FLP-09 Shrew Bullpup Blaster

This is the Shrew! Rush, but the “sh” is in front of the “ru”. It's an 80mm draw pump action using straight Talon magazines. It's got a very nice trigger, PCAR or SCAR built in, quick swap spring cap, and is quite rigid due to dovetail construction throughout. It's capable of up to 250 FPS, and if you want to push more, there is a 120mm draw extended plunger tube version as well- up to about 300, but untested past 275 at this time. 

Print Settings:

• Primary color at 4 walls 20 percent infill. Supports on upper receiver and shroud.  
• Secondary color at 4 walls 20 percent infill. Supports and brim on cheekrest. 
• Orange at 100 percent infill, except for SCAR/PCAR options. Supports for plunger, spring cap, SCAR body.
• TPU, do the buttpad at whatever squishy settings you like, and the ram at all walls. If you can't do TPU, print the ram for rigid filament in the Orange folder- you'll use one of your o rings for padding.

Options:

For EXPT version, you will need different plunger tube, barrel, and threaded rod, as well as a custom prime bar. The parts in the EXPT folder just replace the corresponding normal Shrew parts and should be printed with the same settings- however, the EXPT version does NOT fit on 180 cubed printers.

PCAR and string SCAR are included in the files- big thanks to Chance for his SCAR design, which I've integrated. For the string SCAR, use 10lb monofilament line. EXPT barrel will extend past the front of the blaster, so you'll need to use a different muzzle device for that. 

Tuning:

• 5.5" 788 and 30cm 13mm barrel: 140-150 FPS
• 6" 788 and 30cm 13mm barrel: 150-160 FPS
• 5.5" K25 and 30cm 13mm barrel: 200 FPS
• 6" K25 and 30cm 13mm barrel: 220 FPS
• SF25-TC+2 and 30cm 13mm barrel: 250 FPS

EXPT:

• 8" K25 and 50cm .509: 275… overbarrelled, untested past that. 45cm should be about perfect for this build. 

Build Guide:

https://imgur.com/a/6KYUiCJ 

BoM:

• 4" plunger tube (SLAB, Rush length)
• 30cm barrel
• C4 bar
• 3x M3x250mm threaded rods
• 1x Talon Claw length mainspring
• 2x springs, approx 4mm diameter, 20mm long- pen springs are good.
• 2x 6x7mm ball detents
• 2x M3 heat set inserts, Voron spec
• 3x dash 123 O rings
• 3x 016 O rings
• 2x 012 O rings
• 6x M3 hex nuts
• 20x M3x8 screws
• 1x M3x16 screw
• 6x M3x20 screws
• 3x 10-32x5/16" screws
• 3x 10-32 hex nuts
  • Optionally, for EXPT version- 45cm barrel, 300mm threaded rods, Talon Claw length plunger tube. Also, custom prime bar instead of C4.

Availability:

Hardware kits, DIY kits, and full builds from BearsWares:  https://bearswares.shop/products/shrew-by-shoelesshistorian-1 

Acknowledgments:

Big thanks to Bear for supporting prototyping and beta testing on this one, as well as AMSpawn006, Spyder, Ross from 3DBlastedHawaii, Zoey from Foxfire, and honestly like a bunch of other people who did testing and gave input on this design. I appreciate you all so much!!