Mixing Bullet Lots by Length

[Killick]

Since there is a consensus among some F-Class high level shooters that it is futile to sort bullets by weight but ought be sorted by OAL, would it be feasible to mix lots of,say, Berger Match Hybrid bullets of the same weight and caliber but different lots? The purpose being to reduce storage clutter of several different containers on the loading bench/shelves. Please, no weight sorting debate on this thread.

 

[Link]

What is more important trying to sort weight, OAL or bearing surface?

 

[Straightshooter1]

What is more important trying to sort weight, OAL or bearing surface?

In my limited experience, sorting by bearing surface is more important . . . as is BTO, which is part of that bearing surface measurement anyway.

 

[Killick]

Brian Litz on sorting and trimming bullets: "For enhanced uniformity you can sort your bullets by length and point them in batches, adjusting the die for each set of lengths to insure the most consistent point and the most uniform BC." Modern Advancements In Long Range Shooting, Vol. II. No mention of BTO, OAL or bearing surface. He has previously advised CBTO as a preferred measurement to COAL.

Base to Ogive « Daily Bulletin

Content tagged with Base to Ogive.

bulletin.accurateshooter.com

 

[Ned Ludd]

In my hands, sorting bullets for F-Class matches by bearing surface or BTO does very little. The only thing you are really changing by using that approach is a very tiny amount more/less shank in the neck at a given seating depth, which could mean a microscopic difference in effective internal case volume, or seating force friction. With a typical Lot of bullets, those differences would be so slight that most F-Class shooters would be unable to shoot the difference. Further, I have measured the dimensions of many, many, many different Lots of Berger bullets that went through my F-Class rifles. In my hands the nose length variance of Berger bullets always far exceeds the BTO variance, which is usually fairly uniform. Because consistent seating depth is a VERY BIG deal, and the two critical contact points for generating consistent seating depth (i.e. caliper insert contact and seating die stem contact) lie on the nose of the bullet, which is outside the BTO region, I view sorting bullet by OAL to be a much better approach. It allows for more consistent seating depth, and is essential to facilitate the bullet pointing process, if you're not using bullets already pointed by the manufacturer.

 

[Ned Ludd]

Brian Litz on sorting and trimming bullets: "For enhanced uniformity you can sort your bullets by length and point them in batches, adjusting the die for each set of lengths to insure the most consistent point and the most uniform BC." Modern Advancements In Long Range Shooting, Vol. II. No mention of BTO, OAL or bearing surface. He has previously advised CBTO as a preferred measurement to COAL.

Base to Ogive « Daily Bulletin

Content tagged with Base to Ogive.

bulletin.accurateshooter.com

Sorting bullets by length prior to pointing is sorting them by OAL.

I think the most important thing to consider in your original question is whether there may be other appreciable differences between different Lot #s of bullets in addition to OAL variance that could lead to loss of precision, even though you sorted the bullets by OAL after mixing the different Lot #s. For example, differences in jacket thickness, bullet weight (if significant), ogive radius, etc. In other words, I can certainly imagine there may be more differences between Lot #s than just the external bullet dimensions. However, I do not know whether any of these differences would be large enough to become limiting sources. I have considered doing the exact same thing a few times myself, but have never actually done it. I suspect a simple test of shooting a few groups (same load) of each different Lot of bullets with the same OAL before mixing them together would reveal whether there was any noticeable difference between the two in terms of precision.

 

[Straightshooter1]

In my hands, sorting bullets for F-Class matches by bearing surface or BTO does very little. The only thing you are really changing by using that approach is a very tiny amount more/less shank in the neck at a given seating depth, which could mean a microscopic difference in effective internal case volume, or seating force friction. With a typical Lot of bullets, those differences would be so slight that most F-Class shooters would be unable to shoot the difference. Further, I have measured the dimensions of many, many, many different Lots of Berger bullets that went through my F-Class rifles. In my hands the nose length variance of Berger bullets always far exceeds the BTO variance, which is usually fairly uniform. Because consistent seating depth is a VERY BIG deal, and the two critical contact points for generating consistent seating depth (i.e. caliper insert contact and seating die stem contact) lie on the nose of the bullet, which is outside the BTO region, I view sorting bullet by OAL to be a much better approach. It allows for more consistent seating depth, and is essential to facilitate the bullet pointing process, if you're not using bullets already pointed by the manufacturer.

My experience with Berger bullets is much the same, in that the BTO variance is small and the OAL has much greater variance. As I posted in a couple other threads in the past, to get that consistent seating depth I'll use a comparator that has the same diameter as the seating stem when I sort bullets like Bergers. . .and that's only if there happens to be enough variance to warrant the sorting. Of course, there's some very small difference between the contact points for the BTO comparator and a comparator with the same diameter as the seating stem. The results I tend to get are some very consistent seating depths when measuring CBTO. And as stated, that's "a VERY BIG deal". Bullets that are are not as uniform as Bergers, sorting by BTO or BS helps does help with getting more consistent seating depths, as doing so tends to do better than sorting by bullet length (in my experience, anyway).

