M203 Build - Page 3

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[ARCHIVED THREAD] - M203 Build (Page 3 of 4)

Posted: 8/21/2014 5:23:25 PM EDT

[#1]

Well it has been while since my last update and I have good news. ATF approved my DD paperwork so I can finish the machining and barrel on this puppy up. Tooling to finish the project will be inbound by the end of the month or beginning of next. The counter bore at the breech face is critical so I will do it in steps with pilot counterbore cutters. I got all of my parts for practice rounds but I do not know what kind of "glue" to use on each part. I have seen pictures that show a black sealant but maybe one of you guys or gals might know the proper stuff to use. I will post up pictures when I start cutting again and a video of the test fire too.

Posted: 8/21/2014 5:32:57 PM EDT

[#2]

Drop me an e-mail Bro with any tech questions you have about the lancher or ammo, and I will help you out. GROG

Posted: 8/28/2014 7:00:44 PM EDT

[#3]

Thanks for the email and info Grog. I will post up some pics of the loading process next week. I forgot to ask, where do you get your orange chalk? Is it anything special or would regular chalk do just as good? I don't want to mark up my woods range with a bunch of orange marks.

Posted: 8/30/2014 4:31:14 AM EDT

[#4]

You are so frickin close, why not make a copy of my Doorknocker Rem 870 Shotgun Mounts? Make a few alterations to the 3D, have a 1 3/16" dia ball endmill altered a bit for the flat on top of the Rem 870 receiver contour, mark locations for the bolt holes/countersunk for sockethead cap screws and you have it. These you could mill from 6061 1.5" square bar, 13 mounts per 12ft bar. You could probably sell a bunch, going by the number of times over the year I have been asked about them.

Posted: 8/30/2014 8:32:05 AM EDT

[#5]

Cool idea, I would have to see a print to see if my CNC guy would do it, but I think someone else sells them and my have a patent.

Posted: 8/30/2014 7:06:12 PM EDT

[#6]

I actually reload using either blue or red chalk from Lowes or Home Depot, that way I know they are my reloads. Plus, when the field is covered with snow, I can paint American flags... :)

Enjoy your build, and keep me in mind for an 80%, after you take care of all the other folks first. I already have my 203s, but it would be cool to finish one myself, with only my name and stuff on it. GROG

Posted: 9/1/2014 9:38:13 AM EDT

[#7]

No problem, I have a line out to a guy that is in the process of getting his Mfg. credentials, he said he may be able to take on the project after the first one gets ATF determination letter. I have to finish the projects I have on the board now before I start anything else big. I just got behind the ball due to cost issues and lack of time. I should be caught up by next month...hopefully.

Posted: 9/7/2014 5:46:39 PM EDT

[#8]

Well all of the machine work is done and I took it out to the range to test fire. I didn't have any chalk in the rounds so as not to stain up my woods too much. All in all I think it turned out well. Here are some pics of the process and a link to a short video.

[span style='font-size: 10pt;']Video Link:
https://www.youtube.com/watch?v=U4-h6ZpT2sU

Posted: 9/7/2014 6:45:45 PM EDT

[#9]

Great job! .....and now I really want one.

Posted: 9/8/2014 4:08:32 PM EDT

[#10]

Posted: 9/8/2014 7:01:56 PM EDT

[#11]

Outstanding!

Posted: 9/10/2014 2:14:13 PM EDT

[#12]

AWESOME!!!!

Posted: 9/11/2014 2:47:25 PM EDT

[#13]

Really nice job Bro, on the projos too! I'd be in for an 80% in both the 203 and 870 versions.... Glad I could help you, and it is nice to see that there are very talented people here. GROG

Posted: 9/11/2014 6:53:51 PM EDT

[#14]

I'd be in for an 870 version if you decide to make it

Posted: 9/11/2014 11:59:02 PM EDT

[#15]

You have mad skills.

Don't neglect the Mossberg owners if you make a shotgun mount... they're a better choice for shotgun mounting anyway.

Posted: 9/14/2014 2:55:42 PM EDT

[#16]

I have one more receiver blank to play with, anyone got the receiver specs for the masterkey mount?

Posted: 10/21/2014 7:37:42 PM EDT

[#17]

Me too

Quote History

Quoted:

Same here

View Quote View All Quotes

View All Quotes

Quote History

Quoted:

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

Same here

Posted: 10/22/2014 12:02:17 AM EDT

[#18]

I really want an 80% especially because they are not regulated up here (non firearm)

Posted: 10/22/2014 12:57:13 AM EDT

[#19]

Huh. I wonder if that Ghost Gunner desktop lower CNC machine could produce a shortened M203 receiver? Could you even make it work with a few inches less rail?

