I'm a newbie to the M1A I bought a standard Springfield M1A had the trigger done by Phil Arrington and I will be changing the stock to one of Fred's Big Red Birch stocks,then have it bedded was toying with adding a Douglas barrel when I do, would like some imput please 1) Medium vs. Heavy Barrel and ,2) Grove 4 vs 6  what do you guys use ? I'm shooting Milsurp ammo from it using a Scope 80 % of the time most likely .
Also is it really worth the $200 -$225 to upgrade from the standard barrel in performance will i really see a difference i guess is what I'm asking .
Thanks for your help in advance now all I need is my Springfield Scope and Mount to get here already

Dave

Have a Air Gauge Heavy on one of mine, 1-12, 4 grove and it shoots great across the course.

The only Air Gauge 6 grove we have is in a 1953 NM M1 , also a 1-12 and is chambered to 7.62 and it hammers knots.

Is it worth the cost? if you are going to shoot it in matches than yes, if not save the money and put it in to something else you can up grade the barrel later.

If you reload, work a load up that the barrel likes and you my not want to rebarrel.

The original M-14 NM (govt) barrels were 12" twist but changed over years ago to 10" to better handle 168 and 180 gr Sierra Matchking bullets (and later, 175 gr SMK also). Six groove barrels handle "softer" bullets like the Sierra Matchkings but don't always like the 173 gr govt match bullets. A four groove will handle anything,especially in 10" twist. A medium or heavy would be equally good for accuracy but will have different balance points and would be lighter or heavier to carry around. The plus with the heavy is that it dampens out some of the wobble and vibrations when Match shooting. The heavy also absorbs more heat but that is only a consideration in shooting a lot of rapid fire. The quality of the rifling is what will affect the performance more than anything else. Go with the big name brands and you will get what you pay for.