It goes without saying, but quality bullets is a "VERY BIG deal" too.

 

[INTJ]

LOL! In LR BR, we consider Berger's inconsistent and in need of lots of sorting. Custom bullets are much more uniform. I sort them all the same way. Chamber ogive, seater, ogive, and spin on the genie.

And I always keep them within the same lot.....

 

[Killick]

Sorting bullets by length prior to pointing is sorting them by OAL.

My bad, that slipped by me.

 

[LVLAaron]

OAL makes the most sense (to me) for long range. The goal being to normalize BC.

 

[Killick]

I think the most important thing to consider in your original question is whether there may be other appreciable differences between different Lot #s of bullets in addition to OAL variance that could lead to loss of precision, even though you sorted the bullets by OAL after mixing the different Lot #s. For example, differences in jacket thickness, bullet weight (if significant), ogive radius, etc. In other words, I can certainly imagine there may be more differences between Lot #s than just the external bullet dimensions. However, I do not know whether any of these differences would be large enough to become limiting sources. I have considered doing the exact same thing a few times myself, but have never actually done it. I suspect a simple test of shooting a few groups (same load) of each different Lot of bullets with the same OAL before mixing them together would reveal whether there was any noticeable difference between the two in terms of precision

Well I guess it’ll be up to me to test it at 600 yards in a few weeks. I’ll shoot the first 2 stages 10 shots Lot 1, 10 shots Lot 2. Last stage stagger them 1,3,5,etc. Lot 2,4,6,etc. Lot 2. We shoot it with ShotMarker targets so the results should tell me something…

 

[bozo699]

Well I guess it’ll be up to me to test it at 600 yards in a few weeks. I’ll shoot the first 2 stages 10 shots Lot 1, 10 shots Lot 2. Last stage stagger them 1,3,5,etc. Lot 1, 2,3,4,etc. Lot 2. We shoot it with ShotMarker targets so the results should tell me something…

Killick,
During the Obammy shortage I did have to sort different lots to finish the season a couple of times I felt it was worth it, I’ve only shot a few F-class matches so I can’t say but at 1000 yard br it seemed to help. I didn’t have a genie but pretty much was anal like INTJ mentioned in his post. I think your plan is very valid and will give you your answer. Please let us know your results
Wayne

 

[Ned Ludd]

Well I guess it’ll be up to me to test it at 600 yards in a few weeks. I’ll shoot the first 2 stages 10 shots Lot 1, 10 shots Lot 2. Last stage stagger them 1,3,5,etc. Lot 1, 2,3,4,etc. Lot 2. We shoot it with ShotMarker targets so the results should tell me something…

Let us know what you find. I rather suspect you will ultimately end up being comfortable with mixing the Lots and sorting them by OAL. However, that is only a guess, so it will be interesting to hear your actual findings.

 

[Ned Ludd]

My experience with Berger bullets is much the same, in that the BTO variance is small and the OAL has much greater variance. As I posted in a couple other threads in the past, to get that consistent seating depth I'll use a comparator that has the same diameter as the seating stem when I sort bullets like Bergers. . .and that's only if there happens to be enough variance to warrant the sorting. Of course, there's some very small difference between the contact points for the BTO comparator and a comparator with the same diameter as the seating stem. The results I tend to get are some very consistent seating depths when measuring CBTO. And as stated, that's "a VERY BIG deal". Bullets that are are not as uniform as Bergers, sorting by BTO or BS helps does help with getting more consistent seating depths, as doing so tends to do better than sorting by bullet length (in my experience, anyway).

It goes without saying, but quality bullets is a "VERY BIG deal" too.

I'm really not trying to be a jerk, but how can sorting bullets by BTO or BS help improve seating depth? That is an honest and fair question. Obtaining uniform seating depth requires the exact same distance on bullets between the two critical contact points, i.e. where the seating die stem contacts the nose to push the bullet down into the case neck, and where the comparator insert seats on the bullet ogive when we measure CBTO. Both of those critical points are located on the bullet ogive and thus fall outside either BTO or BS measurements. In other words, sorting bullets by BS or BTO are unlikely to improve uniformity of the nose length region, of which they lie outside. Thus, I don't think it likely that sorting bullets by BTO or BS will be effective at generating more consistent seating depth.