Posted: 10/23/2014 10:54:15 AM EDT

[#20]

Well here she is, all painted and respectable looking. I worked a little on my AT-4 9 mm tracer trainer but hit a snag in the design of the bolt face. The damn primers keep getting pushed out about 0.010 so I think the head space is off. I am taking a break from that to finish up the prints for the 80% M203 and the "Masterkey" type mount for both the Remington 870 and Mossberg 500 series. I was thinking that since you can get a Picatiny/Weaver rail mount for both guns, it might be cost effective to just machine a female rail slot so my version would work for both or any top rail mounted gun. I don't know if the scope mount and provided screws and holes can take the recoil over time. I am going to do some vice mounted tests to see if the rail can take that kind of pounding. I have both guns in the armory so it will just be a matter of fining the right scope mounts. All the pictures I have of the Masterkey show at lest 4 cap screws and a good amount of contact with the receiver. It's interesting that you mention that desktop CNC unit. My buddy wanted to go in on a co-op purchase but I already have a mill so I passed on the offer. I don't know if is could be enlarged on the x-axis to accommodate longer items like an M203 receiver. I also have no idea how it is programmed but it might be a good tool for someone without access to a shop. If anyone has or sees another M203 forging for sale shoot me an email. Now that I have all the expensive tooling for the project and know the setups I think my next one will be better. Thanks again for all the support and positive feed back.

Posted: 10/26/2014 5:18:13 AM EDT

[#21]

Quote History

Quoted:
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. That's all for now.

View Quote

I am getting tired so I will read the rest of the thread later. I have a coworker that does this kind of stuff for me.

If you know how to operate a Jet mill, we have a few that sit idle, especially on weekends. I could probably get you some time on one, as I plan to go in on weekends and start Iearning how to use them myself. Obviously we can't burn up a lot of tooling for free but small jobs would be a non issue or pay for tooling used.

In terms of materials, I can get things at our cost or buy drops after a job. Small stuff I just grab from our scraps bins.

I am up north, north of Hwy 8, IM me and let me know what you might need help with and I will see what I can do.

Posted: 10/26/2014 11:22:05 PM EDT

[#22]

Quote History

Quoted: Well here she is, all painted and respectable looking. I worked a little on my AT-4 9 mm tracer trainer but hit a snag in the design of the bolt face. The damn primers keep getting pushed out about 0.010 so I think the head space is off. I am taking a break from that to finish up the prints for the 80% M203 and the "Masterkey" type mount for both the Remington 870 and Mossberg 500 series. I was thinking that since you can get a Picatiny/Weaver rail mount for both guns, it might be cost effective to just machine a female rail slot so my version would work for both or any top rail mounted gun. I don't know if the scope mount and provided screws and holes can take the recoil over time. I am going to do some vice mounted tests to see if the rail can take that kind of pounding. I have both guns in the armory so it will just be a matter of fining the right scope mounts. All the pictures I have of the Masterkey show at lest 4 cap screws and a good amount of contact with the receiver. It's interesting that you mention that desktop CNC unit. My buddy wanted to go in on a co-op purchase but I already have a mill so I passed on the offer. I don't know if is could be enlarged on the x-axis to accommodate longer items like an M203 receiver. I also have no idea how it is programmed but it might be a good tool for someone without access to a shop. If anyone has or sees another M203 forging for sale shoot me an email. Now that I have all the expensive tooling for the project and know the setups I think my next one will be better. Thanks again for all the support and positive feed back.

http://i861.photobucket.com/albums/ab177/rncbinc/20141022_121637_zpsb3fa7b46.jpg

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She's beautiful. Post groups!

Posted: 10/26/2014 11:33:50 PM EDT

[#23]

Awesome work; Man, I have an M4A1 where that M203 would look perfect.

Posted: 10/26/2014 11:56:07 PM EDT

[#24]

I need an 870 mount.

Posted: 11/2/2014 5:26:09 PM EDT

[#25]

So I was working a little more on the Masterkey type mount. This is just a rough draft. I still have to decide if they are cost effective to have them CNC to this point then finish to what ever shotgun you need at my shop. I don't know if there would be enough interest. IM me if anyone has questions or wants in on a short run.

Posted: 11/5/2014 4:30:08 PM EDT

[#26]

Maybe a picatiny/weaver slot for a universal mount like this one:

Posted: 11/5/2014 8:26:55 PM EDT

[#27]

Quote History

Quoted:
Maybe a picatiny/weaver slot for a universal mount like this one:
http://i861.photobucket.com/albums/ab177/rncbinc/shotgunscpemount_zps2ba12571.jpg

View Quote

That would look pretty good and would probably work well.

Posted: 11/8/2014 11:47:22 AM EDT

[#28]

It looks like the Mossberg 500 has the safety selector on the top to the receiver so I don't know it that design blends well with the masterkey. I will investigate more.

