My cousin, who is a big time hunter around the world, and very experienced, says accuracy of rifle bullets can be affected by changing from a lower grain bullet to a higher grain bullet. He says if you go from a lower grain (30-06 - 150 gr. to 165 gr. or 180 gr.) the accuracy will change and you should shoot whatever you zeroed in with.
I say it could change but at 50 yards to 150 yards (our usual distance hog hunting) there will be only a slight change and you would still be well within the kill zone. At longer ranges it it would probably be affected significantly.
Opinions please.

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NRA & TSRA
Texas CHL Holder

You're probably correct with your particular short-range .30/06 example but any real hunter and marksman always zeros with the ammunition he intends to use and verifies his zero when he gets where he is going - thus the comment from your cousin. He probably also knows that most rifles favor a particular load and switching around just means you do not have available full capability of the rifle.

^^^^^^^^
What he says.

I consider it both unsportsmanlike and irresponsible to hunt with a firearm that's not sighted in for the load you are using. PETA just loves to hear of hunters that do not care whether or not they wound their prey.

We owe it to our prey a quick and painless death whether they are varmints or world record elk. It makes no difference.

Maybe, maybe not. Guessing is not good enough.
I have seen some dude hunters show up with equipment they are not fully familiar with, and the day usually ends with lost game and the unprepared hunter blaming the guide.
The distance at which you are certain of a shot in the kill zone is the maximum distance a responsible hunter shoots.

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Science plus Art

The point of impact will change with different bullet weights and loads.Most likely (but not always!)it won't be much,but you won't know without testing it.Sometimes the change is huge.

I still consider myself somewhat a dude hunter but I usually zero in before every hunt with whatever grain bullet I am hunting with that day. At about 50 yards there is little, if any, difference in shot pattern when I switch bullet grains. That said, I will adhere to the learned advise from members of this forum. Thanks!
And, by the way, I always use the same brand bullet, Remington Core-Lokt, 30-06.

__________________
NRA & TSRA
Texas CHL Holder

Dirtman, I suggest you figure out which grain bullet of Core-Lokt .30-'06 your rifle shoots the most accurate and stick with it. I always buy two boxes of the same brand ammo / grain bullets and check the lot numbers to be sure they match. The lot numbers are on the back of the ammo box, it basically means that the ammo was made out of the same batch of propellant, primers, brass and bullets, so they should all be exactly the same. Good hunting!

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"Life is short, hunt hard"

Went to the rifle range 9/6/2013 c/o 50 yards............

here is one reason not to change ammo during a hunt !!
Two different powders and two different bullet weights !!

I fired a 4th 180gr after the 200 gr test and the barrel was still HOT and look where the 4th bullet hit........high and right.
(These are only test loads, not my hunting loads )

enjoy.

Yep. You CAN make the points of impact the same for different bullets
but it usually involves playing quite a bit with the velocity and you are
not guaranteed top accuracy.
Find a good bullet you are good with and stick with it.
Memorize the trajectory. Practice at various distances.
Go hunting with confidence.
Have fun!

===
Nemo

Changing weight or Brand can indeed maybe change accuraccy (group size). . But you should assume that it will definatluchange point of impact. If you had said "within 50yds" you could at least have a discussion about "close enough" , but for " up to 150yds" , not so much.

If you were to switch to a different Brand , with same wt , similar shape , similar vel , then you would be better than 50/50 *probably* "close enough. Ie you prefer Rem CorLockt 180gr pointed SP. If you had to use Federal HiShok 180gr pointed soft point , you *probably* would have a similar point of impact within minute of Boar at 100yds. Still best to fire a test group to confirm.

when it comes to guns & ammo don't take anyone's word for anything. Ditto for internet & even written info. the only way to know for sure is to shoot it and see. when hunting you don't want to rely on something the guy in line behind you at waly world told you. be sure cuz you tried it and saw it with your own eyes, you will be more confident and certain. IMO if you are not sure you're gonna make a good shot, don't take it. good hunting.

I did a final test on the 150gr Rem Core-Lokt cxp3 bullet, that I might try to take a deer with this year.
This bullet with 4350 powder gets a fac load at 2900 fps and 1" groups at 100 yards.
Today I tried 4064 powder with the standard OAL of 3.25
and no crimp and the load went from center of bullseye to about 2.5" right and 4 bullets grouped at 2.22 inches.
Here is the kicker................
Same load but the OAL was 3.19" with a crimp on the cannelure and this load was so bad................ I placed only one bullet into the 6" target !!

I think I will use the 180gr bullet for the rest of my test.............

(All the screws were tight)

Mercy.

Dirtman,

Either you or your cousin are confusing accuracy and point of impact.

Accuracy is the ability/tendency of the firearm to place bullets fired from it in close proximity to each other, in other words small groups. Point of impact, or zero, is how the bullets strike the target relative to where the sights were pointed at time of discharge.

Different bullet weights will usually shoot to different points of impact if the sights are not adjusted to compensate. There are generalities as to how a specific change in weight will affect point of impact, but they do not always work out the way the generalities would seem to predict. The only way to know is to shoot the gun and see where it shoots, and adjust the sights accordingly.

Different bullet weights may affect group size in any specific gun, but there is absolutely no way to know except by shooting the different loads in the specific gun to determine this.

Notice I have consistently used the term bullet weight. Grains, 1/7000th pound, are simply a measure of weight. Just as it would sound inane to say "bullet ounces", "bullet pounds", or "bullet grams", it sounds equally strange to say "bullet grains".

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Gunsmithing since 1961

Throw in rifling rate of twist while we're at it. Heavier bullets are longer in a given caliber , and need more spin to stabilize them.

Bullet spin stabilizes it in flight affecting accuracy , but also affects what happens when the bullet hits something

Case in point is the .223 Rem or 5.56 NATO. Rifling twist rate started out somewhere around 1:15 for 40-45gr 'varmint' bullets, then 1:12 for the 55gr used in Vietnam. It proved to only marginally stabilize the bullet in flight. It was sufficiently accurate and had tremendous wounding effect when it hit a body , but it also deflected easily when it hit jungle vegetation. It was changed to 1:9 and 1:8 for the 62gr SS-109/M-855 bullet and now it's down to 1:7 to better stabilize the 69-77gr bullets now in vogue.

I've often been amazed that shooters love to shoot holes very close together but way off the point of aim and bragging about a great grouping! Grouping doesn't mean anything if you miss what you are shooting at!
We always sight in before hunting using ammo from the same box.

__________________
NRA & TSRA
Texas CHL Holder

Putting on my analytical chemist hat, I have to point out that the ability to repeatedly hit the same point(i.e. grouping) is actually referred to as precision.

Accuracy is, in fact-at least in firearms discussion-the relationship between the point of aim and the point of impact.

I appreciate you pointing this out, as it is a pet peeve of mine, however I do notice that some published references do use the same terminology. That doesn't make it correct, however I do think it's understandable why that particular phrasing is so prevalent.

You can always adjust your sights so point of aim coincides with point of impact.