how hard is it to drill a barrel for a fsp? what barrel contour do I need to do this?

[Sidneyious]

ADCO is found on the first page of a Google search for "barrel FSB pinning service". Two other results were War Machine (pretty sure i've heard of them) and Rainier Arms (very well known and trusted).

ADCO re-profiled and re-parked a large frame AR barrel from chamber to gas block for me quite a few years ago, and it turned out great. If they can take material off of a barrel under the handguard, then they can take material off of a barrel in front of the handguard to make it .750".

that wasnt the search keywords I used which I cant remember and I dont let google remember what I search for.

I think militia works might be able to get me a upper or barrel I need without having to get 5 companies to get me 1 item.

[Send it...]

AR15Barrels.com can do it.

[Sidneyious]

AR15Barrels.com can do it.

I will ask them, thanks, MW cant do it because apparently they get theirs from ballistic advantage and would charge almost 3 times the price for one.

[lazar]

AR15Barrels.com can do it.

He did a barrel re-profile for me last month, great work!

[everready73]

Buy everything you need and have John Thomas at Retro Arms Works do it. He is one of the best around and will have it done quickly IME

https://retroarmsworks.com/

[hoopharted]

get a centering bit to start your hole so your drill bit will not walk , you need a drill press , F marked front sight tower if the upper is a flat top , #31 drill bit ,cutting oil and a taper ream for the pins

mount the drill press solid , build a platform flush with the drill press table , take a block of wood drill a hole through it the size of your barrel then cut in half splitting the hole for cradle

if you look at the underside of the tower sight base without the swivel attached there is a hole they drilled to drill the gas port , what i did was tapped that hole and got a set screw from Lowes , with the dimple jig i dimpled the barrel for the setscrew , this ensured the port alignment and the set screw keeps the FSB true through the process

with the upper attached still you need to start aligning the orientation , place the barrel in the blocks you made and support the receiver end so it sits naturally ,clamp it down , take your centering bit and start a hole for on pin through the FSB , the centering bit will only allow you to do a started hole , place a drill bit in the hole so it sticks straight up and start aligning the bit with your drill press bit until the are parallel with on another from all angles, adjust support of receiver as needed to keep the orientation , the receiver will prevent the barrel from rolling and reclamp barrel in place with the bit aligned with the starter hole , you can use a square to double check bit orientation for a butt hole pucker piece of mind

just drill the hole slowly using cutting oil , let the bit do the work only applying enough pressure to allow the bit to cut , do not over heat the bit i would pull out and oil and clear debris , its not a race ,do not cheap out on bits and buy a couple , once the first hole is drilled , i used a nail gun and nailed the bracing i had for the receiver end together so i did not have to redo it all over again , take your taper reamer in a Die handle and start cutting testing it frequently with a taper roll pin , BEFORE it wants to drop all the way in stop reaming and use a roll punch to drive it in the last little bit , error on the side of caution , if it turns out you didnt ream enough then simply back the pin out and cut a very small amount more and repeat until you get it , you want it tight , but you dont want it so tight you deform the pin getting it in , i can see where it would be very easy to go too far , then you would need to find larger pins if they even have them ,so go slow , no rush , take your time , once that pin is in repeat for the second pin , then blue lock tight the set screw or you can do away with it and install the swivel

[NYH1]

I've never done one on a dissy setup. Done them on carbine and rifle setups, in both .625" and .750". All the one's I've done were on barrels that had the dimple on the bottom of the barrel for a gas block. I drill and tap the hole in the bottom of the FSP. Use a set screw to hold it in place on the barrel. Then I slowly drill the holes for the tapper pins from right to left in a drill press. Use a tapper pin reamer on the holes.

I've never had ADCO do any work for me. That said, I've only heard good things about them.

Good luck, NYH1.

[Sidneyious]

One step closer and now to figure out the hard stuff.

Mas Defense upper(cerro forge)
BA barrel, 14.5 middy
Stripped CMMG FSB(im a dolt)

I need a charging handle and a yhm sRx flash hider for a p/w.
I need to figure out optics choice, I am wanting to put my p4xi in a taller mount for my 12.5 but an ADM 1301 mount is too low for a FSB gun.
Still need to figure out optic choice

[grizzman]

The purpose of mock dissipators is to give a long sight radius for use with irons, so optics are irrelevant.

The correct question is, "What rear sight should I use?", and the answer is an A2 detachable carry handle. Another really good answer would be to an LMT cut down rear sight assembly.

[titsonritz]

The purpose of mock dissipators is to give a long sight radius for use with irons, so optics are irrelevant.

The correct question is, "What rear sight should I use?", and the answer is an A2 detachable carry handle. Another really good answer would be to an LMT cut down rear sight assembly.

I assume you mean their L8A?