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Posted: 8/9/2013 8:22:55 AM EDT
Well it is time for another project, some of you may have seen my M249 project from last year posted in the FN section of the armory, I am bored again so I will be spending a lot of time, and money most likely, on a scratch built M203. I will be building the receiver from mil-spec plans with some minor modifications as a title 1 weapon, the sending off the registration as a DD prior to full assembly and testing. It should be an interesting build. I am, as always, open to ideas, suggestions, great stories and of course sources of parts. I will answer the first question I always get in advance. Why build an M203 when I can just file the paperwork, send a check and order one from LMT or one of the other fine Gov't contract suppliers. Because I am about "the build"! I have time, tools and "I think" the know how to pull this off. Posting of progress and pictures to come. Wish me luck.
Link Posted: 8/9/2013 8:48:51 AM EDT
Welcome back. Tag for your machining skills.
Link Posted: 8/9/2013 3:24:01 PM EDT
Sounds likea awesome project. Good luck. Sarco has some parts, and there are other places if you get stuck on a part, let me know. I built my own M79, and it was a to get cool project to get into. I also build ARs from 80% which keeps me busy. My next project is a 45 cal lower that uses grease gun mags. Looking forward to the photos, GROG
Link Posted: 8/9/2013 9:10:34 PM EDT
Thanks, looks like it will be a scavenger hunt for most parts...others I will just make if I can't find them. Too bad I missed the boat on a 0% forging and parts kit a few years back. Oh well, I'm sure it will be a fun ride either way. BTW I love your web site, once my piece is up and running I will look forward to your reloading CD's, they get lots of great reviews.
Link Posted: 8/12/2013 6:49:40 PM EDT
I remember that M249 thread. That was awesome. You should hang out in the WI HTF forum and bring that M249 out to one of our shoots. I'd love to try that out.
Link Posted: 8/16/2013 12:21:58 PM EDT
Update: All the parts are ordered and on the way baring any issues I should have the basic 3D Cad drawings done by end of next week. I am going to farm out the bulk work, like an 80% receiver, to my CNC guy. After looking at how much material there was to remove for a billet receiver I decided that would be the best course to take unless I find a 0% forging out there. I may have him make more than one "paper weight" just in case I screw up on the internals....which has been known to happen from time to time.

Thanks for the invite the WI group, send me a link. I normally attend the Class 3 shoots at my local club near Racine WI(Club Bylaws prevent me from posting it's name on web) I have missed the last one due to a recent back surgery and the replacement cost of ammo is a bit high. I will wait till the "Panic" settles down.
Link Posted: 8/21/2013 3:42:03 PM EDT
[Last Edit: 9/23/2013 8:51:19 PM EDT by rncbinc]
[span style='font-size: 10pt;']Update: 3D went out to one CAD guy today for once over and pricing. Here are a few simple pictures to get an idea of what has been done so far. Most of the bulk work is done. Finishing all the T-slots, pin holes and other cuts should be a fun day in the shop.[



Link Posted: 8/21/2013 10:38:00 PM EDT
An 80% M203 receiver? Depending on price I'd be down for at least two of these, I've always wanted to do this as well but my machining access is very limited. However if the harder cuts were part of the 80% process, the bolt face for example, and the longer cuts so that all that's left could be finished on a mini-mill would be perfect!! Let me know how your progress goes, and good luck!!

Will
Link Posted: 8/22/2013 9:13:39 AM EDT
Tag for badassery.
Link Posted: 8/22/2013 9:31:15 AM EDT
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Originally Posted By eodinert:
Tag for badassery.
View Quote

Me too!
Link Posted: 8/22/2013 8:26:17 PM EDT
I plan on having at least 2 done if the CNC works out to be cost effective. One for my project...and one to send to ATF for inspection and designation as firearm or non-firearm. I have also just picked up a 0% M203 forging to play with in the shop, once my back mends up enough to get out of the house.
Link Posted: 8/22/2013 10:09:28 PM EDT
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By rncbinc:
I plan on having at least 2 done if the CNC works out to be cost effective. One for my project...and one to send to ATF for inspection and designation as firearm or non-firearm. I have also just picked up a 0% M203 forging to play with in the shop, once my back mends up enough to get out of the house.
View Quote


Where did you get the 0%? I've looked all over for one of those with no luck. I hope you get an answer quick from ATF, I'm very interested in how this progresses. Also are you sending in a 80% to ATF?

