I am new to high power shooting and right now all I have is a Garand.  From my experience shooting the Garand from a bench, it is capable of staying in the 10 ring.  It will shoot 2 1/2 inch groups at 100 yds.  But I am not capable in competition of doing that well.  I want to buy a Rock River DCM AR15, but because I am not that good a shot, will I see much improvement in my scores?  In other words, what good is a one minute rifle if it is in the hands of a four minute shooter?  I appreciate all replies.

A 1 MOA rifle in the hands of a 4 MOA shooter is a 4 MOA rifle. Practice, practice, practice.

Shabo

Perhaps the lower recoil & cost of .223 will allow you to practice more, enjoy it more, flinch less, etc.

There are so many variables its hard to say what you should do.  But, if you are serious about DCM competition, forget the garand or M14/M1A.  Every competitive shooter uses an AR15.

Unless your Garand is a NM version I would suggest the AR.  The sights will be better, recoil less (you might be flinching more than you think) and it might just fit your body better.

I have the RRA DCM rifle and love it.  In the clinic I took for DCM shooting I was consistantly in the 9-10 ring both prone and seated my first try.  (Offhand is another story).  Impressive for a newbie.  I doubt I could have done that with a Garand.

If you are serious and can afford it - buy it.  And get a TOP quality sling as well.  These make a huge difference in position shooting.

Lastly, as said above - practice, practice, practice.  Then go practice some more,