Pistol POA versus POI

[Willie Earp, SASS#19022]

Hey!

I have a question from one of the newbies who shoots 45 Colt in the New Vaquero.

With a 200 grain pill, what MV will make it so that your sights and the point of impact will be the same for the typical SASS ranges?

 

I don't shoot Rugers. My 45 Colt loads are the standard 255 grainer Black Powder so I never spent the time to work up a smokeless load for the lighter bullets.

 

Regards,

Willie

[Yusta B.]

With stock height frt. site you will probably not get poa/poi with 200 gr. without trimming the frt site. It will most likely hit low.

[The Original Lumpy Gritz]

No tell'n till the test fire.

OLG

[Dutch Al #22045]

Four factors determine where the bullet will strike, with respect to the point of aim:

The actual sight dimensions, like the height of the front sight, etc.

The weight of the bullet

The power of the load

The strength of the shooters grip

 

So there's no formula to tell a shooter where the bullet will strike. +1 to Original Lumpy Gritz, you have to test fire, then adjust the sights. I would recommend the shooter first find a load he likes. Especially with fixed sight handguns, don't change the sights until you've found a load that works well. After you have a good load, THEN file the sights.

 

You can change the point of impact with bullet weight. Light bullets tend to strike lower (for a given sight setting), while heavy bullets strike higher.

The power of the load seems to have less effect on point of impact, than does bullet weight.

 

With most fixed sight handguns, they tend to shoot to point of aim with heavier bullet weights. For example, 38/357 pistols shoot closest to point of aim with 158 grain bullets, and 45 caliber pistols shoot closest to point of aim with 230 grain (45 ACP) and 250 grain (45 Colt) bullets. The heavier bullets give more muzzle flip than lighter bullets.

 

Differences in grip strength can affect point of impact more than most folks would think. For any given gun, there will be more muzzle flip from a shooter with a mild grip, than from a shooter with a really strong grip.

 

Last, how you hold the pistol will make some difference on side to side bullet impact. For right handed shooters, pistols will often group slightly to the left of the point of aim. Try shooting that same gun with your left hand, and most likely the point of impact will move more to the right.

[ShadowCatcher]

You can almost be sure that you'll have to remove metal if you stick to a 200 grain lead bullet.

Most .45 Colt pistols are traditionally regulated for 25yds with a 250 grain bullet at standard velocities (around 850 - 930 f/s).

 

When I was doing load development for my Rugers (7.5 " and 4.6") I tested with both 250 gr LRNFP and 180 LSWC just to

see which did what and tried a few powders as well. Generally I bounced between using Bullseye (from my .45ACP days)

and Tite-Group and Trail Boss. Both give me the exact same groups, but TG tends to be louder and runs a few f/s faster for similar

loadings. I've decided to stay with Trail Boss for my CAS shooting as I wanted to avoid cutting metal, as it's a one way trip.

 

I've stayed with the 250 loading as it is easy enough on recoil, but the shots hit POA=POI.

 

My results:

 

 

 

[Tom Bullweed]

Every gun and every load is different.

What range is critical? Sights sit on top of the barrel and align the poa/poi for one load at two distances, once as the bullet passes up through the poa and once when it drops back through the poa.

Front sights that are too tall or rear sights that are too short means that the bullet path never crosses the poa.

Poa is a straight line while poi is a parabola, aka a curve that drops more rapidly as it extends.

[Blackey Cole]

It depends on the barrel length I shoot 190-200 gun pills in my Ruger 45s they are my wbas rifle loads now but I have shoot really light loads of trail boss