I have a post 64 G series CRF Classic Model 70 custom rifle in 416 Rem with feeding issues--1 or 2 rounds in the internal box function flawlessly. Put 3 in and the bolt passes over the top of the top/3rd round and does not pick it up. Put 4 round in and it will feed the top round, but not the 3rd round. Any thoughts on how to correct the issue
Bowen475

I am not sure what magazine follower spring that you have. But, if it is the one with the 90 degree upward bend by the floor plate, try a regular flat bend spring. This has cured some feed issues with a couple of M70 classics that I have.

If it's new, I'd send it back to the factory. I had a rather large rumble with Kimber on one of their new rifles that wasn't up to snuff but they finally fixed it.

If that won't work, next guess is the spring, or maybe the follower.

Sounds like you have a drop box magazine if it is holding 4 down.
I had the similar issue with my custom 416 and 375 mod 70 with the deeper box.
In my case what was happening was the flat bottom of the magazine spring was moving forward on the floor plate.
That magazine spring (factory) has a dimple on the bottom of it that will fall into a little crater on the factory floor plate to hold it is place and not move fore and aft.
On my Sunny Hill deep box floor plate there was no crater for the dimple to fall into.
On recoil the spring would move forward and cause the shells in the magazine to stove pipe on working then action (not good!).
Upon attempting to reload I would run into the same situation you are describing.
I had a local gun smith fabricate a little plate he welded in the bottom of the floor plate forward to keep that spring in place.
In my case problem solved.
You might even consider having a gunsmith drill a little recess in your floor plate to accept the dimple on the boron of your spring (if it is a new floor plate).
No body could solve my issue. Just something in figured out myself messing with the gun.
Good luck. Hope this may be of some support.

EZ