I am not familiar with BB's customer service, but since you already are a customer, perhaps a call to them could clear this up?
Regret I cannot be more helpful, I only use 110gr JHP .357 loads in my M&P 340s.
The 340 is a 38 Special/357 Magnum revolver, I cannot imagine any reason that wadcutter ammo cannot be used in it. Perhaps the person who claims wadcutter ammo cannot be used was trying to fire soft swaged lead wadcutters at high velocity. That will lead to significant lead fouling in any firearm. Buffalo Bore's 150 grain wadcutter is hard cast lead, it should not leave a heavy amount of lead in the barrel.
The wadcutter / sleeved barrel / airweight story sounds a little sketchy ...
I'm a big wadcutter shooter ...from 148gr. HBWC to 160 gr. cast sold base WC's . I've never had any problems with them in airweight with sleeved barrel . I'm not sure of this one .
Gary
I've heard people say that the EDM rifling used in modern revolvers lead excessively (IMHO incorrectly). Maybe that's what he was referring to? In any case, I would not hesitate to shoot wadcutters.
Thanks guys. BB confirmed should be fine. Sounds like wrong info so I’m thankful for the info. Let the range fun begin! I’ve only hit about 50 rounds through the 340 but have plenty of options currently.
I can add to this that the 22 mag airtight is one fun gun!!!! I snagged one of those a few weeks back as well. I’m in j frame heaven with the ones I’ve picked up over the years.