Hijinx+/HiLonx/HiMinx Experimental Extended Draw Pumps

Hijinx+: 

Replacement pump assembly and plunger to extend the draw of the Lynx near/past the limit of what k25 can do. Will likely cause k25 to settle a little from the additional compression, but most blasters push beyond the elastic deformation limit of springs anyways. Did 280-300fps on my Lynx using a kury pt, 55cm worker barrel, and worker 1g darts (280 with k25, just under 300 on sf25). The k25 did degrade after more shots to 250 average, but the sf25 has not shown wear yet.

-performance update: A fresh 20 coils of k25 from ood gets me 300 average. with some shots hitting 320 and nitroshot touching 340 at times on a 55cm barrel.

-k18 gets ~260 fps and k24 gets 190fps

The Hijinx++ files test 140mm draw but fits 2-3 fewer max coils. I got 305-320 fps with ~17 coils of sf25. With ~8in of sf25 +2, I got a high of 350 on 1g workers and 370 on nitroshot.

A nod to Cent in the BCFF discord for doing a similar mod (the “Higherjinx”) way earlier and one to Nutty for inspiring the quick change pump block conversion.

Lonx and Minx: 

Add 0.9 or 1 inch (23 or 25mm) of draw to your Lonx to utilize more of your FX-3. The Minx is already utilizing most of an X spring, but some can take 0.2inch (~5mm) of additional compression. SF25-TC can take 10mm more draw, and k25 enables 15mm more if you cut it down further (sf25 tc may also work if you cut off 3-5 coils).

You will need to print a tail for any variant.

If you're using remnant geometry, you can use the hijinx+ pump with a conversion block of the appropriate length instead (hijinx+ is 35mm extension, so add a 10mm block for the lonx, and 20-30mm for the minx)

Print Notes: 

Make sure the transfer bar interface is supported on the pump block. Print the tail on its side and sand a little to avoid introducing print zip. DO NOT print TPU catch3 with a high number of walls because it will shrink the inner hole and drag on the plunger.

The inner only catch3 parts should be printed in TPU to avoid cracking along thin walls.

You may need to switch to .527 barrel or a printed catch3 if you have an SFI kit where they provide 0.5" nylon tubing.

Hardware: 

• Plunger guide cut shorter for every mm you extend the draw (to 54mm for Hijinx+) from 13.4mm or .527in id barrels or tighter if your spacer print can easily fit.

• If using a k25 type spring, cut to length with at least an inch, preferably more, to spare for settling and further tuning. Slowly cut further if it does not catch by half coils. 16-21 coils should fit in the Hijinx+'s compressed space of around 42mm (I used 18). Include inactive coils in the count if your ends are squared. Grind closed ends with a file to help them rest flat and slightly reduce the amount of solid height occupied by the inactive coil.

• Optional PTFE tube slots carried over from the Hijinx that can be stolen from your printer's bowden tubes, though the top does not engage.

Personal Setup and Tips:

• I use the hijinx++ pump because it can convert down to handle any lower draw using converter blocks. The blocks manipulate the ram travel, so you can skip out if it's just 5mm down like from hijinx++ to hijinx+.

• If the tail has a tough time fitting, the threaded rod can be trimmed to reduce thread engagement, though it affects total plunger weight a tad.

• I use the newer k25X dual use plunger spacers with the inner only catch3 so it can accept both k25 and k18 diameter springs with only a toolless sleeve over catch3. You can print the integrated plunger guide or keep the barrel stock if you are worried about friction against the plunger spacer.

• Swapping down in draw entails: adding a conversion block to adjust ram travel, swapping the plunger, and swapping catch3. However, you can use a longer tail and keep the same catch3 to simplify that part; you will just have slightly worse spring constraint and more plunger weight (can be good or bad).

• Tails help ensure the plunger stays aligned with catch3, but they can be dropped if you have enough precomp. otherwise, make sure the tail is long enough to keep the tip within catch3.

Extras: 

• Pump block conversion parts friction fit into the back to make the most annoying part of converting away easier assuming you build spare plungers. Works for the base Hijinx pump and Hijinx++ pump (use 10 less for Hijinx, 5 more for Hijinx++ to get to other lengths). Inspired by ChaosBunny's post of his HiLynx. A no hardware spring guide swap would also be nice, but it runs into issues with how the plunger guide must vary in length and secure against screws.

• Extra Hijinx- spacer thrown in for another tuning option that won't require changing off a hijinx spring guide.

• Modified Hijinx spring guides that constrain k25 better to reduce crunch and rest in 36mm id tubes better

Shortened pump block rear and decreased id of pump block a tad for durability (still fits remnant scar). Extended tail. Tweaked catch3 for kury pt and k25. Shortened plunger spacer and added spring funnel.

Extended draw of the Minx and Lonx