On an 870---even if it was safe to do----you would still have problems with the bolt and ejection port. That's why Remington redesigned the whole thing to handle 3.5in shells.
Wally's around here sells synthetic Super Mags new for $305----seems like it would be cheap enough to get a whole new gun---compared to what the gunsmith would charge you.
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I take the leech that's bleeding me
Can't stop to save my soul
I take the leash that's leading me
-------Metallica
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