jkh62--Over the years, I have built quite a few M1As similar to the job described here. There are a few things that I do differently and I would like to offer them for your consideration. The coat hanger is sort of standard, however, Al Ewing showed me how to use a leaf of a spring from a rifle magazine box. It does not take a set and will help keep the barrel centered in the stock. Before bedding, I use a strip of cloth ¼" wide taken from a used belt from my belt sander to "shoe shine toe area between the front band and the ferrule to get a perfect match between the two. Cut against the band and not the ferrule. I use a Propane torch to heat the clips on the front band and bend them up to better hold the front of the handguard. Make sure that they will clear the barrel and fit the handguard. I use a file and take off some extra on the handguard to make it fit better. You can take the extra length off of the handguard by moving it forward just a wee to clear the receiver in the back. That way there are no marks on the rear of the handguard. To set the front sling swivel, I use 10-32x½" pan head cap screws and screw them into modified T-nuts which I countersink on the inside of the forend. That way it makes the job look more professional. You can use a ¾" Forsner bit to countersink the T-nut. The other thing that I do is to use a full length pillar in the rear so that I get a lockup like on a pillar bedded target rifle.
Just a few thoughts,
Craig
The way I did it is by no means a definitive guide, just the way I approached it and did it.
Using a flat spring has it's merits and if you can obtain the needed tension then use it. A flat spring does not have a fulcrum point like a wire and using the wire you can increase the tension by sliding it towards the gas cylinder or decrease it by sliding it away from the gas cylinder. I will be likely bedding a wood stock so I will use shims under the wire or more tape to protect the wood from being dented. If I have a flat spring I will check how it works vs the coat hanger wire.
As to front sling attachment the modded "T" nuts sound good. I do not have any but I do have key stock and end mills so tapping a piece of stock and milling a slot was cheap & easy. The slot also has good surface area for strength.
Pillars -
Lots of different thoughts on them. My own personal opinion I do not like pillars that make contact with the receiver or go completely thru a stock (bolt guns also). I like pillars completely supported in a solid blind hole. This guarantees a pillar will never work loose or pull thru. In my case the rear pillar is more of a bushing to support the action screw. The entire rear lug is sitting completely supported by Devcon with considerable thickness of stock glass and Devcon around it. It's never going anywhere. This is just my personal preference and I make no claim to it being the best way of doing it.
In the end it comes down to the materials you have at hand, your skill level and equipment you have to use and what you feel comfortable doing to your rifle.
I have never made one shoot worse....
Good tips & thanks for adding to the thread / open discussion.