20 gauge to 9mm conversion project.

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Dr.K
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20 gauge to 9mm conversion project.

Post by Dr.K » Mon Mar 10, 2014 9:27 pm

I know it's not a silencer, but I'm building it specifically for silenced shooting with a silencer I built.

So, I am going to make a full length rifled insert to go inside a 20 gauge single shot shotgun. I'm currently turning the barrel blank down.

Image

I haven't decided if it will be a permanent attach or not. It's just a break action HR shotgun I got from a pawn shop.
Kyle O.

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Re: 20 gauge to 9mm conversion project.

Post by doubloon » Tue Mar 11, 2014 12:04 am

Cool.

I've seen conversions that do this for about $30 but they're not full length.
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Re: 20 gauge to 9mm conversion project.

Post by whiterussian1974 » Tue Mar 11, 2014 12:48 am

Maybe he's doing it to trap the gas and convert the length into a "prechamber."
9x19mm being a straight wall case, the chamber leakage around the case will be a significant sound source. Maybe even more than that from the can muzzle. This could be solved be rechambering for .357 Sig or another shouldered neck design.

I wonder why Dr K didn't choose a larger case volume for a .35 cal. Then he could have shot 250-300gr slugs. Since we don't know his goal, we can only thank that he is allowing us to vicariouly enjoy his toys.
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Re: 20 gauge to 9mm conversion project.

Post by hotbrass » Tue Mar 11, 2014 1:29 am

9x19 case is tapered.

But, maybe not enough to make a difference.

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Re: 20 gauge to 9mm conversion project.

Post by whiterussian1974 » Tue Mar 11, 2014 2:52 am

hotbrass wrote:9x19 case is tapered.

But, maybe not enough to make a difference.
Taper isn't the issue. Headspacing on the mouth instead of shoulder, is.
The 9mm, .40, .45, et al are all known for having gas leakage because the chamber has to be loose enough for the action to cycle. (These were designed as Semi-auto rds.) Only a shoulder or belted base/rim would prevent leakage.
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Re: 20 gauge to 9mm conversion project.

Post by Dr.K » Tue Mar 11, 2014 3:37 am

Well, the reason for my choosing this is I've got a fuckton of 9x19, and wanted a cool way to shoot it besides blasting it away in my handguns.

It's just a toy for me.

I couldn't find a 9mm rifle of my liking, so I am building one. It's an exercise of my tools, and a relaxing of my mind. 8) I bought 2 blanks, so this doesn't have to be my only build, I can make something else if this sucks balls (I don't think it will).

So, here is my progress.

This is the shotgun I'll be using for the project, and the insert after turning down the outside diameter to 20 gauge specs. The blue layout fluid is so I can see where the high spots are that require fine tuning for a perfect fit.
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It took a couple trips back and forth to the lathe to get it all perfect.
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Here is my set up for doing the chamber. Can anyone guess what does not seem right with this setup?
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And here is me cutting my very first ever chamber :D
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Chamber cutting was a breeze, I opened up the back end of it a bit while I decide on which case extraction method I'm going to use.

At first I was thinking a simple slot so I could just pick the hull out with a small screwdriver or knife, but now I'm thinking may be make a real deal extractor with a spring and pin to hold it in there, kind of like what is there for the shotgun shells, and have the.....OH, just had an epiphany, maybe I'll use the shotgun extractor, and modify a piece to work off of that to extract the hulls.....hmmm, some thinking to do I have, and borrow my buddy's milling machine again, lol.

Image

Aside from that, I am going to cut the shotgun muzzle, and the barrel to match up with each other behind the threaded muzzle, so that the silencer squeezes it all tight without being canted off centerline.

Let me know what you think, this is my first time to do something like this, feedback is appreciated.
Kyle O.

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Re: 20 gauge to 9mm conversion project.

Post by whiterussian1974 » Tue Mar 11, 2014 4:11 am

Dr.K wrote:I am going to cut the shotgun muzzle, and the barrel to match up with each other behind the threaded muzzle, so that the silencer squeezes it all tight without being canted off centerline.
Let me know what you think, this is my first time to do something like this, feedback is appreciated.
If you plan to leave the can on most of the time w/o removal for cleaning, that seems OK. But I would drill 3 holes @ 12,4,8 o'clock 1/2" behind the 20ga muzzle and minor indents into the 9mm barrel OD to secure the 2 together once under tension. Otherwise, repeated tightening might wear the threads. It would occur only slowly, but the microfractures will be cumulative.
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Re: 20 gauge to 9mm conversion project.