Will
Link Posted: 8/23/2013 3:59:55 PM EDT
I got the 0% forging off of Gunbroker.com, they come up from time to time. I just grabbed it on a "Buy It Now" for $195 shipped. I know, expensive paper weight until I am done machining it. Yes, one of the finished 80% CNC receivers will be sent to ATF for a determination. There may be some interest depending on the price point...if they can be sold without FFL.
Link Posted: 8/23/2013 9:26:02 PM EDT
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By rncbinc:
I got the 0% forging off of Gunbroker.com, they come up from time to time. I just grabbed it on a "Buy It Now" for $195 shipped. I know, expensive paper weight until I am done machining it. Yes, one of the finished 80% CNC receivers will be sent to ATF for a determination. There may be some interest depending on the price point...if they can be sold without FFL.
View Quote


No way!! i've been looking for ages and haven't come across anything, perhaps its because you snagged it before I saw it Anyway I hope you hear good, no great news from the ATF on the 80%. I'm definitely on board for this, with member braceman doing custom engraving, perhaps I too one day can have a Vietnam era AAI M203!!

Will
Link Posted: 8/23/2013 10:53:30 PM EDT
I am an auction stalker when I am on the hunt for parts. I check all the big ones at least 5 times a day for new items. It had one bid on it but the BIN was only $30 more than the start bid so I jumped on it. I figure the whole deal is going to be about 2K anyway, with the ammo reload parts I bought, so what's another $30.
Link Posted: 8/24/2013 1:55:06 PM EDT
[Last Edit: 9/23/2013 8:52:20 PM EDT by rncbinc]
Hello All,

Maybe you can help me with one of the dimensions on the print for the M203. I have attached a reference picture. The distance listed for the front mount screw holes is "10.25" and it looks hand drawn. That would put it at "0.600" from the front face of the receiver. When drawn to this specification the hole looks like it is in the wrong place? I can find no other reference on the prints. I am guessing the specification is wrong and should be "10.555" not "10.25" Anyone out there have any idea what the mil-spec is?






Link Posted: 8/24/2013 4:04:48 PM EDT
Is there any way you could make 37mm m203 barrels?
Link Posted: 8/24/2013 4:42:21 PM EDT
I could reverse engineer something from a 40mm rifled to a 37mm smooth bore. They would be very expensive to CNC from a solid piece but anything is possible. Maybe start with an aluminum tube T6 6061 close to 37mm ID and 2.5 OD or what ever the rail takes and go from there. I know Mr.40mm used to make them but he is retired and I don't know if he handed the business on to any one.
Link Posted: 8/26/2013 8:11:43 PM EDT
Randy Shivak already makes 37mm M203 barrels. $300 last time I checked. GROG
Link Posted: 8/27/2013 11:21:47 AM EDT
Ok, a helpful brother in arms measured his receivers and the "10.25" is correct. The hole is approximately 0.300 from the face of the receiver, which is where I expected it would be so the print has a bad spec somewhere. If anyone else has the real deal, can you measure the overall length? Accuracy to "0.000" would be best. "11.690 +/- .030" is listed on all the prints I can find, but that does not add up with what we have found so far. Thanks in advance.
Link Posted: 8/29/2013 12:01:40 AM EDT
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By grog18b:
Randy Shivak already makes 37mm M203 barrels. $300 last time I checked. GROG
View Quote


Isn't randy retired ?
Link Posted: 8/29/2013 5:17:48 PM EDT
Yes, Randy is retired.

