FSR (first strike bolt) Bolt for Tippmann / BT markers

this is slightly longer at the back and this in combination with the fine-tuning that you can do with the Inner diameter will this give a better air seal. jet still a smooth running bolt if you do it right.

the tip with the Oring is the better option for a good air seal. but the one with out is a stronger part.

the tip shape it self is made so it can correct some misalignment of a FS round. and there is a small lip that will fit under neath the skirt of the FS round. that hopefully concentrate the air flow at the start at least under the FS round not past the sides.

Roundball use?:
No, I would not recommend it. this really shaped for first strike rounds. the edge of the bolt is to narrow for it. so I don’t think that if would be kind to round balls compared to you stock bolt

FSR power tube mod:
don’t forget to check if your power tube is not sticking out to far into the chamber! this will make the FS rounds flip! or just misfeed in general.

what ID size to select ? if might depend on your material choice and flow settings. but the 12.14mm should be a good one to start with

print settings:
0.2 layer hight should be fine.
you can use the 8 layer walls and a 40% infill.
but personally I moved a bit over to solid prints just to give it more strength in case things go wrong on the field…

in this case would I recumbent to use a raft just with a small extra margin of 4.0mm
this so there is no elephant foot on the part that will mess up the ID size right were it matters…