Did some load development yesterday with 308 150 grain fmjbt using imr 8028 xbr. Started at 39.5 10 rounds each in .5 increments up to 43.5. My rifle seems to have liked 41.0 grains. I had a few groups that vertical was spot on but horizontal had some stringing. Touching but still stringing. I'm sure 99% it's shooter error but I had about 10 to 12 mph winds right to left. Can the wind at those speed move the bullets that much at just 100 yards? Rem 700 22 inch barrel with a brake on it. Thanks
-
Having trouble using the site?
Contact support
308 and wind at 100 yards
- Thread starter Hayn Lo
- Start date
Wind can move a bullet at 100 yards but would not be my first thought.
What matters is not so much the wind as changes in the wind. Wind is not constant, but the changes in wind shot to shot will be less than the velocity of the wind. So if a 10 mph wind will move a bullet half an inch at 100 yards, the change shot to shot might be 20 to 50% of that or less than .25 of an inch.
To answer the question you asked we would need to know the bullet and the velocity.
What you are looking for in the ladder you are shooting is not group size but two or three loads in the ladder which impact more or less in the same spot.
If you load for the middle charge weight you can be confident that variation in powder throws or temperature differences will leave your new best load impacting in the same spot.
Good luck.
What matters is not so much the wind as changes in the wind. Wind is not constant, but the changes in wind shot to shot will be less than the velocity of the wind. So if a 10 mph wind will move a bullet half an inch at 100 yards, the change shot to shot might be 20 to 50% of that or less than .25 of an inch.
To answer the question you asked we would need to know the bullet and the velocity.
What you are looking for in the ladder you are shooting is not group size but two or three loads in the ladder which impact more or less in the same spot.
If you load for the middle charge weight you can be confident that variation in powder throws or temperature differences will leave your new best load impacting in the same spot.
Good luck.
A 10 mph wind will move the 150 gr Hornady fmj by 0.75 inches at 100 yards.
Remember it is not the wind but changes in the wind shot to shot.
Remember it is not the wind but changes in the wind shot to shot.
Thank you. I appreciate any and all info I can get. Have a good day. We'll afternoon I guess it's only morning here
Using Hornady 4DOF, 2,600 fps, 168 SMK, a steady 10 mph cross wind will give you .2 mil of wind drift = .7"
Ah dang, I see I'm Mr. Redundant yet again! haha
Yeah, that's kinda light load (maybe that's your desire???). But nothing "wrong" with it. My ONLY issue with what you said you're doing is the .5 load increments. For a .308 cartridge, .5 is real easy to jump past an accuracy node. Of course, one can always get lucky and hit one depending on the starting point. But, .3 gives you a much better chance of getting it and getting an idea on how wide the node might be. This is what I've found out trying out a lot of different powders in my .308 cartridges.
Last edited:
I was thinking since I found a tight group at 41 and not so bad groups at 41.5 to 42.5 of going g back and making g some loads at .2or3 in that range. I'll go with .3 now thanks for that
Here, you might take a look at the picks below and find the numbers of interest to give you some ideas about your load:
Example of what I'd call a moderate load with 45grs of this powder:
Last edited:
You've got some tight vertical, and the horizontal looks more like you're pulling (or pushing) more than the wind is causing it - surely a combination of the two. It would take some decent gusts to move it that much at 100 yards.
Other notes:
- I don't like shooting at Shoot'n See type targets when doing load dev. Your eye tends to move toward previous shots, and so does your aim - put up 1" orange dots on white paper instead.
- Zoom out as far as you can where you can still consistently line up on the dot. You don't want to see/chase the wobble, and ideally don't want to see the impacts until you go up and check.
Other notes:
- I don't like shooting at Shoot'n See type targets when doing load dev. Your eye tends to move toward previous shots, and so does your aim - put up 1" orange dots on white paper instead.
- Zoom out as far as you can where you can still consistently line up on the dot. You don't want to see/chase the wobble, and ideally don't want to see the impacts until you go up and check.
I have a Wilson Combat barrel that will put 3 shots into 1 hole, shot 4 will be *about* an inch to the left, shot 5 will be *about* an inch to the right.
Every stinking time.
No matter the ammo.
No matter the wind, temp, humidity, whatever.
I fucking hate that barrel, but, at least it's consistent.
So yea, it might not be the wind.
Every stinking time.
No matter the ammo.
No matter the wind, temp, humidity, whatever.
I fucking hate that barrel, but, at least it's consistent.
So yea, it might not be the wind.
Pretty sure it's me. I'm just looking g for something else to blame haha
Attachments
My numbers for the other 2 groups. The final lic of numbers is where it started to open up. No pic of that group the target blew out on the freeway on the way home
It's a good idea to go with .3 instead of .2 as the latter tends to use more components than needs be.
PS: Just a heads up thought, if you haven't already given it a lot of thought yourself . . . being in a place where high humidity is prevalent, you'll not want to have your powder exposed to high humidity any longer than necessary. The powder can absorb that moisture and slow down the burn rate of the powder where velocity can be seen to slow down. So, if you notice your powder slowing down from when you first got it . . . that's probably the reason.
Similar threads
