Quoted: ... The flexitab anti-jam system; the loading shute looks like it was cut on three sides but not completely cut through. I'm not sure how this is supposed to reduce jams. Anybody care to explain this extra on the Remington steal package??
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The Flexitab Conversion Kit was developed by Remington in the mid-1980’s to address a functioning problem that LE agencies were having with the 870.
The problem occurred when a round in the magazine jumped the shell stop, entered the action, and got wedged between the bolt assembly on the top and the shell carrier on the bottom. The only way to quickly clear this is by cycling the action.
However, as you try to pull the forend back, the friction from the bolt assembly (which is linked to the forend) tends to push the round backward. The rearward movement of the round causes the carrier, which is tapered upward toward the rear of the bolt assembly, to push the round harder upwards against the bolt assembly. This wedging effect ultimately freezes up everything.
Immediate action for this problem was to put the safety on, hold the forend with both hands, and very forcefully slam the buttstock into the ground. This would tear up the round, but would also clear the malfunction. Sometimes the buttstock would be broken during this maneuver.
The Flexitab kit cured this by modifying the bolt assembly, the slide assembly (which mates with the bolt assembly), and the carrier. All three of the parts must be replaced for a correct conversion.
The bolt assembly was changed so it was less affected by pressure from the offending round. Minor improvements were also made to the slide assembly.
The carrier had the cut out “U’ shape put in it. Essentially, if a round jumps the shell stop and starts coming backwards, the rim of the round will put pressure on the “U” shaped tab, which will flex downward slightly. The round’s rearward movement is stopped when the rim passes the end of this tab and hits the unflexing part of the carrier. Also, by flexing, the tab relieves some of the upward pressure the round would otherwise put on the bolt.
With the Flexitab conversion, cycling the forend with only slightly more force than normal will clear the malfunction.
Remington has since added this feature to most, if not all, of its 12 gauge pump shotguns. Older shotguns used for self-defense definitely need modification.
This modification is less critical on sporting shotguns since removing the triggerguard, which is pretty easy on an 870, can also clear the malfunction.
Brownells sells the Remington Flexitab Carrier Conversion Kit for 12 gauge 870’s for $54.05 retail, $43.24 dealer. It’s their part no. 767-933-390 (see page 363, third column, of catalog 54). This kit has a black bolt – Remington used to have the same kit with a chrome bolt but I don’t know if it’s still available.
Hope this makes sense!
Apologies to madmedic for wandering a little off his topic.