Post by Dr.K » Tue Mar 11, 2014 2:48 pm

Crowned and threaded the muzzle.
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And everything fits together nicely.
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Test fire with silencer attached.
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Not sure what kind of mumbo jumbo you are talking about noise coming from around the brass whiterussian, cause this thing is silly quiet! Red ryder quiet. The kind of quiet that makes you giggle a little bit each shot. :lol:

Hope you all like my project, All that is left is to work on the extraction method. I will be back with that later.
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Re: 20 gauge to 9mm conversion project.

Post by hotbrass » Tue Mar 11, 2014 3:33 pm

Now you need some sights!

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Re: 20 gauge to 9mm conversion project.

Post by Capt. Link. » Tue Mar 11, 2014 5:31 pm

whiterussian1974 wrote:
hotbrass wrote:9x19 case is tapered.

But, maybe not enough to make a difference.
Taper isn't the issue. Headspacing on the mouth instead of shoulder, is.
The 9mm, .40, .45, et al are all known for having gas leakage because the chamber has to be loose enough for the action to cycle. (These were designed as Semi-auto rds.) Only a shoulder or belted base/rim would prevent leakage.
Ever hear of obturation no modern case has gas problems you describe none!

Sweet job Kyle will you add flutes to lighten it.
A post and ghost ring would do the job for both calibers.
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Re: 20 gauge to 9mm conversion project.

Post by Dr.K » Tue Mar 11, 2014 7:19 pm

Capt. Link. wrote:
whiterussian1974 wrote:
hotbrass wrote:9x19 case is tapered.

But, maybe not enough to make a difference.
Taper isn't the issue. Headspacing on the mouth instead of shoulder, is.
The 9mm, .40, .45, et al are all known for having gas leakage because the chamber has to be loose enough for the action to cycle. (These were designed as Semi-auto rds.) Only a shoulder or belted base/rim would prevent leakage.
Ever hear of obturation no modern case has gas problems you describe none!

Sweet job Kyle will you add flutes to lighten it.
A post and ghost ring would do the job for both calibers.
Thanks Captain. I might flute it later (when I finally get a mill!) but for now, it's not necessary. For sights, right now I'm thinking I'll drill and tap for a picatinny on top of the shotgun barrel, and I've got a 1x leupold I won at a 3 gun match I plan to use on it. Or, whatever else I can scrape up.

The plan is if it is accurate like that, I'll leave it as is. As in be able to convert it back and forth from shotgun to 9. If "9mm" accuracy is not great, I'll likely pin the insert to the barrel with set screws, and pretty much make it permanent 9mm rifle.

Here is the current fix for extraction. I left some room to do another option later if I feel the need (or get a mill of my own) :lol:

Image
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Re: 20 gauge to 9mm conversion project.

Post by doubloon » Tue Mar 11, 2014 8:30 pm

very cool
http://www.youtube.com/watch?v=BDtd2jNIwAU MUSAFAR!
http://www.youtube.com/watch?v=8CrOL-ydFMI This is Water DavidW
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Re: 20 gauge to 9mm conversion project.

Post by daviscustom » Tue Mar 11, 2014 10:20 pm

I was guessing it would be quiet. I have one of the H&R's in .357 MAX and it sounds like firecrackers in a pipe when I shoot 38 Specials in it, without a can.


Have you considered just making like a jam nut to go on your threaded muzzle to lock the insert in the barrel?....then you don't have to rely on the suppressor to hold it in the chamber. Cool project, I have a 10 gauge H&R I bought just for this purpose.
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Re: 20 gauge to 9mm conversion project.

Post by helomech » Wed Mar 12, 2014 1:32 am

Really nice job. Can't wait to see what you come up with for an ejector. Wouldn't mind trying a project like this myself,,,,,,,,, while I'm still waiting for my form 1s to come in. :x

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Re: 20 gauge to 9mm conversion project.

Post by whiterussian1974 » Wed Mar 12, 2014 1:53 am

Capt. Link. wrote:
whiterussian1974 wrote:Taper isn't the issue. Headspacing on the mouth instead of shoulder, is.
The 9mm, .40, .45, et al are all known for having gas leakage because the chamber has to be loose enough for the action to cycle. (These were designed as Semi-auto rds.) Only a shoulder or belted base/rim would prevent leakage.
Ever hear of obturation no modern case has gas problems you describe none!
Right you are. I was thinking of 1906-38. I didnt take advances in materials science into account.
Case bleed was a problem for pistols decades ago, but not really today. Even in 1960s brass cases had largely overcome the problem. Only mild steel still suffers.
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Re: 20 gauge to 9mm conversion project.

