M203 Build - Page 2

[ARCHIVED THREAD] - M203 Build (Page 2 of 4)

Posted: 10/2/2013 2:34:49 PM EDT

[#1]

Today I finished all the vertical work except for the breach face and safety detent hole. I will do those all in one set-up later when the tooling arrives. I re-cut and chamfered the barrel mount, drilled the barrel mount pin hole, finished the trigger recess and front barrel mount recess.

Posted: 10/2/2013 2:40:57 PM EDT

[#2]

Man, that looks great. The refinishing definitely helped.

Posted: 10/2/2013 6:18:08 PM EDT

[#3]

Yes, I was lucky...I shut it down just as the cutter started to grab on the other set up, so most of the screw up was removed on the second cut. I am dreading having to cut the breech face. I think I will set up a scrap piece to try out the cutter when it gets here. 1.750 D is a lot of material to face, even if it is a pilot counter bore and I am only cutting 0.075 depth. We will see.

Posted: 10/3/2013 9:30:29 AM EDT

[#4]

What is the 20% you are not removing, or will it be a 37mm launcher 'til the stamp?

Posted: 10/3/2013 10:55:30 AM EDT

[#5]

If the laws where he lives allow him to make a firearm, as in a rifle or pistol, he can make the whole receiver as long as he has no 40MM barrel in his possession or on his property. M203 receivers are Title 1 firearms, transferred like pistols, until they are Form 1 approved Destructive Devices. He needs no 37mm barrel to finish his receiver. GROG

Posted: 10/3/2013 3:35:35 PM EDT

[#6]

Grog is correct, it is a title one with no 40mm barrel in possession or in constructive possession until my Form 1 is returned approved. The 80% is the CNC print shown at the beginning of the thread. It is still awaiting pricing. I have my eye on a 37mm barrel to pair this up with for fun pyrotechnic flares and stuff. I may also finish my second receiver to what I think is 80% and send that off to ATF for a determination letter. Once I have the letter, then I can sell it without a FFL and pay for the cost of the tooling. Anyway, on to the good stuff. My KAC quick attach mount arrived today, but no screws. Oh well, I guess 1/4-20 it is. I finished almost all the operations, cutting the final contour on the receiver was nerve racking but slow and steady won the race. Compare the third and forth picture right behind the trigger guard ears and you can see how much material had to be removed. I still need to do the last cut out for the cocking arm, tap the barrel mount screw hole and finish the breach face but that will have to wait for more tooling. Here are a few pictures:

Posted: 10/4/2013 3:49:47 PM EDT

[#7]

Ok, I finished the last of the machining that I can do for a while. The tooling to cut the breach face will come after I get more project money next month. Till then enjoy the pictures. Oh by the way, the front mounting holes are 10-24 in a 3/8-16 threaded insert.

Posted: 10/6/2013 12:15:28 AM EDT

[#8]

Very Good Job!

Nice to see someone who can Mill on a budget.

Destiny

Posted: 10/6/2013 7:50:43 AM EDT

[#9]

Quote History

Quoted:
Very Good Job!

Nice to see someone who can Mill on a budget.

Destiny

View Quote

9 post and a member since 2001?!

Posted: 10/6/2013 5:05:43 PM EDT

[#10]

Destiny doesn't say much, but when she does... it's important. GROG

Posted: 10/6/2013 8:06:02 PM EDT

[#11]

rncbinc you have mad skills.........................last hand milled M203 I saw done was by a FNMI subcontractor in South Carolina in the 1990's who hand milled two M203's to go on FNMI's version of the M4 carbine, which was put together to attract DoD contracts against Colts'then strangle hold on the M4 and M4A1 carbine...................................your build is much cleaner, but they did build theirs from Bar stock T7 alloy..................Congrats...........build looks great........................

Also, if you run into a copy of a TV show called Battle Tech.....................they did an episode showing how LMT makes their M203's...............................I think it was called Tac Tech........................showed the whole process from soup to nuts....................and how not to drive a roll pin...........................

Posted: 10/6/2013 10:36:16 PM EDT

[#12]

Thanks all, I appreciate all the complements an encouragement. It may be a while before I post any more progress, but I promise a test fire video as soon it is finished and stamped.

Posted: 10/8/2013 2:27:12 AM EDT

[#13]

rncbinc, when you finish your M203 build, maybe you can put your creative skills to make yourself a usable and compact M203 stand a lone launcher module.....................I have meant to get a Knight unit for my M203 build, but I can't seem to get the nerve to pull the trigger on KAC's unit since it costs more than my original Colt receiver (title 1) cost me............................

