I know in a 1911 trigger job, smoothing up the sear and hammer hooks and trigger channel, and reducing the mainspring weight, play a big part in a smooth, light trigger but... Does honing the mainspring housing make enough difference to warrant spending $17.50 for a hone, and $10 for honing oil, to do 2 pistols? If you have done it, has it lowered the pull weight, or made your trigger noticably smoother? Thanks-

Is this for a race gun or a carry gun or is there an existing problem you are trying to fix?

This is a target gun, for informal shooting. I'm trying to achieve the lightest, smoothest trigger, using methods within my abilities.

I presume you are talking about smoothing the tunnel containing the mainspring. If so, I wouldn't buy dedicated tooling for that to work on two guns.

Cut a slit in a small diameter dowel, or a piece of drill rod. Insert some emery paper in the slit, oil it with any decent lube, and spin it inside the housing using an electric drill. It will smooth out rough spots, but you would have to work very hard at it to remove much stock. Same method used to open cast bullets sizing dies a couple of thousandths.

Charley, what grit paper would you use?

Polishing the mainspring tunnel won't have any effect on the trigger action. If you can feel gritty movement of the spring, a good way to smooth out the toolmarks inside is to cut a cold-rolled steel rod on a lathe to just under the channel's diameter.
This will require a trial-and-error fit...returning it to the lathe for fine-tuning with a mill file. Once it's diameter will allow a slip-fit...coat it with a fine garnet lap...chuck it up in a drill, and spin it while moving the rod in and out fairly quickly. Work to make a cross-hatch pattern. One in/out cycle per second is a good rate. Don't try to remove metal so much as knock down the high spots and burnish. It won't take long. Rinse thoroughly with a spray cleaner. Carb cleaner will work. Blow dry, oil, and assemble.

If there's no actual "crunchiness" or binding when you move the spring through its cycle, there's really no advantage in it.

Charley, what grit paper would you use?

400, 600 and higher!

You could apply a hobby oil, or any existing knife sharpening oil you have on hand to help out. Go slow, take your time. Use a brake kleen or similar to flush out any particulate as you go, and when you change grit. DO NOT applt too much pressure or speed, as you do not want to "egg" the hole where the spring rides.

I do not know if you will even feel the difference in any "lightness" of trigger pull, but at least you will know that it has been polished as much as possible.

I do not know if you will even feel the difference in any "lightness" of trigger pull,

It won't make a difference.

It won't make a difference.
Roger that. IMO, unless your MSH is especially rough, this is more of a "feel good" project.