Edit: I had a chance to look at the Mossberg 500 and I think they have a solid weaver mount that will work too. Getting to the safety will be a little bit awkward but still doable. I know the saddle mount will take the recoil for sure, but I would like to test it in the range. Now I just need to decide on a mount brand. I am thinking UTG with right side rail for the tacti-cool look. Thoughts? Imput? Once I decide on a uniform mount, cost is low and works for most guns, then I can program and send to CNC for milling. BTW I am not trying to do any selling here, but it looks like I can get these(masterkey mount) done for around $250-$300 each if I get at least 10 units for the first short run. PM/IM if you want on the list.

Posted: 11/11/2014 3:18:13 PM EDT

[#29]

By universal mount are you thinking a small bracket front and back of the picatinny rail similar to the Mass M26? That seems like the best way to go back and forth for use as underbarrel or stand alone shotgun

Posted: 11/12/2014 10:11:35 AM EDT

[#30]

No, I was thinking more of using a female picatiny rail slot in a flat bottom M203 mount with enough clearance to mount any short weapon/shotgun with a scope mount that can take the recoil of the weapon it is attached to. Kind of Masterkey'ish but not dedicated to just one weapon. The bonus you would get would be that the weapon should be tighter up the the host gun than a standard rail to rail design. Over/Under's have always be a compromise but I think this design would be strong, light and not too awkward to field. I will post up some more detailed pictures once I have finished blueprinting the 870 and 500.

Posted: 11/12/2014 10:44:57 AM EDT

[#31]

Sounds great

Posted: 12/2/2014 5:48:08 AM EDT

[#32]

Fuck the master key! I want an 80% M203 ASAP!!!

Ok... To be fair I want both... But 203 first

Posted: 12/2/2014 9:29:40 AM EDT

[#33]

A fellow AR15.com member offered to work on the 80% M203 idea and see if can be done for a reasonable price point. The cost goes down when people donate their time and expertise for R&D. I have no idea when it may roll out but I am hopeful it will be soon. The master key turned out to be much less complex from a machining stand point and I can have 10 of them made if there is real interest. I know people say "I want one" but when it comes time to pay, a lot of people back out and I am left holding the bag. The 80% M203 is a different animal all together. I would not try to sell anything like that until I have an ATF determination letter in hand. That requires a submission of a finished sample to ATF tech branch and could take months. We just have to wait and see what happens.

Posted: 12/3/2014 1:32:09 PM EDT

[#34]

Quote History

Quoted:
A fellow AR15.com member offered to work on the 80% M203 idea and see if can be done for a reasonable price point. The cost goes down when people donate their time and expertise for R&D. I have no idea when it may roll out but I am hopeful it will be soon. The master key turned out to be much less complex from a machining stand point and I can have 10 of them made if there is real interest. I know people say "I want one" but when it comes time to pay, a lot of people back out and I am left holding the bag. The 80% M203 is a different animal all together. I would not try to sell anything like that until I have an ATF determination letter in hand. That requires a submission of a finished sample to ATF tech branch and could take months. We just have to wait and see what happens.

View Quote

Quite understandable when it comes to crowd-sourcing a project. Any idea what ball park the master key mount would be?

Posted: 12/4/2014 4:38:17 PM EDT

[#35]

If I get 10 "in the white" and finish the picatiny rail slot myself they should be under $300 each. The end user would have to supply mounting hardware, surplus parts are everywhere these days, and finish to suit. I use Emachineshop for a lot of my projects and sometimes their software is off. On complex item it can be off on the price or ability of the machines but you don't know till the order is up after waiting in line for 20 days or so and you get an email about a price change. Kinda sucks but comes with the territory.

Posted: 12/22/2014 5:32:18 PM EDT

[#36]

Hello all! Happy Holidays and hope you are well and safe with your loved ones. If you are in harms way, stay small and come home soon. Santa Claus came a little early this year and a new 870 turned up in my gun safe. The the universal weaver mount also arrived. I finished up the paper work to register as a SBS and Uncle Sam got his fun tax, god only knows how long it will take, I here 6-9 months for paper applications on a trust. I have a spare M203 receiver blank so before I put any $ into a large group funded project I figured it would only be reasonable to make a functional prototype for field testing. Below are some reference pictures of the shotgun, mount and cut lines labeled A,B and C. Also I saw a cool muzzle brake I thought would work good and was not metric thread. I can cut metric but it requires a change of gears on my lathe and that is a real pain. I originally thought cut at A and C, but then thought if I cut at B and C I will get 2+1 3" shell and the muzzle brake would be about even with a 16" M4 barrel and look better. Obviously no chopping the barrel until ATF says ok, so I will concentrate on the M203 blank. More pics and updates to follow. Input good, bad or otherwise is always welcome.

