Vertical Group Question

HeathSexton · Mar 20, 2010

I finally got a load that looks very promising thanks to POP for the 70gr SBK and my .243, now I have another question. The load was 2 stacked and one flyer at OAL of 2.670 group size .970 @ 90yds. After some tweeking OAL of .2650 gave me .549, .546, .547 @ 90yds. The problem/question is the group is vertical. Is this something to to be concerned with? Can is be adjusted with powder charge the way horizontal flyers are with OAL?

Thanks!

DrMike · Mar 20, 2010

Heath,

Are the shots random? Or do they arrange themselves in a particular order? In other words, is the first shot always the bottom (or the top)? Do the groups consistently string? Or is there a random aspect to the groups? I suspect that with groups that tight, your shots are random and this is nothing to worry about. Try a five-shot group (or even a ten-shot group) and see if this phenomenon persists. It sounds like an artifact from the data provided.

JD338 · Mar 20, 2010

Heath,

You may want to try seating the bullets a little deeper to see what happens.

JD338

HeathSexton · Mar 20, 2010

Mike, the 3 3 shot groups I have fired with that load have random vert groups, it is not 1,2,3 or 3,2,1 top to bottom. I need to shoot it some more just to be sure I guess, but they are not predictable. This is a light sporter weight Savage 110 floated, stock reinforced, tang floated and in all honesty I am giving basically no time between rounds. Shoot, load, settle in breath out, fire, repeat. it is scoped with an Elite 3200 10x40 Mildot.

I have worked depths at 2.670, 2.7655, 2.660, 2.655, 2.652, 2.650, 2.645, 2.640. 2.650 is the winner, the rest throw a horizontal flyer with the exception of 2.660" and it is just not as tight as 2.650".

It may not be nothing to worry about, you know how this stuff is. A group that measures .6 needs to be .4 and then why can't that be a .2 and while I am at it I might as well try to make it a .0 group. :roll: :lol:

Thanks guys!

DrMike · Mar 20, 2010

If the shots are random, you are observing an artifact at this point. While it is statistically possible that you will witness vertical stringing on three shots, the shots are still hitting within predictable variables. Since you are shooting a light barreled rifle, make certain you allow plenty of time between shots to permit cooling to eliminate the potential for the barrel walking. In all honesty, the groups you describe are good, and though we always seek tighter groups, we have to ask what we are after--bragging rights or a hunting load.

HeathSexton · Mar 20, 2010

Caught some decent weather so I headed out to do some shooting today. I set some small Tide bottles on the dam and ranged the steel 11"x20" buffalo and the jugs at 617yds. I had to guess at velocity as my chrono died and I have simply been to sorry to buy another. I think my guess is wrong on the slow side. I guessed I was running 3250fps, by playing with the ballistic calc I had to run the numbers up to 3400 to hit the dial.

.243 Savage 110 - floated barrel and tang, stock had been built up for strength
Win Brass
70gr Sierra BlitzKing
H4895 - a whole bunch
CCI BR2 Primer
OAL - 2.650

I used point blank and dialed up to where it said, over, shot again, over, kept this up as I dialed down. I finally made my way down to 11" over my zero and fired - WHAP! One dead steel buffalo. Fire - WHAP - dead buffalo. Let barrel cool.

Fire - flip Tide bottle over, just under it, fire again - poof - dead Tide bottle.

Cool down - Fire - Poof - dead Tide bottle.

This load is awesome! I had to quit then though and get home. I wound up 5-5 on the buffalo when I got the range and 2-3 on Tide bottles.

JD338 and POP helped me out with some pointers working with the little .243.

I plan on doing some more checking at 200 and 300 later on this week.