This will be my first post, and as I have used the search function and not found the answers I seek, I'll pose this "problem" here.
One of my neighbors runs an extremely effective tyranid army. In a 1500 point game, he runs:
Standard: winged hive tyrant with a 3+ save and double sything talons.
If only one tyrant, it's a winged machine gun tyrant. If two, he takes:
"machine gun tyrant": 2 twin linked devourers, 2+ save, bs 4, str 6.
Note that this tyrant, on average, wipes out an imperial guard squad every shooting phase. Absolutely disgusting firepower.
Standard: 3 shooty fexes with a venom cannon and barbed strangler each.
All have 2+ saves, bs 3. May or may not have 5 wounds.
After that, the remaining points are spent on 5 point "spinegants" to increase his numbers.
Depending on how he feels, he may bring psychic scream on his tyrant(s) and throw in 3 zoanthropes with scream as well (for a -5 ld penalty!)
If not, the points are spent on things like cheap, assaulty warriors, raveners, tyrant guard, or even more spinegants!
Here comes my problem: Generally, our games are very close either way, because I can beat him at mission objectives. However, I cannot figure out how to deal with his monstrous creatures because I become stuck between having the firepower to destroy them and being too slow to avoid the ocean of spinegants.
If I bring broadsides to take out his carnifexes, I may not even kill one before his winged hive tyrant, using terrain, simply avoids them and assaults. In addition, the gants or anything else that gets through can assault them and eat 200 vp's, and the carnifexes instantly kill them if they fail saves.
If I bring hammerheads, they simply cannot hide from the carnifexes, (range of 36" and can move and fire) which usually inflict at least one glancing hit per turn, enough to prevent return fire and often stop them altogether or disable the main gun.
If I bring piranhas, I get within 12" and they just assault or shoot me. Pointless.
If I bring crisis, plasma only wounds on a 4+, so it would take me 16 plasma shots to kill one carnifex, or 20 if he brought the extra wound (which is dirt cheap anyway). The carnifexes move behind a sea of spinegants, so getting within 12" with crisis is almost completely out of the question until the gants are eliminated completely.
Finally, If I try to simply overwhelm one monstrous creature with fire, the toughness 6 combined with the 2+ save usually means that enormous amounts of punishment are required simply to bring down one of the beasts, leaving the fast assaulty stuff to get through unopposed.
Finally, if I ignore the carnifexes, as I tend to do now, I find myself in endgame unable to destroy them, and unable to shoot anything that doesn't have JSJ for fear of uncompromising return fire. 6 turns of three shooty fexes firing tends to do tremendous damage, if not the fast stuff that eats anything without an armor value.
So my question is: what is the best approach to tackling an army like this one in a cleanse mission? (which is what we usually play)
Thanks for reading my incredibly long post, and for any help, beforehand!