Arty armour isnt a good choice for jump pack HQs, because they genearlly cant swarm the HQ model, as he with 10 of his brothers, and hes only in combat with models that are ROUGHLY 3 inches around him. Its hard to muster enough attacks with normal guys to take wounds off an HQ. In almost all cases, your HQ will strike first against infantry, or at the same time with HQs.
So what attacks come his way, will be limited in number. I profer to take a 3 wound Chaplain, so that if he fails an armour save, its not the end of the world.
Hes also saving the life of another marine, which would have died had he been struck by that same number of attacks.
The biggest reason is that in 4th edition, your HQ can be singled out in CC, meaning the commander will often bet that he can kill your HQ with a powerfist, and direct the brunt of his attacks to kill your normal men.
And hes usually right.
Arty armour wont help you against a powerfist.
Arty armour only engcourages your enemy to devote powerfists, or other 8S Armour pentrating devices against him, such as monsterus creatures, wraithlords, demon princes Ect.
For 30 points, and a trait, the squad could have been given furious charge, leaving nothing to strike back at your HQ anyway. This is the profered methid of keeping your HQs alive.
HQ:
Chaplain w/ terminator honours, artificer armor, jumpack, bolt pistol, frag grenades: 157p
So lose that arty armour.
8 Devastators w/ 4 plasma cannons, infiltrate: 284p
Good.
8 Devastators w/ 4 heavy bolters, infiltrate: 204p
Take MLs instead.
8 Devastators w/ 4 heavy bolters, infiltrate: 204p
Ok.
8 Devastators w/ 4 missile launchers, infiltrate: 224p
Excellent
8 Devastators w/ 4 plasma cannons, infiltrate: 284p
Take Lascannons or MLs instead.
10 Marines w/ infiltrate: 180
10 Marines w/ infiltrate: 180
Again your troops are terrable.
Add a sgt with powerfist, to both squads. That should fix the problem. You might also think about taking a melta gun.
FAST ATTACK:
10 Assault Marines w/ (2) plasma pistols, meltabombs, veteran sergeant w/ power fist: 280p
Lose the melta bombs, with the changes above, youll have more then enough anti tank firepower. ID add the trait, blessid be the warriors, and flesh over steal to this list. Then give furiour charge to all assault squad memebers.
This is probably the best list youve ever made.