Now that the cage is solid I could work on the loading port. The filler piece was filed and sanded down. The new loading port starts at the rear edge of the filler piece. I dremeled close to the right shape and finished with files. I put a slight chamfer that matched the existing port. I also finished the ejection port.

The PPS's forend tube isn't made out of steel so welding on an attachment plate wasn't going to work. I came up with a 3d printed piece that slid over the tube and was epoxied in place. It's only for the front screw. The rear one I centered on the tube.

The piece needed some clearance cuts to work. Instead of trying to adjust the model which would make it not print as good I chose to just sand it. The top would hit the barrel while pumping so I just followed the existing curvature. The bottom was catching on the filler piece so I sanded it down a bit and radiused the front and rear.

I made the plate for the grip from an electrical box. I cut it to shape and traced it on the grip. After the grip was recessed and the plate glued in I marked out and drilled the holes.

The grip was positioned on the cage so that the rear hole would be centered with the exposed metal of the forend tube. That ended up making the front of the grip almost flush with the front of the cage. The holes were spot drilled through the grip. Then the magazine tube was removed and the holes drilled through and tapped.

The magazine tube was cut flush with the end of the filler piece. The barrel hole in the cap needed to be opened up slightly to fit over the barrel. The ejection port on the grip was cut to match the new port.

I made a 3d printed jig for drilling trough the front cap to secure the barrel and magazine tube. The holes were drilled for m5 set screws.

The barrel was cut close to the jig, then sanded flush. That left 10mm sticking out.

The shroud needed to be modified a little to fit the trigger guard. I slid the launcher onto the alignment pins and marked where it was hitting. 2 of the posts needed to bee trimmed since they were hitting the 870. I didn't completely remove them so that it would still help hold the cage.

I uploaded the 3d printed files I used for the conversion on thingiverse. https://www.thingiverse.com/thing:5149688

I did a test fit of the parts. The 870 does add quite a bit of weight. It also looks much better than the fake launcher.

Now to work on some of the other inaccuracies. I think I'm going to work on the shroud first. I haven't decided yet if I'm going to keep the stock and barrel vent or replace them with SD Studio versions. It's probably going to depend on how the shroud turns out.

I compared a picture of a HCG and Snow Wolf. There are quite a few differences. Some minor and some major. The HCG is supposedly based on a real prop so I'll try to make it as close as I can.

The easiest way to fit the differences is to believe that they are correct. In real life there are many examples of a firearm having changes without having a type reclassification. They could be changes from the original design to simplify production or to fix an issue. Sometimes there are differences between makers.

The Snow Wolf is wider than the HCG. This is what it's going to be. Trying to change it would be a major rework. It would require trimming down almost the entire seam. Heating and bending would be required to reform it. In the process almost all of the alignment tabs would end up being removed. If I would attempt the conversion it'll turn into a nightmare and end up in the trash. I can try to adjust some of the other areas.

1
The rear is shaped completely wrong. This is going to take some work. The stocks lock will also need to be reworked. I haven't decided how I want to do this yet so it will be saved for later, but is something that will need to be fixed.

2
The area around the HCG grenade launcher's trigger is chamfered. This should be an easy fix by just filling in the rear and filing a chamfer.

3
The shroud on the Snow Wolf sits lower than the runner on the grenade launcher. This should be another easy fix buy just cutting it higher.

4
The corner on the Snow Wolf is way too sharp. I should be able to print out a filler piece and blend it in.

5
The corners on the Snow Wolf are too rounded. I might be able to do something about it, but I'm probably going to leave it.

6
The triangles are different shapes. The HCG is farther to the rear. This will require filling in the existing cutout and making new triangles.

7
The Snow Wolf's holes are recessed too much. This will be another easy fix with a 3d printed plug.

8
The Snow Wolf is notched out and the greebles are part of the mag cover. It looks like they should also be farther to the rear. They are also upside down. This will probably end up being a compromise of just flipping them over and attaching them to the shroud.

9
The grenade launcher sits higher on the HCG. Changing this will require a lot of work. The mag section of the shroud will need to be cut an a section removed to move it up. The front of the shroud will also need to be raised. The grenade launcher's attachment will need to be reworked. The Snow Wolf barrel vent won't be able to be reused. I'm not sure if I really want to go this far.

10
The counter cover's are different. It looks like the HCG's counter is slightly forward. I'm not sure how much can be changed without reworking the electronics.

In my personal opinion I think you have come far enough… the major screaming difference to me for the Snow Wolf (or earlier G&P kits) is the back of the stock being square but you have to carefully consider how you’d approach this if you wanted a rounded back segment… the G&P stock lock is really poor and I assume the Snow Wolf one is the same. It may be worth using a steel stock from SD STUDIOS.

I’d leave the barrel vent and BB counting light gate in place on the Snow Wolf.

I think you’ve done a good job in converting the GL. Where are you running the battery for the Thompson? And what battery are you using?

It’s a pity someone hasn’t made an off the shelf screen accurate functioning airsoft PR with the GL included.

