M32 6-Shot Rotary Grenade Launcher BUILD THREAD

[ARCHIVED THREAD] - M32 6-Shot Rotary Grenade Launcher BUILD THREAD

Posted: 12/31/2014 4:05:26 PM EDT

Now that my M224 is finished I figgured I would do another build thread. This time, I am modifying a Penn Arms SL6 37mm launcher to more closely resemble a Milkor M32.

Penn Arms SL6

Milkor M32

For those of you who are unfamiliar with both weapons systems; The Penn Arms SL6 and the MilKor M32 both fall under the Destructive Device (DD) category, but for different reasons. The SL6 was designed to be used as a riot control tool for police departments and was given a rifled barrel. Even though it is chambered in 37mm and not 40mm, it is a destructive device because of its rifled barrel. The MilKor M32 was designed for military use in combat, not so much as a riot control device but as a Shock-N-Awe tool. The MilKor m32 is classified as a destructive device because it is chambered in 40mm and it has a rifled barrel.

Even though I will be removing all of the DD characteristics from my SL6 I will still be filling out a Form 1 and registering it as a 37mm DD.

The first thing I did was order a Penn Arms SL6 front end. This consisted of the cylinder, receiver, and barrel.

Posted: 1/1/2015 11:31:18 AM EDT

[#1]

In order to save time and only need to register the weapon once, I ordered my Penn Arms front-end first so that I could remove the DD characteristic before I started my build. I recieved the front end in the mail and removed the barrel from the the receiver with a big ass six jaw lathe chuck and a BUNCH of heat. I don't know what sort of epoxy Penn Arms uses but it is some bad ass stuff. I don't have pictures of me removing the barrel (just bad memories of me sweating and swearing) but here are the after shots.

With the old aluminum rifled barrel removed and discarded, I began working out the dimensions for my new stainless steel smoothbore barrel. Without getting into my frustrations with the 37mm community I will just say that in no world does 37mm = 1.5 inches. As you can see from my drawings, the ID of my barrel will be just a hair over 37mm.

Posted: 1/1/2015 11:36:22 AM EDT

[#2]

The barrel is bored out to the proper ID and is profiled according to the sketch that I made. If you notice in my sketch I did not identify the thread pitch. This was because I figgured I would take the measurements on the fly from my SL6 barrel...wrong, the threads are metric and I can't cut metric on my lathe. Anyways here are pictures of the barrel so far.

Posted: 1/1/2015 11:44:24 AM EDT

[#3]

now that the rifled barrel had been removed from the front end and discarded, it was time to begin on the rear section. The safety and thumb latch were first removed in order to better access the guts of the rear end. Next the plastic Penn Arms buttstock was removed

I drew out a net onto a piece of sheet metal and cut it out for the new receiver housing. Once the net was cut out it was properly bent in a sheetmetal break to fit snugly on the rear end. (Sorry no during photos because it took me several tries to get it right).

Once the reciever cover was fitted I began working on the pistol grip. Rather than modifying the SL6 receiver, I chose to open up the tango down battle grip to fit the SL6 receiver. A few quick passes in the mill and it was opened up just enough to slide over the SL6 reciever. Notice that I only removed material on the pistol grip where I needed to. I had to open up the reciever slot so much that it made the walls a little thinner than I would like. I am going to machine a piece of steel to fit in the back of the reciever that the pistol grip will mount to.

Posted: 1/1/2015 3:39:29 PM EDT

[#4]

Looking Great......

Posted: 1/2/2015 4:50:46 AM EDT

[#5]

I guess I'm the only one that can't see the pics? I couldn't see them at 1919a4, either.

Posted: 1/2/2015 4:58:00 AM EDT

[#6]

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Quoted:
I guess I'm the only one that can't see the pics? I couldn't see them at 1919a4, either.

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ditto

Posted: 1/2/2015 7:25:26 AM EDT

[#7]

Your images, they are no here...

Posted: 1/2/2015 8:39:30 AM EDT

[#8]

I can't see the pictures either

Posted: 1/2/2015 12:17:15 PM EDT

[#9]

I guess I need to upload them through photobucket.

