it could be the springs are just still really stiff or too long. I have had stiff spring issues with every new pistol mag, nearly every new semi shotgun and tube magazine rifles I have ever owned or used at the range with a buddy, thats why every gun has a break in period. I fix it by loading and unloading it repeatedly to break in the springs, and what has worked sometimes is to load the mag as much as i can and leave it for some time to compress the spring.
as for having to smack it, if it isnt getting onto the lifter i cant help you, if its on the lifter and not chambering, look at it next time, did it rock off the lifter? I still cant really help with a permanent fix for that other than hold the rifle steady and pretty level so the bullet doesnt nose/rock off to where it isnt supposed to be. also i had feed issues with the winchester ammo, had a problem with the brass lip being too squared and catching before being able to close the lever.
good luck, hopefully it will work out and is just break in