Anyway my 2 cents is consider the stock and rear of the shroud but perhaps leave it all as is now. You’ve taken it more than far enough.

_________________
A02/TQ2.0.52141E1

"Errr... Roger that's a 2-1-6..."

I'm going to be gutting the thompson internals and convert it into a functioning replica.

I modeled up the cap firing m40 grenade and printed one out. Unfortunately it didn't fit. There's a ring on the inside of the chamber that the PPS cartridge slides into.

I changed the model to look like a regular 12ga cartridge that matched the PPS's dimensions. Hopefully this weekend I can do a test fire. Then I'll try to get the m40 design to work.

Also add like. 0.1mm of space so that resin coating and paint applications will not cause jam issues....

_________________
The impossible takes a while longer and goes over budget too...

Everything for the new cartridge printed perfect except the anvil. The tip is small and deformed while printing. I'm going to switch to using a roll pin for the tip.

It fits the chamber and cycles just like the PPS cartridge. The extractor does damage the rim. The base is going to be a consumable, but should be good for a few firings. I'll probably modify the base so the PPS metal cover can be used.

I was unsure if the anvil would work so I loaded it up with a kids toy cap. It took a couple of tries, but it went off. I loaded it up again and it worked.

Next I loaded up the model gun cap and it also worked. It's several times louder than the kids toy cap. Once I remake the anvil I'll give it a try with it loaded with 7 caps.

Maaaake / possst a firing vid pleeease

_________________
Cpl Aron "septic" Williams
A10/TQ0.0.82146E1

see what the metal 3d printing costs on that would be.

_________________
The impossible takes a while longer and goes over budget too...

I removed the greeble from the mag base and sanded it down. I put a radius on the cutout. I 3d printed a filler piece that is tapered so that the greeble would sit parallel with the sides and be slightly recessed. It was attached with acetone and I used the 3d printing pen on the inside for a little bit more support.

I filed off the button heads on the greeble. I remarked the holes so that they would be in line with each other. The holes were drilled and tapped for 3mm button head screws. Keeping the greeble removable will make it easier for painting.

Using a 3d printing pen I added plastic to the inside of the shroud around the grenade launcher's trigger hole. When I made the bevel I didn't go through the shroud, but it is thinner.

On the back and bottom I made a mark at 6mm. I filed at an angle until I reached the marks and the bottom of the radius. For the front I filed at a 45 until the radius was gone. I added a slight radius on the new edges.

I used paint thinner to remove the paint around where I was going to be filling in the shroud. With the paint removed the acetone can make a solid bond. Paint thinner is less aggressive than acetone so it doesn't damage the plastic as fast. It still can, but by only using a little at a time it will remove the paint without affecting the plastic.

I printed out a filler for the corner. I dunked the piece into acetone and quickly wiped some on the shroud. A 3d printing pen was used to fill in the rest of the gap.

I filed until it was flush with the shroud. Then worked on blending in the radius. I used some sandpaper to blend it all together. It could still use a little bit more, but it's pretty close.

It started as a 3mm radius and is now 10mm. When I looked at some pictures of a screen used prop the rest of the corners looked about the same so I'm going to leave them alone.

I printed out a filler piece for the trapezoid cutout. I filed the edges slightly until it would fit. I pressed the side that was touching the bed into the shroud for the best adhesion. A 3d printing pen was used to fill in the gap at the bottom. I should have gone all the way around as I ended up having a low spot around the edges when I sanded.

I filed it close to shape and finished with an orbital sander. Then I filed the radius. I'm planning on paining and sanding it a few times to try to fill in the low spot around the edges. Basically using the paint as a filler.

Now I'll have to remake the trapezoid. If someone who has a HCG could give me the dimensions I'd appreciate it.

The HCG shrouds have the triangle moulded into the aluminium and it’s not an separate piece which I find a bit odd…

_________________
A02/TQ2.0.52141E1

"Errr... Roger that's a 2-1-6..."

I've been experimenting with making some cartridges for a MGC Thompson. I fired one with 3 caps inside. That was pretty loud. It's defiantly not a kids pop gun.

I'm hoping to test fire the 870 again this weekend. This time with a full load of 7 caps. I do plan on recording it. Now I also want to set up a decibel meter.

I've uploaded the shroud mods on Thingiverse.
https://www.thingiverse.com/thing:5149688

For the rear I was hoping to be able to just slice off a section of an existing 3d model. Unfortunately all the models I could find are also shaped wrong. Many of them look worse than the Snow Wolf shroud.

With some pictures and measurements from my shroud I modeled up a new rear. The first print looked like it turned out pretty close.

I printed out some plugs for the shroud's screw holes. After they were welded in with acetone I took a q-tip and acetone and rubbed the top until it formed a slurry and filled in the edges.

I cut the rear of the shroud and tested the new printed end. It lined up very close. There are a couple of small changes that I want to make so it will blend in better.

I did a test fire with 7 caps.

https://www.youtube.com/watch?v=dZ_S95lqJ_A

I had a decibel meter set up at the rear of the stock. It read 72 decibels at the max, but I don't think it is right. It felt a lot louder than that.