I would reccomend not to try this on an 870 remington for safety reasons.
you would be much better off getting a shotgun that was designed to do this from the factory and they are several that will do so .
Winchester model 1897 pumps
Ithaca model 37 pumps
Browning BPS pumps
Winchester 1300 pumps
all of the above mentioned guns will shoot when the trigger is held down and just pumped
after each round is fired
the old Winchester 1897 pumps were reffered to as the ''ole cornshukker'' 6 shots in 6 seconds was what the old catalogs used to advertise for the gun
hope this has been of help to you
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Gun Docc
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