I did some work on my AR-15s a couple days ago.

[Big Frank]

I temporarily put each 16" barrel back on its upper, the stainless steel carbine barrel on the Colt upper it's been on for many years, and 12.7 Brownells barrel back on it's upper, which is a NDS forging. Am I the only one who thinks NoDak Spud sounds like the name of a cheap potato cannon, and not a real gun? "I just bought a NoDak Spud gun on TEMU. I like it better than the old Zamak Spud gun"   These barrels will be swapping uppers very soon, so the Colt lower with a carbine stock will be dedicated to the 12.7 barrel, and eventually the Dead Foot Arms Modified Cycle System (MCS) with GEN 2 Folding Adaptor. I bought the Right Side Folding adaptor so I can sling the rifle close to my chest with the stock folded, and flip it out at will. The 16" carbine barrel, 20" rifle barrel, and Can Cannon uppers will all interchange without an adaptor pin on the DPMS lower with an A2 stock. It's been awhile since I had the 16' barrel and full-length stock together, but that's what I used for years before I bought another lower with an M4 carbine stock.

I put a 1/4" bolt through the lugs on both lowers to line them up and looked at the muzzles. Despite what it looks like in the picture, the 12.7" barrel is shorter than the 16" barrel by less than the thickness of one cent. I figured that out when I held them together and stood them on their muzzles. They aren't exactly the same length, but nearly identical. Good enough for government work, and good enough for me.

I used to have an M2037 Flare Gun that looked like an M203 Grenade Launcher mounted on the 16" barrel. I had a regular M203 mounting bracket for 20" rifles, but didn't have the fiberglass insulator/spacers to go with it. So I wrapped some foil-backed sound deadener I got at work around the barrel. It's like butyl rubber or something gummy and sticky. It's self-adhesive and comes in sheets. I put it on 1 or 2 layers thick, then I folded over the end of the mounting yoke to shorten it about 1/4" and slipped it over the sound deadener. When I took the flare gun off it left behind a sticky mess that I scraped off and painted over with cheap spray paint. I just used Goo Gone and a brass brush to scrub the remainder of the mess off, and sanded off the gloss black paint with old 120 grit sandpaper. When a sheet of sandpaper on my 1/4 sheet sander is worn out and has holes in it, It still has life left for hand sanding stuff like this.

I pegged the handguard cap upside down with a scrap of wood so I wouldn't blow paint into the gas tube hole in the front sight assembly. And I taped the slip ring back out of the way so I could prep the barrel for painting. I put about 5 coats of Rust-Oleum high heat BBQ black enamel on, letting it dry just a minute between coats while I shook the can. In a little while, I'll tape the slip ring to the front sight to keep it out of my way, swab the rear of the barrel with denatured alcohol again, and finish painting the rest of the barrel. Then I might mask off the barrel and paint the slip rig. I scratched it up pretty badly putting the Magpul MOE SL hand guard on the first couple of times. After it dies for 24 hours, it will be ready to go on its new upper. I could blacken the aluminum slip ring but flat black paint will look better than the glossy black finish it has.

BTW, NoDak Spud makes AR-180 type lowers that use AR-15 parts. It has imitation spot welds at the rear that make it look more like an authentic sheet steel lower.

[Big Frank]

I'm done painting my barrel. This looks SO MUCH better than when I sprayed it with 99 cent gloss black paint before. Even if no one ever sees it again, at least I think it looks good. And that's what really counts. And as long as the barrel doesn't get over 1,200 degrees the paint shouldn't burn off. I think the gas tube would fail like it should and save my paint job before that happened.

Rust-Oleum High Heat BBQ Black enamel is also called BBQ & Stove paint. I think that's the new name for it. Home Depot has it under the old name for $6.98. A 12 ounce can will probably do a complete AR-15 from flash-hider to butt-plate with plenty leftover. You could probably paint all the metal on 2 ARs with one can. They also make Automotive High Heat paint that's good up to 2,000 degrees, but I think I'll drop my gun on the ground before it hits 1,200, so this paint should work well enough.

[Big Frank]

I finished painting the slip ring and unwrapped the barrel. The barrel nut sliding around scraped up the paint, and when I rubbed a little oil on, it wiped off a trace of paint. But there are spots where it's completely gone and bare metal is showing.   I guess if you want the paint to stick you have to wash it with soap and water like the directions on the can said, but I don't like washing any gun parts in water unless they're plastic. I could have sprayed it with degreaser if I had any, but I still don't know if the paint would stick after using it.

[Big Frank]

I repainted the barrel again yesterday. I didn't mask anything off, except by hanging onto the front sight assembly with a nitrile glove on my left hand. I didn't touch the barrel again until today, and didn't scratch any of the paint off. I got some overspray on the handguard cap, but kept my Night Fision tritium sight nice and clean. I may take the sight off and paint the rest of the barrel. it was set-screw dings in it from when I had a fake suppressor over it. If I do paint it, I'm only masking the muzzle and flash hider threads.

