I am shooting nosler 155 match and nosler 168's

[yooperchuck]

I am shooting nosler 155 match and nosler 168\'s

I loaded the 155 noslers with 43.5 IMR 4895. Same with the nosler 168's. Both had OALS's from 2.90 to 2.70. I shot them patiently. I have a remington 700 bdl vs. (made in 1992 and bought new in the box in 2004) The 2.80 and 2.75 OAL bullets shot the best. (the 155's) When it came time to shoot and record the nosler 168's I was dumbfounded. Using the mil dot scope I have, I had to hold left of the crosshairs four dots to get the 168's to get on target. Can anyone offer some suggestions why this happened with the 168's?. As I said the 168's had 43.5 grains of IMR 4895 powder...same as the 155 nosler match bullets.

 

[JD338]

Re: I am shooting nosler 155 match and nosler 168\'s

yooperchuck,

The bearing surface is different between the two bullets. The barrel harmonics are different as well. In other words, the barrel oscilates and each bullet leaves the barrel at a different time. That is why you have two different impact zeros.
Are you from the UP of MI? My wife is from Moran on the eastern end.

Regards,

JD338

 

[Bart B]

Re: I am shooting nosler 155 match and nosler 168\'s

You didn't mention the range, but through 300 yards both bullets shoulde strike with a few inches of each other.

Your barrel harmonics are the same for every shot regardless of what ammo you're shooting. Barrel harmonics are caused by the barrel and everything connected to it. The resonant frequency is the same; always.

The barrel whip or vibration that causes problems is 96% in the vertical plane and 4% in the horizontal plane. So even if the bullets exits at different points in the vertical whip the difference will be small.

If you have a windage difference between the two loads, any one of several things can cause that. You may have held the rifle different for each load. Something loosened up in the rifle. I've no idea. Try it again and see what happens.

 

[Guest]

Re: I am shooting nosler 155 match and nosler 168\'s

Bart B, often when you post you come up with something none or most of us have never heard about and a lot is proven different than what you say. My 270 win shoots 90g bullets 4 inches to the right of 130g bullets. (at 100y) Why? Bullet leaving muzzle at a different point of the barrel whip. Not because I hold the gun different of my screws are loose. Been doing this for years, shooting 90g for varmints and 130g for big game.

 

[yooperchuck]

Re: I am shooting nosler 155 match and nosler 168\'s

Hey jd338..........thanks for the advice.......and yes Moran is just down the road from Kinross. My mother was born there in Moran.......thanks again for the help.

 

[yooperchuck]

Re: I am shooting nosler 155 match and nosler 168\'s

Thank you all for the help and insights. What a wonderful hobby we have. !!!!!!!!

 

[green 788]

Re: I am shooting nosler 155 match and nosler 168\'s

I think if your barrel is not free floated, it could tend to throw bullets of different weights and/or speeds any which way, depending on the actual barrel time.

A barrel which is pressure bedded at the forearm tip, and not relieved along each side of the forearm channel, will at some point in its vibration cycle be pressed against one side of the forearm channel or the other. If the bullet exits during this period of time, the muzzle would be pushed to one side, and the bullet would of course go that way.

In a free floated barrel (which, in my opinion, is the best way to obtain good shot to shot consistency) there shouldn't be more than an MOA or two at most of lateral movement, just as Bart mentions.

Dan