Ooooh! Them pieces sure are purrty!!!

Man, now I'm angry that I didn't come up with that idea and made my own parts as well. But oh well, that's one minor detail, and I think my Pulse Rifle is going to be heavy enough without a second layer of metal on those parts.

Cheers!
Roman

I'm currently in the process of adding the aluminium shrouds to my PR which is build of real steel components - it has a really nice feel to it but if you had to carry it around on a con for a day you'd get the arm length of an ape afterwards.

Cheers,
Stefan

I know, that thing is going to weigh a ton!
Since I can't use real firearm parts due to legal reasons, I used airsoft parts, but upgraded everything with metal parts (yes, even the M870 barrels and receiver). It'll be a bit lighter than a real steel version, but not by much. And the HCG shrouds are the icing on the cake.

Cheers!
Roman

Yep Stefan, those be the parts and that's how you make em... Have you bent the vent yet, I'm curious how you did it.

M

_________________
"Stand up for something...Or get knocked down for nothing..."

Here's a picture of the bend and welded part already installed.


You can see that the bend is not in the 90 degree angle of the square tube but at the bottom of the milled slots (the weakest point). If you look at the original vents you can see the same effect.
Also note that this is the 10 hole vent/triangle. The sides the 8 hole triangle are shaped differendly (straight) as the slot between the triangle and the vent is milled down to the bottom:



Bending the part is actually quite easy for the front part. I used a vice to clamp down the bottom to keep it straight. This is especially important for the rear part as the material is not weakend by the cutouts. Luckily, you don't need to bend it much there due to the taper of the barrel. Nevertheless, I had to heat that area with a blowtorch to get it done.

Cheers,
Stefan

Ooooh!
More pics please! Can you post pics of the whole rifle? That looks fantastic! Now I'm not sure if I can live with my thin-walled vent and stock anymore.

Cheers!
Roman

Wow!
Didnt know what i was getting myself into asking the original question. Thanks for all the info guys! And a big thanks to phillip7 (whoever he or she may be) for the 10 hole vent diagram!
Could you do the same with aluminum square tubing for the vent? Also what is the length of the vent holes? I know they are about 1/4 inch wide, how long are they Mabey 1/2 inch?

_________________
I may be synthetic, but im not stupid.

Aluminium square tube usually has sharp edges - so while it's definitely possible it will look somewhat differend.
The length of the barrel vent together with the front triangle is 180mm for the 8 hole version (I'll have to look up the 10 holer).
Have to run now - more during the weekend...

Cheers,
Stefan

We use steel because it's easier to weld, welding aluminum is definately a dark art.

_________________
"Stand up for something...Or get knocked down for nothing..."

Stefan,

Will you be making any more of these?.

I wish I could! I made those about 6 years ago when I was still working at the university (and had access to the tool shop ).
However, I'll rework my plans and post them here as soon as they are done (probably after the easter holydays).

Cheers,
Stefan

Now back to business...

Based on the picture of the Barrel Extension sold by the Propstore I did this overlay:



Based on the fact that the thread had to fit into the Thompson barrel the only fitting (metric) thread was an M14x2.
This resulted in an outer diameter of the barrel extension of aprox. 18mm (so Jon was right ).

From the Propstore pictures it looks like the extension is made of two parts:
- A tube with an outer diameter of 18mm and and inner diameter of 14mm
- A hollow 'screw' that holds the extension tube in place and at the same time acts as a restrictor to create enough gas pressure to cycle the bolt

Here a comparison of a standard Thompson barrel with the modified and extended barrel:



So, what do you think?

Cheers,
Stefan

So, now I know what I'll be making at work tomorrow..

Thanks for the info Stefan.

Two words of caution:
- This is a preliminary version only. So some dimensions might still change.
- Don't use it with a real gun/blank gun!! All of this is just based on the little info we have. So there's a good chance you'll hurt yourself or others if you use it with a real/blank gun!

Cheers,
Stefan

Noted,

Is the other (un-threaded) end of the extension still 11mm or is that now 14mm also?.

Hmm, I think I can't really follow you at the moment.
11mm is the inner diameter of the muzzle of the extension screw (e.g. the visible muzzle). 7mm is the inner diameter of the choke. The shaft/thread diameter of the extension screw is 14mm (e.g. the same as the inner diameter of the extension tube).

Hope this helps.

Cheers,
Stefan

Cheers.

Ok, this took a while longer than expected, but here are the plans for the 10 hole barrel vent and shoulder stock:



If you spot any errors, please let me know...

Cheers,
Stefan

Houuuuuu..... Sexy drawing.
Just one thing I don't see on it would be the milling diameter bit size
for the openings on the stock. 3.5 mm or 4mm? looks to be
a bit less than 4mm.
Thanks again budy for taking the time to work on those
blueprints.

Stephane

Dang, missed that!
Milling bit diameter should be 6mm.

Cheers,
Stefan

Edit: Ok, fixed it and uploaded the new version.

6mm..... noted.
Thanks Stef. You gonna have to update it.

Steph

Already done.

Got it.