Baffle Design suggestions for offset 45ACP (Delisle)

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MikeRomiter
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Baffle Design suggestions for offset 45ACP (Delisle)

Post by MikeRomiter » Wed Jan 05, 2022 5:24 pm

Hello Everyone,

Long time lurker, first time poster. I am in the process of building 3 Delisle 'Commando' Carbine inspired integrally suppressed 45ACP bolt actions (I have the stamps in hand) and I am for the most part staying true to form, however, I would like to consult the experts here to see if anyone has a better idea for baffle design.

I started these projects with the intention of using the original maxim inspired baffles, however I have also considered alternate methods such as building a monocore or an offset and indexed M baffle, as well as lower-tech ideas such as formed freeze plugs/packing. I have a large internal volume to work with, roughly 50 cubic inches (2"diam x 16" long) surrounding an 8" barrel. I'm not really trying to re-invent the wheel but everyone here seems so knowledgeable that I figured someone would be able to suggest something that would work well for this unique application. I have a decently outfitted manual machine shop in my garage, and I do CNC machining full time.

Thanks in advance for the advice.
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Capt. Link.
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Re: Baffle Design suggestions for offset 45ACP (Delisle)

Post by Capt. Link. » Wed Jan 05, 2022 6:25 pm

MikeRomiter wrote:
Wed Jan 05, 2022 5:24 pm
Hello Everyone,

Long time lurker, first time poster. I am in the process of building 3 Delisle 'Commando' Carbine inspired integrally suppressed 45ACP bolt actions (I have the stamps in hand) and I am for the most part staying true to form, however, I would like to consult the experts here to see if anyone has a better idea for baffle design.

I started these projects with the intention of using the original maxim inspired baffles, however I have also considered alternate methods such as building a monocore or an offset and indexed M baffle, as well as lower-tech ideas such as formed freeze plugs/packing. I have a large internal volume to work with, roughly 50 cubic inches (2"diam x 16" long) surrounding an 8" barrel. I'm not really trying to re-invent the wheel but everyone here seems so knowledgeable that I figured someone would be able to suggest something that would work well for this unique application. I have a decently outfitted manual machine shop in my garage, and I do CNC machining full time.

Thanks in advance for the advice.
Build it as a coaxial with a eccentric outer tube. Use K baffles with a 1.375" inner tube. The original was plagued with problems of baffle strikes and inaccuracy. Building holding the barrel in tension will be superior than any tie rod.
The only reason after 243 years the government now wants to disarm you is they intend to do something you would shoot them for!
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Re: Baffle Design suggestions for offset 45ACP (Delisle)

Post by MikeRomiter » Thu Jan 06, 2022 9:22 am

Thats a great idea, I was trying to come up with a way to preserve accuracy while still using the offset design, and that sounds like it would do exactly that. Would you vent the smaller tube into the larger somehow?

Thanks for the help.
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Re: Baffle Design suggestions for offset 45ACP (Delisle)

Post by Capt. Link. » Thu Jan 06, 2022 1:31 pm

MikeRomiter wrote:
Thu Jan 06, 2022 9:22 am
Thats a great idea, I was trying to come up with a way to preserve accuracy while still using the offset design, and that sounds like it would do exactly that. Would you vent the smaller tube into the larger somehow?

Thanks for the help.
The smaller tube dose vent into the larger. The whole idea is to tie the receiver and barrel into the suppression tubes. Where do you wish to start?
The only reason after 243 years the government now wants to disarm you is they intend to do something you would shoot them for!
http://www.silencertalk.com/forum/viewtopic.php?f=10&t=79895

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Re: Baffle Design suggestions for offset 45ACP (Delisle)

Post by MikeRomiter » Thu Jan 06, 2022 3:03 pm

That sounds great, I certainly appreciate the help, I will post some drawings tonight once I get out of work.

Thanks!
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Re: Baffle Design suggestions for offset 45ACP (Delisle)

Post by alordnapa » Fri Jan 07, 2022 10:15 am

Are you building the host rifle from scratch, or have you found a .45 ACP bolt action rifle or converted one? Please, please post your photos!

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Re: Baffle Design suggestions for offset 45ACP (Delisle)

Post by MikeRomiter » Fri Jan 07, 2022 11:30 am

alordnapa wrote:
Fri Jan 07, 2022 10:15 am
Are you building the host rifle from scratch, or have you found a .45 ACP bolt action rifle or converted one? Please, please post your photos!
While I draft the suppressor internal idea for Capt. Link, I'd be happy to share the build progress.

I have a NFA trust with my brother and father, and as soon as I told them I was building a Delisle, they both wanted one too. I am building their guns as basic simplified Delisle clones using Rhineland Arms conversion kits which includes a 45acp barrel and a magwell adapter. I decided that I wanted something weird for mine because building 3 of the same thing was boring to me, and because my gun was in pretty rough shape to begin with.

Here is the original gun, a heavily sporterized Lee Enfield No1 MK3, crammed into two halves of a R700 Stock Image

I eventually figured that I wanted a side folding stock and for the gun to accept grease gun magazines because I recently bought a Stemple 76/45 machine gun, which takes grease gun mags. This bad idea was originally inspired by this:Image

The first step was to disassemble the gun and remove the barrel, which was a real bear, I first made a relief cut to release the tension on the barrel threads. I included a pic just to show how much force I had to put on the barrel (extreme care is required not to bend the receiver) :

Image.
Image

I also decided to just build an aluminum chassis for the gun, because there was no way to realistically fit a grease gun magwell into the current stock.

Here is my initial layout: Image (Stuff on floor is needles from the Christmas tree.)

