[fsfty]

Hi...Im fairly new to shooting and i have a question about my .270 x-bolt mounted with a Bushnell Elite scope. I've only taken the gun on 4 range trips, and noticed today that i was shooting an inch higher without making any adjustments to the scope. The mounts have 4 screws each instead of the normal 2 and everything seems tight. I was still grouping, but just a little off where I had been. Is it common to have to make minor scope adjustments now and then (2 clicks)? I am a new to shooting so maybe I was doing something different today than i had been and its shooter caused? I've used the same ammo each time. Thanks.

 

[SCOTT LAROCK]

SOME SCOPES ARE VERY SENSITIVE EVEN TOO A MINOR HIT.I HAD A BUSHNELL SCOPE ON MY .22 RIFLE AND HAD TO MAKE ADJUSTMENTS HERE AND THERE BUT I THINK THAT WAS FROM HAVING MY RIFLE IN MY TRUNK IN A SOFT CASE AND BOUNCING AROUND IN THE BACK.DID THIS HAPPEN WHEN YOU WERE SHOOTING THE GUN AT THE RANGE OR YOU JUST GOT THERE AND NOTICED THAT THERE WAS A PROBLEM WITH THE SCOPE?DO YOU KEEP YOUR GUN IN A CASE?

 

[fsfty]

After doing some research online, im beginning to think the warm temperatures today were the cause. I was shooting it in 50-60 degree weather before. Today it was in the mid 80's, and apparently the bullets trajectory is different in warmer temperatures, i.e. less drop. Have you guys experienced this?

 

[Gary_Hungerford]

Yes. Temperature is a factor, in shooting and the ballistic characteristics of your ammo. Wind is another factor. Also, you don't mention if you were using the same ammo. That could, also, be a factor. Were you shooting from the same position and at the same distances?
Gary

 

[Edward_Blake]

Yes the weather can and will effect point of impact. Some ammo is affected more than others. The important thing is not to make your self crazy by changing too many things looking for a solution. As you become more familiar with your rifle you can make small tweaks to adjust for these factors.

 

[Vertiviper]

After doing some research online, im beginning to think the warm temperatures today were the cause. I was shooting it in 50-60 degree weather before. Today it was in the mid 80's, and apparently the bullets trajectory is different in warmer temperatures, i.e. less drop. Have you guys experienced this?

Makes sense.. Warm air is less dense then cold air (fewer molecules to pass through). On a cold/cool day the bullet has to force it's way past more air to the target, thus more friction, explaining the 1" higher groupings today.

 

[Johnc]

Yes. Temperature is a factor, in shooting and the ballistic characteristics of your ammo. Wind is another factor. Also, you don't mention if you were using the same ammo. That could, also, be a factor. Were you shooting from the same position and at the same distances?
Gary

There is a possible reason ^^^^^^

Makes sense.. Warm air is less dense then cold air (fewer molecules to pass through). On a cold/cool day the bullet has to force it's way past more air to the target, thus more friction, explaining the 1" higher groupings today

Here is your scientific explanation ^^^^

Another item worth mentioning is crosswind. People only believe that crosswind affects left to right placement of the bullet. This is not correct. A bullet that is affected by crosswind also "climbs" or drops at the twist battles the crosswind. Somewhere I had an illustration of this effect.

 

[Postal Bob]

Two oother factors to consider:1. Were you shooting from a bench rest with the rest on the stock or barrel? Resting on the barrel instead of stock will cause the bullets to impact diiferently. Always rest on stock. 2. Did you do a lot of shooting where the barrel started to get hot? If there is contact between the stock and barrel. Especially towards the front of stock. As the barrel gets hot and expands, it will press against the stock and cause the bullets to impact diiferently. This is more likely as you say it was hot yesterday at the range. You can also check this by sliding a piece of paper between the stock and barrel. There should be no contact, especially at the front of stock. I have a sporterized mauser rifle thet shoots great until it starts to heat up. Then the bullets start to "walk" as it's called, all over the target. But in normal hunting weather,cold, it shoots fine.