Some mags are pretty stiff when new. To be honest though, I'm not sure why anyone would be concerned about stuffing a seventeenth round into a mag, but then again we all have our individual concerns.

I wouldn't lube a mag, as the lube can eventually seep into the cartridges. Not a problem of course if you only load the mags when you are actively shooting, and don't keep them loaded for a long time.

PhilR.

Thanks, it was more as a wonder why, then an actual do it thing.

I can get 15 in without a problem, which I think is enough.

Try loading them up and letting them sit for about a week. I know the Ruger Magazine springs on many of their pistols start out stiff. My Ruger P345 was like that until I let them sit loaded. Now I can load a full magazine without any trouble at all. Most likely it's just a matter of breaking them in.