*sigh*

I need to win a powerball or two to afford everything on my wishlist.

Tell me about it.

The piston has no bearing on the accuracy of the weapon. There is a slight increase in felt recoil since the piston is in direct contact with the carrier. But the AR15 has very little recoil to start with. Both in the Military Police and the Infantry, I have seen plenty of M16s choke because of all the carbon inside the carrier. You get so much crud built up that the bolt does not go fully into battery. I know that with proper maintenance it isn't a problem but a lot of people are not as anal as I am about PMCS.

Actually it has a large effect on the accuracy of the weapon. Most piston uppers shoot groups twice the size of a DI upper. In a DI upper there are essentially no moving parts attached to the barrel. In a piston upper, you have pistons and springs which create additional forces and vibrations on the barrel before the bullet leaves the gun. This reduces accuracy. There is a reason standard DI ARs often shoot very small groups compared to other service rifles and it isn't just the stupid bull barrels every manufacturer throws on them.

The real problem with most of the piston kits is that they try to retain the standard front sight block so you have a drop in unit. That won't work. The gas tube has a bend it it because the port coming out of the front sight block is lower than the hole through the upper receiver to the gas key on the carrier. This bend doesn't matter with DI because you have a pulse of gas moving down the tube. Replace that gas with solid parts and any assembly will see bending moments that tend to bind a piston. You need to replace the front sight block with a redesigned unit so the forces directly oppose each other in a straight line. HK did this with the 416 and I'm sure other manufacturers have too.

I've never seen someone crud up their AR with carbon, but I'm sure you could do it. I imagine it is a lot more difficult to do with a semi-auto AR than a select-fire M-16 though.

little blurry.

Like I said in my OC log the guy said he would throw a rear sight in for me but didnt...
quick order to cheaper than dirt will fix that.

Let us know which sight and how you like it. I have a detachable carry handle on mine right now, but I want to switch to optics or a red-dot with a BUIS.

im looking at getting one off of cheaper than dirt here next pay check, will give a report on it when I have it. I will also take some better pictures with it.

Hows that rear sight working out for you? I'm thinking about picking something like that up so I can drop a red-dot on my AR.