, wind flags, and spoting scopes. I have seen a derth of these things at 3 gun matches As for short gas systems, the gas velocity that impinges on the carrier key is much higher in the shorties making opening sooner and carrier velocity higher. If the chamber is "right" and the brass isn't soft like some cheap ball ammo your ok, but it is right on the edge and some guns just have problems with this length of gas system. KURT Link to comment Share on other sites More sharing options...
benny hill Posted January 31, 2003 Share Posted January 31, 2003 YOU TELL THEM KURT, I'LL PAT MY FOOT. Link to comment Share on other sites More sharing options...
Larry White Posted January 31, 2003 Share Posted January 31, 2003 How much diffrence? I was shooting a 16 with Bennies comp and thought it was slick, well we were practicing one day and I picked up Bennies rifle, next day was new barrel time. Really noticeable diffrence, rifle is much smoother. Lynn, Bennie is on a diet, I had lunch with him today(lunch is a Bennie specialty) and he is alive and well. Larry Link to comment Share on other sites More sharing options...
kurtm Posted January 31, 2003 Share Posted January 31, 2003 Benny: Leave your foot alone and start practicing. Jimmie is shooting open this year at Mesa and I happened to get him a Trijicon ride!! This of course dosen't change the fact that we all also shoot for Triangle Sports, but nuke stuff is cool!! see ya ina month!!! KURT ( I got apple juice!!) Link to comment Share on other sites More sharing options...
benny hill Posted January 31, 2003 Share Posted January 31, 2003 IF I WAS SHOOTING ANY BETTER RIGHT NOW, I COULD'NT STAND MYSELF. READY AS I'VE BEEN IN A WHILE. OF COURSE BEING 56 YEARS OLD NOW REALLY SUCKS, BAD KNEES, LEFT SHOULDER, SLOW REFELEXES, & A SLOW MIND. Link to comment Share on other sites More sharing options...
Bear1142 Posted February 3, 2003 Share Posted February 3, 2003 Guys, FWIW, I just chrono'ed some South African battlepack and some Q3131A yesterday through my 16" dissipator. The SA went 3,030 fps for a 167 pf and the 3131A went 3,075 fps for a 169 pf. The Winchester burns cleaner and is slightly more accurate in my rifle, but the SA is cheaper. Link to comment Share on other sites More sharing options...
SGDM Posted February 5, 2003 Share Posted February 5, 2003 The rule of thumb for velocity is 25 fps per inch, not 100. We have found that utilizing the carbine length gas system produces too much pressure in a 18-20 barrel. Link to comment Share on other sites More sharing options...
PacMan Posted February 5, 2003 Share Posted February 5, 2003 SGDM, I stand corrected, should of re-read my typing before submitting. (Edited by PacMan at 6:59 am on Feb. 5, 2003) Link to comment Share on other sites More sharing options...
benos Posted February 5, 2003 Share Posted February 5, 2003 In addition to the shorter gas systems being more "load finicky," IME they are a tad more finicky on extraction. The harsher, more abrubt rearward movement of the bolt may tend to rip the ejector, especially if it isn't perfectly fitted, through or off the rim. be (bet you never thought you'd see me postin' in this forum.) :-0 Link to comment Share on other sites More sharing options...
BillL223 Posted February 6, 2003 Share Posted February 6, 2003 Regarding 16" barrels making minor: American Eagle 50 Gr. 2948 147 PF American Eagle 55 Gr. 2923 160 PF PMC 55 Gr. 2609 143 PF Black Hills 52 Gr 2978 155 PF Wolf 2853 157 PF All shot through a BM 16" V-Match. I later tried IMI 55 gr NATO and it easily made minor Link to comment Share on other sites More sharing options...
BigDave Posted February 6, 2003 Author Share Posted February 6, 2003 looks like Ol' BE has been playin opossum Link to comment Share on other sites More sharing options...
rhino Posted May 2, 2003 Share Posted May 2, 2003 I later tried IMI 55 gr NATO and it easily made minor There's the key. Shoot something that is M193 spec (and IMI 55gr and IMI manufactured Winchester Q3131A definitely are M193 in every way!) and you won't have problems. You should be able to make minor with a 14.5 inch M4 barrel too. But all rifles are different, eh? Some of the "factory" 55gr is just downright wimpy. Link to comment Share on other sites More sharing options...
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