It's surprisingly hard for me to find info on the 638 - I guess it's not nearly as popular as other J Frames.

Anyway, I'm looking to order a 638 this month, and I want to swap out the front sight for tritium, bog dot, fiber optic, etc. - something better than the ramp. When I look into it, I see option for the longer barrel 638 (2 1/4"), but not the shorter barrel. When I look at pictures of the two, it looks like the longer one has a pin, whereas the shorter barrel does not.

So if I get the shorter barrel and it isn't pinned, can the sight be changed out?

Thanks,
William

The short answer is NO! The 1 7/8" short barrel has the front sight milled right onto the barrel. The longer barrel 2 1/4" may have a removable front sight but was not made to go onto the frame the 1 7/8" barrel came off of. You need to look at the dash numbers for each model. It is not normally an option on early 638's. When S&W went to .357 mag in those little guns the longer barrel came in during an engineering change at that time as did a longer cylinder. The long barrel will have the shorter shank to fit with the longer cylinder. You might be able to find a gunsmith/machinist to make it work.