Here is a copy of the CGN post by Parabellum on how to fit the Norinco M305 to the new Promag Precision stock. The info and pics are complements of Parabellum and used here with his permission. Thanks for the info and I am sure it will help many fit their Norinco M1A’s to this wonderful stock.
LINK to the orig CGN post
The Promag Unit
Now secure the stock in a vise or similar. Be careful to not scratch it
Protect the surrounding area with tape.
Measure from the front of the action opening back 6 1/4″. You will be filing 1 1/2″ forward of this mark.
Also, measure down about 3/16″ from the top of the stock and mark. Some rifles may need less
The tools that will be needed to do the modifications include 2 different files, razor blade and 180 and 320 sand paper
Then start filing making a bevel towards the “inside” of the stock
Lastly, some pictures with a level to show the angle because it is hard to see in the pictures. Enjoy.
Some additional spots that needed fitting
Fitting the trigger pads is next but there are no pics of this step. The fitting is done when the trigger guard will close using firm pressure on both the action and the trigger group. The tighter this fit is, the better. You may find that additional material will need to be removed in the inletting if the action is not sitting flat with the stock
Slowly file material in the stock until the action fits level and flush. Go slow and check your progress often. Like to extend a big THANK YOU to Parabellum for his pics and instructions. I hope you will enjoy this great stock.
Here is another project rifle from another CGN member that will offer more inspiration.