What purpose does the Accatran Mk. II serve

Apart from padding the weapon pool.

The other 2 variants have either high damage and slower firing rate and the other is low damage and higher fire rate.

Mk II has base 30 damage, 11.11/s fire rate.
Mk VId has 30 damage, 16.67/s fire rate
Mk VIIa has base 50 damage, 7.69/s fire rate.

The Mk II has the same damage than the las-hose but the fire rate is a significant chunk slower. The rate of fire is in the middle, but the base damage makes it worse than both of them. They all have pretty much the same hip fire spread and bloom.

Does it have some kind of behaviour or feature that isn’t as obvious?

Well we promised you 70 weapons and so now you have them.

Be a dear and be happy with what you got. Don’t turn new stones.

With hate,
FS

No expert on the Vets weapons by any means, but it seems like the roles for the weapons are:
Mk II: All-round, high fire rate weapon.
Mk VId: More fire rate at the cost on less stopping power.
Mk VIIa: High damage, lowest fire rate.

So basically you choose Mk II if you want more stagger in your shot over the MkVId.

Hope that helps, cheers!

piqued my curiosity so had a look.

Mk 2 benifits over mk 6d

0.3 second reload
higher weak spot damage multiplier
much lower impact

unsure of this one
i think the mk2 is slightly faster in the ready animation.

the mk2 is vastly superior when it comes to hosing a special or elite in the head , you do more damage per shot and you wont stagger them so you can just sit on target till they die, the mk6 will flinch them throwing your aim off.

the mk6 is a weight of fire weapon more usefull for horde clearing with its rof and stagger

i was surprised both guns do seem to share accuracy and auto bloom characteristics i expected the mk2 being the “light version” to win and my tests were only done with mk1 eyeball so i could be wrong but its a small diff if its there

@Typhon actually in this case i think thats unfair these are quite different weapons that do ned to be used differently , not saying i agree with there PR speak.

Bit off-topic, but holy crap, i was not even aware that there was three different marks of that particular weapon type, i have literally never seen a MK VLd.

Edit: Recons in general are a bit weird, i mostly just use them on lower difficulties for a bit of fun, and to melt bosses with infernus stacks.