Post by gunny50 » Wed Mar 12, 2014 5:48 am

Dr.K wrote:
Here is the current fix for extraction. I left some room to do another option later if I feel the need (or get a mill of my own) :lol:

Nice build,
Just back from the IWA show.
For drop in barrels take a look at some of the solutions on the links below, they are really functional systems even if you take the barrel in and out, no need to re-zero.
Image
These systems are used a lot in the EU by hunters.
For small and big calibers. rimmed and rimless calibers, keep in mind some of these use high power centerfire conversions for your shotgun.
Rimless systems mostly use a small plunger that is under spring tension so it locks in the grove of the cartridge.
Most use a brass ring in the rear to adjust it to have a tight and non wear surface against the forcing cone inside the shotgun barrels.
Part of the barrel inserts rim is machined of so you do not extract your insert all the time. Installed quiet a bunch of these over the years, mostly for 222 and 22 hornet but also larger CF cartridge calibers.

Timing is done on extractor from the shotgun.
http://www.einstecklauf.de/Kaliber/KaliberFrame.html
http://www.einstecklauf.de
http://www.frankonia.de/252162/131341/p ... oryId=6788
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Image

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Re: 20 gauge to 9mm conversion project.

Post by Dr.K » Wed Mar 12, 2014 9:25 am

Just when you think you have an original idea! :lol:

That is exactly the type of extractor I'm thinking of!
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Re: 20 gauge to 9mm conversion project.

Post by eric10mm » Wed Mar 12, 2014 4:40 pm

Very cool. But for some reason I was thinking you were doing an integrally suppressed insert to fit entirely in the barrel and was wondering why not use a 12ga instead.

(next project idea for you. :wink: )

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Re: 20 gauge to 9mm conversion project.

Post by Dr.K » Thu Mar 13, 2014 1:04 am

Ok, here is what I've come up with for an extractor sofar.

I cut the same blank on the outside as my 20 gauge chamber. And on the inside I've done what is best described as a reverse image of a 9x19 brass. The plan is to mill a slot in the insert, then cut out what fits inside that slot from this blank. Then, mill a slot and put a pin in so the ejector wont eject itself......man that's difficult to explain via text, ha ha.

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Re: 20 gauge to 9mm conversion project.

Post by Dr.K » Fri Mar 14, 2014 12:52 am

Extractor complete! Check it out, and tell what you think. I'm pretty happy that it only took me one try, and only my 2nd time using a mill.


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Re: 20 gauge to 9mm conversion project.

Post by hotbrass » Fri Mar 14, 2014 1:13 am

Good work!

Now chamber it for a 38 Super and get more power! :D

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Re: 20 gauge to 9mm conversion project.

Post by MCKNBRD » Fri Mar 14, 2014 8:50 am

hotbrass wrote:Good work!

Now chamber it for a 38 Super and get more power! :D
"Giggle quiet" and ".38 Super" have NEVER worked in the same sentence, much less the same firearm...

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Re: 20 gauge to 9mm conversion project.

Post by hotbrass » Tue Dec 16, 2014 12:57 pm

MCKNBRD wrote:
hotbrass wrote:Good work!

Now chamber it for a 38 Super and get more power! :D
"Giggle quiet" and ".38 Super" have NEVER worked in the same sentence, much less the same firearm...
You have more powder space in a 38 Super and can load a heavier sptizer type bullet to max subsonic velocities. More energy at the target!

Or better yet, load a 357 Maximum!

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Re: 20 gauge to 9mm conversion project.

Post by noscoe30 » Tue Dec 16, 2014 3:13 pm

If you permanently fix the liner to the barrel, you should be able to cut the barrel from 18" to 16" since it will now be a rifled barrel and not a shotgun.

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Re: 20 gauge to 9mm conversion project.

Post by Dr.K » Tue Dec 16, 2014 5:23 pm

hotbrass wrote:
MCKNBRD wrote:
hotbrass wrote:Good work!

Now chamber it for a 38 Super and get more power! :D
"Giggle quiet" and ".38 Super" have NEVER worked in the same sentence, much less the same firearm...
You have more powder space in a 38 Super and can load a heavier sptizer type bullet to max subsonic velocities. More energy at the target!

Or better yet, load a 357 Maximum!
I'm guessing you missed the part about me having a fuckton of 9mm? :lol:
Kyle O.

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