Home Forums Reloading Big Game Rifles vertical dispersion stopped...now what?

as i understand it when working up a load, the idea is to start w/ a light charge, and keep going up until vertical dispersion stops. well, i reached the point where the vertical dispersion stopped, but the group was still bad...so, i took the same powder charge and seated the bullet .02 deeper, and that had nearly zero impact on the group size (still bad).<P>so, once the shots stop stringing out vertically, what is your next step?

Something is wrong. Check your rifle. Your groups should be round, not strung vertically. Check scope bases, and rings, and bedding. Are you shooting over a hard rest, like a block of wood ? That will do it too. Are you weighing your powder charges ? E.

every charge gets weighed, and the last 1/2 to full grain of powder gets trickled in. i am shooting off the same bench and rest that has produced some unbelievable groups in other rifles.<P>i started w/ a light powder charge (don't remember for sure, data is not here) 39 grains, and went up 1 grain for each test load. at 39, 40, and 41 grains the groups were strung vertically. at 41.5 grains the groups were strung horizontally (max listed load is 43 grains). poi was the same up and down, but left and right were different.<P>i was always under the impression that you started w/ a light load, and loaded heavier until vertical stringing stopped?

If every thing is right with your rifle, as E said and if you are capable of shooting a small group with another rifle (I am NOT saying you can't shoot but the question has to be asked) and your load is consistent then it is quite possible that your rifle just does not like that powder/bullet combo.<BR>How big a group are we talking here?<BR>BCR

group size when it was stringing vertically ran 2.14 - 2.16" at 100. very consistently that size.<P>when it started stringing horizontally it was stringing right at 2.5" at 100.<P>the thought that this rifle doesn't like this load has crossed my mind, but i want to explore this load, and not overlook something simple that would tighten the groups.

I'm working with a new bullet and am not satisfied that I've got it the best it can do.What I'm gonna do is take a proven accurate load with me and shoot a group with it,then the new,then another with the proven load.A lot of times I aint holding and squeezing.I'm good at calling a shot but I'm not infallible.Lots of times it's me!

i appreciate the input. lord knows i need all the help i can get.<P>let me rephrase the question...<P>when you have a given load that is grouping consistently at 2" (meaning that almost every group is 2"), and 2" is not good enough, what do you do? do you assume that as consistent as the group is, the rifle won't shoot it accurately and start changing components? do you tweak seating depth? primer? etc etc...<P>gene: funny...of course that never crossed my mind! are you saying i had a bad day on the bench (heaven forbid)?!?! thanks for the reminder. it could very well have been me.<P>i'm trying to get at everybody's process... when do you give up on a component? what component is the first you look at?<P>the load i'm working up is giving me the problems i described, and until i can get back to the range and prove/disprove gene's thoughts, i want to assume he's wrong.

Blasphemy!!!!!

well, being as i am never to blame...

Hi big time. I usually change powders first. My ex-wife's .243 was a good case in point. With IMR 4350, I couldn't get anything to group much under 2 inches. I recall one load that shot 1.75 inches. So I switched to H4831. Bingo. Everything under 1.5 inches, and the one we settled on was about .9 inches. <BR> I'm having the same problem with my .25-284. I shot one group at .4 inches with Re-19, and the rest were over 1.0. One, was spread horizontally to 1.4 inches. I suspect gusty wind conditions did some of that. So, I'm going to retest. I'm also going to try loads that are .01, and .02 inches deeper to see if that makes a difference with the 1.4 inch grouping load. E

Bigtime if I was bound and determined to shoot that load in that rifle then the first thing I'd do is fiddle with the charge weight. Sometimes just a grain or two will make a lot of difference. Then I would fool with seating depth next.<BR>BCR

thanks much for all the info, guys.<P>once again, i feel very lucky to have such vasts amounts of knowledge and experience available here. thanks for sharing.

ok...for bcr and gene williams, who both insinuated i can't shoot...had an extended session off the bench today, shooting 25-06 and 243. the 25-06 was shooting consistent .6 - .7" at 100 yards w/ a load that i stumbled upon that has produced impressive accuracy before (today had a 10mph wind blowing).<P>the 243 wasn't doing so well. at 40.5 grains of h4350 i shot (3-shot group) 2.24"<P>41 grains: 2"<P>41.2 grains: 1.03"<P>41.5 grains: 2.57" <P>i didn't get a chance to finish my testing. real warm outside, and i had to quit because it was starting to take a real long time to cool the barrel. i didn't get to test my 41.4 grain loads.<P>anyway, the load at 41.2 grains shot the best today. it put one hole almost touching another, w/ the 3rd going way high, so it was stringing vertically, still. the 41.5 grain load strings horizontal. so, apparently, somewhere between 41.2 and 41.5 grains is the magical load for this combination, am i right in assuming that?<P>if i can't find what i am looking for after my next test session, then is it time to switch powders (maybe to h4831 like emericus suggests), or is it possible that switching primers can make that much of a difference?<P>i concede that at first the 41.2 grain load looks to be a winner, but all the shots were stringing vertically, which makes holdover on a distant target a challenge, at best.

Consider the possibility of barrel bedding being the problem.At high temps it doesn't take much for the barrel to start walking.Try adding a pressure point or making sure it is free floated,whichever is your preference.Hope this helps.Frank.

I concur. It sure sounds like barrel bedding. Can you slide a twice folded dollar bill down the barrel channel to the reciever ring, or just short of it ? If not, does the bill catch under the barrel just down from the forend tip ? Does it catch more on one side than the other ? With the barrel warm, does this clearance change ? <BR> I wouldn't change primers. You've still got lots of other things to consider. E