243 winchester point of aim ????

R

Richard Grantham

New member
Hi all, 243 shooters, how does point of impact seems when going from 80 to 100 grain factory loads ?? Where does the light weight 55 grain loads shoot ??

In other words have you all found big changes and resighting necessary between bullet weights ??

Thanks in advance ps standard weight Ruger 77 old model
Richard Grantham
 
all firearms will respond differently when changing bullet weights. You wil have to shoot each to see where they group. Randy
 
I hesitate to say this but it is the truth, so hear goes. Many years ago with a 7mm Mag. I took 130, 150 and 175 grain bullets with about 5% under max charge, recently I took my 243. T-3 Tikka Lite in 80 grain Fed, Classic, 100 grain Fed. Classic, and a Federal 55 grain. In both cases the target shoot higher and higher with each HEAVIER load tried.These were all shot at 100yards, and went about 1 inch higher with each load, vertical string was very consistent
I was amazed for a while.
Carl
 
Quote:
In both cases the target shoot higher and higher with each HEAVIER load tried.



It's not uncommon for a heavier bullet to impact higher than a higher velocity lighter bullet. The slower heavier load spends more time in the barrel responding to vibrations and barrel whip more than the speedier lightweight bullet. All things being equal. Of course as already mentioned, each barrel is an individual and will respond as an individual.
 
In general, I agree with the above posts.

When Browning came forth with BOSS and the knowledge that the Browning engineering staff had discovered during it's development ............ shooting was changed forever!

Here is a thumb nail sketch of what Browning found:

Like was known prior to BOSS, barrels vibrate (OK, new flash).

As handloaders we were tuning our loads to our particular guns. (another news flash!)

But the why and how was the important point and we were really in the dark.

When barrels vibrate there is a pattern. Every barrel is different. Every gun is also different.

But the trend is for the barrel to vibrate up and down (third news flash) with some deviations (traveling side ways) as it passes through the middle of it's travel.

The top of the stroke is the most important.

The bottom of the stroke is to be avoided!

The reason the bottom of the stroke is bad is that the barrel is contacting the barrel channel and that in of itself creates variability.

I am not a schill for Browning but if I ever get rich and famous enough I fully intend buy a new Browning with the BOSS.

The reason is that BOSS allows one to tune the barrel to the load.

It works great with factory ammo .............

With handloads it should be tremendously accurate.

For me in the meantime .......... a yet non-Browning owner ......... lessons about making ones ammo as consistent as possible were fully appreciated!

Inside debur, neck turning ...... the works.

Bottom-line: one wants to time the release of the bullet to coincide with the top of the stroke as consistently as possible.

Three 44s
 
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simple Newtons law... every action has an opposite and equal reaction... heavier bullet, more recoil, more muzzle rise, gun shoots higher with heavier bullet...
 
Richard, ssorry I should have put this in already. My tikka T-3 , I switched from Fed. 80 grain to Winchester 95. the change was like, 1/2inch horizontal, 1 inch vertical. 100 yards.
Carl
 
Leroy,
With a handgun,and at short handgun ranges you would be probably be correct. With a rifle there are a tad more variables involved than that. Barrel whip, muzzle exit timing and the whole wonderful world of exterior ballistics come to mind. In the end you just have shoot and let the targets decide.
 
As most have said before need to buy a box of each and try them. In handloading sometimes you can hit the right combination and get acouple different bullet weights to hit the same. I've got a 30-338 that will do that with 165,180 and 200gr bullets and I've got a 6mmremAI that I normally use 100gr bullets and playing with some 80gr and they are groups the same spot as the 100gr at 100yds. At 300yds the 30-338 groups kind of separte by bullet weight and the ackley is pretty close enought so I been using it for some LR varmit shooting.
 
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