Follow these steps:
#1 purchase rifle
#2 strip, clean, lube
Now the next step is EXTREMELY IMPORTANT
FOLLOW THIS STEP TO THE LETTER
FAILURE TO FOLLOW STEP #3 COULD CASE CROTCH INJURIES
STEP #3
SHOOT THE $%%#@ GUN!!!!!!!!!!!!!!!!!!!!!!!!
that made my evening LOL
m14 type rifles were not designed for the use of a buffer and most of us with a good understanding as to what is happening inside the rifle when a buffer is used.... know that they have no place in our rifles.
shim kits.....
first off, shoot your rifle after a full cleaning and degreasing
grease your trigger, oprod tab, roller pocket and receiver's oprod track
grease the back of the bolt lugs only, reassemble.
perform the trigger safety test by cocking rifle, pulling trigger and holding it , do not let it off. with your free hand cyle the oprod by pulling back and letting it fly home. release the trigger and pull it.... if the trigger does not "fire" ..... you have issues and report back to us.
if the trigger "fires" yer in business and off to the range.
"if your rifle needs it" accuracy upgrades are as follows
NM oprod spring guide rod
and possibly shim the gas assembly.
test this by removing the gas plug and check to see how much rotation past bottom dead center (6o'clock) the gas lock has. If it hand tightens snuggley at 6:00 gravy, if it goes way past to 9 oclock or more..... a shim kit can be of benefit. flash hider must be removed, most are welded on you might be lucky and have a non welded version.
shim pack can be purchased at marstar.
I no longer use shim kits as they are maleable and wear out fast (in my rifles anyways) and prefer to precision peen the gas band shoulder of the barrel. I can't really walk you through that procedure so shims will suffice.
my advice, shoot your rifle with a few different types/loads of ammo between 147gr to 174 gr(maximum tolerance for this rifle's design is 174gr), find an ammo your rifle prefers and then look at possible upgrades that are proven to help shrink groups in these rifles.
Seriously though, what a beautiful rifle. 
....So the shim kit might be necessary...My flash hider is weld... And i'm planning to take it off in a near futur... 