In fact, Bob Green and others make Comparator tools that specifically sort bullets between those two critical contact points on the bullet ogive. Ideally, the use of such a tool would be even better than sorting bullets by OAL, which admittedly also takes bullet regions outside those critical points into account. For that reason, I also view sorting bullets by OAL as a "poor man's" Bob Green Comparator. However, because the major source of bullet length variance typically resides in the nose section, sorting by OAL does help to improve the consistency of seating depth. I don't see how sorting by BTO or BS will make any contribution in that regard. As I alluded to earlier, many people that sort bullets by BTO or BS do so for very specific reasons that result from having the exact same length of BS gripped in the neck at a given seating depth, which are different reasons from promoting uniform seating depth. To be clear, I'm not knocking sorting bullets by BTO, BS, or whatever other parameter anyone wishes to use. In fact, any sorting procedure might be a possible improvement, and is unlikely to ever make precision worse, even if it doesn't improve anything. I'm merely questioning whether sorting by BS or BTO will help promote uniform seating depth.

 

[46and2]

I'm really not trying to be a jerk, but how can sorting bullets by BTO or BS help improve seating depth? That is an honest and fair question. Obtaining uniform seating depth requires the exact same distance on bullets between the two critical contact points, i.e. where the seating die stem contacts the nose to push the bullet down into the case neck, and where the comparator insert seats on the bullet ogive when we measure CBTO. Both of those critical points are located on the bullet ogive and thus fall outside either BTO or BS measurements. In other words, sorting bullets by BS or BTO are unlikely to improve uniformity of the nose length region, of which they lie outside. Thus, I don't think it likely that sorting bullets by BTO or BS will be effective at generating more consistent seating depth.

In fact, Bob Green and others make Comparator tools that specifically sort bullets between those two critical contact points on the bullet ogive. Ideally, the use of such a tool would be even better than sorting bullets by OAL, which admittedly also takes bullet regions outside those critical points into account. For that reason, I also view sorting bullets by OAL as a "poor man's" Bob Green Comparator. However, because the major source of bullet length variance typically resides in the nose section, sorting by OAL does help to improve the consistency of seating depth. I don't see how sorting by BTO or BS will make any contribution in that regard. As I alluded to earlier, many people that sort bullets by BTO or BS do so for very specific reasons that result from having the exact same length of BS gripped in the neck at a given seating depth, which are different reasons from promoting uniform seating depth. To be clear, I'm not knocking sorting bullets by BTO, BS, or whatever other parameter anyone wishes to use. In fact, any sorting procedure might be a possible improvement, and is unlikely to ever make precision worse, even if it doesn't improve anything. I'm merely questioning whether sorting by BS or BTO will help promote uniform seating depth.

The seating depth we are trying to achieve is where the bearing surface hits the lands... consistantly.
Thats why our comparators measure close to the start of the bearing surface.

 

[CharlieNC]

I'm lazy. For fclass I mix lots within a box, but keep them separate for each 20 shot relay.

 

[JFrank]

OAL makes the most sense (to me) for long range. The goal being to normalize BC.

I don't understand how a tiny difference in oal perhaps .001 or .002 ( a human hair) at the meplat can make any significant difference at any distance on paper or effect BC in a way that's observable, on the other hand seating depth variances of .001 Will show at 1000 yards as well as .1gr powder variances and bushing size can make a huge difference on paper and that I can see but OAL ??? Im not so sure...

 

[Killick]

In fact, Bob Green and others make Comparator tools that specifically sort bullets between those two critical contact points on the bullet ogive.

I have and have used Bob Green's comparator, which measures to the .0001, and found that the inconsistency of Berger bullets is so negligible as to make the comparator unnecessary. It probably has a measurable advantage at 100/200 yards but there are so many factors affecting a projectile on its 9/16 of a mile to the target as to make the difference unmeasurable.

 

[Killick]

I don't understand how a tiny difference in oal perhaps .001 or .002 ( a human hair) at the meplat can make any significant difference at any distance on paper or effect BC in a way that's observable, on the other hand seating depth variances of .001 Will show at 1000 yards as well as .1gr powder variances and bushing size can make a huge difference on paper and that I can see but OAL ??? Im not so sure...

You should read Litz's chapter on "Bullet Trimming and Pointing" in Modern Advancements in Long Range Shooting, Vol.II. The improvement in BC is directly proportional to the quality of the projectile. Consistent lots of bullets show less improvement while the reverse show more improvement.
On a side note I wonder how these efforts to improve loaded consistentcy would improve sling shooters scores. My guess is that it would be tantamount to gilding the lily.

 

[Killick]

Well I guess it’ll be up to me to test it at 600 yards in a few weeks. I’ll shoot the first 2 stages 10 shots Lot 1, 10 shots Lot 2. Last stage stagger them 1,3,5,etc. Lot 2,4,6,etc. Lot 2. We shoot it with ShotMarker targets so the results should tell me something…

edited to correct counting error...