Modern Sporter builds Q&A

[scourge18a]

My barrel has rifle length gas tube

Should be fine with rifle length gas.
check your gas block alignment and possibly the barrel gas port hole size.
I assume you are using a standard weight buffer? Not a heavy buffer?

[Dietz]

It’s only held in by a screw, what future problems do you see?
I think the hook is to thick ,as well

No, it's an interference fit. The rear pin was machined a few tenth (.0002 or .0003 IIRC) larger than the holes and then pressed in.

[Brianma65]

No, it's an interference fit. The rear pin was machined a few thou (.0002 or .0003 IIRC) larger than the holes and then pressed in.

Pressed in?
Once you remove the screw the pin pops out easily

[Dietz]

Simply repeating what they said.

[b_w.]

Make sure it's well lubed especially at initial break in. With tight tolerances it might take a bit to loosen up.

[CobraGT]

Directed at ATRS or anyone else who has done a lot of work on uppers....

I'm using my Colt Canada SA20 as a donor for my Modern Sporter. I punched the roll pin out of the FSB on my SA20 to remove the gas tube. Problem: gas tube will NOT budge. Any thoughts/suggestions beyond just soaking the area in WD40 and seeing if it loosens up? I could remove the FSB, but I really want to avoid doing that if at all possible.

The SA20 upper had maybe a couple hundred rounds through it, so I wouldn't expect that there would be enough carbon buildup in there to seize it solidly. Does Colt Canada do something weird to lock the gas tube into the FSB that I'm not aware of??

Maybe I should just post this in 'gunsmithing'.

[koesdibyo]

Directed at ATRS or anyone else who has done a lot of work on uppers....

I'm using my Colt Canada SA20 as a donor for my Modern Sporter. I punched the roll pin out of the FSB on my SA20 to remove the gas tube. Problem: gas tube will NOT budge. Any thoughts/suggestions beyond just soaking the area in WD40 and seeing if it loosens up? I could remove the FSB, but I really want to avoid doing that if at all possible.

The SA20 upper had maybe a couple hundred rounds through it, so I wouldn't expect that there would be enough carbon buildup in there to seize it solidly. Does Colt Canada do something weird to lock the gas tube into the FSB that I'm not aware of??

Maybe I should just post this in 'gunsmithing'.

A little bit of heat if you can - torch it lightly and then try to wiggle it free. It could also be tight and binding in the barrel nut too, so that could be added pain to get it out.

Just confirming, do you have the BCG out of the carrier while trying to pull it free of the FSB?

Tubes are easily pinched, so if you do have to go vice grip method, wrap the tube well, and only clamp as much as necessary to get grip to wiggle it

[CobraGT]

A little bit of heat if you can - torch it lightly and then try to wiggle it free. It could also be tight and binding in the barrel nut too, so that could be added pain to get it out.

Just confirming, do you have the BCG out of the carrier while trying to pull it free of the FSB?

Tubes are easily pinched, so if you do have to go vice grip method, wrap the tube well, and only clamp as much as necessary to get grip to wiggle it

Ok, thanks for the suggestion, I'll take a closer look at the barrel nut, and find my torch. And yes, I have the BCG out :D

[kagia]

Thinking about ordering a receiver set tomorrow. Can't decide whether I want the slick side or forward assist though. Thoughts?

[griffin86]

Thinking about ordering a receiver set tomorrow. Can't decide whether I want the slick side or forward assist though. Thoughts?

I would say forward assist. I believe they will be ready next.