Some very experienced shooters can fire a pump pretty doggone fast BUT, theres no way the long stroke of a pump can go through it's cycle nearly as fast as a semi auto does. Granted, the pump unlocks the instant the trigger releases, while the semi has to wait for gas pressure to come through, but it is still faster. Toss in the fact that much of the recoil is absorbed with the semi and you just can't beat it.
May be apples & oranges, but with the old .22 pump gallery guns you can hold the trigger down & pump like crazy, firing rounds the *instant* the action snaps shut and it still isn't nearly as fast as a [blowback operated] .22 semi auto.
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