Something like this,

Picture credit Joemomma.

only more streamlined like this,

but as cool as this.....only with a M203 receiver....................................I know, I don't ask for much..................but I don't have skills.........

..............except squeezing the trigger (don't like that H&K 320.......)

Keep up the good work..............

Posted: 10/8/2013 3:34:03 PM EDT

[#14]

I will have plenty of time to draw something up while waiting for the ATF to RSVP on the party.

Posted: 10/9/2013 3:34:32 PM EDT

[#15]

Great machine work! Tagging to follow process!!!!

Posted: 10/14/2013 12:26:45 AM EDT

[#16]

what the hell is this? i like

Posted: 10/14/2013 9:37:08 AM EDT

[#17]

That's the new HK replacement for the M-79. It opens sideways so you can use longer projectiles than the M203 allows. It also mounts on the M-16/M-4 & other NATO rifles, replacing the M203. Think that's the laser rangefinding sight up top, giving much improved 1st hit accuracy.

Posted: 10/15/2013 8:28:34 PM EDT

[#18]

And indirect fire capability to use as a 40mm mortar and rain hell on their heads.

http://www.youtube.com/watch?v=73ZS7zMHwZI

Posted: 10/16/2013 3:13:18 PM EDT

[#19]

Tagging in , very interested in a 80% 203.

Posted: 10/16/2013 3:16:37 PM EDT

[#20]

TAG for invite for test firing

While I have used a 203 in combat and know that it isn't very effective for engagements I would still love to see videos of your build especially if using the M576 shell :)

Posted: 10/16/2013 7:26:03 PM EDT

[#21]

LOL that would be fun. So I am having a real hard time finding a 37mm barrel for this build, I have decided to just sleeve a 40mm to 37mm(ish) I say "ish" because I know 37mm is 1.456 bore, most of the after market reloadable shells have a 1.5" chamber and a 1.375" chamber. All of my black power cases were 37/40 with a flared base and necked down to around 1.375 bore. So not being for "sporting" use I was unable to come up with a saami spec for the chamber. Does anyone know what the industry uses? My question is, if I am going to go to all the trouble of boring out 40mm barrels with tooling cost and all, what would be the most common chamber size people would like to see. Has anyone done this? Do the engineers in the group want to chime in on safety issues there might be?

Posted: 10/16/2013 8:21:57 PM EDT

[#22]

The "industry" uses the dimensions of their casings. Federal makes them one size, Def Tec makes them another... That's the major problem with 37MM. No standards like 40MM. I would stay FAR away from those plastic 37mm casings. Those are horrible. If you want really nice 37MM casings, go with smokeless from reloadableshells.com. His stuff is very well made, anodized, and, reloadable basically forever as long as you maintain them properly. You can go with casings for pyro to start, then after 6-8 months when ATF gets off their collective rears and approves your Form 1, you can always move right into buck and flechette. If you design your barrel around Scot's casings, most others will fit. GROG

Posted: 10/16/2013 10:50:13 PM EDT

[#23]

Quote History

Quoted:
The "industry" uses the dimensions of their casings. Federal makes them one size, Def Tec makes them another... That's the major problem with 37MM. No standards like 40MM. I would stay FAR away from those plastic 37mm casings. Those are horrible. If you want really nice 37MM casings, go with smokeless from reloadableshells.com. His stuff is very well made, anodized, and, reloadable basically forever as long as you maintain them properly. You can go with casings for pyro to start, then after 6-8 months when ATF gets off their collective rears and approves your Form 1, you can always move right into buck and flechette. If you design your barrel around Scot's casings, most others will fit. GROG

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Grog,
Do you still have your Cobray 37mm? I can't remember the dimensions of the rails on those barrels but with rncbinc's skills, maybe he could modify one to fit the M203. I can't remember if they were wider or narrower than that of the m203. I don't think he'd have any problem figuring a way to mount the barrel extension.

Posted: 10/17/2013 9:24:44 AM EDT

[#24]

I have and old Cobray 37mm and the barrel rail is all wrong. Too thin in width and too tall in height....just close enough to slide on a 40mm but none of the hardware lines up right and there is no "meat" to machine to fit. That poor thing has been mod-ed to hell and back, now it sits in a box on a shelf in pieces. Grog I think you are right on the money with the reloadable shells being the way to go. I had a bunch of old aluminum cases from 37mm less lethal once fired, I cut them down to 4", trimmed the case extractor rim and they fit the Cobray 37mm nice. Signal and smokes worked great, I would not trust them for anything else...way too thin. I think if go with the taller smokeless cases they will work for all the rounds I like. I have to talk to my welding guy but I think if I disassemble, overbore the 40mm to 1.625 then press in the sleeve from the breech end with a ID of 1.375, TIG weld 4 spot welds hidden under the grip, bore the chamber with a pilot counterbore and Presto! New 37mm barrel. Oh I left out sand blast, Cerakote and reassemble, lol. Now that I think about it, that seems like an awful lot of work and I will have to think up a rig for holding those monster drill bits. I may talk to my buddy who has a 40" bed lathe and just have him cut it for me.

