[Armed-Citizen]

Can i use the same lower reciever for a gas piston or direct impingement upper?

[bige91603]

Yep, only difference is in the upper. Are you thinking about a piston system?

[Armed-Citizen]

maybe. ive seen various forums and vids on difference on both.
one con that worries me is if the company i buy the gas piston upper from goes out ofbusiness, that gas piston is done and no more parts for it if its unique to that company.
.
why you ask?

[bige91603]

If this is your first ar and you don't have much experience with ars plus if you're not going to be throwing it around in mud and sand, putting thousands of rounds down in a small time frame, a piston system would be pointless for you to buy. DI can be used the the same conditions and slightly less recoil plus all of the parts are interchangeable/cheaper

[SSGN_Doc]

Yep, what he said.

Piston guns bring their own unique set of problems to the AR. DI works fine. As you already noted, one of those issues is non-standardized parts. Carrier tilt is another potential problem with some of the systems available. The guns were designed as DI. If I get a piston gun it would most likely have been designed from the start as a piston gun, like an AK or Sig.

[fsted2a]

Originally Posted by SSGN_Doc

Carrier tilt is another potential problem with some of the systems available.

Most of the piston AR systems, factory or drop-in, come with their own proprietary carriers, which has mitigated the carrier tilt issue. They added weight and mass at the back end by making them all full auto carriers and adding metal to their mass. You may see some shavings in the buffer tube after a lot of rounds. Other than that, a properly built AR with high quality parts will shoot about as reliably as a piston gun, the quality of either being the deciding factor. Like Bige said, I wouldn't buy a piston gun as my first AR. Now, if you happen to get one free or a super low price, go for it.