Gas on the 10.5" AR

[codygjohnson]

So I've got a nice 10.5" barrel and a good upper receiver laying around and decided to do an SBR build. Form 1 is sent off and I'm just waiting for it to come back to do some shopping. I've got enough parts here that I don't want to buy a complete upper, but, this rifle will probably carry a supressor most of the time. I start looking into adjustable gas blocks and a gas buster charging handle and bolts and forends, and start to notice that the money I spend on all of this would buy an aftermarket piston system. I'm not a big fan of piston ARs, but I've shot enough short guns with suppressors to know that I hate the gas blowback. Piston ARs aren't much better, but they do give noticeably less blowback. What do you guys think about the drop in kits? Any of them worth a damn?

 

[Texas1911]

Adams is good to go from what I've seen.

 

[AusTex]

AA all the way.. however you might have to tweak the gun a little to get it to run correctly. Put a cam roller pin on your bolthttp://www.pof-usa.com/images/223rollercampin1.jpg and use the right buffer. My buddy runs an 11.5 aa with DD 9.5 fsp great looking gun and it functions awesome. The AA is neat b/c it has gas off, suppressor mode, and full gas so it is like an adjustable gas block. I run a suppressed 11.5 with DI and I have a BCM CH and I have no issues(no smell or burnt eyes) that is my gun though. The aa is also nice on the full kit b/c it has an anti-tilt follower that comes with the kit annnd good looking options in the future for rails. I would not use a Osprey or other kits.. spend a few more bucks and get the AA unless you plan on running the stock hand guard set up.

Draw back I have seen to the AA is it adds some noticeable forward weight to the gun.. Why I stuck with my DI actually on my sbr.

 

[atacorion]

IMO pistons are kinda a fad thing and I havent seen them offer any advantage to a DI gun other than heat reduction on the bolt and Carrier. If you run suppressed it'll still kick alot of fouling back into the bolt and receiver.
Also more moving mass = less controlability however slight its still less accurate and controlable.
I think LWRC makes some great guns but for me DI all the way. AA cans are great also Knights Armament makes some great cans aswell.

 

[AusTex]

Come shoot a 2k gas piston setup with the proper parts, buffer, and not a jerry rigged gun.. and you will change your mind.. Watch the video and watch the tip of his barrel.. Do you notice him shooting without eye protection? No gasses getting kicked into his face. He was shooting hot military loads also.

Shoot a 30 round clip fast.. grab your bolt but I would have gloves on when you do it... then take a gas piston gun shoot a beta mag full auto and take the bolt out and lick it... It will be slighty warm.. I don't see how people can argue that the ar does not have a fundamental design flaw when it comes to DI systems.. I know this is kicking a dead horse but again the gun sh*ts where it eats. The amount of stress and heat that is prevented on your system is huge.

People get a drop in gas piston kit.. they don't change their buffers they don't use anti-tilt or change their gas cams, and they are possibly already using a mix of mil spec or non milspec parts in their gun then they go shoot Winchester white box ammo out of it and they wonder why the things don't run. If you do it right you won't go back. Also if you have ever cleaned your DI gun after suppressor use you will be amazed when going to a piston.. If you don't run a suppressor you can get away with not cleaning that sob for 3x as long as normal.

Sry to jump on you but are you talking from experience with all these products or is this what you have read or seen at a range? I have personal experience with the 3 major types of pistons on my guns and my friends guns in conjunction with multiple cans on multiple barrel lengths(sbr, carbin, mid) and it is night and day to me after thousands of rounds of 5.56 and many a cleaning session.

 

[atacorion]

I am talking from exp, I have run classes like EAG tactical and Magpul Dynamics and many others where its not uncommon to shoot 3000 rounds in 3 days, like I said if you run em supressed they still shit where they eat. And I am not talking about drop in kits, to me thats just asking for trouble, I am talking about well made built from the ground up as piston guns......LWRC, ACR's, POF, SCAR-L, even Rob arms.
Heat doesnt bother me, who licks their bolt? Again more mass moving translate into more uncontrol ability and you really have to drive that gun that much more. I dont bag on Pistons if they work for you by all means run and gun with them.
If the DI system was really that big of an issue the Military would be jumping on it faster than greased lightning. As long as you keep a DI gun wet it runs, I've never seen one fail cause of fouling if it was wet.

Tell you what lets go shoot when I get back to Austin in 6 months or so I'll bring a case of ammo and we shall see if I have any issues.

 

[AusTex]

Well interesting stuff atacorion let me know when you get to Austin and we can try and do some shooting. I disagree with you about the military though. Point being military contracts on a few key factors one if which is price. Just because its a weapon purchased by us doesn't mean it is top quality they are still issuing Beretta's that have been so shot out that clips wont even stay in them. Some of the m-16's, Ar-15s are so over the maximum round limits its a joke(those are quotes from two of my marine buddies). American guns jam. In the Korengal a tactic that the Taliban has adopted is to attack our fire bases and wait for our guys to shoot their gun barrels out and jam up(Saw, m4's, 50's) then they try to over run and of course their AK's, Rpks, are still shooting strong. Something is wrong in my opinion if the enemy can adopt a tactic like that because of our equipment issues.

I guess the wet part then gets us in the two different arguments and schools of thought on wet vs dry... might need to leave that for another time.

I don't think anyone licks their bolt but you could with a piston is all I am saying and if the metal stays cool it is a plus for me. If we are talking about private use of ar-15s yeah you are most likely never going to be failed by the weapons system on DI because of the issues we are debating.

Good discussion and good points!

Jeremy

 

[atacorion]

I aint seen any base being attacked be nearly over run by that tactic, and I aint seen any weapons go down for more than 30 secs. the damn USGI mags are the biggest issue from what I have seen not the DI system. I'm in Helmand Province BTW as we speak. So you could say I have first hand knowledge.
Lets take a look at the SCAR L program, it was cancelled due to the fact that no serious advantage was offered over the M-4 so SOCOM cancelled it, was price an issue, its the government and we are in a recession so I'm sure it was but it was by no means the nail in the Coffin.

Lets face it if you try and go outside the box and operate anything other than how the manufacturer recommends its 50/50 if its going to work.

 

[codygjohnson]

Well eeeeeeeeeffffffff me! I just dropped the dough on the Adams Arms kit. What ended up selling it was the "quick-changeability" for the suppressor. The adjustable gas blocks just won't cut it for a quick change and if I went with something like a Noveske switchblock, it was going to cost an arm and a leg by the time I put it all together. I figured I'd try out the piston setup and see if it's worth a damn or not. Update to follow...

 

[JustaPhule]

IIRC, the main reason the M16 is DI was the same reason for the little 5.56 cartridge- weight reduction. The military was looking to increase the round count an individual G.I. could carry and lighten the primary weapon. They had a perfectly good piston rifle that was just to damn heavy with a full load of ammo, the M14. There is only so much equipment an individual can carry before they have to use an alternative form of transpotation. For any civilian, piston vs. DI boils down to vanilla vs chocolate. Operators, .mil and others, have many other criteria in their choice of gear besides weight.

Go ahead an flame if you want, I'll consider the source and not take offense.

codygjohnson-keep us updated, I looked at the AA piston, but couldn't pull the trigger on it. (sorry)

 

[codygjohnson]

I've gotta say, the UPS guy has been busy over here...

This is going to be a fun rifle!

 

[ThrottleHead250]

Nice man!! I just finished up my first build and I'm hooked! Can't wait to see your PSBR together!

 

[codygjohnson]

Here's the assembled upper.

I'll probably throw it on the m16 lower to get all the bugs out this weekend, then put it up until the SBR stamp comes back.