What are the best of the alternative carbine gas tubes on the market? I'm aware of several offerings from PRI, La France, and there are likely some companies I've never even heard of. I have no experience w/ any of them however, I'd like to get opinions on the different options, their effectiveness in reducing operating pressures, and their durability when exposed to less than optimal conditions. (I already have enough range guns).

Please don't just tell me to get a mid-length, I've already got one, and it runs well. But I'm looking to convert my shorties to something a little less abusive.

MGI makes a whole system?  RRB, gas tube, and d-defender.  I think thats it.  they also offer a music wire 2x spring.  I have not used these products but plan on getting te RRB ror my carbine.  as far as wear this sounds like what you might want to look at + other preformance improvements the buffer offers.FWIW