[RedDragon]

So, the title should explain the basics. I'm mostly interested in weapons, and guns in particular. Being an amateur firearms enthusiast (and a somewhat less amateur sci-fi enthusiast) myself, I've picked up Gun Fu, High-Tech, High-Tech: Adventure Guns, both of the High-Tech: Pulp Guns books, Tactical Shooting, and most of the relevant Pyramid editions (including Military Sci-Fi, which is fantastic, BTW). I've just been wondering how ammunition types and accessories from High-Tech and Tactical Shooting work with the guns from Ultra-Tech. I'm worried less about caseless and ETC guns than I am about Gauss Weapons. Of course, as the GM, I could always just arbitrarily lay down the law, but I'd like some outside clarification on both the RAW and the RAI. Ideally, I'd want someone with a pretty good understanding of both ballistics and firearms (including theoretical near-future developments in those fields) and the GURPS rules, but someone with one or the other would be helpful too. I understand that all these weapons are just extrapolations and may not work as presented in Ultra-Tech, but some sort of instruction would still be great.

With that out of the way, here goes:
Silencers (HT and TS): Are these able to be used with Gauss Guns? Would they even have an effect?
Flash Hiders (TS): Would it be reasonable to assume that these are still standard on the guns from Ultra-Tech? Would Gauss Guns even need something like this?
Compensators and Muzzle Ports (GF and TS): The descriptions for these mention venting the firing gas. Does that mean these wouldn't work on Gauss Guns?
Slide-Locks (HT): Less of an Ultra-Tech question and more of a general one. Would it be feasible to have a "switchable" slide-lock? (as in, you flip a switch and the gun becomes a manual repeater)? Would a Gauss Gun benefit from such a device?
Ammunition (HT, TS, UT): This was my main question. High-Tech has a massive list of ammunition types, and I was wondering as to the feasibility of using some of them in Gauss Weapons (and to a lesser extent in caseless and ETC guns). Specifically, those that mention modifying the propellant, such as Subsonic Rounds, Match-Grade and +P Bullets, etc. Also, RAW I believe that APFSDSDU rounds (for example) are capable of being used even in some of the medium-sized caseless handguns from Ultra-Tech. Is this RAI? Can APFSDSDU rounds be used with Gauss Weapons?

Much appreciated.