Remington 870 Take Down Instructions Question

[toyon2]

Greetings!

I just purchased a new Remington 870 (Wingmaster), and am new to shotguns. The instruction manual that came with it warns, under "How to Assemble" (p.10): "Do not pump the action or pull the trigger repeatedly with the barrel removed." I'm wondering why this is so. What parts would pumping the action with the barrel removed damage?

[Synchronizor]

Normally, the breech bolt assembly stops against the barrel breech. But if the barrel's off the gun, and you ram the slide forward, instead of the action stopping when the bolt hits the barrel, it'll stop when a small shoulder on the left action bar hits a little finger on the left shell latch. Those parts are only really meant to keep the fore-end, slide, & bolt assemblies from falling out of the gun when you're changing barrels; they're not meant to repeatedly handle the stress of arresting the cycling action. Also, without the barrel to stop it, the bolt will tend to slide farther forward when the fore-end is in the forward position. This means that instead of striking the firing pin & bolt squarely the way it's designed to, the hammer will strike at a weird angle, which can deform the metal if done again and again.

As the owner's manual implies, these things have to be done repeatedly to really hurt anything, and it's not the end of the world if they happen once or twice accidentally. But it's best for the gun to ensure that it happens as little as possible.

[toyon2]

Much appreciated. Thanks!