Posted: 12/23/2014 2:53:28 AM EDT

[#37]

If you cut @ B, you're going to have to reweld the magazine tube boss into the B position on the bbl. Thus, I suggest you cut @ A & C once the $200 proof of your patriotism comes in.

Posted: 2/13/2015 10:17:20 AM EDT

[#38]

Good news, ATF sent back approval for my SBS so I can really start working on the project now. First day back in the shop will be Monday, I will post pics as I go.

Posted: 2/27/2015 10:45:03 AM EDT

[#39]

Well I finally got into the shop and started the work on the mount. It is a bit ugly as it was a re purposed M203 receiver forging I screwed up on during my M203 build. I am waiting on tooling to finish the weaver slot but I may get to finish the machining of the mount before it gets here. I will post up pics as soon as I get something worth looking at. Good news on the 80% M203 receive project. Through contacts here I have located a manufacturer who may be willing to do the first run. We still need a determination letter from ATF before proceeding and will be looking for more interest as the manufacturer is looking for a run of no less than 500 units. I don't know if there are enough buyers to justify that kind of production run. I did put a bug in their ear about a short run of 37mm M203 barrels to match their current line of 37mm shells. I am currently booked up with projects now and will not have time for the prototype till spring.

Posted: 3/2/2015 5:48:47 PM EDT

[#40]

So I was able to get into the shop for a few hours and worked on the project a bit more. I finished the forward mount relief and threading and then completed the weaver rail slot. My cutter was a bit tall so I modified it to fit the plan. I think a relief cut above the slot will help on the production model. Anyway, here are some pics. I will finish up the mount next time I am in the shop, then start working on modifying the 870. I have decided to go shorty with 8.5 barrel. I just like the look of the shorter gun with maybe a side folding forward grip. i am still tossing the idea around in my head on how to re-thread the magazine tube w/o taking it off the receiver. I may just replace the threaded cap with a plug with side screws for disassemble.

Posted: 3/3/2015 1:34:35 PM EDT

[#41]

That looks great!

Posted: 3/3/2015 8:46:18 PM EDT

[#42]

More work today. The blue tape on the barrel marks the 8.5" I will thread the barrel for the muzzle brake/cigar stand and that will add another 1" total length. I am going to make a custom plug for the receiver to keep out the dirt and crud. I am still thinking about the barrel brace and grip. The stock bolt was soldered on so I may use that hole to attach the receiver plug. Anyway, more pics:

Posted: 3/3/2015 10:23:20 PM EDT

[#43]

Awesome work

Posted: 3/3/2015 11:59:27 PM EDT

[#44]

Will those two transverse screws be able to handle the recoil, or will you be fastening it by additional means?

Posted: 3/4/2015 10:43:52 AM EDT

[#45]

I think most of the recoil will be transferred to the receiver via the bolt. The standard magazine tube nut does not bear any load during recoil so I think they will work, if not then I will have to come up with something else...perhaps re-threading the magazine tube.

Posted: 3/4/2015 12:26:41 PM EDT

[#46]

Where are you finding these cast aluminum items?

Really interested in making my own M203.

Posted: 3/5/2015 2:26:01 AM EDT

[#47]

Just some ideas. Could you machine a steel piece that would go between the top of the receiver and mount and continue back to angle downward to match the open rear of the reciever? You could do away with the optic mount and the receiver would be supported by the screws in the top and the rear of the plate together. The interface between the steel and the mount could have notches or whatever to make it shear proof.
Another idea I had was to just machine a new receiver out of steel and make it pretty much squarish shaped and basic since you don't really need the ergo's. You could really trick it out like the Balios light AR receivers to save weight make it look unique/high tec.
Damn I need some machines and skillz.

Posted: 3/5/2015 11:38:54 PM EDT

[#48]

Every once in a while they(M203 receiver forging) pop up on ebay, gunbroker, gun auction, ect. You just have to do a daily search for them and buy them up when you can.

Any mount with a top rail would work, that is the nice thing about the slot design, you are only limited by your imagination..oh and ATF NFA rules and regulations. The optic mount is just the cheapest way to go as it is plug and play.

Posted: 3/8/2015 7:59:48 PM EDT

[#49]

I have decided on this as the final design, to date. It will use 3-5 set screws with a pin protrusion slightly smaller than the slot in the picatinny rail. It will require me to drill the corresponding holes in the saddle mount. I think it will be strong enough to handle the recoil but only testing will tell. I should be able to get into the shop this week or next to work on the SBS part of the project.

Posted: 3/26/2015 12:10:00 PM EDT

[#50]

This is the greatest thread on the internet. Man I wish I had machine skills!

[ARCHIVED THREAD] - M203 Build (Page 3 of 4)

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