Oryx Chassis competition upgrade

UPDATE: 7/3/2025
I have added fusion360 and step files for the backend, if someone want to run wild with it and make modifications. If you do make changes, please upload as a remix. These files are not intended for commercial use.

It started with a but pad that was adjustable in height… Then it slowly evolved into this 3d printed monstrosity. Basically as soon as i started adding more pieces, the remaining parts didnt really match the rest of the rifle, so i ended up replacing all of the original plastic parts. This mod does not alter the original metal parts of the chassis, this was one of my design constraints.

All parts were printed on a PRUSA MK3S+. Designed to fit the build and in a way not to require supports.

Disclaimer: This is not an “easy” project and requires lots of extra hardware, and drilling and fitting.

Added features over the original:

-height adjustable butpad (tool-less)
-length of pull adjustment (tool-less)
-longer cheek rest
-multiple attachement locations
-front weight to balance the rifle about 2 inches in front of the magwell
-custom color scheme

Printing instructions:
I printed everything with a 0.6 nozzle and PETG. Other temp stable materials should be good as well (ABS, ASA, Carbon filled filaments etc..). Use many perimeters (i used 4) and 30% infill. I think none of the files require supports, but holes have one full layer printed that needs to be drilled out.

But stock:
Midsection has two embedded M5 nut. You need to pause the print and add them, then resume printing. If you want the adjustment knobs on the other side, you need to mirror both the midsection and the sideplates. The midsection has many holes for the side plates. These need to be drilled and tapped for the screws you will be using. I used M4x10 screws. Use the original screws to attach to the chassis. Most other holes are undersized by design (especially the ones printed on their side) so that you can drill them out and make the nice and round. At the bottom of the midsection, there are two holes for M6 heatset threaded inserts (to attack bag rider)

Knurled adjustment knob has an M10 embedded. Pause the print and insert it, then finish the print. Finally, clean the hole with a 10mm drill bit.

For the adjustable length of pull, I used 1 fully threaded M10 screw for the adjuster and then two M8 screws with threads only at the last 25mm. I cut the threads off and kept just the hex head and smooth part of the bolt. Cut to your desired lenght. 

Important: there is only about 4.5 mm space for the hex bolt head (in thickness). Most bolts will be much thicker so i grinded the hew heads down to the required thickness. One of the files is a tool to do this on a belt grinder and keep it square.

once bolts are prepared, you need to glue the connector and female slider together with glue or a chemical solvent. I used PETG gloop from 3d gloop.

all adjustment knobs are M5 hex bolts with a 3d printed press fit cover. They are different lengths so they don't stick out too much, i think i used M5x20 and then shortened them accordingly.

Frontend:
sideplates have quite tight tolerance into the chassis, but fit. There are embedded M4 nuts in the print, you need to pause the print and add them, then resume. There are over 20 on each side. When you remove the original side plates, there is one extra hole that is not threaded. Print the plastic nut and tap it, to allow you to screw the end to the rifle.

Front weight:
Printed in several pieces for best print orientation and max strenght. Again I used PETG 3d gloop to glue all the pieces together. I used a resin printer to print the mold for the lead. The lead weighs about 900 grams.

Final words and disclaimer:

This project took a lot time… :-) Honestly, I didn't even want to share it and thought about selling it. maybe i still will, so please print and use only for yourself or your friends. If you come up with cool attachments for the front rails, please share them as a remix, so that others (including me) can find them as well. 

Also, this is in no way associated with MDT or Oryx.