who in MO has both a benelli m4 and an hk sl8-6?????

The pistons actually are free floating kinda, when the bolt goes fully forwards it pushes them back in. Very simple design with less moving parts. Don't worry about them moving back and forth freely, they are supposed to do that! (and DO NOT oil them at all, they should be cleaned and degreased, but only after a couple thousand rounds. I do them once every 2000-ish)

For the barrel, it shouldn't "click" really as much as get a "clunk" when it fully seats. When you tighten down the mag tube clamp it will fully seat it anyway. Since the handguards are a bit tight it will usually prevent it from thudding right down.

The bolt handle goes in easier than it comes out. When you take it out, pull and TURN it. Should come much easier that way!



As for the shell drop button (the part UNDER the receiver by the trigger guard), it requires a bit of explaining so hang on. You can pull the bolt back on the M4 and it will not cycle a new shell from the mag tube into the lifter. This is designed so you can extract a live round a put in a "specialty" or different round in without messing with your mag tube. (say you want to put a slug in when your mag tube is full of buckshot).

When you pull the trigger to fire the gun, it automatically "engages" the shell drop lever and the mag tube feeds a new round into the lifter. This way when the bolt cycles (it cycles really fast) the new shell is already on the lifter.


The round button the SIDE of the receiver is essentially the bolt close button. The M4 locks the bolt back on the last fired round, so when you feed a new shell into the gun, you push that button the close the bolt. It works essentially just like the bolt hold open button on an AR15 for dropping the bolt. A proper reloading procedure when the bolt locks back, is to drop a shell right into the ejection port and close the bolt (gun ready to fire) then load up the magazine tube.

You can also unload ammo from the mag tube by pushing your finger upinto the lifter (like you're going to load it) and pushing the little round button OUT from the inside, it will let a round out exactly opposite of how it went in.


Hopefully this explains it a bit better for you, really the M4 only goes together one way, so as long as the mag tube cap is screwed on nice and snug it should work fine! Again, you need to use your discretion, it should be tight but you should not need a tool to remove it. It will be tight the first few times you strip the gun.

mike_r said:

thanks raptor! awesome explanations. i get it now.

so to recap the shell drop button. basically if you want to fire normally and have the next shell automatically load into the chamber, then ignore the shell drop button.

if you want to swap in a specialty shell, just push in the shell drop button so the orange dot is not exposed. rack the bolt carrier back, extracting the live round. the next round in the mag will NOT be fed in.

you manually insert the specialty round you want to use. you let the bolt carrier slide forward. now you are ready to fire your specialty round.

i pretty much figured out the whole ar15 ish bolt carrier release button. the instructions were crappy but not that crappy! the bho feature is nice, makes it very ar15 ish.

Click to expand...

Actually just opposite for the shell drop button, in order to put in a "specialty" round you do nothing but pull the bolt back, put the new round in the ejection port and let the bolt fly forwards. That little teeny button on the side of the trigger guard is what "advances" the next round from the mag tube. So if you had lets say a mix of slug-buckshot-slug-buckshot-slug in your mag tube and you wanted to quickly get rid of a slug and go to buckshot, THEN you would hit the bottom button and charge the weapon, which would eject a live round and feed the new round without actually firing it.

Think of the bolt carrier/barrel/lifter and the magazine tube as 2 completely separate systems. The bolt can operate completely by itself without causing the mag tube to do anything, but when you pull the trigger (or hit the shell drop lever) it activates the mag tube and spits a new round into the lifter.


If you get a couple snap caps, it really is simpler than it sounds to actually mess with it. There are very few times when you'll actually use the shell drop lever, except when you want to lock the bolt back when the gun is empty (say if you store it with the bolt forwards but want to transport it with the bolt open, you can hit that lever and it will cause the bolt-hold-open to engage, then you pull the bolt back and it will lock open), or if you want to load the gun from the magazine only, say if you're out in the country and have the tube full but none in the chamber - you'll hit the button and rack the gun to load the shell into the chamber.