So each of the 3 calibers this gun can fire shoots differently. I shoot all 3 regularly. Not my carry gun. I have the sight (only rear adjustable) adjusted for 357 Magnum 158 grain load. Good groups there. Is there a standard approach to this? Not critical since it is for target only mostly. Thanks.
Which Caliber to Use to Adjust Model 66 Sight?
- Thread starter MagDiddy
- Start date
It technically shoots two calibers, .357 magnum and .38 special. .38 special +P is not a separate caliber. It is simply .38 special loaded to a higher pressure. Sighting is up to the individual, but the Model 66 would traditionally be sighted for .357 magnum 158 grains at 25 yards.
Impact points could shift when changing to different ammo of the same caliber.
buck460XVR
New member
Unless you are using it for home defense or self defense. Then you zero it to your expensive hollow point "war loads" not your cheap practice ammo.
If it's just a range toy, it doesn't matter as much. You may find a zero that isn't spot on for any load, but close enough for all the ones you shoot.
bamaranger
New member
get lucky
Experiment a bit.......if you can find sufficient ammo.
Two of my .357 revolvers ( a 4" M28 and a 4.5" Ruger B-hawk) will shoot magnum 125 gr JHP's, and .38 wadcutter, to very close enough POA/POI, that I can use the same sight setting for both loads. My midrange 158 gr LSWC load is not far off on the M27 either.
You might find that your gun will do the same, or with some other combo given some experimentation.
Experiment a bit.......if you can find sufficient ammo.
Two of my .357 revolvers ( a 4" M28 and a 4.5" Ruger B-hawk) will shoot magnum 125 gr JHP's, and .38 wadcutter, to very close enough POA/POI, that I can use the same sight setting for both loads. My midrange 158 gr LSWC load is not far off on the M27 either.
You might find that your gun will do the same, or with some other combo given some experimentation.
If you want to be really technical, both .357 and .38 Special are the same caliber, .35...
They are different cartridges, but the same caliber.
Caliber denotes bore size (and also barrel length in artillery) but it is common American usage to use the cartridge name as the gun's "caliber" so its easy to get confused.
This is the most practical answer.
there is a point to this, if you are only using the gun as a self defense piece.
However, the beauty of adjustable sights is that they move, easily, and can be moved, and moved back, repeatedly.
What matters is that you shoot both your defense loads and your practice loads and determine how much (If any) difference in point of aim vs point of impact there is.
At usual defense ranges there may not be much difference, or there could be a large difference, each gun and ammo combination is a rule unto itself about that. Usually they will be pretty close, but you might have an unusual situation so you need to shoot them both to verify what you have.
Once you have the gun sighted in "dead on" for one load, shoot the other to see how far off (and in what direction) it is. Then adjust the sight for that one, COUNTING the clicks and direction it takes. Make a note (I suggest you write it down) of how much you change the sights for each load.
IF, for example, you sight magnum load dead on, and then learn that its 3 clicks up and 2 left to be "on" for .38s, there you go, make a note of that and keep it somewhere you can find it, in case you forget.
Once you are sighted in for one load, make a reference mark, such as a thin stripe of contrasting color (paint, nail polish, Sharpie ink, etc) that goes over the adjustment screwhead and the sight body so you can see when they're lined up for your chosen load. You only need one mark, it fits lined up you're sighted for "A" if not you're sighted for "B". If you're anything like me, you WILL forget which load you last sighted in for, unless you have a witness mark of some kind.
Having sighted in for both, with a way to know which is which and what the difference between the two is allows you to change back at forth at need with just a proper fitting screwdriver.