*Before I go on any further, I just want to stress that I know the design of the gun is wacky-- maybe even really dumb, but I have had so much fun with this build and only spent $250 on the project so far(not including stamp), that I'm running with it.
Last edited by MikeRomiter on Fri Jan 07, 2022 12:27 pm, edited 1 time in total.
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Re: Baffle Design suggestions for offset 45ACP (Delisle)

Post by MikeRomiter » Fri Jan 07, 2022 12:18 pm

My next step was to build an adapter that mates the Enfield receiver to the folding stock and the ar15 grip. in these first pictures the adapter is only roughed in, as I wanted to be sure the ergonomics were right later once I had the chassis closer to completion.

Here is the stock adapter with the wood stock and 45 acp barrel mocked up, to get a feel of length of pull and cheek weld.

Image

The next step was to mock up the chassis, so I did that with paper.

Image

Over all I really like the look, and the 2inch diameter suppressor really ties everything together.

My next step was to start shaping the chassis, however the variable frequency drive on my mill released its magic smoke and died, so I had to switch to lathe work until a replacement came in.

More to follow.
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Re: Baffle Design suggestions for offset 45ACP (Delisle)

Post by MikeRomiter » Fri Jan 07, 2022 12:56 pm

While I waited for the replacement VFD, I began work on insetting the barrel into the receiver, the original Delisle recessed the barrel into the receiver to facilitate feeding rounds into the chamber. A .303 British round is about 3" long, while a 45ACP is about 1.25". I didn't want the short cartridge flopping around freely as it stripped out of the mag, and I wanted to shorten the bolt throw to get rid of the wasted movement that comes with a rifle length bolt on a pistol cartridge.

My first step was to extend the threads on the new Rhineland barrel. The Rhineland conversion kit does not shorten your bolt travel, and is designed to be easy to install for someone that doesn't have access to machinery. Overall I highly recommend the kit for people looking for a relatively cut and dry project. I simply bought the barrel from them instead of the whole kit for this conversion, but if I could do it over I would have bought a generic 45acp barrel to save a little coin, and also due to the integral suppressor I am cutting off about 8 inches anyway.

The first step for this op was to load it up in the lathe, center it, and grind a thread cutter. Enfields were threaded with 55 degree threads, instead of 60 degree, which is most commonly used today.

Here the barrel is indicated, you can see the length of the original threads.
Image

Here is the barrel, with its threads extended. Image

Then I cut off the old threads so I could simply counterbore the receiver instead of threading it.
Image
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Re: Baffle Design suggestions for offset 45ACP (Delisle)

Post by Capt. Link. » Fri Jan 07, 2022 1:36 pm

When doing your draft the key to the suppressor is the base that is fixed to the receiver. It establishes the eccentric timing of the outer tube and strength to hold everything from getting knocked out of line. The barrel is put under tension with a section of tubing fixed to the receiver base and pushing on the muzzle brake. The inner tube that hold the baffles is held in tension between the brake and front end cap. The F cap puts the outer eccentric tube in compression.
Your construction is nearly identical to the originals nice!
The only reason after 243 years the government now wants to disarm you is they intend to do something you would shoot them for!
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Re: Baffle Design suggestions for offset 45ACP (Delisle)

Post by MikeRomiter » Fri Jan 07, 2022 1:38 pm

My next step was to bore out the receiver using an offset bore, luckily my VFD came in before I had to wait on it. Jigging this up took hours, but it was worth it.
Image
My next step was to cut the bolt down to fit into the new space. Enfields use rear locking lugs, which aren't as strong as front locking lugs but make for a much faster action. Careful planning was required to cut the bolt to the correct length to ensure that the rear lugs got the headspace in close to final dimension, as I would clock the barrel later to fine tune it. I initially tried to make the rough cut in my bandsaw, planning to take the rest down in my mill, however I found that the bolt body was very hard, to the point of a file skating across the top. I had no choice but to anneal the bolt, doing my best to concentrate the heat where I would be working and leaving the locking lugs alone.
Image

After annealing the bolt was soft enough to cut. After a quick chop in the band saw I finished the length on the mill.
Image

The bolt head uses a wonky thread, so I made a tap and tapped it, looking back, I bet a 7/16-20 UNF tap would have been close enough. but I had fun making a tap, so there is always that.
Image

After a quick harden and retemper, the bolt was good to go as far as externally anyway. The firing pin needed considerable work to fit into the short bolt. So I started on that next.
Last edited by MikeRomiter on Fri Jan 07, 2022 1:40 pm, edited 1 time in total.
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Re: Baffle Design suggestions for offset 45ACP (Delisle)

Post by MikeRomiter » Fri Jan 07, 2022 1:39 pm

Capt. Link. wrote:
Fri Jan 07, 2022 1:36 pm
When doing your draft the key to the suppressor is the base that is fixed to the receiver. It establishes the eccentric timing of the outer tube and strength to hold everything from getting knocked out of line. The barrel is put under tension with a section of tubing fixed to the receiver base and pushing on the muzzle brake. The inner tube that hold the baffles is held in tension between the brake and front end cap. The F cap puts the outer eccentric tube in compression.
Your construction is nearly identical to the originals nice!
Thanks Capt. Link, that is really helpful, I had been really wondering how I would keep this thing clocked correctly!

Also, I have considered using "flat-oval" tubing for the gun pictured, mostly because you can get a huge amount of internal volume while still keeping the gun narrow side to side, and because the gun is already pretty odd to start with. Do you have any thoughts on using something like this for the offset part of this design? A 16 inch length of 2.125" x3.5" has an incredible 113" cubic inches of volume, the equivalent of using 3" diameter! I'm sure the project would be difficult but it might be a fun challenge if I could make the most out of the space.
Image
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Re: Baffle Design suggestions for offset 45ACP (Delisle)

Post by quiettime » Thu Jan 20, 2022 12:21 pm

I like the oval tubing. Have often considered using it myself on an Integral.

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