I have both carbine gas tubes soaking in the bucket of gun cleaner in the kitchen. When I take them out I'll swab them out with some extra long pipe cleaners made just for cleaning gas tubes. They're almost 16 1/2" long instead of 6 1/4", and a little bit thicker too. If you think you have carbon building up in your gas tube you can soak the pipe cleaner in something like the Modern Spartan Systems Carbon Destroyer I have, stick it in and let it work for awhile.

Carbon Destroyer has “shock & awe” power. This proprietary formula was originally designed to replace dangerous high VOC solvents used to remove the heavy baked-on carbon deposits from fighter jet engines and machine gun ports, such as on the 30mm GAU-8 Avenger and its cannons. It quickly and aggressively destroys the carbon, including the deeply embedded carbon hiding in the microscopic gaps of the substrate. Shooters tell us all the time that “it is BY FAR the BEST FIREARM CLEANER ON THE MARKET.” (Watch the video to see carbon melt away).

I have a bottle of their Accuracy Oil too, but haven't used either one of them yet. They make Carbon Destroyer XX, the double concentrated BIG BROTHER to the already EXTREMELY tough and powerful Carbon Destroyer. A Suppressor Shield Pre-Treat Kit, an engine oil additive, etc., too.

https://modernspartansystems.com/product/carbon-destroyer/



https://www.youtube.com/watch?v=nob84zGst10


https://www.youtube.com/watch?v=M6GVqqHFNg0


https://www.youtube.com/watch?v=64oQSILZJrU

[Big Frank]

One upper done, and two to go, plus some work to do on both lowers. I don't have any fancy black nitrided gas tubes, but I have black spray paint. I painted both of them for the 16" barrels, except for the ends, and will paint the one for the 20"barrel when I paint the barrel and DTA Mil-Brake with its jam nut. That's what I bought the spray paint for in the first place, and might need to buy another can to finish it. The paint on the gas tube on this one ends dead even with the rear of the barrel extension. I didn't paint all the way to the end because I didn't want paint rubbing off inside the bolt carrier key. No one can see this gas tube, but the other two will be visible through the handguards and I painted both of the carbine gas tubes the same time. 

I torqued the barrel nut to 35 ft-lbs 3 times. With a new barrel and new upper you have to because the parkerizing on the nut wears down, and threads on the upper stretch so much, but I always do it, even when I put an old barrel on an old upper. I have an alignment gauge that goes in the bolt carrier key, but the first 8" of an extra gas tube, or a #15 twist drill (.180") would also work. You just stick it as far in the carrier key as it will go, and see if it clears the teeth on the barrel nut. If not, you have to crank it down until you get to the next space. I barely had to go any farther to get it lined up this time. I changed a lot of barrels in the army, and sometimes I had to crank them down to around 80 ft-lbs to line up right. Since I only had aluminum jaws around the barrel then, I had to take something like a scrap barrel and shove it through the front sight assembly to keep the barrel from spinning in the vise when I changed barrels. My OCT 1984 USMC TM says to use a pry bar through the front sight, and use the buddy system to hold the pry bar. The bench top was my buddy system.   Once the "pry bar" hits that, it's not going any farther.

When I first put this together, I cut a piece off the top of the left handguard, to clear the cheap flashlight mount that fits the MI Pic rail so well since I modified it. Then I took it off and mounted the Olight Baldr Pro 1,350 lumen light with green laser in its place. And secured the APG Defense Bayonet Lug Extender - Adapter with red Permatex threadlocker. It (barely) makes up the difference in length between a 16" barrel and 14.5" gas system. It works great but should be 1/16" longer IMO. The bayonet ring would fit the flash hider better if there wasn't a washer in place. This is the first crush washer I ever used, BTW. I turned it finger tight, plus 1/4 turn, then had to crank it WAY around to index it. I don't think it could go much farther. I think they max out at 1 1/4 turns past finger tight and I had it about 1 turn past. I have no idea what the torque value was, but it was higher than the barrel nut! I think I went a few degrees too far but can't back it up. Peel washers are better in some ways, especially the fact you can reuse them several times.

I have the Magpul MOE SL hand guard and AFG angled fore grip, with a MI Tactical Bottle Opener, ​M-LOK. One strip of M-LOK Rail Covers, Type 1, cut in half covers both sides of the hand guard 3 + 3 slots, and a small piece covers the single hole between the AFG and bottle opener. When I took my Night Fision tritium front sight off prior to painting the barrel, the plunger and spring parted my hair as they got away from me. They use a plunger that's slightly different from stock because their sight is 2 layers of metal thick, so I need to get the parts from them if I can. I need to swap the large aperture peep sight over to this upper, too. After I got a little molybdenum disulfide grease on the barrel from installing it, I wiped it down and liked the sheen it gave the paint. So when I put the flash hider on, I greased the threads on the barrel and rubbed the tiny bit of grease that squeezed out on the front of the barrel, plus I dipped my finger in the grease to get a bit more on it. I don't know if it penetrates and sticks to paint the same way it does pores in metal, but that's as close to plating as the stainless steel barrel will ever get. The Mil-Spec grease is pretty good protection.

