X-shot Thrasher tactical upgrade kit (with bcar)

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X-shot Thrasher tactical upgrade kit

Looking for a tacticool aesthetic and some extra utility for your Thrasher? This comprehensive upgrade kit has you covered!

What’s Included in This Kit

• Tactical Foregrip: Ergonomic front grip that pulls double-duty by holding an extra magazine for quick reloads.

• Picatinny Rail Stock Adapter: Converts your blaster's rear to a standard Picatinny rail, allowing you to use a wide variety of aftermarket stocks. Comes with a sling point too.

• Folding Stock: A sleek, functional folding stock for maximum compactness and easy transport.

• Extended Frontend: Gives your blaster a rugged, SMG-style silhouette. The longer variant support M-lok attachments and greatly expand the battery compartment.

• Internal BCAR & PCAR Barrel: Custom-engineered rifling profiles for builders looking to boost accuracy.

• Replacement Flywheels (Experimental): The stock wheels are a bit loose on the motor shaft, so I made this for drop-in replacements. Note: These are mainly experimental and offer little to no performance gains over stock ones, even though they have higher crush.

• Mag Bumper: Mostly for aesthetic, while +1 to capacity (the stock spring wouldn't allow adding more)

Bill of Materials (BOM)

To fully assemble and install this kit, you will need the following hardware:

Installation & Assembly Guide

Installation is pretty straightforward.

Frontend Prep & Internals

1. Disassemble the front shell of your X-Shot Thrasher.

2. Recover the mounting screws and m3 hex nuts from the original front piece.

3. Load the m3 hex nut to the nut retainer piece.

4. Slide the retainer piece into the little pocket at the very front of the stock under-barrel Picatinny rail. (Skip this if you want to use the extended frontend).

5. (The battery connector wire must be extended for at least 6 cm in order to use the  extended frontend)

6. Install the wire holder, it's compulsory if you want to use BCAR, it safely routes internal wiring to prevent them from rubbing against the spinning BCAR bearings. (as shown in build guide p.1)

7. Replace Rev-Trigger Delete (Optional, available for free in my page)

8. Reassemble the blaster.

9. Secure the new frontend piece(normal or extended one) to the blaster body from the front, and lock it using the original screws from both sides.

10. Remove the thumb screw from the stock battery door and use it with the new battery door.

11. put back the barrel+dart guide (or BCAR barrel), use the muzzle cap to lock it firmly. (Pay attention that the barrel should be a little recess below the muzzle lip, as shown in build guide p.2).

12. Install the pic rail stock adapter.

13. Attach the foregrip.

Folding stock

• To assemble the folding mechanism and attach it to the pic rail stock adapter, please refer to build guide p.3.

BCAR & PCAR

Rifling systems in flywheel blasters are still a bit of a frontier, and tuning them for lower-velocity blasters like the Thrasher (which hits around 110–120 FPS) is tricky. Because dart foam variance is massive—a fresh dart sits around 13mm, while a heavily beaten dart can compress down to below 12.5mm—finding the right balance is a tightrope walk. If the inner crush is too tight, it will kill your FPS; if it's too loose, the rifling won't engage at all.

Because of this, these SCARs are included as tuning options rather than guaranteed performance boosters. I used a couple of flywheel-specific guidelines during design: keeping the rifling as close to the flywheels as possible, and using a much lighter crush than you would find in a springer.

The BCAR Option

In my testing of many iterations of BCAR, I find that while it improves accuracy, it drops FPS by quite an amount inevitably, especially for brand new darts (20+ FPS). Inspired by the roller scar testing of Flygonial, I move on to try printed rollers instead of bearings, and find that they give a similar boost in accuracy while not dropping FPS that much (~10). YMMV, but it's the outcome of my testing. I have settled in 12.5mm crush staggered row roller scar for now.

Please note that if you decide to give printed rollers a try, half-threaded screws are recommended, as the smooth session of the screws lets the roller spin smoother.

Little tips with the bearings: Use acetone to wash them before installing, it should be able to free spin at least 1 sec when flicked by finger, it's crucial for them to provide real effects.

Remarks: BCAR/PCAR work best when your flywheels are aligned. If they are mis-aligned, you may experience even more FPS lost or no accuracy difference.

The PCAR Option (Straight Guide)

During development, I found that twisted rifling on a friction-based, printed PCAR caused too much friction drag at this FPS range. Instead, I went with a much more conservative 0-degree (straight) design with a generous 13.5mm inner diameter. Rather than trying to spin the dart, this PCAR acts purely as a gentle, smooth centering guide as the dart exits the muzzle. In my testing, it offers a subtle, minor cleanup of the dart path compared to stock, without severely impacting velocity.

Comparision video here:

Print Settings for BCAR/PCAR

• Layer Height: 0.12mm (critical for keeping the internal geometry as clean as possible).

• Post-Processing: Give the internal channels a light sanding. It doesn't need to be perfectly mirror-smooth, but removing the worst of the print lines is highly recommended to reduce dragging as much as possible.

Printed flywheels (use with caution!)

Printed flywheels (especially with non-enginerring materials) are notorious for creeping and lead to slipping. For some reason my stock wheels are very loose that can't be use anymore, so I made those printed flywheels as a last resort, don't try them unless you know what are you doing. In my setup, they can boost FPS for about 10-15. I am using worker 132 (non-neo) motors and 3S lipo, with these flywheels my max FPS is 135 with worker 1.2g darts.

There are some tips if you decided to try them:

1. Besides engineering materials (which I don't have), PETG is recommended.

2. Follow the suggested print setting in the description of stl files.

3. After printing, allow them to cool down for at least half an hour.

4. You may have to adjust "XY Hole Compensation" if you find the fit is too loose or too tight.

5. Use the flywheel install helper tool, clip it to the motor, under the flywheel when installing. So that you can just press the flywheel all the way, and they will sit perfectly aligned.

6. If you decided to use that flywheel permanently, you may apply loctite to it before installing, in that case you should open up the hole a little bit by adjusting "XY hole Compensation". I have a pair of flywheels that installed with loctite 609, they never came off, even with bruteforce prying.

Flick-open folding stock

To make sure it works smoothly, please sand them a little bit to smooth out the layer lines, as shown:

Print Volume

180 x 180 x 180 mm

Printable with small printer like Bambu lab A1 mini!