Dusty Stevens
Shiner
Its all in what game you play
I've lost my mind - Bullet Sorting
- Thread starter treillw
- Start date
Tpb10505
Gold $$ Contributor
I thought sorting was a waste of time when I looked at it from how consistent most bullets are. But when I look at it as finding those fliers that are 6 or 8 thou short or long (or worse), I think it’s worth while. Those could be the fliers in a match that make you scratch your head and question your entire loading process and shooting fundamentals.
There is a machine that spins the bullets, I have no experience with it but just thought I would mention it.
dstoenner
Silver $$ Contributor
Brian did experiments of meplet trimming pointing alone and combinations. Found it didn’t help. He said if you are going to do anything sort by OAL or buy LRHT that are guaranteed to be 1% BC out of the box.
david
Longtrain
Gold $$ Contributor
I had to sort back when I shot Sierra’s, mainly .224 80’s and 6mm 107’s. Sorted they performed well. I haven’t shot SMK’s in a while since they pointed and tipped some, they may be better now.
But, I switched to Berger 105 and 108’s in 6mm. I load them and shoot them as is, they work just fine, no sorting.
However, I did buy a batch of 103 gr. 6mm Bison Bullets from @damoncali, I am astounded to their uniform weight and LTO, I’ve never had bullets so uniform. Once the snow goes, we’ll see how they perform.
Another thing I’ll never do is weigh primers.
But, I switched to Berger 105 and 108’s in 6mm. I load them and shoot them as is, they work just fine, no sorting.
However, I did buy a batch of 103 gr. 6mm Bison Bullets from @damoncali, I am astounded to their uniform weight and LTO, I’ve never had bullets so uniform. Once the snow goes, we’ll see how they perform.
Another thing I’ll never do is weigh primers.
Let me amend my earlier post. I just had a good friend make a very valid point. IF you’re using a PRODUCTION off the shelf bullet go ahead sort your ass off.
My thought process is based in the Custom Bullet world where you know you’re getting bullets out of the same die.
Thanks @dmoran
Bart
Following your tip to sort by OAL versus BTO I've noticed more consistent CBTO measurements, in turn giving me a more consistent level of precision on my seating window
This particular batch of 136L's im seeing .007" variation, sorting to .0015 groups I'm only getting a few on the low and high sides leaving me with a good curve in the middle covering .0045" in length variation.
I'm seeing better scores and tighter groups. Thank You!!
I found using a comparator i could measure a bullet 3 x's and get 3 different BTO measurements.
With a boat tail bullet you could very well be seeing a variation due to inconsistent boat tail lengths. Using dual comparators to just measure bearing surface could be exacerbating the inconsistencies.
Internal ballistics only care about weight and bearing surface. If the bullets weigh the same and have the same bearing surface they will act the same inside the rifle. Weight makes less difference to internal ballistics.
External ballistics care about 3 measurements practically since some exterior dimensions are controlled tight enough to make little difference in the air. Meplat diameter, nose length, and weight are the three that still matter for external ballistics. Meplat diameter can be tricky to measure but luckily nose length correlates very strongly when bearing surface has already been controlled (and still correlates pretty well when it hasn't been). Longer nose (with the same bearing surface) smaller meplat higher bc.
So we end with 3 practical measurements that probably can produce a difference that is quantifiable. By order of probable importance: Overall length (proxy for nose length), bearing surface, and weight.
As an example a .3gn difference in a 175 grain .5 g1bc 308 bullet going 2750 will add ~.3" vertical to the group at 1k. The lighter the bullet and longer the shot the more weight variation matters. Proper tune can eliminate this vertical error.
just as a reference
External ballistics care about 3 measurements practically since some exterior dimensions are controlled tight enough to make little difference in the air. Meplat diameter, nose length, and weight are the three that still matter for external ballistics. Meplat diameter can be tricky to measure but luckily nose length correlates very strongly when bearing surface has already been controlled (and still correlates pretty well when it hasn't been). Longer nose (with the same bearing surface) smaller meplat higher bc.
So we end with 3 practical measurements that probably can produce a difference that is quantifiable. By order of probable importance: Overall length (proxy for nose length), bearing surface, and weight.
