reloading high flyers

[hillhippie]

2I just
I just picked up a savage axis in .308, 1in 10 rot,22in barrel.


I was loading up 168g and 178g hornady bthp(at the same time), starting low(8208xbr) and working up by .2g and found the 178g landing three inch's higher then the 168's, have-not got to max for the 178g yet; for those with concern.

I was looking for the bullet weight the barrel would like but there both doing inside 3/4in at 100yrds/ just 3 inch's higher with 178g?.

Can Anyone tell me why, and what the outcome at med to long-range might-be?. Thanks

[adammiddagh]

Different barrel harmonics. What contour barrel? Thinner barrels have more flex and show a larger difference.

[hillhippie]

48
I would have thought the heaver 178g-ers made more pressure and barrel harmonics would make some of the 168g-ers to fly wild too?.

[adammiddagh]

If you are getting good groups with both, you must have found or be near a node with each. I visualize the 168s exiting the muzzle on a node down, and the 178s on a node up.

There could be something else going on, but I would just pick one and zero your optics.

I am still curious what contour your barrel is.

[sharpshooter]

The heavier bullet has more recoil and spends more time in the barrel. It lands higher on the target because the muzzle has risen more when the bullet left the barrel. Primary recoil happens the instant the bullet leaves the case.

[Justin.D]

I think sharpshooters theory hits the nail on the head. Only other thing I could think of that could play is that the 178s have a higher ballistic coefficient as well, so they are less effected in flight.

[hillhippie]

65
the Barrel is 22 inch factory(pencil).

I can agree with "Sharpshooter", more pressure slower bullet making more lift with recoil.

But I don't know if the "BC" will do that much at 100yrds?, 168g BC is .450 to the 178g "BC" .530.

and the guy with all the "A's" and "M's" and "D's" in his name is probably right just pick one and zero it. Thanks All !!!!!!!!!!!!