Yesterday while sighting in an old (1964) Savage chambered in 338 Win, I experienced a 4 inch change in POI when shifting from 225 gr SSTs to 225 gr Trophy Bonded Bear Claws. The powder charge was the same. I checked the mount and rings and the scope positioning and nothing had changed or was loose. The SSTs were 2 inches high at 100 yds and the Bear Claws were 6 inches high. I also fired 2 other makes of 225 gr bullets and all were about 6 inches high. I had no more of the SSTs with me so I don't know if they would also be at 6 inches or still be at 2 inches. Any one here have any input as to the extreme (for 100 yds) 4 inch difference in POI?
POI shift
- Thread starter reomack
- Start date
That difference in POI is not really unusual at all.
Differently constructed bullets act differently on the target as well.
That is why the final sight-in before hunting should ALWAYS be done with the
load and bullet you intend to actually hunt with.
Dave.
Differently constructed bullets act differently on the target as well.
That is why the final sight-in before hunting should ALWAYS be done with the
load and bullet you intend to actually hunt with.
Dave.
Yup , quite common . 1-3" anyway don't know if I've had any go four inches . I put it down to the barrel harmonics and the bullet leaving from 1 o-clock to 12 o'clock . I used to think it should be up and down but they shift around the clock , so much so I keep a sight in book recording different scope sets for different bullets and loads
Alpheus beat me to it and said it better
Alpheus beat me to it and said it better
I've had major changes in p.o.i. just from different lot numbers. I zeroed my 9.3mm using RWS H-Mantels, and was down to the last box and a bit. I tried a few shots of the same ammo, different lot number, and they weren't even on the paper at 175 yds.
If you desire to pose the question: What causes a POI shift? be prepared for a massive lesson in physics and all its related variables.
The fact is that a change to any related variables can cause a POI shift. While some precision shooters will capitalize on these variables, most of us average homeloaders try to achieve the best group then adjust our scopes to meet it.
The fact is that a change to any related variables can cause a POI shift. While some precision shooters will capitalize on these variables, most of us average homeloaders try to achieve the best group then adjust our scopes to meet it.
Yeah. I'm 75 and have been reloading and shooting for a long time and have experienced many POI changes such as the one I described earlier and I even understand most of the reasons for such changes. What puzzled me was that every load and bullet I tried except for the 225 SSTs were about 4 inches higher than the SSTs. I even shot one group with 200 gr bullets and they were also in the higher group. I'm still a bit puzzled.
