Gas piston AR rumor corrections...
Not all gas piston AR designs have carrier tilt, in fact very few cases of carrier tilt on a few models have actually occured, but just like anything else, rumors fly faster when they are juicier. Keep in mind I bought a piston AR that has a gas piston design built to the rifle from the tried and true POF design, not a retrofit kit.
Second, retrofit piston ARs have the factory bolt carrier adapted, but some come with a carrier that is built just for that purpose (heavier in the back, shaped a bit different, and the point where the op rod pushes on the carrier is a solid machined part of the carrier, not bolted there).
Piston ARs do get hot in the front sight/piston assembly area (so do DI models when fired alot), but they cool down fast.
Keep in mind that they are ALOT cooler in the upper reciever/bolt/carrier area. In fact a piston AR can be fired rapidly for hundreds of rds, then the bolt/and carrier can be held in your bare hand, it wont even be warm.
The bolt carrier in a piston AR stays wet with oil, and very clean regardless of how many rds you fire through it.
Now to address the subject of the increased weight issue. This was covered by a few of us who actually own piston ARs. Below is a list for reference of the actual weights of comparable 16 inch, 20 inch, and 24 inch AR models from one manufacturer alone, this should put an end to the front heavy rumors.
Keep in mind that the gas piston design (M4) I have weighs 4.48 ounces more than a standard 16 inch M4, to add to its weight difference it has much larger double heat shielded handguards, and 3 solid rail sections attached to the front of those handguards. I believe that someone here weighed the gas piston assembly to a whole 3.5 ounces at most.
Remember this, when you see these AR carbines with quadrails, the weight difference between a DI AR with a quadrail and with plastic handguards is over a pound, a 20 inch rifle would be heavier with a quadrail yet.
Gas piston M4 with POF gas piston design, 6.5lbs or 6lbs 8 ounces.
Standard DI M4 with 16 inch barrel, 6.22 lbs or 6lbs 3.52 ounces.
6.8mm DI M4, 16 inch barrel, 6.5lbs.
DI M4 patrolmans carbine, 16 inch barrel, 6.35lbs, or 6lbs 5.6 ounces.
16 inch carbine Hbar, 7.28 lbs, or 7lbs 4.48 ounces (flattop model, A2 is 6.93lbs).
11.5 inch entry carbine, 6.81 lbs, or 6lbs 12.96 ounces (flattop A3 model, A2 is a bit lighter).
16 inch midlength rifle, 7.44lbs, or 7lbs 7.04 ounces.
Carbon 15 flattop rifle, 5.77lbs, or 5lbs 12.32 ounces.
20 inch (flattop) A3 rifle, 8.78 lbs, or 8lbs 12.48 ounces.
20 inch Hbar, 9.6lbs, or 9lbs 9.6 ounces (without buttstock insert, with insert 13.6 lbs).
24 inch stainles steel varmit AR rifle, 8.84lbs, or 8lbs 13.44 ounces.
Gas piston ARs have adjustable gas systems in some cases, they can be adusted for stronger recoil or lighter, for use with a supressor, or without.
Why did the gas piston design pass the toughest tests our special forces (H&K 416) could throw at them if they are so "untested", and have all of these problems that are mentioned by those who have never owned one, let alone shot one? Why was the gas piston design bought to be used in the desert (Iraq, and Afganistan) by our special forces units, better yet it was these soldiers and sailors that helped to design the gas piston replacement rifle until the SCAR was purchased.
The primary differences felt with DI and gas piston ARs when firing, the gas piston model has a higher percieved recoil from the movement of the gas piston assembly, is louder, and takes a few rds getting used to when firing accurately when your used to the DI model. Id venture to guess that most soldiers would be less accurate with a gas piston rifle over a DI rifle, but thats the DI rifles advantage. With practice there is no big difference among many shooters.
Gas piston ARs clean in a hurry, the longest part of the job is cleaning the barrel (easier than a DI rifle), next the gas piston assembly (a few minutes), the rest takes a few minutes to wipe off and re-oil.
Depends what you are looking for, if you want a gas piston or DI AR, chose which you want, weigh the real differences, not rumors, or half truths to decide. If you buy a gas piston AR, buy one that has the gas piston design built and assembled by the manufacturer on the rifle with a warrantee, not a retrofit kit. The original designs are much better designed, and are much more substantial built.
Heck, buy one of each, their both fun to shoot.
Heres the big POF design that weighs a few ounces more than a small gas tube.
Im sure 3 of these rails make up a few ounces of that 4.48 ounce difference..
I to believe that regardless if the AR/M16 design being used for over 40 years in our countries military, it will probably be the last DI rifle used in its service. Being a combat vet that went to war with the M-16A2, I liked it, I trusted it, I mantained it, and it worked. In the conditions it worked, but religious maintance is needed on a daily basis. Its not hard to see why it sometimes fails in the nasty gritty dirty deserts with more frequent fire fights than if kept constantly clean. Keep in mind I had no complaint with the M16A2 (a full sized rifle with full sized gas system) neither did the Marines that used the M-16A4, today most soldiers are using the M4 which is more sensitive to the dirty environment, and more sensitive to lack of maintance.