Do Any Precision Rimfire Shooters Here Sort Ammunition?

South Pender

South Pender

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I'm not thinking here about sorting by either (a) rim thickness or (b) weight--both practices having shown no replicable empirical advantages. By this I mean that the occasional shooter may find that on a particular day, sorting seemed to improve group size, but the long-term evidence for either kind of sorting just isn't there--at least that's what my reading of this has indicated.

On the other hand, two other variables would seem to offer promise: (a) concentricity (runout) of loaded rounds and (b) working length of the rounds (distance from inside of rim to driving bands). Has anyone on this forum who competes in rimfire benchrest tried sorting on these variables?
 
Rim thickness does improve group size in quality ammo up to 30%.
Also you may find what rim thickness shoots better in your gun, my Cooper model 36 prefers 0.042"to0.43" of SK Standard, the 0.041" always keeps me down at least one 9 in each group.
My friend how some step more that I and weight sorts and his groups prove out the improvement in his CZ 455, shooting consistent .3 and tighter groups.
You need not buy junk ammo, but buy a consistent quality ammo and then either rim gauge and weight sort to see the difference!
But do at least a brick of ammo to prove it out?
This pertains to BR50. Shooting PRS and 25yard shooting are totally different discipline's, but this info can be applied, it can't hurt?
Other than this, your going to more than likely having to buy $20/box ammo to get the consistency, but some people get lucky and the gun and ammo shoot excellent right out of the box.
Good luck in your endeavor :)
Cheers Dale!
 
out of the rim thickness, weight and distance to driving band I found the length had more effect of groups then rim or weight, but when the sorted ammo was then sorted by both rim thickness and weight the world really came together.

SK rifle match was a solid 1/2 inch ammo at 50 meters, but sorting the ammo showed 4 distinct 1/4 inch groups that made up that 1/2 inch, unsorted ammo landed within the predictable 1/2 inch and the sorted landed within it's predictable 1/4 inch zone.

However......

Sorting any ammo that does not provide decent groups in your rifle will not created a sorted ammo that will, you need to start with a brand/lot number that will shoot decent, every level you step up in price is going to reduce your fliers by a good percentage...but...

sorting a decent lot number of SK Rifle Match yielded the same results I get with unsorted Eley Match

take all this with a grain of salt, your rifle and or shooting ability may not be worthy of being a test platform, my extensive research was done with a Kelby Swindlehurst custom benchrest rifle in a Robertson JRS stock shot off a Seb Neo front rest and rear bag, tests were also conducted on different days in different conditions with mirrored results, sorting ammo is so much fun that I doubled down on my credit card and went with the eley match.....
 
I did a little digging and found an interesting thread regarding working length on the CYankee Accuracy (Bill Calfee) site:

http://www.wwaccuracy.com/showthread.php?3890-Measuring-the-working-length&highlight=sorting

It appears that these guys define working length as the distance between the front driving band and the case head. I'm guessing that this is one variable that might be a good candidate for sorting. Assuming that anyone on this forum is sufficiently OCD to put in the time on this. I've done the rim thickness and cartridge weight sorting gig in the past and have noticed no improvement in group size.
 
Tried rim thickness and weight sorting and didn’t find any improvement however sorting by ogive to rim length was a noticeable improvement in some CenterX and SK lot #’s I tried. I now have a couple of cases of Center X that are able to group 1/4” and less. This is the tool that I used. http ://www.neconos.com/category/Accuracy-enhancement-23
 
22forever said:
Tried rim thickness and weight sorting and didn’t find any improvement however sorting by ogive to rim length was a noticeable improvement in some CenterX and SK lot #’s I tried. I now have a couple of cases of Center X that are able to group 1/4” and less. This is the tool that I used. http ://www.neconos.com/category/Accuracy-enhancement-23
Click to expand...
That's interesting, 22forever. I read the Neco ad along with the Accurate Shooter Bulletin about that tool, the G3 Rim to Ogive Measuring Tool. It measures the rim to ogive distance, which is pretty close to what Calfee and others have called "working length." The only difference being that the front measurement point with Calfee's "working length" is the front driving band rather than the ogive. Using the front driving band as the datum point might be slightly superior since it is the first point of contact for the bullet with the lands.
 
South Pender said:
That's interesting, 22forever. I read the Neco ad along with the Accurate Shooter Bulletin about that tool, the G3 Rim to Ogive Measuring Tool. It measures the rim to ogive distance, which is pretty close to what Calfee and others have called "working length." The only difference being that the front measurement point with Calfee's "working length" is the front driving band rather than the ogive. Using the front driving band as the datum point might be slightly superior since it is the first point of contact for the bullet with the lands.
Click to expand...

I think either measurement would be of the same, the important factor is that they are all sorted and grouped to length, I sorted to groups that were 2 thou apart, you don't really need to be that fine but your measuring everyone of them anyway.
Sk rifle match all measure within 18 thou shortest to longest, however there is the odd really short one and of course the odd really long one, some rifles will prefer longer bullet/base length and of course some the lesser. Somewhere I have a chart as to what the base line measurement of the ammo is by manufacturer. This is handy if you know your rifle likes either the longer or shortest of offerings, interesting also to note that out of a box of eley match ammo the base/ogive measurement was within 2 thou of the 50 I measured, and the rim thickness all at 41 thou, needless to say I didn't sort anything nor measure a second box, lot number testing for accuracy at both 50 and 100 meters was all that was required
 
I batch by rim thickness the bulk packs of budget rimfire cartridges, I find it makes a good difference on accuracy. I have tried it on more expensive match ammo, not very successful, there was too little variation. I tried it once with Eley Tenex, pointless!

Candocad.
 
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