.308 ballistics question

[npaull]

Hi all,

I am hunting blacktail this fall for the first time with a rifle (I've hunted with a bow for over 20 years, drew a rut tag, bought a Henry single shot .308, intend to use it this season).

I got the rifle pretty nicely sited-in with 165 grain bullets. Recently on sale I bought a bunch of 180 gr bullets by accident (thought they were 165 and was mistaken).

Am I correct that for hunting purposes, taking shots of 100 yards or less (maybe 150, I very much doubt farther given blacktail country) that this won't affect my site-in too much to worry about?

I welcome any opinions. I am going to take some shots before Nov 1 and I'll tinker, but thought I'd ask anyway.

[Hilltop123]

Take 5 rounds and find out, you have time.

[npaull]

I will. But I would still like opinions.

[bobcat]

I would either shoot it with the 180 grain bullet, and adjust as necessary, or go back to the store and get a box of cartridges that's exactly the same as what you're sighted in with. I wouldn't feel confident hunting with it otherwise. But chances are your point of impact will only be two or three inches different at 100 yards. It could be more, and there's just no way of knowing without shooting it with that load.

[Dan-o]

I would either shoot it with the 180 grain bullet, and adjust as necessary, or go back to the store and get a box of cartridges that's exactly the same as what you're sighted in with. I wouldn't feel confident hunting with it otherwise. But chances are your point of impact will only be two or three inches different at 100 yards. It could be more, and there's just no way of knowing without shooting it with that load.

 

[Yondering]

Am I correct that for hunting purposes, taking shots of 100 yards or less (maybe 150, I very much doubt farther given blacktail country) that this won't affect my site-in too much to worry about?

No, you should absolutely expect it to change your zero point. Any ammo change, but especially bullet weight, can change point of impact and more in some rifles than others. Any guesses as to which direction it'll change at 100 yards are just guesses, you need to shoot it to find out.

[PlateauNDN]

I like the 180 great match points for my .308. Shot really good groups with them.

[jrebel]

From a bullet weight perspective....no the 15 grains difference won't make a difference out to 100 yards.  Now....... different bullet, different powder, rifle like or dislike......those favtors make all the difference in the world.  Same holds true with same weight bullet with different box ammo manufacturers.......gun may like one and not the other.  Go shoot them and make sure it shoots well.  Easy....fun.....and most importantly most ethical for the deer you want to hunt. 

[WapitiTalk1]

What JR said 

[wadu1]

From a bullet weight perspective....no the 15 grains difference won't make a difference out to 100 yards.  Now....... different bullet, different powder, rifle like or dislike......those favtors make all the difference in the world.  Same holds true with same weight bullet with different box ammo manufacturers.......gun may like one and not the other.  Go shoot them and make sure it shoots well.  Easy....fun.....and most importantly most ethical for the deer you want to hunt.

No  about it

[Bob33]

At 100 yards or less it will more than likely not make enough difference to worry about on a deer. If you can shoot the different load you will know for sure.

[npaull]

10-4 on the need to shoot the new bullets, and I most certainly will (as intended). Thanks all.

[SteelheadTed]

I'd go back and get the same ammo you've already been shooting.  It works, why mess around?

What happens when you run out of the sale ammo?  Are you going to go back to the 165? 

[yakimanoob]

From a bullet weight perspective....no the 15 grains difference won't make a difference out to 100 yards.  Now....... different bullet, different powder, rifle like or dislike......those favtors make all the difference in the world.  Same holds true with same weight bullet with different box ammo manufacturers.......gun may like one and not the other.  Go shoot them and make sure it shoots well.  Easy....fun.....and most importantly most ethical for the deer you want to hunt.

Couldn't have said it better myself. 

[Bill W]

The 15 grains difference between bullet weights isn't the main problem. It's barrel harmonics and where the end of the barrel is pointing when the bullet exits.   The new loads needs to be sighted in and scope adjusted.   Not confirming where things hit and adjusting sights is just plain wrong.