Me and my brother are looking to get into soem long(er) raneg hunting, specifically groundhog. Between 300-600 yards. We have a savage model 11 .243. With a Laminate wood stock, bipod and a BSA Platinum 6x24. We are shooting Federal Power Shok 80 grain soft points. We can shoot .75 MOA at 100 yards with this setup easily. We took it out and shot 300 yards today and couldnt get consistent groups. We put 14 shots on a 1' wide by 2' high target, No misses, but about a 1' spread. I have all of the math and calculations pretty much figured out, the way it SHOULD be, of course the gun probably wont hold true to the theoretical ballistics but we should still be able to get good groups right? So at this point I dont really know what to do because we can't check the ballistics out to 600, or even at 300 because we cant get groups. Shooting conditions today, 10mph gusting wind going from 5 o'clock to 11 o'clock, accounted for as quarter value.
On figuring wind values, at this range an 11:00 or 5" wind only carries with it about a 10% value.
[/quote]Didn't make much of a difference because the shots didnt group, as I mentioned, although it was gusting, so that could be some of it. Other factors shouldnt matter much because we re-zeroed it at 100 before shooting the 300 yd target but here they are anyway, 93 degrees out, 29. 72 in of Hg pressure. 80% humidity. Shooting off of the bipod with a log as the rear rest in prone. on the same zoom as the 100 yd target(24x), so that shouldn't have affected it at all.[/quote]I'd suggest backing way down on your zoom at 100yds to no more than 6-10x and see if it makes any difference.
Using a log for a rear bag isn't a really good plan. I'd suggest making yourself some cheap bags out of used shot bags or just order some online.
Any thing that could be causing the inaccuracy (besides the shooter, my brother is a VERY good shot, and I'm pretty confident that it wasn't him, escpecially with the amount of support he had in that position) Gun not accurate enough for this?
Very good shot as measured how? Does he have experience shooting beyond 100yds targets? Keep in mind at 300yds you can be off by more than 12moa and still effectively kill deer and larger sized game pretty consistently. You have a kill zone on a deer of about 12-16" up/down and as much as two feet left, right if you are shooting just below and behind the shoulder (depending of course on the size of the deer) and it's considerably larger on Elk, Moose etc.
should we try different ammo?
Odds are pretty good that .75MOA ammo at 100yds is still shooting at or below MOA at 300yds so I doubt it's the ammo.
Quote possibly optics and/or mounts but the latter is less likely because it should show up a 100yds. Shoot a box test with it.
The modified box test I use is this. Lay out a perfect 10" square with small 1"target squares in each corner.
Shoot the top right box. Dial down the appropriate number of clicks for 10".
Aim at the same box. Fire one shot. If it's tracking properly your shot should be in the box directly below.
Dial the appropriate number of clicks to move 10" left. Again. Shoot the top right box. Shot should fall in the bottom left box.
Dial up 10". Fire again at top right box and shot should fall in the top left box.
Dial 10" right, and shoot again the top right box.. Shot should fall within your .75MOA range of the first shot.
If it doesn't your clicks are off or not engaging properly.
In all likelihood the problem is related to the shooters as we are more often than not the biggest impediment to our own shooting success. People often get intimidated when they first start stretching it out and that tends to have a consistently negative effect on shooting techniques as we tend to try and push shots almost willing it to hit where we want it to, rather than just relaxing, getting comfortable, practicing good breathing control and trigger squeeze.
Don't let it frustrate you because we all pretty much to a man or woman went through the same thing at some point.