Model 520 front sight height?

[Tom K]

Hey, can someone with a Model 520 (the blue, six shot, fixed sight, N-frame .357) measure the height of the front sight for me? I have one that I bought a few years back and the front sight has been filed down to only .088 above the top of the ramp.

The GB seller theorized that someone was trying to sight it in for 125gr ammo. My theory is that they didn't know what they were doing and were trying to lower the point of impact by lowering the front sight. After all, you lower the sight to make it shoot lower, right? And you can't get the rear sight any lower so....

Firing a 158gr SWC at 1370 fps, the bullet strikes about 3-1/2" high at 20 yards. I haven't really tried it with 125gr ammo.

 

[Alk8944]

Probably trying to get it to shoot POA with 110 grain ammunition. Doesn't mean he didn't know what he was doing, just that he was an idiot to make such a non-reversible change to a gun with a un-replaceable front sight.


I don't have a 520, but to raise poi 3.5" on a gun with a ca. 5 1/2" sight radius @ 20 yds the front sight needs to be aprox. .087" higher, or twic what that sight is. That would make the front sight for the 520 ca. .175" Simple arithmetic!

 

[kennethg]

my sight blade measures .138

 

[Tom K]

my sight blade measures .138

Thanks, that's good to know. That's about the height that I calculated that it should be based on how high it is currently shooting.

 

[WR Moore]

I've no idea if that sight blade is integral to the rib or a separate part. If separate, you should be able to replace the blade. If not, there's enough meat in that rib to allow machining a dovetail slot for a new sight. A really classy job, you could retain and extend the current ramp at a higher height.

IIRC, the typical non adjustable sight setting was around 2-2.5 inches high at 25 yards. This gives an POA/POI at about 50 yards and a useable point blank situation overall.