Agreed. Imo, the main utility is NOT resin walls, but colony walls. The ammo restriction is there- So I’ve found that using the shotgun to blow up colony walls (which otherwise need C4 or BC) is the most efficient use, unless you’re hell pushing through the hive or something.
Being able to wipe through walls easily and inexpensively is huge- People don’t seem too recognise just how fucking bad walls are for marines, and how massive of a buff they are to xenos. Being able to kill colony walls fast and effectively imo, the biggest advantage it has over the U7. Not so much the resin walls.
Sadly, most XM-51 users just don’t actually use the gun often, or don’t pro-actively kill walls, probably due req sucking at sending down ammo resupplier.
It’s a very powerful utility weapon (as it should be), and can definitely have round-changing impacts (blowing open walls to flank for marines, or breakthrough the choke by widening it, instead of a 20 minute stalemate).
Alas, as with all weapons- The potential power is hampered by marines being marines. It’s a great gun, fun to use. Imo, merge immediately.