Is that any good?

Step 1: Equip a multi-melta.

Step 2: Join a Tyranid Lair PvE mission.

Step 3: Shoot a Tyranid.

Step 4: Observe the results.

that sounds like awfully bad

Let me translate:

If you spend the same time going into the nid lair or even training ground and checked in on actual nid, you'd knew already instead of wasting your time to make thread and our to reply to it.

Sounds like science! Here's some questions you should try to answer.

-Can you reliably not hit your allies?

-Can you get multiple nids at once?

-Can you kill them before they get to you?

-Does your ammo holdout?

People are going to have opinions, but the best opinion you can have is the one you develop for yourself. A lot of people might scoff at taking the MM into a lair, but you could find a new way to use it that breaks that pattern of thought. And you'll probably drop a tyranid warrior in short order, so it has that going for it.

In other words, we have no clue

Plasma Cannon is pretty good on a group of 'nids at range. It's less good when they're close. When I say less good, I mean instawipe.

Reaching the XP cap is pretty easy on Hard Horde mode with a good spot, the right trio or quartet of Heavy weaponry and one or two supports. Taking down the big guy on wave 10 is not so easy. Cue the music...

Spoiler

take the ork cannon on lair it wont kill your entire team lmao

Most people don't seem to want to fight the warrior anyway, which is the only thing I can imagine the MM really being good for. There are also other reliable methods of taking out warriors, such as M-bombs, kraks, fists etc. If anything, a tactical with a meltagun would probably be a bit better, since he can at least use pistol on the gaunts.

I can't imagine heat being all that good against nids because they die quickly. Heat deals high damage at high affliction and low at low affliction... which has anti-synergy with low-health targets. Like... the MM will take longer to kill nids than other weapons, basically, because by the time you ramp decent heat, they are dead (slower than another weapon).

SO basically, a proper squad could be:
3x Devs, 1x Apoth, 1xMeltaTact(With the nade if possible)/1ShieldFistBro? (Or maybe gun fist bro?)