Just got a Ruger Mark ll. It is like new. Took it to the range and had several stove pipes. Was shooting federal target ammo. I don't know if it just needs broken in , different ammo or different springs. The two Brownings I have shoot the federal fine.

Make sure to lube the bolt and try a different ammo.

The ammo is likely just under the power threshold to reliably operate the gun.

You are likely seeing the results of not quite hitting the ejector hard enough to get out before being trapped.

Another thing you can do is oiling the rounds in the magazine.  Learned that at the local Bullseye matches.  Really helps with extraction for under powered rounds

Try CCI mini-mag.  Do not oil cartridges.

The ammunition is too weak to cycle your particular pistol.

Maybe after a break in period it will operate reliably with it.

Volquartsen Exact Edge extractor.

Fixed all my stovepipes/FTE's on my MkII's.

I just bought a near perfect Mark II myself. It appears to have less than 100 rounds shot thru it since it was born in 1990... And I have the same exact Federal "Target" ammo as the OP. I'm taking it to the club Saturday and will update here how it shoots this ammo. I have CCI Mini-Mags and some other full powered ammo to break it in. The Federal Target is rated at 1200 fps so I figured it was full power and good to go for breaking in this pistol but haven't had a rim-fire pistol in years. I'm glad I ran across on this thread. I'll be sure to take 3-4 different types of ammo for break in now...

I have found 200-300 mini mags are the easiest quickest way to break in Mk's.  After that, mine gave eaten almost anything.