243 sighting in

[JUDGE]

I was sighting in the 243 yesterday, using Winchester 100 grain soft point, and Hornadys 58 gr v-max.
Had the 100 gr dead on at 100 yards, then switched to the 58 gr. With the 58 gr all shots were 2 inches to the right.
There was no wind as I was in the woods for the sighting in.
It seems odd that the were both at the same height but one would shoot to the right.
Any thoughts on why this would happen.

[rf2]

Barrel harmonics?

[jaycee]

Try that with any rifle and you will get different results again, as was mentioned "barrel harmonics ".
Pick the load that you want to use and sight your rifle in "for that load".

[Gun Nut]

My best guess would be barrel vibration. With the lighter bullet the bullet velocity I would imagine is much faster. Faster bullets shoot flatter, leaving the muzzle at a low point in the barrel vibration. Your heavier bullet is moving slower leaving the muzzle at a high point in the barrel vibration. The heavier slower bullet is leaving the muzzle at the top vertical point in the vibration. The lighter bullet is leaving the muzzle in a lower lateral point in the vibration. A barrel vibration is not just up and down, the vibration gyrates around the center of the bore. How it gyrates is influence by the velocity of the bullet as it passes down the bore. For this reason any time you change your ammunition you really need to re-sight-in your firearm, because the point of impact will change, because no two ammunition manufacturers use the same component to load their bullets. Every time you alter a component you change the point of impact. Different primer, different brass casing, different powder, different powder charge, different bullet weight and composition. When you hand load you get to control the components being used, which tends to provide better consistency.

You don't stop hunting because you grow old. You grow old because you stop hunting.
- Gun Nut

[gbk]

Hi Judge-this is "normal'different ammo,different POI.Even two 100 gr ammo different bullet/manufacturer will shoot differently(harmonics-vibration-wind-the fact is ,they will)
Now-i have a 243,bought about 10 boxes of different ammo over time,to find one light(for coyote)and one heavier (deer)to shoot"close"to each other at 100yards. Took me some time and some $ but i am almost there(almost).You could get"lucky"but that does not happen often.

[rick_iles]

For yotes, you will love the 58's. No worries of ricochet at all. I use them because of the close proximity to buildings and roadways. They can be a bit rough on pelts though !!

[JUDGE]

Thanks , I am not a target shooter, so I was not sure what the reason was.
I am a hunter who sights in his rifle and goes hunting.
But I knew some of you would know the answer.

[Roper]

I think that is normal with most rifles. Your concern for a particular load should be MOA. Group size. I find my .243 BLR has tighter groups with the heavier bullets in the 90 to 100 grain range. The lighter 50 to 60 grains fly a bit. I suspect that relates to the twist ratio of my particular gun.

[Mount Sweetness]

Completely normal

[Gun Nut]

I think that is normal with most rifles. Your concern for a particular load should be MOA. Group size. I find my .243 BLR has tighter groups with the heavier bullets in the 90 to 100 grain range. The lighter 50 to 60 grains fly a bit. I suspect that relates to the twist ratio of my particular gun.

Actually you have a good point, but from what I've read, it is not so much bullet weight as it is bullet length. Rifle with a fast twist ration (1-10) handle longer projectiles better than rifle with a slower twist ratio (1-12). My 30-06 handles my 200 gr. cash bullet well, with its (1-10) twist ratio. I ran the same bullet through my .308 with its slower (1-12) twist ratio and the results were spotty. Then I dropped back to my 180 gr. bullet in the .308 and there was a decided improvement, although the bullet was lighter it was also shorter. It seems to boil down to the length of the bullet's bearing walls/surface.


You don't stop hunting because you grow old. You grow old because you stop hunting.
- Gun Nut