Well it looks like the scavenger hunt took less time than expected. The forging and all the parts are here as well as reload components for 25 practice rounds, except for the 38 cal. blanks which I am in no hurry on as I can't barrel this puppy until I get the stamp back from ATF.

I am still waiting to hear back on the CNC side of this project and I will update everyone who expressed interest in an 80% receiver.

The forging is very solid, a little corrosion from storage but no major pitting or voids to fill. As I have never done one of these before, I have no idea where to start or index off of. As you can see from the pictures most of the top detail is done and the barrel latch pin location is clear. I also noted the trigger guard pin location is fairly easy to locate off of too. I think by next week I will get into the shop for a few hours and clean up the flashing from the edges from the forging process, then square the receiver face line "N" to the rail line "L" Once all that is done I can square the rear face and front face of the forging to the proper length. The total overall length still concerns me, with the error on the print, but I will match the forging to a real M4 at work before I do the final cuts.

I have to think of the best order to do the cutting and I think I might have it engraved first once I have it cleaned up an true to square. Anyway, I am open for comments and suggestions as always. Enjoy the pictures. Oh I almost forgot. Project budget is $1500, right now I am at $1078.09 including ammo!












Link Posted: 8/30/2013 7:40:58 PM EDT
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Originally Posted By home_alone1:


Isn't randy retired ?
View Quote View All Quotes
View All Quotes
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By home_alone1:
Originally Posted By grog18b:
Randy Shivak already makes 37mm M203 barrels. $300 last time I checked. GROG


Isn't randy retired ?

I am retired too... We ain't dead yet...

The OAL is 11.700 measured from the very rear of the receiver (flat rear portion) to the very front.
It is 10.500 measured from the flat in front of where it goes into your AR nut (flat portion) to the front. GROG
Link Posted: 8/30/2013 10:13:39 PM EDT
Thanks for the measurements Grog, I looks like the numbers are right on the drawing then...just the reference point is drawn incorrectly. It is over 40 year old drawing, LOL it is bound to have a few errors. Normally these are noted in the QA but I don't have a copy. I will keep an eye out for one of Randy's barrels to come up on Gun Broker or I will just mill one myself while I am waiting for my tax stamp. Last one I sent for took 9 months.
Link Posted: 9/1/2013 12:17:21 AM EDT
He, ive been following your m203 build and wanted to let you know if you need any 38 blanks or cases let me kno2. I have thousands of once fired that ive cleaned and sorted out the best of
Link Posted: 9/1/2013 1:52:51 PM EDT
Thanks, I do need 38 blanks with the M9 load. I can always use more cases too. Shoot me an email at RNCBINC@msn.com with some pictures and prices please.
Link Posted: 9/1/2013 7:21:30 PM EDT
One thing to remember about this and other similar projects: the production will become significantly simpler in the coming years. The patents on laser sintering are set to expire in Feb 2014. Much like the patent expiration of 3d plastic printing heralded in an era of significantly cheaper 3d printers and a huge uptick in 3d printing tinkerers, so too will the sintering patent expiration open the door to extremely high resolution 3d printing technologies in the coming years.

This will likely take the better part of a decade for such developments to transpire, but in the mean time being able to model these weapons will be a critical piece of the equation.
Link Posted: 9/18/2013 5:56:38 PM EDT
Well I got a little work done today in the shop. The sides, top and breech face have been squared and I drilled the barrel release latch pin hole. I have a feeling the castings I have are seconds because some of the features are about 0.030 out of spec. No problem, I will adjust as I go. This is a very odd shaped piece, I think a jig would help if I do another one in the future..