Posted: 1/2/2015 1:00:36 PM EDT

[#10]

They;re working for me..im using Chrome. Ben, where did you buy the launcher from, and if you dont mind my asking, how much was each half??? Oh, and did the Penn Arms launcher use standard rounds? or was that a differen one im thinking of that used the Proprietary cases? Not ARWEN, but there was another one as well

Posted: 1/2/2015 1:06:39 PM EDT

[#11]

Quote History

Quoted:
They;re working for me..im using Chrome. Ben, where did you buy the launcher from, and if you dont mind my asking, how much was each half??? Oh, and did the Penn Arms launcher use standard rounds? or was that a differen one im thinking of that used the Proprietary cases? Not ARWEN, but there was another one as well

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Sage is the one that uses the rebated rim rounds

Posted: 1/2/2015 1:41:39 PM EDT

[#12]

Quote History

Quoted:

Sage is the one that uses the rebated rim rounds

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Quoted:

Quoted:
They;re working for me..im using Chrome. Ben, where did you buy the launcher from, and if you dont mind my asking, how much was each half??? Oh, and did the Penn Arms launcher use standard rounds? or was that a differen one im thinking of that used the Proprietary cases? Not ARWEN, but there was another one as well

Sage is the one that uses the rebated rim rounds

Ok, thanks....ours at work were all single shot Federal or S&W's, but I remembered a discussion on Grogs about the Sages using different cases

Posted: 1/2/2015 4:35:48 PM EDT

[#13]

Quote History

Quoted:
They;re working for me..im using Chrome. Ben, where did you buy the launcher from, and if you dont mind my asking, how much was each half??? Oh, and did the Penn Arms launcher use standard rounds? or was that a differen one im thinking of that used the Proprietary cases? Not ARWEN, but there was another one as well

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Hopefully that fixes the picture problem for everyone. the rear half was like 250 on Gunbroker and the front half was 300ish on Gunbroker but i purchased them a while ago. As far as the cases go, the chamber is quite a bit larger than most 37mm launchers but is not quite 40mm. I will take some measurements for you guys the next time I head out to the shop. I may be able to re-size 40mm brass to fit in my launcher but I am afraid that if I do that the projos will be to large for my BBL. I suppose I could always open up the bore on my BBL...

Ben

Posted: 1/4/2015 2:29:57 PM EDT

[#14]

Great looking build!

Posted: 1/4/2015 3:07:28 PM EDT

[#15]

Quote History

Quoted:

Hopefully that fixes the picture problem for everyone. the rear half was like 250 on Gunbroker and the front half was 300ish on Gunbroker but i purchased them a while ago. As far as the cases go, the chamber is quite a bit larger than most 37mm launchers but is not quite 40mm. I will take some measurements for you guys the next time I head out to the shop. I may be able to re-size 40mm brass to fit in my launcher but I am afraid that if I do that the projos will be to large for my BBL. I suppose I could always open up the bore on my BBL...

Ben

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Quoted:

Quoted:
They;re working for me..im using Chrome. Ben, where did you buy the launcher from, and if you dont mind my asking, how much was each half??? Oh, and did the Penn Arms launcher use standard rounds? or was that a differen one im thinking of that used the Proprietary cases? Not ARWEN, but there was another one as well

Hopefully that fixes the picture problem for everyone. the rear half was like 250 on Gunbroker and the front half was 300ish on Gunbroker but i purchased them a while ago. As far as the cases go, the chamber is quite a bit larger than most 37mm launchers but is not quite 40mm. I will take some measurements for you guys the next time I head out to the shop. I may be able to re-size 40mm brass to fit in my launcher but I am afraid that if I do that the projos will be to large for my BBL. I suppose I could always open up the bore on my BBL...

Ben

You may find that only the Rim end of the chamber is larger, most of the newer (in the last 20 years or so) CS/CN/OC rounds are 37/40 MM and can be used in both launchers, the very bottom of the case is a tad wider for about 3/4 Inch or so. I have one here, i'll take a photo and see if it resolves.

ETA, Crappy Pics I know, but this is the best i could do

Posted: 1/7/2015 10:29:04 AM EDT

[#16]

Holy shit, I can see the pictures....and they are full of win!!!