Posted: 10/20/2013 5:44:12 PM EDT

[#25]

If you decide to sleeve a few barrels Im me, I could use one. I'll compensate you of course.

Posted: 10/21/2013 12:01:25 PM EDT

[#26]

Once I get the process down, I will put it on the board and folks can PM me. It will be at least another month till I can get more play $ to buy tools unless I get another build order for an AR between now and then.

Posted: 10/31/2013 5:35:24 PM EDT

[#27]

Quote History

Quoted:
Tagging in , very interested in a 80% 203.

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Same here

Posted: 11/2/2013 9:53:07 PM EDT

[#28]

If you do not want to engrave the usual Colt Pony, you can always look to the inventors of the M203.................AAI.

Just dont use the same serial number

Posted: 11/3/2013 10:19:05 PM EDT

[#29]

Quote History

Quoted:
If you do not want to engrave the usual Colt Pony, you can always look to the inventors of the M203.................AAI.

Just dont use the same serial number

<a href="http://s1120.photobucket.com/user/LogSu2/media/aaim203_zps0766f1de.jpg.html" target="_blank">http://i1120.photobucket.com/albums/l481/LogSu2/aaim203_zps0766f1de.jpg</a>

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Where did you find this!! I've only ever seen an old b&w photo that was serial #4, the markings were radically different though. You don't happen to have a pic of the new Airtronics markings do you?

William

Posted: 11/4/2013 1:16:29 AM EDT

[#30]

William,

Sorry, I do not have any idea where this pic came from. It was sent by a friend in the Army.......I am pretty sure it was an receiver offered for sale some where.

A friend had an unassembled AAI M203 several years ago, that he never assembled. I think it came out of an estate in Baltimore, MD.......but probably walked out of AAI when they sold all the crap they had in their bunkers from the XM203 and later ACR program......old timers will remember all the AAI flechette rounds and unassembled components.

That AAI was sweet - nicely machined and the markings were very distinct..............but he said the parts from a Colt M203 would not fit......so maybe it was before the MILSPEC was decided on.........

No idea about Airtronic markings.....................I was never satisfied with Airtronic M203........................I like LMT, Colt and Knight..............even had a Bushmaster marked one from 1993.................I am pretty sure LMT makes all of the receivers for Knight and later Bushmaster...................never could confirm they made them for Colts...........................and I ran into a box, literally, of 50 M203 forgings at the West Hartford plant in 1995-6....................those completed receivers assembled onto M16's were later returned along with several hundred M16's that were purchased by a front company and used in a Customs sting down in Texas against some South African group.......................all were destroyed by Colts still new in the box...............but they kept the payment for them.....................those uppers and M203 parts were kept for later guns..................since........COLT never threw anything away.

Posted: 11/4/2013 2:12:14 PM EDT

[#31]

Quote History

Quoted:
William,

Sorry, I do not have any idea where this pic came from. It was sent by a friend in the Army.......I am pretty sure it was an receiver offered for sale some where.

A friend had an unassembled AAI M203 several years ago, that he never assembled. I think it came out of an estate in Baltimore, MD.......but probably walked out of AAI when they sold all the crap they had in their bunkers from the XM203 and later ACR program......old timers will remember all the AAI flechette rounds and unassembled components.

That AAI was sweet - nicely machined and the markings were very distinct..............but he said the parts from a Colt M203 would not fit......so maybe it was before the MILSPEC was decided on.........

No idea about Airtronic markings.....................I was never satisfied with Airtronic M203........................I like LMT, Colt and Knight..............even had a Bushmaster marked one from 1993.................I am pretty sure LMT makes all of the receivers for Knight and later Bushmaster...................never could confirm they made them for Colts...........................and I ran into a box, literally, of 50 M203 forgings at the West Hartford plant in 1995-6....................those completed receivers assembled onto M16's were later returned along with several hundred M16's that were purchased by a front company and used in a Customs sting down in Texas against some South African group.......................all were destroyed by Colts still new in the box...............but they kept the payment for them.....................those uppers and M203 parts were kept for later guns..................since........COLT never threw anything away.

