10.5" DI or piston?

[Mortar]

Currently looking to move from 8.5" LWRC upper to a 10.5". Making the move for a couple of reasons, mainly going to be suppressed.

I have a piston upper on my 8.5" to increase reliability.

Do I need a piston 10.5 or will a BCM DI function as reliably?

Do the benefits of a piston carry on to 10.5?

Is piston necessary to have reliable (suppressed) 10.5"?

 

[KevinB]

Why 10.5"?

Generally best reliability out of DI guns is in 11.5" or greater, IF you can, get a gun built for your can - ie ported to run for it.

If you cannot get a Hk416, I tend to discount AR piston guns - as the reliability across the fleet is erratic.

 

[JBowles]

Neither, like Kevin said anything less than 11.5 is asking for headaches at least for 5.56mm.

 

[Mortar]

So 11.5" is the answer to my question? The best of both worlds length and reliability with DI.

 

[Bourneshooter]

I have a 10.5" Noveske upper that is usually ran suppressed with a Surefire can. It has yet to malfunction other than what is directly attributed to a bad magazine or reloaded ammo. It has ran wolf 55gr that is under powered as well as Hornady TAP 5.56

 

[rob_s]

What percentage of your shooting will be done suppressed?

 

[Mortar]

I would say roughly 90% shoot several classes a year and will also hunt with the rifle.

 

[rob_s]

What I would lean towards, on what I would consider a full-time suppressed gun at 90% suppressed use, is a 10.5" DI with either a reduced gas port or adjustable gas block and a suppressor on a muzzle-brake mount to act as a sacrificial baffle. One way some others have achieved the reduced gas block is to take a 14.5" barrel and cut it down to 10.5", but in the event that this DOESN'T work you have to start a lot of fiddle-fuck in terms of tearing the gun down to drill it out. Range in backyard = not a problem, having to drive to a public range = major nightmare.