870 Super Mag Loading Issue

[mrnj]

All - I recently purchased two 870s, one compact 20 gauge, and, one 12 gauge Super Mag. Both are pure stock (no modifications), and, I've run about 125 rounds through the Super Mag and about 75 rounds through the 20 gauge. The 20 gauge has been perfect, but, I've had a few issues with the 12 gauge Super Mag.

I've been shooting skeet, so, we're typically only loading two shells at a time. During the 125 rounds with the Super Mag, this has happened 5 or 6 times. After loading the 2nd shell, the carrier returns to the normal position, but, I can see the shell has slipped back under the carrier. In order to clear it, I press the action bar lock, open the action, and, both shells are visible - tilting the gun, they fall right out.

The gun was brand new, I fired 75 rounds, and, this happened a few times. I took it apart, cleaned it, lubed it lightly, and, fired the next 50 rounds and it happened a few more times. I wasn't wearing gloves, so, I didn't get a glove caught in the carrier.

Not sure if it matters, but, I've been using Remington 2 3/4" target loads (#8) in the Super Mag, but, I used Winchester 2 3/4" target loads (#8) in the 20 gauge.

Questions
- Does this sound familiar? Any thoughts on what might cause this?
- Could it just be me not being forceful enough inserting the shells?
- Could it be an ammo issue?

I find it a little strange that my son who was shooting a shotgun for the first time put all those rounds through the 20 gauge without any issues, and, I had trouble with the 12 gauge.

Any thoughts/suggestions?

Thanks for the help,
Mark

[Synchronizor]

Normally this malfunction is purely due to operator error. When loading shells, it's important fully insert them until they click past the shell latch. If you don't, the shell will not be secured inside the magazine tube; it will be pushed out by the magazine spring to either hang up on the tip shell carrier, or slip back between the carrier and the slide assembly.

This isn't usually that tough to get right, so you may want to look at your shell latches and see if they're operating properly. If you take out your trigger plate assembly, you can work the slide freely and watch the shell latches move without having to look around the shell carrier. You can also test loading and feeding with the gun like this (preferably using snap caps or dummy shells), just make sure to replace the front trigger plate pin before doing so, as it's needed to properly secure the shell latches against impacts from shells.