FGC-6: TPU fixed hup up Bucking barrel set

keep in mind this barrels are not the best option. but's it's one option to use with the GBB version of the FGC-6.

these barrels can be fully 3d printed. and the hop up piece can be printed with TPU or other flexible material so it can function as a detent so you dont get barrel roll. (BB rolling out of the barrel.) and a bit of a hopup effect if the tpu can give enough friction for that.

a view things to keep in mind are. 
the hopup is adjustable but only by swapping TPU pieces.

the inner barrel size will be smaller then you think, 6.60 looks to be a lose fit.
6.50mm ID looks to be normal, 6.40mm ID looks to be to tight but if you choose to use a stick and sand paper it might give a smooth finish and fit.

the barrels need to be matched with the nozzles / bolts

it's hard to match a polished official barrel

-

how to select the parts
make a small test print of the barrel tip to see what ID barrel you need

print a TPU model and see what haves a good fit with your nozzle. with the amount of flex and shrinking you are dealing with. making a airtight fit is good but the nozzle must be able to go in the TPU piece other wise you will have miss feeds

then look at how the barrel and TPU preforms and see if you have selected the right amount of hopup or at the very least prevent the BB's from rolling out of the barrel when it's pointed down. with out making it to hard for the BB's go past that hopup bump in case you use a 95A tpu those get stiff fast.

print settings:
0.2 layer height should be fine.
you can use the 6 layer walls and a 40% infill.
ironing on

printing it barrel tip up with tree supports seems to work well