As an example a .3gn difference in a 175 grain .5 g1bc 308 bullet going 2750 will add ~.3" vertical to the group at 1k. The lighter the bullet and longer the shot the more weight variation matters. Proper tune can eliminate this vertical error.
just as a reference
Bullet Sorting Experiment - Part One - Ammolytics
A detailed experiment to measure the actual effects of bullet sorting by weight and length for precision rifles.
blog.ammolytics.com
Last edited:
Ned Ludd
Silver $$ Contributor
Regardless of the component, sorting is a process that can pay dividends IF the item being sorted has sufficient variance to warrant sorting. In the case of bullets, what that typically means is that commercial production bullets will likely benefit from some kind of sorting process, whereas with high end custom bullets it may not be necessary.
If you're going to attempt sorting bullets, the best place to start is by taking measurements from 5 or 10, to as many as 20 randomly selected bullets from a single Lot, including OAL, BTO, and bearing surface measurements. Once you have these measurements in hand, look to see which one exhibits the greatest variance as a potential sorting guide. For example, the many Lot #s of Berger bullets I have used over the years seem to have very consistent BTO and bearing surface dimensions within a single Lot. Thus, sorting by BTO or BS would not be productive for those particular Lot #s of bullets.
On the other hand, OAL for the same bullets typically varies about .015" to .020" or so within a given Lot #. There are a couple pieces of information that can be gleaned from this observation. The first is that length variance within the Lot #s of Bergers I have been using largely resides in the nose region of the bullets. This is important for a couple reasons. First, seating depth consistency is dependent on the distance between two critical contact points; i.e. the point out toward the bullet meplat where the seating die stem contacts/pushes the bullet, and the point where the caliper insert seats when we measure CBTO of a loaded round. Both of these points lie within the nose region of the bullet, so length variance in that region can affect seating depth consistency. I also point bullets, which means that producing consistent points requires minimal OAL variance. For these reasons, I sort bullets into overall length groups of .0015". That way, each length group will differ from the adjacent groups by .002" overall, but there should only be .0015" length variance within a single length group. This is sufficient to ensure very uniform points without having to change the pointing die micrometer when pointing bullets from within a single length group. Thus, with the specific bullets I'm using, sorting by OAL improves consistency of both seating depth and bullet pointing.
For the OP - in order to determine how sorting might best benefit your needs, you need to have some feel for the dimensional consistency of the bullets you're using, as I mentioned above. It would be better to determine how the bullets you're using stack up before arbitrarily selecting some parameter by which to sort them. If that seems like too much work, you can always start out sorting solely by OAL. Because all three bullet regions (nose, bearing surface, boattail) each contribute to OAL, sorting by OAL can help improve consistency regardless of where the greatest length variance lies within the bullet. However, sorting by OAL would only be an indirect method for specifically improving length variance within the BTO region, for example. So knowing where the greatest variance lies within the bullets you're using is usually the place to start.
Another important question is how do you expect to benefit from sorting? In other words, what exactly are you trying to accomplish by sorting bullets? In addition, how can you test to determine whether the sorting process you choose actually provides some benefit? For example, I have tested otherwise identical loads on numerous occasions where the only difference was using either bullets straight from the box, or bullets I had length-sorted and pointed. From these tests I know conclusively that length-sorted and pointed bullets generate tighter groups at distance (i.e. 300+ yd), and improve the bullet BC by about 3 to 6% as evidenced by the reduction in scope elevation adjustment required to keep the group center point at the same height on the target at a given distance. At 300 yd it is fairly easy to distinguish these differences (group size and elevation adjustment), whereas I cannot readily tell the difference between the same load with sorted/unsorted bullets at something like 100 yd. The groups simply aren't large enough at that distance to clearly reveal differences between the two in my hands. So it's important to know what you hope to achieve by the sorting process, as well as how you're going to test to determine whether there is actually a quantifiable benefit from whatever process you choose.
I don't even compete - I just have OCD and wanna have my rifle tuned as well as you all.
recently I was reading a thread and the machine you spoke of was mentioned...Bullet Genie iirc....measures the "internal ballistics" I went to the website mainly because the creator/inventor is an accomplished shooter at matches I sometimes attend. Glad I did because his videos of the machine made me think and learn of another aspect of sorting...was good info
If the centers of the two comps aren't aligned, there will be variations.
Perfect alignment feels impossible.
Worth sorting 215 Bergers and 147 eld match?
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