gas port diameter on RRA LAR8?

[GunTroll]

Any one know what diameter the gas port should be on a RRA LAR 8? It use to be 26 inch but was cut down to 16 and doesn't cycle right. I just took it in today and haven't test fired it yet, just taking the customers word on it for now. I know the port diameter/ barrel length/barrel diameter/ gas port distance to/from the muzzle all are a factor in this. Just thought one of you AR freaks might know or can point me to some info. It has an adjustable gas block so I'll start with adjusting it before heavier machining.

Thanks guys!

[The1andOnlyKC]

I have a LAR-8 A4 in the safe if you need I can pull it out and measure the OD of the gas tube for you.

[GunTroll]

I'm sorry if I wasn't clear I mean the port in the barrel not the gas block. Thanks though.

[GunTroll]

Ok shot the rifle yesterday. I could use some help on this one guys. I'm not the biggest fan of AR's in general (don't hate me) I like em' I'm just not all knowing on this platform. What happened was....I was trying to learn the adjustable gas block system to narrow down the issues with this rifle. On "low" the action almost cycled correctly. Bolt retracted half way. When adjusting the port,Closed.....stuck, high ..stuck. I found it funny that the bolt would not retract manually in all settings. Once I did get the case out I did find some frosting on the case. I'm leaning towards thinking the chamber is rough. The customer did tell me when he lightly oiled the cartridge and then fired the rifle it worked fine. What say you AR people?? What would you advise?

Also what is the best tool or trick to get the damn free float tube off of this rifle. My strap wrench spins and I'm getting nowhere. Any suggestions on a better tool?

[Backinblackrifles]

If the frosting is bad I would start with the chamber before milling a new gas port since a little polish will not hurt anything. I would also look for dents or kinks in the gas tube that may be spreading out the peak pressure. Also look for bends in the tube where it comes in contact with the carier key to by stripping the bolt carier asembly and runing it back and forth by hand make sure the two mate without binding ( listen, feel ). Make sure the ammo is not using ball powder it won't burn fast enough, Use flake or perferated powder. On the free float tube if it is round the belt wrenches are what I like it probably has lock tight on the threads a little propane torch should loosen LT.

[Backinblackrifles]

Also ask if it has been shooting laquer coated surplus or wolf..... AR no likey. Really sticks up the chamber.