Bullet gr make a diff on target ?????????

[winxp_man]

ok here it goes i looked a little through a few of the fourm pages but no luck. i will post my results of what happened. today i shot some reloads through my Remington R-15 its a great gun. I have a 1/9 twist barrel.

my reloads were as follows......

my start

LC 03 brass
wolf primer
Tac 21.6 gr
Sierra MK 69 gr bullet

next

LC 03 brass
wolf primer
Tac 22.0 gr
sierra MK 69 gr bullet

LC 03 Brass
wolf primer
RamShot Tac 22.5 gr
sierra MK 69 gr bullet

LC 03 Brass
wolf primer
RamShot Tac 23.0 gr
sierra MK 69 gr bullet

LC 03 Brass
wolf primer
RamShot Tac 23.5 gr
sierra MK 69 gr bullet


I also shot some Hornady 55 gr sp rounds that shot about a 3/4 of an inch group all around at 100 yards. so not 3/4 of an inch between the farthest shots but as a whole group.

now i go to shoot the 69 gr sierra MK reloads and im shooting groups about 3 1/4 to the right and about 2 1/4 high from center of the target while the hornady rounds were almost right on center amybe about 1/8-1/4 off. then i shoot the hornady again and its all good. My question is does grains increase in a bullet make that much difference ?

the reason i ask is cause i did something similar with my .308. i shot 150 gr SP Fed rounds the groups were nice then i shot my reloads which were

Fed brass
Fed 210m primer
43.0 gr imr 4064 power
sierra MK 175 gr bullets

and i got Sub MOA .540



I appreciate any input thanks for your time folks

[Darklyte27]

high grain powder will make the round fly straighter less arch.
less arch, can mean the bullet will hit higher.

when you zero with x cartridge, thats the zero for that ammo.
it changes with different ammo as its diff specs.

[morphius]

WinXP,

TAC is a great powder for the heavier bullets to reach higher velocities that other powders can't.

With the increasing powder charges, it will change the point of impact. Some bullets with different ballistics will be more affected.

I've had issues with some stick powder bridging in my powder measure and throwing .5-.7 gr difference and I ended up with 2 points of impact on the target. Again TAC is ball powder and will be much more consistent in charge weights.

Barrel twist rate is probably fine as 1/9 will stabilize a 69gr projectile. (But I'm curious what a 1/8 barrel will do.)

Ultimately the load that gives you the best groups is what you'd want and if you will shoot a bunch of them, adjust your sights to zero for this load.

Are you chronographing these loads? You may want to chronograph the loads and compare the load statistics. Sometimes the load that gives you the best groups may not have the best chronograph data. They usually correlate, but not always.

[winxp_man]

ok thanks guys it now makes sense. its just that my .308 was different. and i thought i was maybe doing something wrong. i guess i just have to work with the loads than and adjust my scope to the new loads. the groups are not bad so far i have about 1-1.5 inch groups with about 22-22.5 gr of TAC. i have to get a chrono also. i had one but sold it a while ago thought i wouldn't need it again.......... thanks for the info guys i appreciate this.

[ar15barrels]

My question is does grains increase in a bullet make that much difference ?

Yes.
Your zero will be different with each load.
You may find multiple loads with a similar zero and other loads with a radically different zero.

I'd hazard a guess that loads with a similar zero are probably more highly developed in your gun because the bullets are exiting the barrel more consistently to land on the same zero location.

[Bug Splat]

yeah, I've had different loads have drastically different impact point (2-3 inches to the side). Might not seems like a lot for a normal AR or any gun but this same AR shoots 1/4 moa so an impact of 3 inches to the right is like the next shooting lain over far. Personally I like Varget for my 69SMK.

[winxp_man]

Varget yes it looks like i might get better loads. also im getting some federal 210m primers and i hope that will give me better results.

[razorx]

I can understand vertical displacement difference, but that much from side to side? Why would that be the case? Assuming stabilized bullet.

[Fjold]

I can understand vertical displacement difference, but that much from side to side? Why would that be the case? Assuming stabilized bullet.

Your barrel flexes with every shot and a change in any component in the load can effect how the barrel moves, resulting in different impact points both vertically and horizontally.

I'm trying to find 300 grain solid loads that will impact close to where my favorite 300 grain TSX load hits in my 375 H&H Magnum and some of the solid loads hit as much as 4" different than the TSX loads in all different directions. And that is in a very thick walled, heavy barrel at modest velocities of 2500 fps.

[razorx]

Thanks for the explanation, I learnt something new today.

[winxp_man]

Your barrel flexes with every shot and a change in any component in the load can effect how the barrel moves, resulting in different impact points both vertically and horizontally.

I'm trying to find 300 grain solid loads that will impact close to where my favorite 300 grain TSX load hits in my 375 H&H Magnum and some of the solid loads hit as much as 4" different than the TSX loads in all different directions. And that is in a very thick walled, heavy barrel at modest velocities of 2500 fps.

well i know the barrel will move and i guess even in a .223 its enough to make a difference in impact.

and Fjold what range are you shooting at ? standard 100 yards ?

[winxp_man]

thinking of it now i think thats whats causing the windage change is the 2-5 mph winds. i guess like it was mentioned the heavier rounds will have a flatter trajectory down range.