Its a really powerful effect. The reduced minimum range roughly corresponds to hot loading, but without any accuracy or cluster size reduction. Heavy smoke on an Archer is likewise really strong. The reduced ammo effect is a nod towards balance, but if you allow the players to customize their mechs the ammo reduction isnt really gonna help--they will always include this ammo as a no-brainer for when the enemy gets close, so 1-2 tons for a +3 to hit bonus thanks to minimum reduction.
From a player POV, they provide too much action economy. To get heavy smoke, which I would want for sure cause smoke is super over powered, I would normally need to devote 6 shots (1 full ton) and a firing action from the LRM20, AND I would need a friendly unit to handshake smoke with me so we both benefit. This ammo lets the firing unit not rely on team work, and not have to move to get the smoke benefit. Granted, the normal smoke only needs to be refreshed once in 3 turns, while this one needs to be refreshed every turn, but that means 1 extra LRM20 shot into the enemy, and I dont have to move to benefit from my own smoke.
Unless the smoke is intended to only exist for the physical phase? It says the smoke dissipates in the end phase... That would be less OP... you would get a little defense against melee after the weapon attack phase, but after physicals in the end phase it goes away and wont make the heavy woods LRM sniper a +4 terrain mod next turn from woods and smoke. If that was the intention, I think thats cool--it wont save you versus death from aboves but you may dodge a kick in the thick exhaust of the LRMs.
The lack of LRM indirect fire isnt a drawback, because as an alternate ammo type you can still make indirect attacks with normal ammo, and presumably if you are making LRM attacks you wouldnt need the smoke defense or min range reduction. Id add a cluster penalty to offset the +3 accuracy bonus from minimum range... +3 accuracy at short range is when this alt ammo would be used, so thats where I would seek to balance it.
