Interchangable front sight and zero, 625 JM

[MarkL_01]

This is not so much gun-smithing as parts-changing. I put a HIVIZ fiber optic front site on my 625-8 JM. I had to shorten the 'feet' on the base of the sight and slightly narrow the base to get it into the slot on the barrel. No filing was done on the revolver. Elevation didn't change, but the point of impact was changed substantially to the left, such that the rear sight adjustment range would not center the group at 25 yards.
I took the sight off and put the original back on. Just slipped it back in, no fitting of course. The point of impact at 25 yards is still substantially left of center; about 2 inches left with the rear sight all the way to the right.

Any idea what I might have done to cause this?

The barrel seems to be very slightly canted to the right, so that the edge of the barrel rib is a little closer to the edge of the frame on the right side, but getting a good center zero did not require the rear sight to be much off of center before I messed with the front sight.

Thanks for any suggestions, or even ridicule (although I'd probably just ignore that). <smile>

-Mark

 

[brian_a_mcmillen]

I recently had the same issue with a model 13-2 that had a barrel change and because it was "clocked" slightly to the right (as you're looking at the sight as you're shooting) it shot about 3" left at 50'. I took it back to my smith and had him torque it more which centered the front sight, it now shoots fine. As it turns out, a few degrees off center make a huge difference at distances.

Brian

 

[Gunhacker]

How does the front sight look? Might it be canted too?

Checkout my post regarding my 625-8 experience with a canted barrel and a canted Hi-Viz sight blade:

http://smith-wessonforum.com/s-w-revolvers-1980-present/443081-2-wrongs-sometimes-makes-right.html?highlight=wrongs

 

[MarkL_01]

How does the front sight look? Might it be canted too?

Checkout my post regarding my 625-8 experience with a canted barrel and a canted Hi-Viz sight blade:

http://smith-wessonforum.com/s-w-revolvers-1980-present/443081-2-wrongs-sometimes-makes-right.html?highlight=wrongs

I will read your post. Thanks for sending the link.

I'm second-guessing my statement that this problem started with the installation of the Hi-Viz sight. I'd only shot this revolver casually at short ranges before, and I don't think I'd previously adjusted the sights. I've had it for several years, but have only shot maybe 100 rounds through it.

With the original sight reinstalled, the group was 2 1/2" left at 25 yards (measured this time, instead of 'ballpark'). Neither sight seemed noticeably canted.

Looking from the muzzle, the top of the rib is obviously not level with the top of the frame. Measuring from the edges of the rib to the corners of the frame, I get 0.36" on one side and 0.18" on the other.

Just messing around today, out of curiosity I cut a slot in the Hi-Viz sight to let it sit farther to the left (fitting over the ridge on the inside of the slot in the barrel rib) and shimmed it to keep it there. I'm going to see what that does at the range and then I'll probably give S&W a call.

Thanks for your reply.

-Mark

 

[MarkL_01]

How does the front sight look? Might it be canted too?

Checkout my post regarding my 625-8 experience with a canted barrel and a canted Hi-Viz sight blade:

http://smith-wessonforum.com/s-w-revolvers-1980-present/443081-2-wrongs-sometimes-makes-right.html?highlight=wrongs

That was an interesting read. I'm sad that others are getting revolvers that have assembly problems, too, but at least I know it's not just me.

The comment that most have no problems might be correct. I only have three post-1980 revolvers, the other two are 629-6 and they're just about perfect. I had a model 15 from 1980, and running the rear sight to the end of its adjustment would not even bring the shots into the black at 25 yards.
I traded that for one of the 629s.

-Mark

 

[Gunhacker]

I only have three "recent" models of S&W revolvers. After the 625-8 experience, I really inspected my next potential purchase with a fine tooth comb.

I was looking at the new 4" bbl M69 L-Frame .44 Mag revolver, I had to go to three gun shops before I found one that did not have a canted barrel... pretty sad comentary.

 

[Baltimoreed11754]

I had to return a .45 acp Thunder Ranch back to Smith to have a shorter front blade and the bbl turned. It was obviously off, don't know what the bbl installer was thinking. Shoots ok now though. I also did a high viz on my 625 JM as it's my zombie match gun. Whole lot easier picking up the front sight now.

 

[MarkL_01]

I only have three "recent" models of S&W revolvers. After the 625-8 experience, I really inspected my next potential purchase with a fine tooth comb.

I was looking at the new 4" bbl M69 L-Frame .44 Mag revolver, I had to go to three gun shops before I found one that did not have a canted barrel... pretty sad comentary.

That is sad.

The only new revolver I might consider at the moment would be a 4" Model 19. Hopefully, having a barrel shroud separate from the actual barrel would avoid this issue. I haven't tried to find out anything about that yet, though.

-Mark

 

[MarkL_01]

I had to return a .45 acp Thunder Ranch back to Smith to have a shorter front blade and the bbl turned. It was obviously off, don't know what the bbl installer was thinking. Shoots ok now though. I also did a high viz on my 625 JM as it's my zombie match gun. Whole lot easier picking up the front sight now.

My current interest in the 625 is to try it in a steel challenge match. I'm tired of losing brass. <smile>

I've had this revolver for a good while, but so far had only plinked with it at short ranges and hadn't tried to adjust the sights.

-Mark