[Sponsor]

[Big Frank]

Here's the other gas tube I painted. I took pics from both sides. I used regular masking tape to mask off the end with the gas port, and the end that goes in the bolt carrier key. Everything that will show through the holes in the XM177E2 submachine gun / M4 carbine handguard is solid black. It's more tacticool and stealthier looking this way.   The paint seems to be sticking better than it did on the barrel. I couldn't even pick it up and move it across my desk without scratching paint off it.

[Big Frank]

It took me HOURS to clean all the metal shavings and black crap out of the 12.7 inch". It had a big brass colored bump sticking way out where it was pinned and welded. It was too hard to file, so I know it wasn't brass, but I don't know what it was. It felt like a hard stainless steel but the surface was yellow.   I used my angle grinder to very carefully grind it down, but at 12,500 rpm, mistakes happen fast. I just bought a new roll of 120 grit sanding cloth, mainly made for cleaning copper pipes before sweating them, and had about 11" left of the last roll. I tore that in half, and folded it in thirds lengthwise so I could sand around the divots where I ground a bit too deep. When the middle of the sanding cloth was worn out. I wrapped it around a flat file so I could use the ends of the cloth. The 2 little pieces were enough to sand it down before I painted the barrel. See the center of the groove where the arrow is in the 3rd pic. It looks really good to me. I know I should have let the paint dry overnight at least, but went ahead and put the upper together not too long after I painted the barrel. A little paint rubbed off, but it would be easy to touch up if I didn't run out of paint.

I took the Magpul extended mag release off the DPMS lower and put it on the Colt. I like the Armaspec B1 Extended Magazine Release - Aluminum a lot better, and put it on the DPMS instead. After I had both extended mag releases Loctited on, I noticed that when the button on the Armaspec B1 is fully depressed, the mag release doesn't stick out half as far as the one with the Magpul button. I think I need to take the top off the button and unscrew the latch at least one turn so it's easier to drop the mags. The bottom part of the button may be thicker than stock, and the latch screwed in farther. It's always something. So, the Colt upper and lower are finally reunited, but with the CAR-15 barrel now. It's the same length as the other barrel, but looks shorter because the other barrel has the extra length of a flash hider in addition to the 16" barrel. The M4 carbine stock has a longer maximum L.O.P. than the A2 rifle stock, especially with the rubber butt pad adding another 1/2" or so. I didn't measure it but I think it's a maximum 15" with the pad.

[Big Frank]

SAY HELLO TO MY LITTLE FRIEND!!! It will be even littler when I put the folding stock adaptor on it. In the 2 pics of both carbines, you can see the Samson Swivel Stud QD Adapter attached where the front slip loop used to be on the 12.7" barrel. After I took the sling swivel off, I squeezed the sides of its attachment point together in the vise, and hammered them down until they touched. I ended up grinding and filing some metal off the bottom, drilling out the holes for the sling swivel rivet and the unthreaded hole in the QD adaptor, and filing the inside of the QD adapter to get it to fit over the 2 swivel mount projections, instead of the parts being halfway inside each other. It was a lot of work, and although I think it looks better with the Swivel Stud QD Adapter over both sides of the swivel mount, it was so much work that if I had a choice to do it all over again, I wouldn't! I'd just have them overlap each other instead, and not risk breaking anything.

I think I'll get the Samson Quick Flip Stock and once I get the folder installed, put that on too. The hinge adds 3 1/2" to the length, so the buffer tube will be long enough without the additional length of the M4 stock. And I can buy another carbine buffer tube, and put the M4 stock on the DPMS rifle with the 20" barrel, 16" barrel, and Can Cannon uppers. That way the 12.7" barrel stays on the Colt permanently, and I don't have to screw around with adaptor pins for any of the uppers. And this year, I'll FINALLY be able to fire "my little friend" as much as I want to with the stock folded. The quad-stack Schmeisser 60-round mag should work well since it only sticks out about 1/8" past the edge of the magwell.

[Big Frank]

I don't think it was until a couple nights ago when these 2 ARs were lying side by side, that I finally noticed how the newer lower is reinforced in the area I highlighted. I think that was one of the improvements made when the M16A2 came out. It may have even been on some M16A1s but it wasn't on all of them, so I really don't know when the change came about. It's approximately the area I marked on the forging where it's flat.

[Big Frank]

I got back from the store 20 minutes ago and when I took my coat off I saw the front sight detent spring I lost April 3rd just lying on the carpet by my feet. I found the Night Fision detent with its slightly longer nub 2 feet away last week. I couldn't find then when I was no my knees with a high-powered flashlight, sweeping the area with a 4.5" x 1" x 1.25" industrial magnet, but after I gave up and decided to buy more parts, they just showed up. I don't know if I have a house  fairy or magic mouse or something else helping out, but I would never pray for anything as trivial as that, so I don't think it's divine intervention. But you never know. God works in mysterious ways. Whatever brought my parts to me, I appreciate. It just seems to defy logic, but maybe something got kicked around and they flew out of their respective hiding places. Now I just have to find the front sight. I think it's in the pile of receipts and stuff next to me on the desk. If I find it, I need to take the large aperture rear sight off the Colt upper w/Brownells barrel and put it on the Brownells upper w/16" barrel.