Hi there!

So I am using a WE GBBR Thompson as basis for my Pulse Rifle and want to preserve the blowback functionality. That means that I need access to the bottom of the magazine to fill it with gas. There’s also the problem that the WE magazine is slightly too long and protrudes at the bottom of the HCG shrouds.

This rules out using the SD aluminum mag bottom I have, since these only work with magazines that are flush with the shrouds. Also, the SD mag bottom seems to rely on the magazine being screwed onto the mag bottom or the resin inset, which I obviously can’t do since I can’t drill into the gas magazine.

So I had to invent a mag bottom which fulfils the following criteria:
1. aluminum mag bottom
2. usable with different mag lengths
3. magazine bottom needs to be accessible
4. as screen accurate as possible

First, I was thinking about devising the whole mechanism in Aluminum, but cost quickly proved prohibitive. I also would have had to devise individual mag bottoms for each mag type. So I decided to only have the mag bottom itself machined and keep it as simple as possible. The rest of the mechanism can just as well be 3D printed, since it’s going to be painted anyways and the mag attachment of the SD was resin also. Plus, I need the flexibility (see below).

As for screen accuracy, I am going with the best close-up shot of the magazine visible in the film:


This is what I came up with:


And here is the first 3D printed prototype in action:
https://www.youtube.com/watch?v=HuDzLNyMyw8

For the prototype, I had the mag bottom 3D printed as well (just to test the fit; there's also no threading yet to attach the mag holder part), but I’m already in talks to get it machined in aluminum. The top “clip” of the mechanism fixes the magazine in place so that it’s secured and can’t fall out, but it can be quickly removed to allow access to the bottom of the magazine. In the video, you can see that I also got a second “clip” that I painted with normal spray paint, and the paint doesn’t seem to have any problem with flexing the “clip”.

Best thing is, with little modification, I can use different magazines; for display purposes, I’m even planning on making a mag bottom for a real Thompson mag. Since this one is flush with the shrouds at the bottom, I won’t be able to insert it into my Pulse Rifle, but the real mags don’t fit anyways. Also, the mechanism isn’t aimed at “live fire” PRs, not sure if the 3D-printed parts could handle the stress.

Of course, you currently also have to swap the magazine inset for different magazine types, i.e. you’d need a dedicated mag bottom for each magazine type (gas mag, real mag, etc.).
All in all, I’m quite happy how this turned out. Now to get the mag bottoms machined…

Cheers!
Roman

Amazing!

Does this have the potential for a future run? If so, I'm in for 2 mag base kits for sure!

_________________
Lt. Melissa L. Klassen, ALG
AL Colonial Admin. - Executive Officer (XO) -- 2021-2022
RCCM | Royal Canadian Colonial Marines - Commanding Officer (CO) -- 2021-2022

Read the AL Charter Rules & Regulations: https://docs.google.com/document/d/1i3gd9QUyIqI_6rfk8kpxspbKU-JT4MBAjLPxfCkvGJ8

A great solution, I'd like one myself!

Looks great! Where is the thumps up emoji when you need it?
I'm looking forward to see how this will progress.

Cheers
Stefan

Damnnnnnn that’s so impressive. I switched from GBB to cap fire Thompson. Wish I still kept it. That was my only issue with it.. how long the mag was.

I still need to do a mag base for my AEG Pulse rifle. Just hasn't been a huge priority in life for me.

Your design looks really nice!

_________________
"A writer needs a pen, a painter a brush, and a filmmaker an army." - Orson Wells.

http://www.rookscastle.com
http://www.alchemyarms.com

Hi all

Sorry for the late reply, I've been extremely swamped at work.
Thanks for all the kind words. I was able to attach the part with the screw holes to my prototype mag bottom and it sits perfectly, you can hold it at the mag base and shake it and the mag won't fall out. I believe I'm going forward with my order of the aluminum mag bases.

As for the questions:


Sure, I can do a few extra ones. The thing is: this is specifically prepared for my setup. I know yours is almost identical, but it's possible that there are slight differences and the mag bottom could sit too low or something. If you want, I can send you the .stl files and you could print a test setup. Most parts will be 3d printed anyways, except the aluminum mag bottom, and you could then adjust the 3d printed parts if needed and I could include you in the aluminum mag base run.


Same here, if you want, I can send you the 3d files for fine-tuning and you can then let me know if you want an aluminum mag base.


That's what's nice about my setup: I'm pretty sure I could adjust the 3d printed parts so that the same mag base could be used with a real magazine. I.e. with the right 3d printed parts, you could use the aluminum mag base for a variety of different magazines. Still, there are limitations: the forward position of the mag on the mag bottom wouldn't be that easy to change, so you'd have to adjust things as per your Pulse Rifle setup...


