SBR 5.56 AR Piston or DI? 10.5" or 12?

[dtibbals]

I am new to the class 3 world and am waiting for my first stamp to come back for my M4-2000. I am looking to SBR a lower and trying to decide if I should buy a Noveske upper with switch block or a piston upper by someone like HK or LWRC. My main interest would be in an HK416 10.5" upper. All my AR's are now Noveske rifles, I have 14.5"-18" rifles set up already for my suppressor and plan on shooting the SBR suppressed all of the time.

With all that said is a piston upper a better choice than a Noveske with switch block? Also I see some manufactures aren't offering a 10.5" and only a 12". Is there a reason to go 12" over 10.5"? The warranty of the M4-2000 is void with less than 10.5" barrel so that is as short as I plan on going.

Thanks for your help!!
David

[justlikeanyoneelse]

I see no one has touched this subject yet...

Since its a sbr I recommend you go with a piston system. With that short of a barrel there are issues with a DI system. Its the same principle issues of chopping the M16 down to a MK18, It will work but not quite up to par. In fact I remember Larry Vickers commenting that the HK416 piston system is optimal with a short barrel, and DI was fine with longer barrels. 10.5 or 12 I think is more of a personal preference, others on the forum can tell you more specifics.

I am new to the class 3 world and am waiting for my first stamp to come back for my M4-2000. I am looking to SBR a lower and trying to decide if I should buy a Noveske upper with switch block or a piston upper by someone like LWRC. All my AR's are now Noveske rifles, I have 14.5"-18" rifles set up already for my suppressor and plan on shooting the SBR suppressed all of the time.

With all that said is a piston upper a better choice than a Noveske with switch block? Also I see some manufactures aren't offering a 10.5" and only a 12". Is there a reason to go 12" over 10.5"? The warranty of the M4-2000 is void with less than 10.5" barrel so that is as short as I plan on going.

Thanks for your help!!
David

[romanowe]

Some relevant first-hand knowledge

http://m4carbine.net/showthread.php?t=105274

[Cameron]

No need for a piston. A correctly built direct impingement short barreled AR will run with zero issues with or without a suppressor.

Cameron

[usmcvet]

I wouldn't suggest a piston. Get a 10.5" or 12.5" gun from a good maker, LMT, Colt, DD, BCM and Noveske would be choices. I have an LMT 10.5" and a few BCM 11.5" guns and a new BCM 12.5" but not much experience on the Kino.

[Toxicodendron]

I would reccomend the Noveske w/ the switchblock. I have 10.5" w/ the Switchblock and the thing runs like a champ. Suppressed or un-suppressed zero issues. You want something with a piston buy an AK.

[duece71]

I am considering getting into the SBR world myself and am glad there are threads/questions like this out there. Its all a part of the grand pre-buy research project that should be mandatory for newbie NFA/potential SBR or restricted firearm owners.

[Pax]

As others have said... If you can make it run with DI then use DI. You can make it run with DI. Therefore, use DI.

It will be easier to sort out proper buffer weight for reliable cycling with the longer barrel (11.5-12.5") and you will have a greater range of compatibility between your M4-2000 and any rail system. I highly recommend building an 11.5" upper, thats just my taste though.

As no one else has said... There is little to no reason to use a switchblock if you plan on using this upper suppressed 100% of the time.

[bugeyes]

I would reccomend the Noveske w/ the switchblock. I have 10.5" w/ the Switchblock and the thing runs like a champ. Suppressed or un-suppressed zero issues. You want something with a piston buy an AK.

I totally agreed !!!

[justlikeanyoneelse]

You want something with a piston buy an AK.

I respectfully disagree, if your statement was correct than SOCOM has been making some huge mistakes. IMHO piston vs DI is a lot like the AAC vs Surefire debate, I can find lots of supporters for DI but not enough for piston. Most of the problems I have read with piston systems were due to poor design/manufacturing. If I were just getting in the NFA SBR game, just stating, "Use DI, it works" does not really help me much, every rifle works if it didn't than all you would have is a metal club. If there is any error in my logic please feel free to correct me.