Horizontal spread?

During load testing I came across two different powder charges that gave about .5" to .75" of vertical at 300 yds but about 3" of horizontal. The amount of vertical spread was nice and both of these groups were around the same powder charge that yielded the smallest groups so far during test.
40.5 imr 4350 2.800 coal 1.153" CTC 3 shot group
http://farm9.staticflickr.com/8115/8...40648bd9e7.jpg

41.5 imr 4350 2.800 coal 3.301" CTC 3 shot group not much vertical spread
http://farm9.staticflickr.com/8262/8...7ac099386a.jpg

44.5 imr 4350 2.795 coal 1.806" CTC 3 shot group .816" vertical
http://farm9.staticflickr.com/8258/8...eb3bdd3cf2.jpg


45.0 imr 4350 2.795 coal 3.658 CTC 3 shot group .455" vertical
http://farm9.staticflickr.com/8249/8...25392b95d9.jpg

All groups shot at 300 yds. So what causes this much horizontal spread? Was going to load some up between 44.5 and 45.0 to see if a happy medium can be found.

Could have been your shooting technique or the wind; looks like they are stringing to the right (was the wind blowing from the left that day?). It is not unusual that when looking for the node, the horizontal variability can go hand-in-hand with the vertical; but since your vertical is flat I would guess it's not the load. To get a more reliable answer it would be better to shoot one round each for each load, then the second round per load, etc; in this manner changes in the conditions are spread across all the loads.

Honestly I dont recall there being much wind that day maybe a little breeze. The shooting lanes at this particular range have trees on either side going down range so it is kind of protected from the wind. It very well may be my technique I recall coming close to a seize fire so i through the last 3 being 45 grs down range rather quickly. It would really be nice if I can get that amount of vertical with very little horizontal so I am going to load some more up this week between 44.5 and 45 possibly 3 of each at .1 gr increment to see what that yields. And definitely take a little more time to practice better technique. This new barrel is really showing some promise. Thanks for the reply I was just thinking it was a little odd how the horizontal became so far apart with seemingly only a powder charge as being different, was thinking that it would be more of vertical spread over horizontal to look out for.

I have found on my 308 loads and SIL's 338 federal that seating depth can have a big effect on horizontal with the load being the largest factor on vertical.

I had heard about seating depth causing horizontal spread. Heck if I can get shooting 1" at 300 I'll be happy

just gotta know....why 300?

That's the furthest range I have access too with targets. There is another range out here but it is further away and hard to get to after work due to traffic, they have paper and steels at 250 and steels only at 500, 750 and 1000. With shooting a berger I figured that the further out I can do my testing the better off I would be. Besides I like getting the practice in at 300 for now.

understood:
how does your pattern look like at 100

Haven't tried at 100 yet. Plan was to get something shooting good at 300 and see what its like at 100. I've heard of some loads that shoot great at 300 or more but look horrible at 100 so I'm not too sure what to expect but hopefully they shoot proportionately as good at 100 as they have been at 300. I will probably load some up tonight and test them out again Thursday but time is getting tight with a coastal fishing trip coming up this weekend may have to wait until next week some time.

heres my train of thought.
if you figure out your barrels sweet spot with what ever weight of projectile your gonna use thru ladder test and such and get the patterns down to a consistant 1/4" 5 shot pattern @ 100...then odds are....the projectiles flight will be that much closer for you out to distance. If you find that your patterns have a 1/2-1" spread @ 100, then by the time it gets out to distance, the amount of difference will increase. If your off by 1/4" @ 100 then you,ll be off by a full inch @400.
Just my 2 cents