What AR15 barrel length is the most relevant.
- Thread starter cancer
- Start date
Smak, 3rd groups don't count, in fact 5rds groups really don't count unless you have multiples.
http://www.ar15.com/forums/topic.html?b=3&f=118&t=279218
http://www.ar15.com/forums/topic.html?b=3&f=118&t=279218
- Location
- big sky country
I know, I know. That load is gold through every AR I've ever tried it in.
Shorter gas systems need to have a more violent ejection cycle.
You need to impart enough energy into the bolt carrier for it to cycle. Over a longer gas system the load can be spread out, in a shorter gas system its a harder shaper rap.
This is the same way a piston gun has a sharper recoil than a DI gun.
Kev, You got any experience with increased buffer weight in carbine length gas systems? A heavier buffer is supposed to smooth out the cycling and reduce the violence of the motion. Just not sure how much buffer weight is needed.
You can do it, hence the H, H2, and H3 buffers.
However you are increasing the moving mass, so you can slow the speed of the carrier, but at an increase in either/ your spring rate, and/or the buffer weight.
All else being equal, its easier to lengthen the gas system.
However you are increasing the moving mass, so you can slow the speed of the carrier, but at an increase in either/ your spring rate, and/or the buffer weight.
All else being equal, its easier to lengthen the gas system.
Coyote Ugly
CGN Ultra frequent flyer
Just like your pecker, the longer the better.
Barrel length = 20"
If it ain't USGI, your #### will fall off.
Longer ain't better if its pencil thick.
Ha! Good one.
But returning to the discussion, one should buy one lower and an upper of every barrel length, and bring the upper(s) relevant to the mission.
Putting more weight in the buffer essentially increase the amount of energy needs to initiate and cycle the system - if gas port size stays the same, it means more time is needed ( pressure stays the same- no change in cross section area of the path of flow, volumeric flow rate stays the same - therefore time duration needs to be increase)
It "feels" smoother probably due to the velocity of buffer in the tube. So far I haven't seen springs of different spring rates for different buffer - therefore, the heavy buffer moves slower with the regular spring. That probably changes the pattern of the "felt recoil".
At the end of day, you can calculate the buffer weight ..... if you have the right tool or know enough to write your program.
I'm trying to say what I can without expanding to much into where I am compromising our programs.
The M16 FOW is dependant upon port pressure and chamber pressure for the amount of energy that is released into the carrier.
All esle being equal the higher chamber pressure will actually retard carrier speed as it takes more energy to unlock it.
Looking at high speed video and bolt carrier velocity from Suppressed and Unsuppressed system - the data is transverse.
Suppressed guns actually unlock slower due to the higher chamber pressure - but have higher carrier velocity once they start to move.
Muzzle Mount cans versus BOTB/Reflex cans are also interesting to see the difference in.
The M16 FOW does not have a lot of room to play with the cam path angle - LMT's new Enhanced Bolt is a case in point, it delays unlocking but is really just chnaging the angle for a more agressive crash which delays it more than the few thousands extra travel.
You would need to alter the design of the bolt tail and firing pin to gain any real room to manuver as well as the bolt carrier itself.
Gas Systems being these days, the Carbine, Armalite Midlength, KAC "Battle Rifle/E3" Midlength, and Rifle Length.
The longer gas system will be able to give a longer "push" as opposed to a sharper one for shorter system. Ideally you want the longest gas system where you can have enough pressure to cycle the gun, and this is where a lot of 5.56mm Disapator guns run into troubles is there is not enough barrel length after the port to maintain pressure for reliable operation.
PRI tried with their "Fat Boy" gas tube to equate rifle length volume in a carbine length tube, and generally they work well in 16", 14.5" and 11.5" guns, but have problems in the 10.3-10.5 guns unless they are dedicated suppressed guns.