Are you talking about a Snow Wolf Pulse Rifle or your own setup? It could easily be rigged to work with a Snow Wolf, but my mag bottom is specifically aimed at the HCG shrouds and will be too short for the Snow Wolf Pulse Rifle. However, you could easily adjust the mag bottom file and 3d print the mag bottom (it doesn't need to be aluminum if the shrouds aren't either).

If anyone wants to give this a try, let me know, I'd have to dig out the files but will share them (as long as you're not going to sell the design ).

Cheers!
Roman

Whatever works for dr_slurpee will work for me. He's far more skilled at modeling than I am, and originally I was having him build mine along with his (may still). At the very least, I'll have him do my mags, I hope!

Thanks!

I still want to bug you about the Thompson grip! I'm prepared to spend stupid money on a Shapeways printed grip, but I need it to fit with the screw I have

_________________
Lt. Melissa L. Klassen, ALG
AL Colonial Admin. - Executive Officer (XO) -- 2021-2022
RCCM | Royal Canadian Colonial Marines - Commanding Officer (CO) -- 2021-2022

Read the AL Charter Rules & Regulations: https://docs.google.com/document/d/1i3gd9QUyIqI_6rfk8kpxspbKU-JT4MBAjLPxfCkvGJ8

If you do a run of these I'd like to order one.

Thanks

Same here. Or purchase files with stipulations on no sharing and such...

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

same here

_________________
Reformed Pacifist

Once I can test this with the aluminum mag bottoms, I‘ll post here and will see how to best go about this.

Cheers!
Roman

My shrouds ARE modded HCG shrouds. I'd take a copy of the STLs if you're willing to share.

_________________
"A writer needs a pen, a painter a brush, and a filmmaker an army." - Orson Wells.

http://www.rookscastle.com
http://www.alchemyarms.com

Hi all!

So for anyone interested:
My 3D printed magazine bottoms for the Auto Ordnance M1A1 magazines will work with original magazines.
The only thing I cannot test if this will fit a setup with a real Thompson M1A1 and HGC shrouds, as I do not own a real M1A1.
But if anyone uses the models, I'd be glad to hear if it fit (and if not, what mods would be needed).

The files for the mechanism for the WE M1A1 are there to download as well. These are tested and work, there's even a video.

Get all files on my page: http://www.pulserifle.net

Cheers!
Roman

Roman, I've just checked out your shapeways er listing [?] for the mag bases, have you thought about offering these in other materials? Would be interesting to see what one cost in alu (probably heaps ).

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

It would mainly make sense for the actual mag base (i.e. the bottom part) itself to be aluminum. The "clip" of the mechanism needs to be flexible for the mechanism to work, so I don't think it would make sense to have it made in aluminum (and therefore most likely for the other parts of the mechanism either).

I just checked, and to print the mag base itself in aluminum would cost $567.47, which is ridiculous.
I had my aluminum mag base machined by one of those "upload the file instant quote" services for a reasonable price.
The files are all downloadable on my page, so it might be best to just see where you could get the mag bases for a good price. Or I could do a run of these, but might take a while until I get to that...

Cheers!
Roman

Thank you for sharing the files with the community, that was very generous!

_________________
"A writer needs a pen, a painter a brush, and a filmmaker an army." - Orson Wells.

http://www.rookscastle.com
http://www.alchemyarms.com

No problem, it's a hobby I love and stuff like this is what I think about at night, so I want everyone to know.
Don't forget that half of the models downloadable on my page are based on designs by or co-creations with Bug Stomper, so lots of credit for him.


I seem to have gotten into an unintended squarrel with this guy on facebook simply for posting my site, so I'm not gonna post any more details over there. I like the atmosphere here better, so if anyone has better theories (most of the stuff on my page are theories), please post it and I'm open for discussion.

Cheers!
Roman

Yeah, I was just thinking the base in metal. Damn, that is ridiculous Thank you for checking it out.

And to echo Russ, thank you, most kind!

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

added your site link to 3d files thread.
Here:
viewtopic.php?f=3&t=19391&p=275978#p275978

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

Thank you for sharing

_________________
Reformed Pacifist

If you want to share, I can get a price to have it killed from aluminum. That will be much less than printing, and quite likely stronger.

_________________
DON’T call me eighty-five.

Assistant Superintendent Leach,
Fiorina 161
"Serenity Through Confinement"

Ahhh, yeah... THAT guy! I wouldn't let him run you off of Facebook completely. Your research is incredible and your page is a welcomed addition to the archives.

I like it here the best too though

_________________
Lt. Melissa L. Klassen, ALG
AL Colonial Admin. - Executive Officer (XO) -- 2021-2022
RCCM | Royal Canadian Colonial Marines - Commanding Officer (CO) -- 2021-2022

Read the AL Charter Rules & Regulations: https://docs.google.com/document/d/1i3gd9QUyIqI_6rfk8kpxspbKU-JT4MBAjLPxfCkvGJ8