Finally got the ITRA late last night after bit of grinding. Hadn't realised I had got the most expensive collection item in a drop and only had the 8900 item to buy to unlock it DOH!!!!
Anyway only had a few games and was tired but I see what you mean about inconsistent
Had a few up close encounters and full four shots from burst hit close in and it doesn't kill then other times it rips. Also noticed the strange quick double burst you mentioned when you are getting killed. Prob have more joy with it once I unlock attachments for it
Was actually quite enjoying using the M2. Fires really slow but it has virtually no recoil and decent at range. Just good to have some new guns to play through as the event hasn't added much I don't think and just passing time in game until the new maps