Load development for point of aim

[awaveritt]

I have shot a thousand or so 158gr. lead boolits over 3.5 gr. of Bullseye thru my S&W 638 and have become used to the point of aim relative to my sighting hold. Now I'm casting some 125 gr. RN and am wondering what kind of change in point of aim I can expect. I plan to also use 3.5 grs of Bullseye to start out, but will this raise or lower the expected point of aim? I'm assuming an increased charge will be needed to return to my original point of impact with the 125 grain boolits. Anyone already invented this wheel?

[leftiye]

Try it, is all I can suggest.

[EDK]

Conventional wisdom is that lighter boolits hit lower. Shoot it first...then file front sight to raise point of impact. Remember that adding metal isn't easy! It doesn't take much to change things drastically.

If you really like this little gun, go to bowenclassicarms web site. He does a conversion with dove-tailed front and rear sights that give an excellent sight picture, but stay very low profile.

:cbpour::redneck::Fire:

[Echo]

My guess is that you will need a heavier load of BE, to increase recoil, to make pistola kick up more, so that the 125 hits the same point of aim as the 158. And if you are going to shoot both, DON'T file the front sight! The new Lyman reloading book shows a max of 4.4 grs BE for a 120 grain boolit. I would try 4.0 and move up or down .1 as required for hitting the POA.

[HORNET]

Lighter boolit with the same powder charge: point of impact usually lower due to higher velocity giving the pistola less time and impetus for the barrel to rise. You probably ought to try those 125's with something more in the 2.8-3.0 range and see what you get. Might need more or less powder to get close or it could go bonkers on you and show a heavy shift to one side, just to confuse you....