Link Posted: 9/19/2013 5:08:41 PM EDT
[Last Edit: 9/19/2013 9:53:40 PM EDT by rncbinc]
I tried an alternate method of squaring the receiver to the trigger housing. The set up appeared to work much better at +/- 0.010 over entire 12 inches of the receiver but again, a milling jig would make production much faster. I noted almost 0.050 of material on both sides of the center line needed to be removed. I think if I use an extra long length 3/4 ball mill for the next one to be able to get the body contour and side milling all with one tool set up. It also appears my concern for accuracy may not be as critical as I first thought. I noted the hole placement in a photo from on online auction on GB. Note how far off the hole and the center of the forging are in the third photo down. Of course, this could be the reason it was de-milled.





Link Posted: 9/20/2013 3:42:39 PM EDT
[Last Edit: 9/21/2013 4:29:25 PM EDT by rncbinc]
Ok, day 3 in the shop...I am still on the mend so I can only work a couple of hours...I finished up the barrel slot and did a dry fit of the barrel. It will not fully seat until the fire control group machining is finished and since I don't have a DD letter yet I will use a dummy barrel for final fitting of that area.



Link Posted: 9/21/2013 4:40:04 PM EDT
Today I went ahead and finished the front and rear dimensions and opened up the barrel latch pin hole. I also cut the radi on the sides of the breach face. Cutting the 1 inch radius on the breach face is going to present a challenge for me as my little mill is limited in reach and ability. I will work on the barrel latch slot, barrel rail slot detail and trigger guard detail next time. She is starting to look better each day.













Link Posted: 9/21/2013 5:36:44 PM EDT
That's beautiful. You'll have the perfect turkey gun.
Link Posted: 9/21/2013 6:50:21 PM EDT
LOL, can you imagine what a 40mm shot round would do to a poor turkey!
Link Posted: 9/22/2013 3:51:32 PM EDT
That is really looking good.

Are you going to get Colt markings engraved when you are done with it?
Link Posted: 9/22/2013 4:05:58 PM EDT
Thanks, today I did the rail end at the breach face and finished up the front mounting area. I did not tap the hole because I don't have a set of mounting screws yet. Once I get my quick connect mount, then I will finish up that detail.









Link Posted: 9/22/2013 8:37:36 PM EDT
Any body know the thread count for the front mounting screws? My plan shows a 3/8 insert but that is 40 years old. I think they are 1/4-20 now but I would like to be sure before I tap the hole.
Link Posted: 9/22/2013 10:15:16 PM EDT
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By rncbinc:
Any body know the thread count for the front mounting screws? My plan shows a 3/8 insert but that is 40 years old. I think they are 1/4-20 now but I would like to be sure before I tap the hole.
View Quote


I don't believe they've changed? We had Colt 203's that were from the 70's that we would outfit with the Knight's QD no problem. I've got a few screws but can't find my tpi, when I do I'll let ya know.

William

P.S. Looking good on the receiver, I can't wait for ATF's ruling on you 80%!!
Link Posted: 9/23/2013 3:40:29 PM EDT
Cool, thanks. Another day, a few for operations done. Today I finished the barrel latch cut out and machined the area for the barrel lock lever. I also took a 3/8 ball end mill and cleaned up the top side of the forging. I didn't have to take off much and it trued up nice. Lots of pictures for those interested in the set up process..





























Link Posted: 9/23/2013 3:42:44 PM EDT
Looking good so far. THis is peaking my interest.
Link Posted: 9/23/2013 8:25:58 PM EDT
Very good job there Bro. Nice machine too. Wish I had a mill that big... I'm stuck with a drill press and a lathe... GROG
Link Posted: 9/23/2013 8:58:26 PM EDT
Thanks, it's just a Smithy Granite 13/24 combo mill-lathe, it gets the job done. I wish it had more table travel, it only has 7" on the cross slide and the mill head is 7" from the end so sometimes I have to do two set ups for one operation. Next shop I have with have a good knee mill for sure. I think by then I will be making guns and stuff for my living, I am about 7 years from retirement and it will be nice to work and have fun at he same time.
Link Posted: 9/23/2013 10:29:24 PM EDT
[Last Edit: 9/23/2013 10:33:20 PM EDT by jrpett]
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By rncbinc:
Thanks, it's just a Smithy Granite 13/24 combo mill-lathe, it gets the job done. I wish it had more table travel, it only has 7" on the cross slide and the mill head is 7" from the end so sometimes I have to do two set ups for one operation. Next shop I have with have a good knee mill for sure. I think by then I will be making guns and stuff for my living, I am about 7 years from retirement and it will be nice to work and have fun at he same time.
View Quote


