Unfortunately the only places a JH will beat a common-pool shotgun are ranges where you'd be better off using a SMG or CQ-LMG.
unless you are talking about a very recent post its already been done (for the jackhamer), they changed when the jackhamer starts reciveing damage falloff and when it ended pushing its effective range out a bit. as a note the jackhamer always had a higher min damage at range compared to the clasic shotguns, clasic shotguns damage range being 143-60 and jackhamers 112 to 90. Would be interesting if someon has the start end ranges of the fall-off, then we could chart at what range the jackhamers superior fall-off profile overcomes clasic shotguns superior initial damage.
PS1 Already had that; you could equip Armor piercing rounds or normal ammo. A HA with Armor piercing rounds in the jackhammer downed a MAX with 2 clips.
Second times the charm? Why use the Jackhammer when the Piston is better at close range and the Claw is better at long range.
I know it was in FNO 23 doing 7cav spotlight i know they talked about the jackhammer and the heavy pass they gonna do and buff im sure it was early in the video when cav was making fun of the vanu. http://forums.station.sony.com/ps2/index.php?threads/recap-friday-night-ops-episode-23.100903/
They haven't been buffed yet MCG and Lasher are gettin some love too Didn't see anything about em in GU04 though :\ Hopefully in a couple more weeks in GU05
Replace the joke burst fire mode with something unique, like charged shot that fire all remaing rounds at once wit increased spread. It can be ballanced by charge up delay with some loud warning sound & it unavoidably empty your clip.