The mad scientist went back to his lab and developed *Robot Enforcer Mark II* fresh off the assembly line. Is this any better?
(Please be aware, too, that the gun is detachable and can be used without needing the robot as a power source. Smart players can take a robot down and use a gun against other 'bots.)
Robot Enforcer Mk II --- Level 3 Artillery (Elite)
Medium Natural Animate (Construct) XP 150
Initiative +6 Senses Perception +9; Darkvision, truevision 10 (sensor suite)
HP 40; Bloodied 20
AC 15; Fortitude 16, Reflex 18, Will 15
Immune: charm, disease, fear, poison, sleep; Vulnerable: 5 lightning
Speed Fly 10 (hover) overland flight 15
Action point 1
{m} Tentacle Claw (standard; at-will) * melee
Reach 2; +10 vs AC; 1d6 + 3 damage
Target is grabbed (until escape). A target trying to escape the grab takes a -4 penalty to the check.
{M} Choke (standard; at-will) * Grabbed target only
+8 vs Fortitude; 1d6 + 3 damage
{M} Meat Shield (Immediate interrupt when targeted by a melee or ranged attack against Reflex or AC. Recharges when the robot makes a successful tentacle claw or choke attack.) * Immediate interrupt
Robot makes its grabbed victim the target instead. The robot cannot use this power to redirect attacks made by a creature it is currently grabbing.
{r} Electric Gun (standard; recharge 5,6) * lightning
Ranged 10; +8 vs Reflex; 2d10 + 3 damage
Target is dazed (save ends).
Alignment: unaligned Languages: -
Str 14 (+3) Dex 20 (+6) Wis 14 (+3)
Con 16 (+4) Int 6 (-1) Cha 6 (-1)
Equipment: Small, detachable electric gun
Ok, first off this is an elite so it should have x2 the HPs of a standard creature. I also think your defences are a little out, on a side note the robot having a dex of 20 is above what would be expected for a level 3 artillery (14, +3 from as it is primary give 17 or maybe 18, 20 is quite high)
Anyway from your stats the defences should be (including giving it +2 to up to 3 stats because it is an elite)
HP: 80
AC: 17; Fortitude: 18; Reflex: 20; Will: 15
#edit: speed 10 is a bit too high as well, this thing could kite the PCs quite easily in the right enviroment
Tentacle Claw
The to hit value is good, however the damage should be either 1d6+2 (str)
or 1d6+5 (dex) - note this is a direct effect from having too high a dex
stat.
Choke
This is a conditional attack (a creature must be grabbed first) so I would either make it a minor action (1/round) for low damage or a standard action for high damage. The slight problem I am having is that this is an artillery creature that grabs......that seems to be going against type.
Bearing all that in mind I would go for something like:-
{M} Choke (minor; at-will) * 1/round; Grabbed target only
Target must be grabbed at start of Robots turn; +8 vs Fortitude; 1d6+2
damage; on hit target is dazed (save ends)
Meat Shield
Thats fine.
Electric Gun
Personally I would say that 2d10+3 is far too much damage for a level 3 creature. I would change it to 2d6+5 lightning damage (dex again); as I have suggested using daze for the grab power I would think about changing the auto daze here to a; on hit secondary attack +8 vs. Fortitude; on hit target takes a -2 penalty to all actions (save ends)
{r} Electric Gun (standard; recharge 5,6) * lightning
Ranged 10; +8 vs Reflex; 2d6+5 lightning damage; on hit secondary attack
+8 vs. Fortitude; on hit target takes a -2 penalty to all actions (save ends)
On the whole I like the idea of what you are trying to do, but I am a bit uncomfortable with an elite artillery creature that doesn't have access to a ranged attack every turn, but is designed around grabing people in melee.
Creature ROLE is very important in creature design as it determines many key abilities (i.e. HPs, AC; attack values; and expected effects)
ADDITIONAL -
I have just read where you say that PCs can take the gun. If that is the case I would highly recommend having a ammo track for it and saying it can only have 5 shots (or so) before recharging.)