Effect of bullet OAL for Berger 85.5

[JPB4BAMA]

So maybe I'm late to the party here, but I just started to measure and sort my bullets. Overall I have been pretty happy with the Berger 85.5 Hybrids and just never thought that sorting was going to be necessary since all of my local competition has been at 600 yards (both BR and F Open). But since I acquired a new 284 Win the start giving 1000 a try I got the accuracy one comparator as I understand that consistent length is much more important at that distance.

So long story short I decided to go on and sort some 200 of my 85.5's. The vast majority fall within +/1 0.004, with a smattering just outside that, but then there were a few (like 4 low and 3 high) at -0.008 up to +0.010, for a total spread of 0.018". Now I have "routinely" experiences random shots that just seem to come from nowhere that go hi or low by something close to an extra inch or so. With this type of variance just wondering if this is the culprit or if I am chasing a red herring here.

To that end if anyone has advice on sorting bin sizes I would appreciate it, Right now I decided on a bin size of 0.002.

Thanks in advance for any education

 

[Ned Ludd]

I sort bullets by OAL for the purpose of pointing them more uniformly for use in F-TR competition. I sort into length groups that cover a total length range of .0015", which leaves .002" between each group. For example, 1.2500" - 1.2515", 1.2520" - 1.2535", 1.2540" - 1.2555", etc. In my hands, a typical Lot# of Berger bullets might exhibit about .015" OAL variance, with a very small number of additional bullets I label as "extreme outliers" that are even farther from the mean OAL.

For my purposes, sorting bullets by OAL is solely a means for improving the consistency of the bullet pointing process. I have tested unpointed bullets straight out of the box versus length-sorted and pointed bullets on many occasions. Even at distances of only 300 yd, the unpointed bullets straight out of the box required 0.125 to 0.25 more elevation to center the group on the target as compared to the length-sorted and pointed bullets. The length-sorted and pointed bullets also generally grouped better/tighter. However, I never directly looked at how much of the improvement was related to length sorting (i.e. I never tested length-sorted but unpointed bullets against length sorted and pointed). It would not surprise me at all if the length sorting process had a small but beneficial effect. That is certainly a testable hypothesis.

It is also important to note that sorting bullets by OAL is not only a means to improve consistency within a single group, it is also allows one to cull the "extreme outliers", which can then be used as foulers/sighters. There is no guarantee that length sorting will make a noticeable improvement in accuracy/precision. The effect is probably very small and may have to be quantified over a long time before any conclusion can be drawn. Nonethelss, it is unlikely that length sorting bullets by OAL will ever hurt anything, so the only thing one might lose by trying it is the time it took to accomplish the sorting process.

 

[dstoenner]

Sorting by OAL of the bullet is banding your BC into tighter groups. Since BC is directly proportional to OAL. This is what Brian Litz says to do if you are going to any sorting of bullets. He said in his latest book that the LRHT are supposed to have the tightest BC, 2%, of any bullet on the market but a .018 observed might say otherwise. 2% of ~1.200 inches is .024. So??

I have and will continue to sort my long range by length regardless of marketing hype.

David

 

[dcali]

The impact of oal on BC is small but real. if you're going to sort them, .005 groups is plenty good. The berger 90s I shoot in F class tend to fall into a +/- .010" range, so 4 buckets. Unsorted, that's a big enough range to see, but only if you're already shooting very good scores. Sorting is quick and not hard, so I do it, but I wouldn't be fussed if I skipped it. If they were +/- .005 to start I'd probably skip it.