Sorting bullets for accuracy

Dave,
You can blame me.
A few years back I was at a small bore match, and a friend needed a few more rounds so we could shoot the team match, I ran to the truck to retrieve some shells, but all I could find was a couple of boxes of federal GMM that had been setting on the dash board for a couple weeks through the oklahoma summer. They were hot enough that the lube had liquified and dripped from them. Shooting those bullets, he cleaned 6 100yd bulls. he dosn't weigh loaded rounds anymore, but there is always a brick of 22's on the dash!
Course... if those sorted bullets shoot great, do I get partial credit? /ubbthreads/images/graemlins/confused.gif
let us know how it turns out!
 
Have you ever weighted bullets? I've found that they don't weight the same. Alot will weight the posted weight and alot weight different weights. That might be why all the rounds don't go into the same hole.
 
I have in the past weighed the bullets too. They vary a bit but usually (guessing here) in .10's of a grain. That would put the variance in the 1000's place. 175.0 vs 174.9 or vs 175.2... I don't know if that's enough variation to worry about??? The variation on the shape of the bullet and the distance the loaded bullet must jump to make contact with the lands as a result of this variation and these effects are unknown to me so I'll try this shape-sorting as being a more significant contributor to reducing my big (relative) groups.

If I were to start shape and weight sorting in unison I'm sure I'd end up with lot# groups of one bullet per sort specification. /ubbthreads/images/graemlins/smile.gif I'd be down to one shot groups!!
 
But dave, those one shot groups sure are small!!! /ubbthreads/images/graemlins/grin.gif
As long as the bullets are consistant to a half grain or so, ive never seen a differance. Now weighing 22lr ammo... thats a completly different thing.
 
Just came in from shooting at 1350 with my first group of sorted bullets. I only had time for one group as it was getting late, and I decided to fire 4 shots, since I had just cleaned the barrel.
4 shots in 13"
3 closest in 8"
2 closest in 3.25
For referance, my last 2, 3 shot groups shot on 2-17 was
3 in 23"
2 in 9.5"
and
3 in 14.75"
2 in 2.75"
Ill run up the hill and take a pic or two in the morning, and if the wind is light enough, see if I can throw down another group this size to lend this test some meaningful results.
maybe there is something to this after all...
 
STOP IT... STOP IT RIGHT NOW!!! DROP THE CALIPERS and BALANCE AND BACK AWAY....

geeez... Today I bought a comparator and 1000 Sierra 30 cal 175 MKs, a new body die for my brass. Life will never be the same... /ubbthreads/images/graemlins/frown.gif

I'll let you know how things turn out. I'll work and load this weekend, maybe even fire a few test loads the shoot for long range groups (accuracy more than groups) the weekend after next.
 
I know what you mean...
The first thing I thought when I saw that cluster of holes was "grrreat... now ive gotta measure all my bullets..."
well...maybe I thought that after I quit smiling.
If this was a custom, id be happy, but being a bone stock rig(except the trigger) im elated!

Now im wondering if I get a sharpie marker and draw tiny pictures of smiley faces on the boattails....
/ubbthreads/images/graemlins/grin.gif /ubbthreads/images/graemlins/grin.gif /ubbthreads/images/graemlins/grin.gif
 
Didn't get a chance to shoot, kinda under the weather today, but I did run up and take a couple of pics,
No need to make fun of the camera, I already know it's horrable.

1350ydgroup3.jpg

1350ydgroup4.jpg

Here is a pic after they have been pasted over... you can see them better here.
1350ydgroup1.jpg

And finially, a overall view, the black rectangle is 18"x27"
1350ydtarget2.jpg
 
I just measured these 300 grain .338 Sierra MKs to shoot at 2000 yards this weekend. I have found from previous experience that .002" difference in ogive to base measurements can change POI about 27" at 1 mile! So it is very critical to me to measure each bullet before and after seating, even with great bullets like MKs. This lot is much better than my last lot.

338mkbsd.jpg
 
Thanks

I just got another comparator yesterday and plan to load some 308 Win (the best and mightiest, most wonderful and accurate, all around class "A", top notch, one-size-fits-all chambering) today for some initial break-in and testing in a new rifle tomorrow.

I didn't think too much about the spread of the bullets measured but when I saw your non-Gaussian distribution I got a little worried. I could end up with little groups of bullets that don't conform. I guess they will be for those pesky barrel break-in sessions and plinking.

Who's comparator is that???
 
I ran across a question posed by Dave Tooley over on benchrest central, and the response from Henry C. (HBC).
I thought id post it here, along with the link, since it bears directly on this topic.

Dave Tooley:
Henry,
"We can measure a bullet for a very wide range variables, in order of importance what do you think is the most crucial? If we can establish this , we can focus on the most important variables.
In the few tests I have done ogive to base length had much less an effect on BC than meplat uniformity. We have shot 10 shot strings with.030 difference in Ogive to base(6MM) and found a very small difference in BC. If I remember correctly it was about 1/3 - 1/2 as much as untrimmed meplats.
I feel that other than having a good bullet to start with, the single most important thing we can do is trim the meplats. It seems to have, by far ,the greatest effect."

HBC:
"Dave,

I think consistent base to ogive is important for consistent velocities since with consistent base to ogive the bearing and engraving length will be consistent.

Once bullets are checked (and possibly found to be very consistent in the base to ogive dimension or at least segregated in equal lots) for base to ogive then one can segregate into lots of overall length or simply trim to equal length to get a consistent ogive length, consistent meplat diameter and more consistent BC to reduce vertical stringing at 1000 yards.

Then, probably the most important, is to look at the base for defects and eleminate those from record round bullets.

Probably least important, for match grade bullets, is weight variation but for a 1000 yard match it does not take long to weigh the record bullets to avoid a gross error in bullet weight.

Henry"

http://www.benchrest.com/forums/showthread.php?t=21318

Just a little more to think on....
 
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