Posted: 1/9/2015 12:19:34 AM EDT

[#17]

I was finally able to get out to the shop this evening and make some more progress. I completed the ar15 pistol grip lug that will connect the m32 receiver firmly to the penn arms receiver. I can post a step by step narrative of how I made the part on my Gorton mill if anyone is interested by I figgured most of you guys just look at the pictures anyway. Here they are.... Sorry I didn't get a photo of the pistol grip on the new pistol grip lug.

I'll post pictures of the gun put together tomorrow.

Thanks,
Ben Radcliff
[email protected]

Posted: 1/10/2015 12:09:43 AM EDT

[#18]

Ben

Nice work!

I wish I had the skills since I spent many a summer day firing a M32A1 GL on a Military range to test ammo.

I'd love to have one for knee knocker rounds or in a pinch the bid bomb 37mm rounds!

Thanks for posting your project!

Posted: 1/10/2015 1:03:57 PM EDT

[#19]

The pistol grip lug has been tapped for the pistol grip and plug welded in place. I was finally able to have the metric threads machined on the bbl. Up next is the buttstock lug.

Thanks,
Ben radcliff

Posted: 1/15/2015 9:38:07 AM EDT

[#20]

After looking at the barrel I think it may be a little long. It is the same length as an m32 bbl but it just doesn't quite seem right.

I was able to make a little more headway on the project though. I have the buttstock lug cut and ready to be drilled out so I can mount it to my m32 receiver. The lug is as close as I could get it to the real thing but is not an exact coppy. My reciever is a little shorter so the lug will appear longer. The stock is probably going to look like it is a little far back but I may be able to shorten the buffer tube in order to make it look right. I welcome any suggestions as I am pretty much making it up as I go.

Here is the pic of the piece I made and what I modeled it after

Posted: 1/16/2015 1:06:19 PM EDT

[#21]

Honestly?? Yours looks better and more secure than the model one.

Posted: 1/17/2015 2:50:54 PM EDT

[#22]

Just mocking some stuff up today. I'm still not 100%sure I will be able to use an ar15 buffer tube. I may cut the threads off and sleeve a solid piece on the end to give me more rigidity. Here is what I have.

Thanks,
Ben Radcliff

Posted: 1/17/2015 3:32:17 PM EDT

[#23]

I was watching Godzilla (1998) the other day and in oe of the scenes i noticed a bunch of the Soldiers running around with the Penn Arms launchers.

Posted: 1/17/2015 3:44:59 PM EDT

[#24]

Mine is SN 74... Maybe mine was there!!! That would be pretty bad ass to say that my launcher went up against Godzilla!

Posted: 1/18/2015 10:36:59 PM EDT

[#25]

This thread is awesome!

Posted: 1/19/2015 11:16:43 AM EDT

[#26]

I am still trying to figure out how I want to tackle the buttstock hinge and buffer tube adapter. In the mean time I figgured I would put a little rattle can paint on some of the areas that I had worked on to keep them from rusting. Aside from the color not being quite right... I must say, this thing is starting to look pretty close to the real deal. As soon as I get the buttstock worked out this bad boy is off to cerakote.

Thanks,
Ben

Posted: 1/19/2015 11:17:15 AM EDT

[#27]

I am still trying to figure out how I want to tackle the buttstock hinge and buffer tube adapter. In the mean time I figgured I would put a little rattle can paint on some of the areas that I had worked on to keep them from rusting. Aside from the color not being quite right... I must say, this thing is starting to look pretty close to the real deal. As soon as I get the buttstock worked out this bad boy is off to cerakote.

Thanks,
Ben

Posted: 1/23/2015 5:39:42 PM EDT

[#28]

Badass! Where did you get the m32 handguard? Also, here's a pic of mine. It came with the Cerakote on it. I think it's flat dark earth. I really wanna get one with the 6 inch chambers someday. I think they look better than the 8 inch chambers.

Posted: 1/30/2015 11:58:31 AM EDT

[#29]

looks awesome OP!

Posted: 9/22/2015 10:33:58 AM EDT

[#30]

The handguard came directly from MilKor. After building several unsuccessful prototypes I called the good people at MilKor and explained what I was doing and they sent me one.

I am still running into an ammo problem... I am pretty sure that this launcher takes special sage ammo however I have approximately 400 rounds of 37/40mm aluminum batton shells that are about 5 inches long and about .010 too wide. Obviously I would like to use the shells I have rather than buy new ones especially since these are easily reloadable hi-Lo rounds. My thoughts right now are to either chuck each round up in the lathe in order to thin and shorten them or to make some sort of resizing die to shrink the shells down. Just my initial thoughts but I think .010 is going to be too much to try to shrink and I am going to destroy a lot of rounds trying to resize them.