A little off topic, but is this what you have http://server2.smithy.com/iadmin/sites/default/files/pictures/products/granite1324.jpg

I've always been interested in one of those combo setups.
Link Posted: 9/23/2013 10:51:44 PM EDT
[Last Edit: 9/23/2013 11:13:22 PM EDT by rncbinc]
Yes, but with a 220 volt engine and DRO's for upgrades. If I had to do again I would get two separate machines. The lathe head stock is too small on the bore through for bigger round stock but it's not bad...just a compromise between two machines so you run into limitations on larger projects. To be fair, I never thought I would be milling 12" runs or threading 1.5" tubes back when I first got it either.
Link Posted: 9/26/2013 6:23:03 PM EDT
Ok, lots of work done and lots of photos! Both sides of the receiver and trigger guard contour are complete. I finished the pocket for the barrel extension and the center holes for the breech and barrel mount. If anyone wanted to know the limit of a Smithy...this is it! Some of the tools had 0.020 clearance from the top of the receiver seated as deep as they could go. Anyway, I will send off my ATF paperwork next month, then put this project on the shelf for a year until the stamp arrives.























Link Posted: 9/26/2013 8:12:23 PM EDT
Noooo, don't stop with the pics!! This is the most exciting thread I've read in a long time, any idea what the 80% receiver will still have left to machine.

William
Link Posted: 9/26/2013 9:03:21 PM EDT
Well I was going to take a queue from what ATF has approved before in the AR15 80% and do everything but the fire control group machining. The 80% M203 could be finished with two or three set-ups but a few specialty bits would need to be purchased like extra-long reach end mills but nothing too crazy. The only real issue would be to ability to do the vertical set-up like seen in the last photos.
Link Posted: 9/29/2013 3:49:47 PM EDT
I finished up some of the fire control group area...and found out how NOT to cut the barrel recess. Oh well, I will have to fix that by using a different tooling set up. Here are a few pictures, even the ugly ones.







Link Posted: 9/29/2013 4:29:17 PM EDT
[Last Edit: 9/29/2013 4:30:32 PM EDT by squirrelslayer1]
Link Posted: 9/29/2013 5:08:53 PM EDT
That's badass man!! Yeah you can finish the receiver and just not install a barrel, or just install a 37mm barrel and say it's just a flare launcher. And soon as your Form 1 comes back approved you can install the 40mm barrel :)
Link Posted: 9/29/2013 8:49:15 PM EDT
That is the plan. If anyone has a line on a 37mm barrel feel free to PM me. That is the one part I am having a hard time finding. All of the old sources like MR40mm(Randy Shivak) and Clyde Armory have dried up.
Link Posted: 10/1/2013 2:17:02 PM EDT
[Last Edit: 10/1/2013 2:17:28 PM EDT by rncbinc]
I got a little work done today. I decided to try another type of set-up for holding the receiver vertical. It seems to be much stronger with less vibrations and chatter. I finished most of the fire control group pocket and had a "Doh!" moment when I double checked the depth on one cut. Thankfully it was just too short not too long in depth. I will finish it up tomorrow or the next day. Doing this on a manual machine requires a lot of set ups and operations. You get a real appreciation of what the designers/manufacturers had to do back in the 60's and 70's before CNC.











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