Scratching my head!!!!

[boomer84]

Howdy guys,

Now for the life of me i cannot figure this out!!! Ive been shooting 32 and 39gn SBK's and 26gn BVG's and i understand that they all have and will have a different POI (Usually with a vertical variance). But i've been testing the 40gn Nosler BT and so far they have been shooting .5MOA with no keyholing out of my 1:12 twist factory barrel.

All sounds wonderfull but heres the kicker!! POI is 6in to the left of the bull . Perfect (to me) .5MOA all day long! But 6in to the 9 O'clock.

OK now 4 seperate days all moderate sunny windless days shot over 100metres.

So guys can any one explain it? Otherwise i will just use them on those 100km/h windy left to right days

Any other info needed just let me know.

Cheers guys, i await your replys.

[Rick in Oregon]

boomer: Frustrating yes, but not all that unusual.

If the 40gr BT shoots .5 MOA for you (and I'm assuming you'd like to shoot it), why not just re-adjust your scopes POI to coincide with the 40gr BT's impact point and call it good? You'd have to reset your scope of course for other bullets, but if your shooting .5 MOA with the 40gr BT, I'd call it good.

Just a thought.

[204cat]

i think it is called yaw. i forget the technical term. what you are dealing with is torque of the heavier projectile. the torque causes drift. also a lighter weight bullet guessing 10 grains should go 9 inchs or so to the right.


edit
this should also be noticable in different twis barrels. changing from one twist to another.

[boomer84]

Well this is what i want to shoot but because it is drifting that 6in if i reset my scope will it be still 6in out at 200? Guess i should try!

Thanks guys for your always helpful Knowledge.

Boomer

[204cat]

think of it like windage. it will vary in distance.

[boomer84]

Sorry for my late reply but thanks for yours! I will just stick with the sierras for now.

Cheers

Boomer

[KiwiMonkey]

Well this is what i want to shoot but because it is drifting that 6in if i reset my scope will it be still 6in out at 200? Guess i should try!

Thanks guys for your always helpful Knowledge.

Boomer

Think of it in terms of not the bullet drifting left, its the scope pointing right of the line the bullet is following.

So the current 6" difference at 100 is 12" at 200, or 3" at 50 - it doubles when the distance doubles. If it was only 2" left at 100 it would be 4" at 200, or 1" at 50. And if you dial your scope so that its 0" at 100, its 0" at 200 or 50 as well because double zero is zero.

Hope that helps!

[Zeus]

Boy you've got me really confused....lol But I think it's as simple as adjusting your scope and you'll be in business.

[Bill K]

Boy you've got me really confused....lol But I think it's as simple as adjusting your scope and you'll be in business.

Me too, I guess. Just readjust your scope for the bullet you are wanting and going to shoot. Sight it in and adjust as you must for wind, etc. Bill K

[boomer84]

Thanks guys yeah i think i really over thought this one cos every time i think about i come up with a different answer in my head. Which hurts!!!

[Sth Oz Dan]

Just got a new .22lr. Shoots both Winchester Powerpoint and T22 at around 3/4" at 50yds. But if zeroed for Powerpoint, the T22s land 2" left.
Same elevation, just way left.
I guess different projectiles just do that. Frustrating though, when they both group so well, coz you have to re-zero.

[Johnnu]

Just happen to be wandering by again and saw your post Boomer. I have different projectiels that shoot to the right of center and others that shoot on the center line (in my 204 Savage Predator Max). I simply adjust my scope for the bullets that shoot the best group at 100yds...... They stay on the center line at 200 and 300 (within reason and wind of course). My rifle happens to group ONLY Berger's (just my luck) at .5 MOA; everything else is never better than 1 MOA. Go figure. John.