I bought a new 460XVR today, and I was unable to check the timing due to the store requirement to keep the plastic trigger lock in place. Checking it at home on a new, never fired revolver, three of the five chambers do not lock before the trigger engages the sear. Check with snap caps in place.

However, if the revolver is held on its side with the cylinder release facing up, it will lock on all five. Why would this have an effect?

Very disappointed, but I received a shipping label and will send it in tomorrow.

Did you do this while cocking the hammer slowly?
Did you check it while pulling through DA?

The XVR has a very heavy cylinder and due to "tolerance stacking" can demonstrate failure to carry up when the hammer is slowly cocked, yet worked great with a full cylinder being rotated quickly as it is in normal use.

The "hand" initially engages the cylinder ratchet and drives it upward as the "trigger" is cocked...the hand is attached to the trigger, not the hammer. When thumb-cocking, the SA "sear" drives actuates the trigger which moves the hand.

As the cylinder nears alignment the ratchet presents a different face that allows the hand to slide alongside it which avoids parts binding, and helps rotate the cylinder the final bit so the cylinder stop can snap into place. This is why quick rotation tends to work cleanly while trying to cock it slowly can fail to fully carry up.

Application of a viscous oil or grease to the ratchet can "cure" the problem, while running the cylinder dry makes it more prone to happen.

I had the same problem with my XVR and daubing some vaseline on the ratchet "cured" it. Interestingly my 500s don't have the problem and I wonder if it's because the cylinders are just that little bit lighter.

Well, after nearly four weeks in Springfield, I received 460XVR and the timing issue still remains on three of the chambers and one chamber it will lock when the trigger is back 99%. This is even worse than when I sent it in in regards to the timing.

Repair order says the cylinder, extractor and hand were replaced and the yoke repaired. The BC gap went from 0.004" to 0.008" with the new cylinder. The rear sight track being offset 0.030" from the centerline was determined to be with in specification. The paperwork said it was functioned tested and test fire, but there is no burn mark on the front of the cylinder. The original cylinder had one chamber with a burn mark.

Are these X-Frame revolvers different from all the other Smith & Wesson revolvers and don't rely on the had to push the cylinder into lockup and also rely on angular momentum to lock?

Nope. Send it back again.
I sent mine in for same issue while in double action.
Returned in 6 weeks with perfect timing.

If there is a 0.000001% chance the cylinder wont align it needs to go back. .

A 22 you would get a scare. A 460 you get prosthetics