Grant Timberlake (of G&R Tactical) designed the softest shooting 10.5" suppressed gun I have shot, he used a LMT Enhanced carrier, small gas tube hole, and it runs well with a SF 556K suppressor, but will not lock the bolt back unsuppressed, this gun is also remarkably clean running, cleaner than an unsuppressed Hk416 over the same shooting schedule, I am however concerned that if it gets dity from outside elements (like a chopper ride in durka-durkastan) it will not cycle reliably even with the can.
The M16 FOW is dependant upon port pressure and chamber pressure for the amount of energy that is released into the carrier.
All esle being equal the higher chamber pressure will actually retard carrier speed as it takes more energy to unlock it.
Looking at high speed video and bolt carrier velocity from Suppressed and Unsuppressed system - the data is transverse.
Suppressed guns actually unlock slower due to the higher chamber pressure - but have higher carrier velocity once they start to move.
Muzzle Mount cans versus BOTB/Reflex cans are also interesting to see the difference in.
The M16 FOW does not have a lot of room to play with the cam path angle - LMT's new Enhanced Bolt is a case in point, it delays unlocking but is really just chnaging the angle for a more agressive crash which delays it more than the few thousands extra travel.
You would need to alter the design of the bolt tail and firing pin to gain any real room to manuver as well as the bolt carrier itself.
Gas Systems being these days, the Carbine, Armalite Midlength, KAC "Battle Rifle/E3" Midlength, and Rifle Length.
The longer gas system will be able to give a longer "push" as opposed to a sharper one for shorter system. Ideally you want the longest gas system where you can have enough pressure to cycle the gun, and this is where a lot of 5.56mm Disapator guns run into troubles is there is not enough barrel length after the port to maintain pressure for reliable operation.
PRI tried with their "Fat Boy" gas tube to equate rifle length volume in a carbine length tube, and generally they work well in 16", 14.5" and 11.5" guns, but have problems in the 10.3-10.5 guns unless they are dedicated suppressed guns.
Grant Timberlake (of G&R Tactical) designed the softest shooting 10.5" suppressed gun I have shot, he used a LMT Enhanced carrier, small gas tube hole, and it runs well with a SF 556K suppressor, but will not lock the bolt back unsuppressed, this gun is also remarkably clean running, cleaner than an unsuppressed Hk416 over the same shooting schedule, I am however concerned that if it gets dity from outside elements (like a chopper ride in durka-durkastan) it will not cycle reliably even with the can.
I think that swapping out a buffer would be a lot easier than changing gas system length which requires swapping out the barrel.
And this is exactly the kind of info I am interested in. As a lefty, shooting suppressed AR's has been highly unpleasant in the past as I get a face full of back splash. I am trying to delay unlocking enough to reduce the amount of crap I get in the face. Then I need a heavier buffer to reduce the carrier velocity so it doesn't beat the rifle to death.
BOTB cans have a much larger initial expansion chamber and so tend to drop pressure in the barrel faster than a conventional muzzle can with its much smaller primary expansion chamber.
Yeah please elaborate for us
Looks like he doesnt want to come out and play.
Certainly higher magnification optics help, but I'd make a better than good guess the exceptionally high V count on the deliberates is due more to the use of single loaded, vld-loaded, handloads than >20" barrels...
For SR type competitions where long range and positional shooting are both factors, I think the 20" is probably the best choice, and a very close 2nd (and maybe parallel) is a mid length 16".
Gunnerlove
CGN Ultra frequent flyer
- Location
- Vancouver Island
NSCC was won with a score of 750 shot with a space gun.
CFSAC was won with 745 out of my rack C7A1 with a 3.4X C79 Elcan.
Not really an ass kicking point spread.
And remember - the military is limited to C77 balls , but the space guns people are all loaded with handloaded match ammo. The ammo makes a big difference - potential sub MOA handloads versus 1.5 to 2 MOA at best issued ball ammo. They get less margin of error - they know exactly the wind effect on the ammo instead of being clouded by the dispersion due to the quality of the ammo.
