Sigh. We've already been through this on another thread. I've given you five separate canon sources specifically identifying the APC the Imperial Marines use, and it is not the Astrin. Whether Astrin is a @standard@ APC also in service with Imperial forces or not doesn't alter all these specific and detailed descriptions of the APC the Marines use.
And in 993, if they aren't using the "Standard" Imperial APC what are they using?
And your super-BD runs on? Moreover, how does neutrino do IFF out of line of sight? Moreover, read MT rules again, targeting at Regional range is either Impossible or Formidable task. Good luck with that orbital direct fire.
My Marine Battle Dress runs on Batteries. (48 hours endurance, if you are using the Grav Drive significantly longer if you are using the legs.) How long can your troops stay in the APC in a hostile environment? (Rules say less than 24 hours unless they are supplied with staterooms.) As for IFF, If you have no Fusion reactors in your force, all Reactors belong to the other guy.
Personally, I seriously dislike the MT rules. (And never used the Striker rules, because I didn't find a copy of them until long after I started using the T20 rules.) This is because personal combat, remember this is primarily a Role Playing game, goes from being deadly to personal weapons can't hurt anyone in rudimentary armor. But OK, Looking at the table you are apparently referring to. The heading is Crew served weapons and vehicle mounts. It doesn't apply to starship turrets. Starship turrets treat Lunar orbit as "Far" and for that a Starship Laser gets a -1 to hit. Since your vehicle is likely under 100 DTons, that is an additional -2, you can have your agility, if you are mobile, which for a Grav vehicle is a max of 4. Giving you a -7 DM to hit. Snagging the CA out of Shattered Ships of the Fighting Imperium, a Beam Laser Battery has a UWP factor of 8 (+7 to hit), Model 9 computer (+9 to hit). I don't see an issue hitting at all.
You're being a bit harsh, we all know Kinunir was the first adventure and has a few curious and inconsistent elements cf later canon. Picking holes in the detail doesn't alter the fact of the basic setup - mech, pro forces inf.
Using an organization that is obviously seriously flawed as a basis for something and then excusing it because it is written early? It has nothing to do with any Marine organization discussed in any Traveller canon later, in any source. I am not being harsh, you are holding it up as ideal, I am telling you that it certainly is not even viable as a military unit. Real world example a Squad that encounters a fireteam or larger is supposed to establish a base of fire and wait for the rest of the platoon to maneuver and take out the unit being faced. Anything bigger than a Squad requires more than a Platoon. What use is a single Mech Squad out of a Platoon? BTW you have two short fireteams and the vehicle. (Aside from the fact that you can lose your entire Mech capability to a single hit.) Either mech the entire platoon (And organize it better) or drop the mech concept. (I vote for dropping the concept, but the Kinunir, unlike most Naval Vessels actually has plenty of Cargo Capacity.)
Huh? 4518th is not a Marine organisation nor an Imperial Army unit and has few organisational parallels with canon Marines - see JTAS 12 or Striker II for Marine organisations.
It is serving as a Marine unit in "The Spinward Marches Campaign." Isn't JTAS 12 the one that said all Marines wear Battle Dress?
Come on, give us a link...not that I know much about T20 designs, sorry.
It was in the F-Library. There are a couple of threads with early models in there from back in 2005. I'll find it and upload it eventually, but since you don't have a clue on T20, there isn't all that much point.
It must have been a very quick glance at CT/Striker Book 2 page 35 because I see quite clearly maintenance requirements for Battle Dress and grav belts, communicators and sensors. As I've demonstrated on the other thread (Stealthy BD) under these rules your troops will require a maintenance technician with toolkit per eight-man squad to keep things running. Or try TNE/Striker II page 54, which has similar detail of support personnel requirements for military units.
Your APC Marines have the same requirement as my Marines for that part of it. Like I said, I don't use Striker, but I don't see it require that the Technician not be a member of the squad. Further the maintenance rules are extremely simplistic. A Grav Vehicle, regardless of cost, size or complexity requires 5 maintenance points? So a 100 Ton Grav Yacht, a 30 Ton Grav "House Boat" and an air/raft all require the same amount of maintenance, regardless of Tech Level? Talk about hand waving. I had to look at that page three times to find Battledress. (Hidden among electronics.) And Battledress with an integral Grav Drive? (T4 has them for the Imperial Marines, as well as mine.) Is that covered under the Grav Belt, Battledress or do you have to use both?
Striker 2? Never bought it, I didn't like the basic rules or the setting for TNE so that is as far as my purchases went, even if I could have found Striker 2.
Sounds interesting, can't comment on T20 beyond saying that is not the case in CT/MT/TNE where BD is significantly less useful as protection. Without seeing the design its hard to judgeit - for instance orbital range commo with what? A radio? Great until the enemy jams it. Dunno how bulky orbital range laser/maser is in T20, but useless if the ships go over the horizon anyway or when the troops are in those closed in areas you're so keen on.
In an enclosed area, you aren't going to be using orbital fire support in any event. in CT and MT Troopers are protected by dispersal. Autofire rules there say you can engage one target and hit adjacent targets. Not sweep a 45 degree cone selectively. You don't even get to hit targets in the same line if they aren't close enough. In MT it takes a VRF Gauss Gun, FGMP or HEAP grenades to penetrate BD. So against infantry it is as effective as being in an APC and there are only two or three weapons that will penetrate Battledress but not penetrate a typical APC, making them very close to the same. Add cover and concealment that Infantry can find easier than vehicles can and they are rather well protected. Sure if you are going to march across a tabletop in nice straight lines, in parade formation you are going to get killed. No surprise there. Anyone that has spent a couple of weekends at an outdoor Paint Ball facility, knows better. (You don't need to have served in the Infantry to see that.)
And I think I'm on safe ground saying that under any ruleset only a vehicle can carry and power the meson communicator that the canon Imperial Marine APC has, which is unjammable and can communicate with ships out of LOS. So what is the reliable and secure way your Marines get their orders and call in that fire support you depend on? What kind of sensors, a radar/ladar? Crumbs, how do you power all this stuff?
Internal power on the BD works just fine for powering its sensors. Why would I want Radar or Ladar. Those say, "Here I am, Shoot me now!" Passive sensors. Laser/Maser Comms are enough, secure and also not subject to jamming. Why would a supporting starship go beyond the horizon? (Geosynchronous orbit is significantly closer than the definition of Far Orbit.)
Your point being (I can give you five that say it), aren't we talking about your non-standard Marines anyway?
Nobody said my Marines are non-standard.

The design concept in my T20 Marine Battle Dress is very similar to the Marine Battle Dress described in T4, or so I have been told. What TL is Battledress? What TL is other standard Marine Equipment? No advances were made in Battle Dress worn by Marines through 4+ wars? My point being that in comparing cost, maintenance requirements, or other things, that Battledress cancels out, so you are only comparing Grav Belts to APC.
I apparently have to split my reply.

Continued.