This is a Caliburn for kids. These files only work with the K31 spring. I just made one for an 8yo and he can easily prime it.
1. You should buy an o-ring
...Plus sealed aluminum ram from slug. Not using an o-ring sealed ram will give you very inconsistent shots.
2. Print this in .2mm. No support needed
3. The piston is hollow and the spring goes near the top to give the best prime and performance.
4. Best with a 14 inch barrel. 14" and workers = 140fps, 12" and workers = 130fps. Accufakes and a 14" = 120FPS, average numbers.
5. You can use typical nylon spacers in place of the railgasm
6. Print the barrel shroud x4 if you want one for the front like the photos.
7. The rear butts are lengthened so they allow the handle and butt to connect.
8. This design allows for the stock ram or CS o-ring sealed ram to be used.
9. I included a jig tool to drill and shorten the stock aluminum rails the same amount.
10. Cut the K31 spring 3/4-1 extended out of the back butt. Pre-loading the piston slightly.
Edit: Added railgasm adapter. Print 3 of the standard railgasm pieces from Captain Slug and the integrated front butt.
Edit Added a non-rail front grip
Edit: 12/10/2018 slight piston improvement.
Edit. 12/13/2018 improved the front rail grip
Edit. 12/13/2018 Print 2 x "Spacer 10x5" to use in place of the rear nylon spacer, optional.
Edit!!! 12/27/2018 I have a working K26 hollow piston. The prime action is not bad at all. I would expect the piston to be a maintenance item and fail just based on the thickness between the sear contact and the inner spring area. However, the prime action is very good and my Workers and Stefans are a solid 210-220 FPS with or without a worker scar. I used silicone lube on the piston at the sear contact area, wow, my dream trigger also. I loaded two test pistons, the size is the ID for the spring.
Edit: 12/29/2018. New front muzzle with additional supports, pink photo. Also the railgasm has been edited to fit close to the barrel spacers so the rail will align with the barrel spacers and wont turn. You have to print 3 new rail pieces and the new muzzle to make it work. Print in .2.
Edit: Totally not needed, made a front grip with extra support that is much more ridged than stock. Also cut the top off. The other front grip is still there.
