I went out shooting today. Shot from 120 yards and 240 yards. At 120 I shot 14 shots in a 5inch group. Out to 240 yards, however, and I shot 3 shots within 1 inch. This seems really weird to me. I was shooting my Weatherby Vanguard 30-06 with fusion 150gr ammunition. What could cause this?

Also I shot the other day from 120 yards also but with federal 150gr and my group size was within 2inchs. Do you think my gun responds better to these bullets? What could another explanation be?

Do you use a lot of oil in your barrels?

I've experienced the same results, but with the same ammo. I think that I have too much confidence at the closer distances and rush the shots. When I stretch the distance, I pay more attention to my breathing and set-up.
Also, a three shot group and a 14 shot group is hard to compare to each other. If you shot 14 shots within a few minutes, the barrell temp will make a lot of difference. I like to shoot 4 rounds and check the target, but open the bolt and wait a minute or two between shots, just to get the temps out of the picture when checking a rifle's grouping.

I usually saturate a piece of barrel cloth, run it through once and then mop it twice.

Okay thanks for the advice. I usually try and keep my barrel temp down but once you get into a string sometimes it creeps up there. The one hundred yard group was weird because within that 5 inch circle i would be low right one shot then the next be high left. I was all over the place.

I think I might try the 14 shot group at 240 and see how that goes.

I also want to try the federal load again. Maby it is just a better load for my gun!

When you are shooting at longer distances, it seems that our concentration level is heightened and we try a bit harder on centering the target which often results in better groups. I often do this when practicing with the bow. I'll shoot at longer distances which makes me settle down and concentrate on the sights and a good release. Try a smaller center ring at shorter range. I think you will find that your groups will improve there also.

To answer your question, yes. Most guns do better/worse with diferent ammo. Tune your gun with dif. ammo and you will be surprised!!!

If you let the barrel heat up when you shot the 14 shot group it can move the impact. I have the same gun and when the barrel got hot it would shot about 3 inches to the left and up. It also shoots different bullets differently. I use 168 grain handloads in mine though it also shoots the 150 grain Winchester very well.

Nice, another newbie / moderator post. Why don't you guys give it a rest?

You know I once bought what was supposed to be 1 lot of 125 rnds turns out after much cussing and frustation that there were infact 3 differant case capacities . The result on paper however at 1st looked like 12" groups,shooting upto 10 at a setting . I finally after the 5th or6th setting desided to just empty all the brass and start from scratch,at about 50 rnds I found not a 12" group but 3 very separate 3" groups. This same rifle when hand loaded will put 5 in a 4 cut hole add .3 grns it opens to 1.5 add another .3 and its out to 3". Some rifles are just picky .

My standing advice shoot the load that yields the best groups even if its the bottom shelf white box after all those old school cup and core bullets probably only killed a couple of million deer ,elk and moose before Mr.Nosler or Mr Barns were born.