Author Topic: POI Change with bullet weight (Read 2024 times)

RonO777 · « **on:** February 24, 2004, 04:45:30 PM »

I was shooting this weekend and I changed bullet weight on my 243 from 100grain to 55grain. The POI moved but not in the direction I would have thought. It moved about 2inches to the left. But still printed a three shot group that was touching each other. A few clicks an it was back on target.
On my 223 I went from 55sp's to 45jhp's and the poi was about a inch to the left also. Is this normal? I though the point of impact would move up or down. Not right or left.

Ron

handirifle · « **Reply #1 on:** February 24, 2004, 07:21:07 PM »

I'm not an expert on this at all but my guess if the change in barrel vibration timing was influenced by something making the barrel move from left to right. Do your groups have their widest measurment from left to right or top to bottom?

RonO777 · « **Reply #2 on:** February 25, 2004, 02:06:21 AM »

The 243 was putting the bullets in a vertical lineall rounds touching. I couldnt tell ya in which order they hit. But before with the 100 grains the best it would do would be 1 1/2 inch groups at 100 yards.
The 223 I dont remember off the top of my head. Ill have to get the target to check that out.

Ron

jrcanoe · « **Reply #3 on:** February 25, 2004, 07:25:29 AM »

My best gun changes poi every time I take it to the range. It allways groups very well but takes a few clicks to get it to hit thumb tacks at 100 yards. I can be shure of hitting a half dollar everytime I take it out of the case but cant be shure of which side it will hit. This is the same thing I observed when I shot on the rifle team in high school but there once one of my team mates clicked in his gun useually I could move my sites by the same amount and be right on when it was my turn. When I buy a new gun I buy several types of ammo these allso print groups around a point of aim if they group at all.

handirifle · « **Reply #4 on:** February 25, 2004, 07:30:54 AM »

rono
A number of things can cause the verticle part. Resting on the front part of the forend (handi's are sensitive to this), varying ammo velocities, firing rounds too close together, time wise, if you have the ultra light, this is common.

RonO777 · « **Reply #5 on:** February 25, 2004, 03:15:40 PM »

The 223 is a bull barrel, its not really stringing the shots. A five shot group is well under an inch. I thing if I was to put the scope off the 243 on the 223 my groups would be a lot tighter. It has a lot finer crosshairs an twice the power. I konw Im splitting hairs here. The POI movement would still put the bullet in the killzone on just about anything I wanted to hunt under a 100 yards.
But in a couple of months Ill be in north Texas p-dogs and most of the shots we took last time were out past 250 yards. I want to get a kill with my Handi past 350 yards. And past 500 with my 243.

Ron