Different ammo for different ranges?

[5ptdeerhunter]

I shot my Savage 93R17-F this past weekend and I was shocked with my grouping. I fired my CCI first because I know it shoots great in my gun. So I started at 50 yards and I can put all my shots of a 5 shot group within a nickel about 3/4" high but right on center horizontally. I was very pleased so the next day we decided to move out to 150 yards which I thought my gun would be right on. I decided to shoot some different ammo I had. I had with me Federal and Remington and the CCI. I fired 10 shots of each and wasn't to upset with the groups. The Remington was the worst with about 3" groups high and to the right. Then I shot the CCI and the group was good except for 2 shots. The main 8 were within 1 1/4" but the 2 fliers made it out to about 2" and they were high and to the left. Then I tried the Federal which to my surprise was all around the nail in the center of the plate. I had shot a 1 1/2" group with no fliers.

I was shocked. I don't understand. I know I am not a steady shooter, but I thought that were I had the CCI sighted in at 50 yards would be a low at 150 yards. Not high and to the left. DERN IT. What did I do wrong? Has anyone else had an experience like this? I need to know what I did to mess myself up so I can try to stop it.

 

[sumpnz]

Was there a significant difference in the weather between the two days? If temps, pressures, humidity, etc were different that will affect ballistics, and hence rise and fall of the bullets. Also, what were the wind differences between the two days? A slight difference in wind can make a big difference in horizontal shot placement with such a small round. If you went from head wind to tail wind that could also explain the vertical results.

Also, you can really only compare CCI to CCI, unless the other makers are using identical bullets being launched at the same MV. So the fact that the Federal were dead nuts and the Rems were high and right means nothing WRT to the CCIs.

Also, and changes to your shooting posture can make a difference. If you used a rest, did you use the same set up both times, or were there changes to that?

How many rounds total have you fired through the rifle? If it's brand new, it may take a few hundred rounds for it to settle into consistant shots.

Your best bet for checking if it's you or the equipment making the difference is to go out and shoot at 50, 100, and 150 yards on the same day and pick the time when you think temps, and such will be the most consistant over the time it takes to shoot all those groups. Keep a thermometer (a $10 outdoor one from Wally World is good enough) out with you and check it periodically, and also set up a flag/windsock/streamer so that you can note changes in relative wind speed and direction. That way, if conditions change you be able to explain some changes in patterns as the day goes by.

 

[5ptdeerhunter]

Both days I used a picnic table and bench with an ammo can with a sandbag on top. The day I shot at 150 the wind was not much if any, but first day the wind was about 10mph or so.

But Thank you very much for your help.

 

[30Cal]

Not familiar with .17 cal ballistics, but it's likely that the bullet is still rising at 50yds. Could be perfectly normal, but you'd need to look at some tables to say for sure.

A good rifle will shoot to more or less the same point. If the scope/mount are moving or if the action is moving in the stock, it won't.

Ty