Stagecoach Dart Blaster Seal Tuning Guide

This is a guide for troubleshooting the seal on the Stagecoach Side By Side Double Barrel Nerf Blaster. Check it out here:

https://www.printables.com/model/1468057-stagecoach-side-by-side-double-barrel-dart-blaster

Getting the best seal possible on the stagecoach requires your printer to hold tight tolerances. However, given so many different 3D printers and filaments out there, it's difficult to have a one size fits all solution. This guide will take you through troubleshooting common seal issues, and includes some files to help solve them.

Checking Your Seal

How good is your seal? This is easy to check by inserting 2 blank shells (No dart holes) and firing the blaster. If you have a good seal, the plungers will move forward slowly as the compressed air can't escape. If you have a bad seal, the plungers will rapidly move back to their “relaxed” position.

As you move through this guide, check your seal using this method to see if your seal has improved.

Unlock Latch

The unlock latch is designed to be adjustable to allow tuning the seal. Tighten this screw a quarter turn at a time until the blaster no longer latches closed. Then back off the screw a quarter turn. This will give you the tightest fit between the barrels and turnaround.

When doing this, make sure you shut the blaster with some force. A gentle shut will usually not latch successfully.

Part Warping

If one of your barrels seals better than the other, it's possible that some of your 3D printed parts may have warped during printing. Check these parts with an straight edge or flat table. Most often the warping occurs on the bottom of the part. If you find that parts are warped, reprint them and ensure a level print bed and good bed adhesion.

You may need to remove the orings to get an accurate measure of flatness. Carefully use your fingernail to roll them out of their recessed pockets.

Keep in mind that even if your parts are “flat”, that doesn't necessarily mean that they are square/perpendicular.

Main Pivot Block:

Turnaround Block:

Trigger guard:

Ejector Tuning

The way the Stagecoach generates it's seal is by bottoming out the Ejector Sled on the Middle Top Tubes. This causes an interference fit with the orings, giving you the proper airtight fit. This is highly susceptible to tolerance issues. 

Ejector tuning involves measuring how far away you are from the “perfect” seal, then printing a compensated Ejector Sled to fix the issue.

• First print 2 of each of the shell shims in this printables listing. These insert into most standard silly shells, but I recommend the 1x elite. The shims increase in thickness in increments of 0.2mm.

• Place a pair of the same thickness shims on the back of the shells loaded into the blaster. Then shut the barrels and check the seal. Basically, you are temporarily turning your shells into “blanks” that are slightly longer than normal.

• Determine which pair of shims gives you the best seal without keeping you from shutting the blaster. Remember, you may have to adjust the Unlock Latch Screw as you do this. 
• Once you find the best configuration for your blaster, print the associated Compensated Ejector Sled.

• Replace your existing ejector sled with the compensated ejector sled. To remove the pins from your existing ejector sled, gently tap a small allan wrench from the bottom of the ejector.