With three down in the magazine first one feeds fine, sometimes the second will catch on something after traveling about a inch to an inch to half. If I release pressure on the bolt and pull it back just a hair the feeding will continue on. Third round feeds fine.

If I am working the bolt fast all three feed correctly. Any ideas?

I believe the .375 magazine in the Ruger is a stagger feed 3 round. If it is stagger feed, that means you are having trouble with the only round on the left side of the mag well. That would make sense because the first and last rounds feed ok. I would look for a burr or ridge on that side that might be catching on the case shoulder. Look on the brass for scrapes. The other possibility is the rim may be catching a bit on the extractor hook from that angle.

Don't think that is it. For some reason the middle round sometimes comes up butt first and I think case rim is catching on the underside of the bolt.
Maybe to little or two much spring tension. What do you think?

Take your little finger and feel around under the left feed rail, especially the joint between the mag well and the receiver. There might be a ridge there catching the case on that side. There is something preventing that left round from feeding up smoothly. Apparently when you cycle quickly, that is giggling things enough to release the round. Also, push down and release the follower to see if it is catching on something. Look at the boltface and see if there is a burr or ridge there.

I took my Ruger 35 Whelen Ackley that was balky feeding. Made some dummy rounds and put lip stick on cases. Gently polished the mag box where it left the teltale red lipstick. And now it feeds great. Just work on the mag box if you screw it up you can replace cheap. Also see if stock is binding mag box. My LH Ruger 375 feeds great.

Is this a new gun? Why don't you invoke the warranty. Feeding issues can be real time consuming...EVERYTHING must work in sync.

If this is with factory ammo, you have a real complaint. handloads...all bets off!

Take it to a real gunsmith if waranty and handloads are not an issue. Nobody can diagnose this without actually hands on.

Thanks folks. Not gonna get to carried away with this since it only happens when I cycle slowly, and then only about 40% of the time, if that high.
No burrs anywhere that I can tell but still think there is to much spring pressure on the follower as the rear of the second round is what is catching under the bolt. May order a new spring so I have a spare in case the stock one breaks as I try to bend it.

check the end of your brass, if its squared off, its probably that bullet to brass lip that is hitting the very rear of the chamber. My mod 70 does this and I can reprodice it every time and with crimped handloads that have a very smooth flow from brass to bullet they do not do it. When I cycle at regular speed it never happens, only when goign it slowley...

Its not hitting the chamber. The magazine spring is pushing up the rear of the case first and this is what is catching on the underside of the bolt.

Really dumb question, but here goes. Is the magazine spring in the right way round?

Not a dumb question. Spring can only go into the follower and the floorplate one way as the top and bottom of the spring are different lengths. Am sure this is just as simple as bending the spring so the follower sits level in the magazine.
Played with trying to bend it and feeding improved when I cycled it slow. Non issue when feeding fast. Still, might give Ruger a call and see if they will send a replacement spring.

If the geometry of the feed rails, ramp, bolt face, extractor and ejector, follower are not right..the spring won't help.

Managed to bend the spring so the second round sits closer to level and the problem disappeared.
Maybe I should hang out my Gunsmith shingle now, lol.