I know this is an old post, but it sometimes it takes me a while to wakeup. This procedure is for people who are going to take their 464 apart anyway. I am just trying to help them...
This is a caution: do this procedure only if you're mechanically inclined preferably with experience disassembling firearms, do it where you stand a chance of finding any dropped parts, pay attention to what you're doing, taking pictures with your phone as you proceed is a good idea, if you can't get it apart you're doing something wrong, both pins are an easy fit, if you can't get it together you're doing something wrong, don't pound on anything, don't over tighten anything.
The bolt on my 464 SPX is actually very easy to remove, 2 screws and their associated pins and that's it. On the left side of the receiver there is what looks like a large screw, unscrew it and you find out that it's just a plug. Keep the Lever closed almost all the way and turn the rifle over and put a small punch or screw driver into the little, open hole and gently tap the pin out. The pin will come out via the the hole on the left side. This will disconnect the lever from the Bolt. Then remove the screw at the forward end of what Mossberg calls the Link. The Link is the piece that the fore end of the Lever goes into. Once the screw is out, using a punch and small hammer tap out the pin. The Lever will come loose, and by operating the Lever you can move it around and disengage the back end of the Link from the Locking Bolt and remove the Lever and Link as an assembly. Make sure the Locking Bolt is low in the receiver, and holding the hammer down, slide the Bolt rearward and out of the receiver. Note that the Firing Pin is loose and will drop out of the Bolt if given a chance. The Firing Pin is not symmetrical and must be oriented correctly in the Bolt. If you look at the back of the bolt, just make sure the angle on the back of the Firing Pin matches the angle on the back of the Bolt, or look at the underside of the bolt, into the slot that the Lever fits into, and turn the firing pin until it looks like the Lever will fit.
To put it together, put the firing pin into the bolt, making sure it's oriented correctly. Make sure the Locking Bolt is low in the receiver and holding the hammer down, fit the Bolt into the back of the receiver. The angle on the rear of the bolt faces down since that's what gives the hammer a ramp to ride up on to cock it. Turn the receiver over and put the front of the Lever through the slot in the Carrier, then moving the Link around engage the rear of it with the Locking bolt. Put the pin through the receiver and through the front of the Lever. Close the lever most of the way, and push the Link up into place. If you look through the hole where you removed the plug screw you'll be able to see the holes in the Bolt and the Lever and when they are aligned. Put the pin in the hole, smooth end in first and gently tap it in.
Hold the rifle and gently cycle the Lever making sure there are no problems. Finally put in the plug screw and the screw that retains the pin at the fore end of the lever.
That's it. Once you've done it a few times you can have it out and back together in a few minutes...
