POI high & left

[gareth96]

Finally got my 9mm leading and accuracy problems sorted out, but the result is that the group is about 3" high and left at 15 yds (nice 1.5", 10 shot group from rest). I'm using Unique right now with the Lee TL356-124-TC.. you think changing powder will get it where it's supposed to be? Shooting Rem or WWB it shoots right dead center.

[mdi]

Not sure how much a different powder/load will move a POI (although I'm sure it will), but FWIW here's a chart I found interesting. What I found with my Magnum shooting was POI in the upper left on the chart; I was anticipating recoil and was pushing just enough to move my groups a couple inches...

[MrHarmless]

Are your sights adjustable for drift? If that's what you want to shoot, that's an option.

[gnostic]

Most of my handguns shoot high with cast bullets, I use a 6:00 o'clock hold and that puts me on. Left or right of the target's about how I make contact with my trigger finger.

[bigboredad]

Faster powder should lower the impact also increasing the velocity will lower the impact. as the bullets leave the barrel sooner giving it less time to effect the gun. I'm sure others can explain it much better than I can

Sent from my SM-T377V using Tapatalk

[Rcmaveric]

Pick your load then shoot off sandbags. Adjust your sights for poi. All bullets and loads impact differently. Once your sights are adjusted then you csn use the hand gun shooting target.

Sent from my SM-G950U using Tapatalk

[gareth96]

Loaded up 10 rounds each of suggested starting loads of Zip and True Blue, see how they do when the rain stops. Faster with the Unique was giving me **** for precision (large spread), but seemed more centered on the point of aim.... maybe... Slower and I have good precision, but bad accuracy (not near point of aim). Maybe the other powders will give me more speed and better accuracy with some semblance of precision.. I think I have some HP38 too to try.

[mdi]

When you mention "precision" are you talking about group size? And "accuracy" as POA vs POI?

(I've only had one cup coffee this morning so my old mind may not be reading korektly :veryconfu)

[gareth96]

yep, I have to look it up every time I think about it...

[mr surveyor]

I've always considered "precision" is hitting the "X" ..... and accuracy is putting the shots in the same place. "Precision" can be adjusted by the sights ... accuracy has to be worked out based on the load itself (if the firearm is capable).

But then again, I could be thinking backwards (it's beginning to happen more often lately :-( )


jd

[Rcmaveric]

I've always considered "precision" is hitting the "X" ..... and accuracy is putting the shots in the same place. "Precision" can be adjusted by the sights ... accuracy has to be worked out based on the load itself (if the firearm is capable).

But then again, I could be thinking backwards (it's beginning to happen more often lately :-( )


jdI dont use the term precision much. Never really thought about it. I would say i agree with you. Precision would be my ability to hit the X and accuracy would be the size of my group (probably around the X lol).

Sent from my SM-G950U using Tapatalk

[gareth96]

Google it.. it's actually the opposite. Precision is how tight the group is, accuracy is if you are hitting the intended target.

[Dusty Bannister]

Getting lost in the weeds of over thinking are we?
The objective was to regulate the load to the sights.

[mr surveyor]

Google it.. it's actually the opposite. Precision is how tight the group is, accuracy is if you are hitting the intended target.


yep, I believe that's right ..... since my late, great medical malady of 2016, what should have been the normal age progression into the "senior moment" has become more of the "senior day". Funny thing is, for the last 20 or so years of doing precision gps work I've been able to equate gps statistics to firearms targets. It's basically the same principles applied to the final target.

Thanks for clearing my head fog. :)


jd

[JoeJames]

Faster powder should lower the impact also increasing the velocity will lower the impact. as the bullets leave the barrel sooner giving it less time to effect the gun. I'm sure others can explain it much better than I can

Sent from my SM-T377V using TapatalkHeard it called "Dwell time"; slower loads take longer to get out the barrel. Barrel is moving up by the time boolit clears = hitting high.

[mdi]

Getting lost in the weeds of over thinking are we?
The objective was to regulate the load to the sights.

Yep, I wuz just unsure of terms. Sometimes folks from different areas (of the country and world) have different terms. Wasn't questioning the OP, wanted info for myself...

[dondiego]

Lower the rear sight an move it a bit to the right.

[fredj338]

In all my handguns, regardless of caliber or bullet/powder combo, ever changes POI @ less than 25y by more than 1" or so around the clock face. Not saying it doesn't happen but I suspect it is the shooter more than the lead bullet/powder combo.

[fredj338]

Heard it called "Dwell time"; slower loads take longer to get out the barrel. Barrel is moving up by the time boolit clears = hitting high.

I have often disputed this because it Is easy to test. Fire any bullet wt in your gun, say 9mm, from 90gr to 165gr, all at the same vel of say 900fps. If there is a POI shift, it will be the heavier bullets shooting a bit high, lighter bullet a bit low. Dwell time is identical.

[gareth96]

Well I shot the 20, and the leading came back... I know I shouldn't change so many variables at once, but I decided to size the boolits, and then put a double PC on, then sized again.. loaded with 4gr of ZIP, and made the crimp as light as I could get it to still pass plunk test.. got a little under 2" group at 15yds, horizontal was right on, but about 1" high vertically. No leading. Speed averaged 1020fps, but about half the cases had slightly flattened primers. Due to other stuff going on, going to have to set this project aside for a bit.. I have some different expanders coming, so will prob start fresh in a few weeks.