Good morning, Bill.
Last nights schedule changed a bit and I was not home until after 9:00. I didn't get anything I had planned done. Except, I did look at my Firefly and the instructions. Believe it or not, I didn't have much of any fit problems with either A27 or A9! Go figure. It seems to me I had to push and prod the rear hull sides to match up with A27, but it worked out okay. I do see what you're talking about on the weld seam on that part, but as I didn't have to use any putty there, I left it as it straight from the box. My rear deck fits close to perfectly, if a little tight. Actually, I have a very small gap at the front of the plate, right behind the turret. With the turret in place, I don't think it will be able to be seen.
The little plastic knobs you were talking about are, I believe, areas where "excess" plastic can flow during molding. That way they can be sure the plastic didn't leave any voids. Also, I think they are yet more ejector pin areas. So maybe they have a double purpose.
I was going to glue the box on the front of the hull in step 10, but could not make it fit so that it looked right. So, I glued it on the rear hull as per step 11.
One place I had a major fit problem, at least it looks like it, but maybe it's right, was step 19. When I glued the B12 box assembly onto the rear of the turret, I wound up with a pretty sizable gap between the top of the box and the turret. Maybe I glued it too high up on the turret. I don't know, but it sure looks weird.
Also, be careful gluing B18 to to turret in step 16. It looks, to me, like it goes right next to the square hatch (B21). If you look at step 19, it shows where I think it goes a little clearer. Both drawings show that there are locator marks on the turret for them. Mine certainly didn't have any!
Hope you're having fun with it. It still was a lot of fun to build, even with all these little challenges. (But I'm about ready to get some Friul tracks for it, if I can find any!)
Bill
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DML M4A2 Red Army
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-- There is a fine line between "hobby" and "mental illness". (Author unknown)