Because the spring loaded yoke screws depend on a rather small center pin they are more prone to issues than the older design. I would suggest that you purchase a couple of spares from Brownell's or Numrich's. With the recoil the 460 Magnum can produce you'll probably need to replace it a lot more frequently than a milder caliber.
BTW, the thread size is a standard 4mm Metric but I don't recall the pitch, vague memory has it being either .75 or .80 but don't count on that. However, it is a standard Metric pitch, that I do remember because I got one at a local screw supplier.
I mention this because it may be possible for you to locate a 17-4 Stainless screw in this size and "fit" it to your yoke to obtain a solid one piece screw. I did that with my 617 when it still had an Aimtech sideplate secured mounting rail on it and the yoke screw that it came with only had 1 1/2 turns of engagement. Aimtech had copied the appearance of the standard spring loaded screw and that took away a lot of threads for engagning in the frame. What I did was purchase a Metric Socket Head screw and beveled the tip to fit the groove in the yoke and kept adjusting that bevel until the yoke JUST stopped dragging on opening with the screw fully tightened.
If you want to do something similar and have it look factory, you'll first have to locate a metric screw that is slotted and made using a high strength stainless steel such as 17-4. Next I expect that you'll have to reduce the diameter of the head of the screw because I suspect it'll be slightly smaller than the standard. Use your existing yoke screw to determine sizing and I've found a Dremel holding the screw and using a stone will work well for reducing the head diameter. It also help to keep the stone "wet" with either water, oil, or beeswax so it doesn't load up. One you have the head turned to size, flip the screw over and chuck the head in the Dremel and once it is running true, snug it up FIRM. Then use the stone to bevel the tip so it eyeball matches the groove in the yoke. After that you snug the screw LIGHTLY in the frame and check the yoke for dragging as you open it. Keep going back and forth until the drag vanishes with the screw snugged LIGHTLY and then start dusting it down until you can tighten it fully with either a tiny hint of drag or the drag has just disappeared. Based on my experience it'll probably take about an hour to fit it perfectly, however you'll then have a yoke screw that is a lot more suited to the recoil your 460 Magnum can produce.
BTW, if you can't find a slotted stainless screw you could use a blued socket head screw. If won't look "factory" but who cares about looking factory at the range. When you want to dress it "factory" just install the standard yoke screw. If you go with a socket head screw, two tips. One, start out with the yoke screw a bit loose and keep an eye on it tending to shoot loose. Use the amount of bend you see in the hex key with a fingertip on the end as a guide to how tight to set it. One issue with socket head screws this small is they tend to strip the hex key and then the socket, so you never want to set it "stupid tight", you want it just tight enough it won't shoot loose. Second tip, keep and eye on that hex key and if you see any hint of the corners rounding over, grind the end back for a fresh tip. One thing I've learned from years of experience is that it's easy to over torque one of these smaller screws due ot the length of the moment arm and if you strip the socket it's a nightmare getting it out.
