I'm thinking of buying a CMP stripped reciever and assembling a new rifle.I have plenty of parts,but I am concerned about timing. Will it be an issue or can I just throw some GI pats on the reciever and have a functioning rifle? Thanks in advance.
The bigger worry here is not the timing, but the headspace on the barrel. If you just stick a used GI barrel on it, it may or may not headspace correctly. Incorrect headspace can make a dangerous rifle. If you put a NEW barrel on it, it will HAVE to be headspaced by a gunsmith. Incorrect timing can usually be corrected pretty cheaply, but could go so far as requiring a new or different op rod.
A new, short chambered barrel, would be easy to headspace with the proper pull through chamber reamer.
Headspacing thi sway is almost as easy as checking the headspace.
Pull and turn as you are closing the bolt. As soon as it closes, you are at proper headspace. They sell different bushings. I always headspace to minimum spec.. Chamber has a longer life, and besides, it is easier to remove more metal than to ad back later:
As CornBread said, if you use a barrel, bolt, receiver, and oprod that are like new, but previously mounted and headspaced, you should have no timing issues, Barrel bolt and receiver should index and headspace correctly.