MountainMark

I shot 100 shells thru it today and it is shooting better. Fired most mags of Remington and Federal 1 /18 oz without jamming. If it continues to improve this way maybe the break in is working.

I have one and it is not running well. I have sent it back to Standard and am now working on break in. Will see how it goes.

I have an SKO-12. The first few boxes of shells tested fine with no jams. Then I took it to a 3-gun match, shooting 1 oz Estate shells. I was getting head separation. Either the ammo was faulty or perhaps the pressure of pushing the shells into the magazine weakened the joint between head and case, I don't know. Anyway, this was before Standard's current break in recommendations. So, I bought some quality ammo and retested. It continued to jam. I sent the gun back to Standard and they "re-certified" it. Their recommendation is to break it in with 100 rounds of Remington 1 1/8 or 1 1/4 OZ at over 1200 ft/s. I did this today. During break in I was getting 1 or 2 jams per 10 round mag. At first it was the case that the trigger would click on a chambered shell and nothing would happen. Perhaps the bolt was not completely locked. As testing went on I got some classic jams where the bolt went only halfway forward. In other cases the bolt went forward on an empty chamber with shells still in the mag. These were high brass shells so I took advantage of that and was careful to load each shell pressing down brass on brass, rather than brass against plastic, hoping to avoid any deformation of the shell. I will clean it well and do more tests. Test suggestions: 1) Try loading more of less rounds in your magazine to see if magazine spring pressure is an issue. 2) Between each shot try pressing forward on the charging handle to see if this prevents failures to fire. This might distinguish between failure of the bolt to lock vs other malfunctions. 3) Take note of how malfunctions progress during the course of a test. Do they remain the same or change? 4) Standard is recommending using heavier loads so try to get these working before switching ammo, since changing ammo will confound with other factors, like fouling, during each test. I'll be very interested in hearing how things go for you and likewise will keep you posted.