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Why were you not satisfied with the Airtronic M203? An M203 is an M203, right?

Posted: 11/4/2013 9:42:48 PM EDT

[#32]

I was not satisfied with the poor finish machining on the Airtronic.

All M203's basically start out the same, but the last Airtronics I have handled and fired seem to lack a couple of steps on final finishing.

To be fair, the last batch of Colt Defense marked M203 also had crappy finish (surface treatment). The Colt had nice machining and looked professionally assembled, with the exception of someone needs to go back to school to learn how to drive a roll pin correctly............................I had to replace all the spring pins..........................even had to change over a press to do the job on more than one. The surface showed blems that were covered with what looked like an aluminum marker touch up.................but they were still far and away better than the Airtronic M203's.

Just my 2 cents...............................I started out liking what Airtronic was doing...............but I guess they have to make a profit on a fixed price contract too.................They still fired every round and where just as accurate as any M203 I have fired with training rounds and HEDP on the demo range......................so they are what they are.

If I were buying one for myself, I would still pay for a LMT first, then a original Colt.

Posted: 11/9/2013 9:57:08 AM EDT

[#33]

I just use my initials, city and state as the "makers mark" on all of my builds. Not very imaginative I know...but it fills the basic requirement. One of these days I may come up with a cool logo or something.

Posted: 11/12/2013 3:16:52 PM EDT

[#34]

One of these days I will get one of these.

Posted: 11/12/2013 4:06:50 PM EDT

[#35]

Quote History

Quoted:
I just use my initials, city and state as the "makers mark" on all of my builds. Not very imaginative I know...but it fills the basic requirement. One of these days I may come up with a cool logo or something.

View Quote

Actually, it doesn't fill the basic requirement. The requirement is your full name as it appears on the Form 1 or Form 2.

Posted: 11/13/2013 11:58:40 AM EDT

[#36]

Good to know, I will add that to the build.

Posted: 12/14/2013 1:02:03 AM EDT

[#37]

Any news?? I know I'm not the only one following this but I may be the biggest fan

Have you done anymore work to the reciever or are you in limbo with ATF ( my form 4 should be here nay day...the bastards).

William

Ps you can always post more pics for yutes like me

Posted: 12/22/2013 1:54:56 PM EDT

[#38]

Well it has been a while an you all are do for an update:

ATF paperwork is still in processing, I have purchased extra 40mm barrels to convert to 37mm but I am trying to decide on a chamber. I think most folks either use once fired less-lethal cases which are made to fit both 40/37mm or cases from MLR Distributing and Reloadableshells.com both appear to be high quality shells. Reloadable Shells has an I.D. of 1.375 for their 37mm, which is smaller than 37mm but very functional. What case do most of you all use? After the new year, I will order a few cases and see which one I like best. Then I will turn up a prototype barrel for show and tell to see what you all think. Input needed on cases.

Posted: 12/22/2013 10:22:57 PM EDT

[#39]

A lot will depend on if you want to go smokeless or black powder. As far as I know, MLR specializes on black powder, and reloadableshells does mostly smokeless, and of course the cannon casing which I designed. They are also smokeless. Check them all out, as I know both manufacturers and they are both good people with good products. I personally prefer smokeless, as I do a lot of testing and don't like to clean my launchers all that much. (Sure I like to clean them while watching FMJ, but who doesn't?) So, I don't go black powder too much. There are those that prefer black powder, just not me. GROG

Posted: 12/23/2013 8:16:26 AM EDT

[#40]

Good advice Grog, does everyone seem to use the 1.625 OD and 1.375 ID on their cases. That seems to be a number that keeps coming up. My M203 40mm barrels have a 1.635 chamber but it is short for the 40mm rounds. I am in contact with a company that does custom extrusions in aluminum. I am thinking 6160 T6 aluminum in 12 inch cuts with an exterior barrel OD of 1.875 and an ID of 1.375 the extrusion will have the rail built in so all I will have to do is the finish machining for the notches, cuts and chamber. With the smaller ID the walls will be very beefy but I think fluting will help drop weight and also make the barrel look kind of cool too. I could do 9 inch barrels to, with the fluting under the hand guard to cut weight.

Posted: 12/23/2013 9:17:36 PM EDT

[#41]

Quote History

Quoted:
That's the new HK replacement for the M-79. It opens sideways so you can use longer projectiles than the M203 allows. It also mounts on the M-16/M-4 & other NATO rifles, replacing the M203. Think that's the laser rangefinding sight up top, giving much improved 1st hit accuracy.

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That looks a lot different than any 320 I've seen.

