I installed the HiViz (Green) front sight on my S&W 617-6 (4" barrel) and the results were excellent. It's easier to get good sight alignment and sight picture with the HiViz versus the OEM black front sight. I've included installation notes (long) below in case anyone is interested:

You will need to drill a hole in the HiViz base tab for the roll pin to install it on a S&W 617. You can pay a smith to install it for $20 - $30 or you can install it yourself if you have the right tools and skill level. I installed the HiViz on a S&W 617 in about an hour. Here are instructions if you plan to DIY:

Tools/Materials needed: .050 cup tip punch (Brownells); a 2”x2”x3/4” piece of plywood; small hammer; 1.35 mm (.053) drill bit with a 1/8” shank (get at least two drill bits, available on eBay for about $1.99 each) and a variable speed Dremel tool. You will need to reuse the OEM roll pin.

The OEM front sight blade is secured by a roll pin that should be driven out with the .050 cup tip punch. The pin should come out easily with several light taps. Once the pin is removed, you can tap the front sight blade out with the piece of plywood and a small hammer. Place the plywood on the back of the blade and tap it forward with the hammer until the front edge of the blade clears the barrel, then using the plywood again, tap the front of the blade upwards. Use Kroil or similar if the blade is difficult to remove. You don’t have to and shouldn’t have to use pliers to remove the blade.

You may want to very lightly sand the sides of the HiViz tab where it will sit into the groove of the front sight mount on the 617. This will help with the installation because right out of the box, the HiViz will be very, very snug. However, don’t take off too much from the tab. The HiViz was made to be somewhat snug in the mount. Also, remove a little material from the base of the HiViz tab to ensure a flush fit between the sight mount on the 617 and the bottom edges of the HiViz. You’ll only need to take off very little from the bottom of the tab (1/64” or so). Next “eyeball” the HiViz so that the front end looks somewhat flush with the front barrel and start to sit the HiViz (by hand) into the groove of the front sight mount (note the optic side of the HiViz faces the rear sight). Place the plywood so that it is flat on top of the HiViz ensuring that it covers both ends (to prevent damage to the fiber optic cylinder). Gently tap the plywood until the HiViz bottoms out in the mount. Hold the 617 up to a light source and check if the HiViz is seated flush with the sight mount. If you see light coming from between the HiViz and the mount, you will need to take a little more material off the bottom of the HiViz tab. Remove the HiViz from the mount using the same technique that was used to remove the OEM blade and take off a little more material from the base of the tab (light sanding may do it).

Reinsert the HiViz into the mount with the plywood and hammer as describe above if it was removed for adjustment. Check that the front of the HiViz is flush with the front of the barrel. If not, use the plywood and hammer to adjust horizontally as necessary. Finally, lay the plywood on the top of the HiViz and tap lightly to ensure it is flush with the mount on the 617. Now you’re ready to drill the hole through the HiViz tab for the roll pin.

Use the existing holes in the front sight mount as a guide to drill the hole in the HiViz tab, start on one side of the 617 sight mount. Use a low/medium low speed on the Dremel and carefully start to drill a hole in the HiViz using very light pressure on the Dremel. Be careful not elongate the hole of the mount. Drill about halfway then drill from the other side of the mount. Take your time. The HiViz tab is soft metal and it won’t take much to drill a hole straight through. CAUTION: TOO MUCH PRESSURE OR HIGH SPEED WILL BREAK THE DRILL BIT. Use the .050 punch to check that the hole is aligned then insert the roll pin and you’re done!

Note: Some use a .054 drill bit for the roll pin hole but I went to a .053 drill bit instead to get a snug fit when reusing the OEM roll pin. The plywood block was used as a “tool” because it’s soft and not likely to damage OEM blade or the HiViz.