Tried my SP-12 today.
Gun was disassembled, inspected, and reassembled without the magazine tube spring retainer to have 6 2.75" shells in the tube as advertised in the Tactical imports page. A longer spring was added to ensure proper feeding, as factory spring was barely the length of the mag tube + extension. New spring was approximately 2.25x the length of the magazine tube with the extension.
No extra cleaning or lubrication.
Put about 75 shells of mixed Score buckshot and slugs through it. Issues found:
- Experience double feeds every single time the gun was fully loaded, with less double feeds as the gun emptied.
- Occasional failures to feed, hull ejected from chamber but next shell hung up halfway out of magtube. Disassembled at the range with no apparent cause for issues.
- Pump mechanism was engaged. First shot in pump mode caused the action to seize shut. Had to mortar the charging handle to eject spent hull. Rest of pump mode shot ejected correctly, while still experiencing double feeds and failures to feed.
- The two screws that attach the heatshield to the barrel had come loose. Heatshield could move 3-4 mm front and back on the barrel.
- Choke quickly got loose, no wrench provided to tighten so it was removed for the duration of the tests. Choke attaches externally to the barrel which has external threads, so no damage was done while shooting the gun with the choke removed.
There were glaring issues out of the box as well. Some potentially so significant I can't talk about them.
- Gun is so tight out of the box, the bolt release cannot be used with one finger. Both hands needed to be gripping the receiver tightly, and then the bolt release button had to be pressed with significant force to get the action to close from the locked open position. Working the action is helping to loosen up the button, but it is still significantly tight.
- In the folded position, the stock latch was locked into the rear sight so tight, stock had to be removed from the receiver to release. A rubber guard was pressed into the stock, tensioning the entire stock against the receiver. It has been removed, and the latch can be operated freely now.
- The mechanism for switching between pump and semi was insanely tight. The instructions literally say to "wiggle the forend to help the switch". Wiggling did not help. Applying oil to the mechanism and the forend track did.
- The doublefeed was being caused by the aluminum follower, which was binding up in the magtube. Replaced it with a basic plastic orange 870 follower and issues went away.
- Heatshield is attached to the barrel with two crappy screws. They came loose, and heatshield rattles. Had to apply loctite, and retorque them.
Another shoot is planned for later this week.