Posted: 12/23/2013 9:36:06 PM EDT

[#42]

Sounds like a good plan. I would not flute the barrel close to the casing, for safety sake. Towards the end should not matter much. I know Scot at RS makes at least two different sizes of casing sidewall. A thinner one for larger od payloads, and a thicker one for larger size lift charges. The thinner sidewalls can deform if you use too much lift. I love all the new products on the market these days. For years we had nothing but expended stuff from Brassman Brass. John and Christy there are really good people, but those were used casings and not much variety. If you get a chance to pick up some MK Ballistic casings (they are long and anodized green) buy them. They are super easy to reload, and nice to work with. If you get some, let me know and I will guide you in how to load them. Good luck, Grog

Posted: 1/1/2014 10:15:10 PM EDT

[#43]

In for any updates.

Posted: 1/3/2014 10:50:09 AM EDT

[#44]

In regards to the AAI discussion above, this is an M203 that's in my shop at the moment. I can take better pics if anyone needs...?

Awesome looking work rncbinc!! I would definitely be interested in an 80% receiver!!!

Posted: 2/12/2014 10:20:26 AM EDT

[#45]

Update: Well the company quoting my extrusion fell through. They quoted for press that could hold +/- 0.005 with 100 lb. slugs and were later corrected by the press operator who advised they could not use that particular press for my short run project. The normal press is +/- 10% with 500 lb. slugs. Needless to say that is way too much material and way out of spec. so I am back to the idea of using over sized aluminum tube machined to print on CNC. On that note, my CNC guy got back to me with quotes for the 80% receiver, I too am embarrassed to post the quote because it is higher than to purchase a finished one unless I do a large run of over 100 pieces. So the 80% receiver idea is on permanent hold, unless any one out there has a CNC station and will work up a program from Solidworks. I will post the ATF determination letter from the firearms technology branch when/if it arrives. That's all for now.

Posted: 2/12/2014 12:11:26 PM EDT

[#46]

Quote History

Quoted:
Update: Well the company quoting my extrusion fell through. They quoted for press that could hold +/- 0.005 with 100 lb. slugs and were later corrected by the press operator who advised they could not use that particular press for my short run project. The normal press is +/- 10% with 500 lb. slugs. Needless to say that is way too much material and way out of spec. so I am back to the idea of using over sized aluminum tube machined to print on CNC. On that note, my CNC guy got back to me with quotes for the 80% receiver, I too am embarrassed to post the quote because it is higher than to purchase a finished one unless I do a large run of over 100 pieces. So the 80% receiver idea is on permanent hold, unless any one out there has a CNC station and will work up a program from Solidworks. I will post the ATF determination letter from the firearms technology branch when/if it arrives. That's all for now.

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That's a bummer, but it doesn't surprise me. Being a machinist myself, I have people ask me if I can make them something, and very often my answer is this......go to the hardware store and buy it, it'll be cheaper.
I'm not saying you should have known that would be the answer when you approached your manufacutrer, just that getting machinework done is not an inexpensive endeavor. Kind of makes you wonder how any manufacturing concern got it's start, and why so few succede. I would have been up for an 80% receiver for sure. Niche markets are doubly risky.
All we can say is Thanks for trying.
Stoner25mkiv

Posted: 2/28/2014 1:23:19 PM EDT

[#47]

Very nice work!
Would be interested in something that is CA legal (37mm/80%).

Posted: 2/28/2014 6:10:59 PM EDT

[#48]

Quote History

Quoted:
Update: Well the company quoting my extrusion fell through. They quoted for press that could hold +/- 0.005 with 100 lb. slugs and were later corrected by the press operator who advised they could not use that particular press for my short run project. The normal press is +/- 10% with 500 lb. slugs. Needless to say that is way too much material and way out of spec. so I am back to the idea of using over sized aluminum tube machined to print on CNC. On that note, my CNC guy got back to me with quotes for the 80% receiver, I too am embarrassed to post the quote because it is higher than to purchase a finished one unless I do a large run of over 100 pieces. So the 80% receiver idea is on permanent hold, unless any one out there has a CNC station and will work up a program from Solidworks. I will post the ATF determination letter from the firearms technology branch when/if it arrives. That's all for now.

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Damn...

Posted: 4/6/2014 9:13:09 AM EDT

[#49]

I saw this item on a GB auction and thought it may be a good base for an 80% if anyone was thinking of doing one. (I'm not trying to sell for anyone just noted an item of interest) The only tricky cut I see missing is the breech face. It also looks to be the limit of "legal" non-gun. The barrel is a loss unless one intended to bore and sleeve it to 37mm.