https://imgur.com/a/FnEj1R0

I’ve been using this rifle for larger game for a decade and this issue has always perplexed me. Determined to solve it. Tends to hang up on the 4th round, sometimes the 2nd and 3rd. Magazine spring and follower seem fin, clean and lubed. Any ideas?

Weatherby vanguard synthetic 270

Since it has problems feeding from both the left and right side it's probably not the mag/follower.  Maybe making dummy rounds using bullets with different ogives will help diagnose the problem.  I've had rifles that will have feeding problems if the bolt is worked slowly, but if I pushed the bolt forward quickly the problem would not happen.

It definitely happens more often when I’m sloppy with the bolt, but it still happens regularly. Good thought on building dummy rounds to test, that’ll be a nice reason to dust off the reloading.

Finding a way to differentiate between follower and any sort of ramp/receiver issue to would be helpful

What exactly happens when the round 'hangs up?"  Does it not feed at all, partially feeds, where does the bullet "clock?", etc.  Pics of the hang up would be helpful. 
Does the bolt completely stop or does the round eventually feed if more pressure is applied?  Do you load the first round from the magazine or do you drop it into the chamber and force the extractor over the cartridge rim? 

If the middle to last rounds in the magazine are problematic, it could be that the spring tension is the problem, have you tried a new spring?  It could also be that the follower is canted or hanging up in the box.  Is the magazine spring oriented properly? 

Any burrs or nicks in the magazine/feed lips?  Is the bolt face or extractor nicked, chipped, scratched.  Is the bolt face/extractor clean?  Lubed?  Dry?  Is the internal box clean and free of nicks, scratches, etc?  You get the picture.

Are your cartridges factory or handloaded?

Did you buy the rifle new or used? 

There are obviously many things to check.  Good luck!

What exactly happens when the round 'hangs up?"  Does it not feed at all, partially feeds, where does the bullet "clock?", etc.  Pics of the hang up would be helpful. 
Does the bolt completely stop or does the round eventually feed if more pressure is applied?  Do you load the first round from the magazine or do you drop it into the chamber and force the extractor over the cartridge rim? 

If the middle to last rounds in the magazine are problematic, it could be that the spring tension is the problem, have you tried a new spring?  It could also be that the follower is canted or hanging up in the box.  Is the magazine spring oriented properly? 

Any burrs or nicks in the magazine/feed lips?  Is the bolt face or extractor nicked, chipped, scratched.  Is the bolt face/extractor clean?  Lubed?  Dry?  Is the internal box clean and free of nicks, scratches, etc?  You get the picture.

Are your cartridges factory or handloaded?

Did you buy the rifle new or used? 

There are obviously many things to check.  Good luck!

Stretch the spring out.

Check the mag (front portion where the bullet may or may not rub, while going into chamber.) I had a problem with an ar15 in x39. I dremeled the mag bout half a millimetres to solve my problem.

Does it come with metal or plastic mags?