Can ammo shift left/right POI?

[Boris_LA]

Would that be gangsta style by any chance ?? That would account for the L/R quite handily.

Following this logic one could shoot around the corner too.

[SlvrDragon50]

Went back to the range yesterday for my CCW class, and it was definitely my new grip. I suspect by taking my weak hand thumb off the frame, I was using more thumb from my strong hand causing the shots to fly right. I got 21/25 shots in the red today with one jerk I felt.

[SoCal]

You should be able to adjust to the new grip, it will take a few practice sessions.  And it's a good reminder how one small change can affect your shooting.

[Joe L]

Went back to the range yesterday for my CCW class, and it was definitely my new grip. I suspect by taking my weak hand thumb off the frame, I was using more thumb from my strong hand causing the shots to fly right. I got 21/25 shots in the red today with one jerk I felt.

Excellent!!  keep practicing with it.

Joe

[rhart]

I am currently experiencing similar issues sighting in new sights on my compact with a steel rail. I thought I had zeroed at 25 yards using 147 gr. rounds (round nose and then hollow point new FM ammo) and 135 gr. JHPs (again, Freedom Munitions new). Today, I shot 115 gr. new FM hollow point ammo and the rounds are consistently impacting 2" to the right of where the 147s and 135s impact. All shooting done off a bench with a sandbag. Groups from the 115 gr.s were tighter.

[Boris_LA]

Were 115rg groups also lower than heavy bullets?
You may want to stick with one type of ammo and sight your gun with it.

[rhart]

Were 115rg groups also lower than heavy bullets?
You may want to stick with one type of ammo and sight your gun with it.

Yes. the 115 gr. bullets were about 3 inches lower and to the right.

[IDescribe]

This is trigger pull.  If you don't pull exactly straight back, you are generating a lateral force with your trigger finger that tries to move the muzzle laterally, and you're grip/hand reacts with an opposing lateral force to compensate.  You can't see this because the sights don't come out of alignment, but the tension is there, and when the trigger breaks, the lateral force from the trigger finger disappears for just a moment, creating a lateral wobble.

Heavier bullets move slower, leave the barrel later, and exaggerate the POI impact of any muzzle movement.  With the vertical shift of POI with heavier bullets, that's normal.  With horizontal shift, that's the shooter creating that movement.

Every shooting tutorial and every bullseye shooter emphasizes pulling the trigger straight back, straight back, STRAIGHT BACK, ad nauseum, because if you don't, the release of that lateral tension at the moment the trigger breaks moves the muzzle at exactly the worst moment.

[rhart]

Sorry, I can't buy that in my case. When I don't pull the trigger correctly I shoot left or low and left (right-handed). I was shooting off a sandbag on a bench and being extremely careful to pull straight back while keeping the sights on target. My trigger pull is around 3 lbs (maybe a little less) in single action which is the mode I was shooting.

I place six 4" round black stickers on a target and send it down to 25 yards. When shooting 147 gr. the bullets impact on the 4" rounds - all six of them (ok a couple low left flyers that i called). I shoot 5-shot sets, reload between each set for rest, and I shoot all six targets before bringing the target back to look at it to avoid subconscious corrections from target to target.

Same thing with the 115 gr. bullets - six targets and every one of the groups were to the right just off the 4" dots, all six almost exactly the same distance from the center of the black rounds.

Same sight picture, same careful pulling straight back on a light trigger, six blind targets --> same results over and over.

Actually, I was intrigued by your theory about bullets engaging the barrel and deflecting it.

[rhart]

I adjusted my sights for the 115 gr. ammo and it's hitting right on target laterally and a tad low vertically (actually almost  POA = POI with my six O'clock hold). I can adjust my 6 O'clock hold easily to offset the low. The 147 gr. bullets are still impacting to the left - just outside the left edge of the four-inch round target. I will just have to remember to cheat to the right a couple of inches when shooting 147 gr. ammo. Maybe it does have something to do with the longer bullets.