My M1 is currently zeroed at 100 yards, but the elevation dial is somewhere random.  Is there a hash mark on the dial that corresponds to 100 yards, or 100 meters?  I want to zero the dial to the sights.

Yes you can zero the rear sight.

Sight the rifle in at 100 yards.
Hold the elevation knob TIGHTLY so it can't turn.  You can use some slip joint pliers if you pad them with some leather to prevent damaging the knob.
Unscrew the screw in the knob.  It's a captive screw and won't come out.  DON'T try to remove it.

Pull OUT on the knob to disengage it from the splines on the receiver and turn it so the mark lines up with the 100 yard setting.
That's the line UNDER the 200 yard mark.

Push in the knob and grip it tightly so it can't turn at all, and tighten the screw tight.

To highlight the markings on the sight and knob use White Lacquer-Stik from Brownell's.  This is what armorers use to fill sights and serial numbers.  It's permanent, but comes out with some lacquer thinner and a toothbrush.
This is paint in a solid form.  Scrape the end to expose fresh material and rub it into the markings.
Use a rag with a little lacquer thinner to wipe off the excess, leaving the markings filled.
Let dry a few hours and apply a lube to prevent rust..........

https://www.brownells.com/tools-cleaning/general-gunsmith-tools/files-engraving-tools/color-fill-lacquer-stick/

Thank you!

Make sure you know how many clicks from bottomed out your 100 yard zero is before changing your drum position. If you accidentally move the sight while try to loosen the screw you will still know where you zero was.

YouTube has many videos on how to do it.







When you get your elevation done. Might as well get the front sight adjusted so your windage is centered on the rear sight. Remember the M1 rifle front sight moves 0.008” per 1 moa. Here is a good method for that,

Thanks - I was lucky enough to stumble across a video saying to make sure you count the clicks to the bottom, since the very act of loosening the screw will turn the knob, screwing up one's zero.

I have yet to watch the videos that you linked,  but don't worry,  I will.  The windage scale is also in some completely random position, but setting it back to zero wasn't a high priority.

Is there a drift tool for the front sight?  Is there a torque value for the front sight screw?

Front sight adjustment tool

As to torque, opinions vary from "just snug it up" to "use blue locktite and snug it up" (what CMP recommends) to "crank on it until the wrench bends". Personally, I'd tend to follow CMP's recommendation.

Thank you.

I need to get some more ammo for this gun.

That tool is not necessary or common. It should only take an allen wrench to adjust the front sight. Sometimes dirt and rust may bind it a little. Most people with basic skills should be able to figure out how to remove it and clean it so it slides freely on the dovetail when the screw is loosened.

For a torque, 87 in-lbs should work, 120 in-lbs even better. I am not making a Arfcom joke with that number either, https://www.almabolt.com/pages/catalog/bolts/tighteningtorque.htm

I just push the end of the hex wrench until I see it bow a little bit.  That should be tight enough.  It's worked for me for over 40 years without any problems.

I also take a caliper and measure how many thousandths of an inch from each side the front sight is from the base and enter the data in my rifle log.  That way if you remove the front sight for any reason, you have a good starting point for a no wind zero.

It seems like it would be INCREDIBLY difficult drift the front sight precisely enough to zero the weapon, without this tool.

When you loosen the front sight screw, the front sight freely moves side to side on the dovetail. Watch the last video I posted and it will become obvious how it is done.

Even sights that require being drifted with a punch, I can move precisely to a location using a similar measuring method without a sight pusher tool.

Maybe I'll just try that, and save myself $50.

Does the windage dial reset in the same manner as the elevation dial?  It won't be zeroed on the scale beneath the rear sight, but that isn't a high priority at the moment.

Zero the rear sight windage(center it). Then make your coarse adjustments by moving the front sight. Remember, front sight is moved opposite the direction you want to go.
It’s easier at 25 yds(military uses 1000 inches, or 27 3/4 yds). Then fine tune using the windage knob
at 100 yds.