I am looking to change the front sight on my 66-8. Most of the suppliers offer a .250 or .300 high sight. If I am measuring it correctly, from the top of the rib to the highest point of the factory blade I am getting just under .250. Does this sound correct?
.300 would be from the center of the cross pin hole that attaches the sight blade to the highest point on the blade.

Thanks

Going from a .250 sight to a .300 sight will make you POI LOWER with respect to your POA. Is that what you want?
Sight Calculator

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Science plus Art

The .250 is right.. top of the rib to top of the sight blade.

You'll need to drill the new sight blade, and the best way to do that is to alternately drill from both sides until the holes meets in the middle, ensuring that it will be in alignment with the pin holes on either side of the rib/base.

A number 54 drill bit is the correct one to use.

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Conrad
SWCA #1830 SWHF #222

I don't want to change the height I just want to ensure I am selecting the correct height from the two options offered by my measuring methods. I really appreciate the link to the sight height calculator. This will prove helpful in the future.



Thank you for the confirmation. I felt I was correct but with so much info available on the forum why not double check and buy once. I appreciate the tip on working it from both sides to prevent a "bind". I have a table top drill press and a set of number drills so good there but i will pickup a new #54 to ensure its sharp. The cross pin appears to be a roll pin, do you recommend getting a new one or reuse the existing pin and is S&W the best place to get one if needed?



Thanks again gents, you both have been very generous in answering.

The drilling from both side is not prevent a bind, it's to make sure that the existing holes in the rib/base are in alignment on either side of the sight blade. I would not drill straight through from one side, as the hole on the other side may not be exactly perpendicular to the one you're drill through, and you'll end up enlarging/elongating the "exit" hole.

In fact, I don't think they are perpendicular... when the old pin is driven out, there's usually a very slight arc in it.

I think the holes are drilled in such a way to cause the pin to draw the sight blade down against the the top of the rib as the pin is driven through, and place tension on the pin to keep everything together.

Use a new pin, they are cheap enough... Midwayusa has them in stock: Smith & Wesson Front Sight Pin S&W 36 14 16 17-8 19 24 27 29

I think the way things are going at S&W, you get it faster (but not cheaper) buying from Midway.

People have also made their own using the shank end of a drill bit.

Update: Ok, I just noticed in your post that you have a -8 version and that the pin looks to be a roll pin. What I described above is with the older solid pins, so the link to Midway is for a solid pin... sorry about that. Looks like you'll need to go to S&W.

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Conrad
SWCA #1830 SWHF #222

Thank you sir and greatly appreciated!

Just an FYI in case someone else needs one or more Brownells has the front sight pins in stock.