I have been using my MKII Ruger's in Bullseye competition for the last seven years or so. The MKIII was a horrible kludge, so bad that Ruger had to bring out a redesign as smart shooters were walking to other brands. A bud of mine purchased an early MKIII and the pistol was a jam a matic. Could not finish the magazine without one or two stove pipe jams. His pistol had the early, all steel, loaded chamber indicator (LCI). That thing knocked fired brass off the bolt face during ejection, hence the frequent stove pipe jams. When we examined the LCI, we learned that the flange actually rested on the rim of the cartridge. This meant, if you dropped a loaded MKIII, and the LCI made contact with the ground, the force of impact would be transmitted through that LCI to the rim of the cartridge, igniting the cartridge! How such a dangerous design made it out of the factory, I will never know. Anyway, we took that MKIII to a gunsmith who milled off the flange, and bud's MKIII ran great after that. Still the magazine disconnect was a total failure as you have to pull the trigger a number of times to get the hammer strut to align with the mainspring, and that disconnect complicated the disassembly and reassembly procedure.
I do have a Ruger MKI, and it is a early 60's target model with the factory tuned trigger.
I had to pay $100 for a local gunsmith to drill and tap the thing for the Ultradot.
A MKI is a very simple mechanism, and I can tell William Ruger designed it with Bullseye pistol competition in mind. The mechanism uses the safety to hold the bolt back during reloads. You have to rack the slide, and hold it back while locking it into place by flipping the safety up. So, during the load command in a match, you insert a magazine, hit the safety, and the bolt goes forward. As much as I like the simplicity of the mechanism, I much prefer the bolt open feature of my MKII's as I don't have to count number of rounds fired during timed and rapid fire. When I shoot this MKI, I frequently lose count of fired rounds and end up pulling the trigger on an empty chamber. Not that means anything, if I got my rounds off before the target turned, but it is an aggravation. It also takes two hands to open the slide and push the safety upwards to lock the slide open. And it is easy to sweep the line while doing that.
I recently paid Clark Custom Guns big bucks for a trigger job on this MKII
and Clark did an outstanding job of installing one of their triggers, which reduces trigger take up and over travel. And of course trigger creep during pull is gone. I have found that too much trigger take up results in low shots if I am not concentrating on taking up the trigger slowly. This shows up in the timed and rapid fire stages, and if my timing is off, and I am panicking, I will pull right through a long first stage takeup and hit the trigger too hard. That results in low shots.
Clark's is on old Hwy 80 in Louisiana. Hwy 80 parallels the I-20 which replaced it as the main drag, but it is interesting to drive down old Hwy 80 and see the gas stations, towns, from decades ago.
The MKII is the best of the series, but, after market parts are being phased out. I called Volquartsen for an extended magazine release, and Volquartsen stopped making them two years ago as MKII parts sales no longer sustained the effort to make and stock the things. I was able to buy a
Majestic extended magazine release, so things were not a total fizzle, but it could have been. Volquartsen claimed sales of MK IV parts are going well.
A shooting bud of mine, call him Big Boy, likes his Ruger MK IV. Big Boy shot on the All Guard Pistol team when he was in the military, and he is still active. As I have shot next to him, his MK IV shoots reliably, and tight groups. Nothing wrong with that.
If you want a 6 7/8 MKII, go for it. I would try to make sure it is drilled and tapped for an optical sight base, as the older you get, the less you can see irons, and the cost of drilling and tapping adds cost to the pistol, without increasing its value. I would also buy whatever parts you think you might need, and avoid paying scalper prices later. I really like my Volquartsen extended magazine release and the extended slide release. And now, I really like my extended Majestic magazine release.
Otherwise I'll keep the guns of my youth.