Any thoughts?

Posted: 9/23/2015 9:16:43 AM EDT

[#31]

What's the needed OD above the rim? I think I have some plastic shells that are slightly smaller, I'll measure for you.

Also, you mentioned in your first post you bought the front end. Did you buy direct from CT which now owns Penn, or did you buy third party? I've not been able to get CT to sell me any parts for my 40mm DDs. I've been asking for years, now.

Posted: 9/24/2015 11:57:38 PM EDT

[#32]

The front end was purchased on gunbroker a few years back. I believe they came from a police dept. I'm not sure about the OD off of the top of my head. I am currently away from the shop on buisness but perhaps one of the other guys with a sage launcher could chime in.

If I recal correctly the company that was selling the front ends also had a few pelican cases that were fitted for the launchers. I would have loved to have gotten one but they sold out before I could buy.

Thanks,
Ben

Posted: 9/25/2015 7:38:52 AM EDT

[#33]

Ben, you might look into honing the chambers out .010 using a brake hone, start with a heavy grit paper attached to the hones, and work your way to the size you need in each. That way, you can use the casings you want, without having to modify 400 of them... I did this method to an old RPB, to allow me to use 212 casings and it worked fine. GROG

Posted: 9/25/2015 10:41:58 AM EDT

[#34]

I've been "online" since 1981....so I've seen a ton of cool stuff on the net...but this may be the most bad ass build thread I've ever seen. Epic! Good work, man! I look forward to some videos of this thing in action!

Posted: 9/26/2015 10:25:32 AM EDT

[#35]

Thanks for all of the positive comments this has been a ton of fun to build.

Grog, I have been debating whether or not I should do that. The only thing that is holding me back right now (and please God let us not turn this thread into a legal debate

) is that the shells I have are 37/40mm. I believe they were fired out of a 40mm launcher causing them to expand. The chambers on the sage launcher are already so oversized that 37mm rounds rattle around. I'm just worried that if I open it up anymore and begin using, what is essentially a 40mm round, that i would run into problems later when register the gun. 37mm dd? 40mm?

Thanks,
Ben

Posted: 9/26/2015 10:26:30 AM EDT

[#36]

Thanks for all of the positive comments, this has been a ton of fun to build.

Grog, I have been debating whether or not I should do that. The only thing that is holding me back right now (and please God let us not turn this thread into a legal debate

) is that the shells I have are 37/40mm. I believe they were fired out of a 40mm launcher causing them to expand. The chambers on the sage launcher are already so oversized that 37mm rounds rattle around. I'm just worried that if I open it up anymore and begin using, what is essentially a 40mm round, that i would run into problems later when register the gun. 37mm dd? 40mm?

Thanks,
Ben

Posted: 9/27/2015 2:24:29 PM EDT

[#37]

I'm pretty sure (check with nfa lawyer) that the barrel ID is the registered ID, just as if registering a SBR in 5.56, the caliber is 5.56, not the OD of a casing.... just a thought. Grog

Posted: 9/27/2015 6:34:42 PM EDT

[#38]

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Moved to another thread, off topic discussion.

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Posted: 9/28/2015 10:09:15 AM EDT

[#39]

double tap

Posted: 9/28/2015 10:15:52 AM EDT

[#40]

Moved to another thread, off topic discussion.

Posted: 9/30/2015 12:24:41 PM EDT

[#41]

pyotr_k, since we obviously disagree, and the OP does not wish to turn this thread into a legal debate, I propose we either start a new thread here in DD, or move our discussion to Class 3 Legal Issues And Questions. That way we can all figure out the correct answers. I think it would get more traffic in the other forum.

Posted: 9/30/2015 1:14:04 PM EDT

[#42]

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pyotr_k, since we obviously disagree, and the OP does not wish to turn this thread into a legal debate, I propose we either start a new thread here in DD, or move our discussion to Class 3 Legal Issues And Questions. That way we can all figure out the correct answers. I think it would get more traffic in the other forum.

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Sure thing! Would you like to start the thread or shall I?