I've just picked up AFV Club's new M42A1 Duster. A very nice kit, which will make an interesting nosatlgic comparison with the old Tamiya one that I built about XXX years ago.

Poking through the bags I've noticed something odd. There are three or four part-sprues bagged separately from the rest. So far as I can tell:
* they're duplicates of parts that are provided on full sprues - D13-18, L6 and L27-31
* they've been clipped from bigger sprues; they don't form complete sprues in their own right
* they seem to be no different from the parts on the full sprues, with one exception: on the runner next to the spare part L6, there appear to be two lines of small bolt heads that I assume are meant to be shaved off and added somewhere.

This is a mystery. The instructions don't mention them. I've not found a review that explains them. I suspect they may be improved versions of the parts in question, but if they are, the improvements are impossible to discern. Plus, if they've come from bigger sprues, what happened to the rest of the parts on them - were they improved too?

Does anyone know what happened here - and, most importantly, which parts should we use?

Does anyone have any ideas about this?

Got no ideas about this but I've noticed that Terry's PMMS review sprue pics show these very parts clipped from the sprues indeed...
http://www.perthmilitarymodelling.com/reviews/vehicles/afvclub/afv35042.html

Maybe you were not supposed to get them in your kit My own kit doesn't include these extra parts...

Frenchy

I suppose it's possible, but they did take such care over separating and packing them ... I'll just assume they're there for a reason and use them instead of the ones on the full sprues.

sometimes manufacturers do this when they update/improve parts and have some stock from before the update that hasn't been shipped to distributors yet that have the old parts.

Usually this comes with an addendum to the instructions, but not always. You might want to do some research to see if AFV club was correcting an error in that kit or some such.

does it have anything to do with this (from PMMS review)?:

No, the parts are on other sprues. 'Tis a mystery, ennit?