I also stopped short of neck turning and primer pocket uniforming, but I use Lapua and Norma Brass as they seem to be pretty uniform.
This was exactly my thoughts, I was surprised when I started turning my new Lapua 308 Palma brass. I was expecting to only touch bumps after ironing the inside of the necks to move any imperfections to the outside. Instead, in the lot of 100, I got 50 that about half the necks were reduced by .0005 and the other side not touched. The other 50 behaved as expected. Clearly one half was produced with one set of tooling and the other half with another. Of course I have no idea if this would affect accuracy or velocity variation but one side of the necks was much thicker than the other side for those 50 cases.
Primer pocket uniforming did nothing for all 100 of the Lapua, they were perfect. It was a very different story for my Federal brass there were all kinds of variations, and probably 10 grains of brass cut from the primer pockets uniforming 100 of them.
When posts about accuracy appear, I am always interested in an intellectual sense like Speedy. Secondly, I always turn to “Rifle Accuracy Facts” to read what Harold Vaughn said on the subject. For those of you who do not know, Vaughn was the real meal deal. He flew fighter aircraft in WWII, then finished his education in aeroballistics before working at several government laboratories, ending his career as Supervisor, Aeroballistics Division at Sandia National Laboratory. He was adept at both theory and experiment, a rare enough combination but also a machinist, presumably at least competent, which makes him a very rare triple threat. Vaughn was also an avid hunter, with a grand slam of sheep among other hunting trophies. The secondary title of his book is “A distinguished scientist’s lifelong pursuit of the secrets of “Extreme Rifle Accuracy”” Enough said.
Pages 142-146 in “Rifle Accuracy Facts” contain the section on Case Neck Asymmetry.” Quoting, “The goal is to have the bullet enter the throat perfectly and exactly on center with the bore… Consequently case neck asymmetry may have more to do with bullet-in-bore canting than the shape of the bullet, and if one is really striving for good accuracy something has to be done to correct this situation.” Vaughn then goes on to describe what he did. What is unclear to me is the relative importance of two effects: (1).The longitudinal axis of the bullet parallel to the axis of the throat but offset; (2). The center of mass of the bullet on the axis of the throat but the bullet’s longitudinal axis at an angle to the axis of the throat.
Vaughn also discusses how bullet shape and bullet density inhomogeneity can cause in-bore bullet canting, other variables that must be controlled to have a good experiment.
Along with other Buds I await with interest the results of Bob’s experiments.
I'm starting to see some patterns or differences between standard full length resizing and seating with standard dies compared to what I call the bench rest methods, which consists of neck turned, neck sized cases that have been weight sorted, and the flash hole reamed and primer pockets uniformed.
By far more important is developing a load that is tuned to the rifle. No amount of precision reloading can fix a load that isn't tuned to the rifle.
I am using three calibers, 204 Ruger, 6.5 Creedmoor, and 308 Winchester. I have LE Wilson neck size dies appropriate selection of bushings, and seating dies used in my K&M arbor press. The standard dies are Hornady, RCBS, and Dillon along with a shoulder bump die for the 204 by Forster.
I'm now up to four loadings of the neck sized cases with no problems with bolt closure yet but I can feel some increased resistance now so it won't be long before I need to bump back the shoulders.
In general, the bench rest techniques do produce more accurate and more consistent cartridges than the standard loading process, but not always. In a few examples accuracy degraded with the benchrest techniques or was statistically indistinguishable. One such example was the 204 when I turned just a little to much brass off the neck causing insufficient neck tension for consistent ignition.
The bench rest methods do significantly reduce how fast the case growin length, .0005 to .001 for the neck sized brass per shot vs .003-.004 for the full length sized cases. I am forced to trim cases on the full length sized lots every two or three loadings even though I'm careful to move the shoulder back only .002-.003". It appears that neck sizing will result in much greater case life. In retrospect, I should have just loaded the same case repeatedly until failure to get a solid understanding. I guess I'm just to lazy to haul my reloading gear to the range and camp out.
It is labor intensive to prep cases for the bench rest methods, but once the cases are prepped the first time there is no need to turn necks or debur flesh holes for the remaining life of the case. There is also no need to uniform the primer pockets but they do need to be cleaned. On the plus side, the neck sized cases don't re quire lubrication so that also saves case cleaning. It is relatively fast once you get over the initial investment of time required to prep the cases the first time.
The extreme spread and standard deviations are reduced with the Bench Rest methods, some times significantly but not always. I've achieved standard deviations of less than 3 fps with the bench rest methods where I seldom achieve less than 15 fps with full length resizing. Perhaps that is good enough, but at 1000 yards I suspect that is a noticeable difference but so far all my testing is at 100 yards.
So here are a few groups for comparison, they are somewhat representative but there is still a lot of variability I want to eliminate or at least understand.
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Interesting, I tried neck sized and FLS in my 308win with no difference.
That was however with a lee die set so they were hardly match grade, but from a hunting reloader perspective when your not super fussy it makes little difference.
I think I now have a handle on the benefits of precision handloading and practical hand loading after a little over 600 rounds fired in the three calibers that I have all the equipment to compare, 204, 308, and 6.5 Creedmoor.
It really depends on your goals. If you are a big game hunter and not concerned with brass life and will limit your shots to 800 yards or less, don’t bother with the precision loading gear or techniques. Just tune a load to your rifle that shoots 1/2 MOA and call it good. Simply use full length sizing dies and conventional seating dies. There is no need for even neck bushing dies, it is all about the recipes.
This is what I thought I would find but now I know, and don’t have to take others experiences, I have my own experience to draw upon.
If your goals are to shoot tiny bug hole groups, or extend case life, or like me you want to shoot tiny varmints at mid range, and Big Game at truly long range then the precision loading techniques and tools can help. But they can only help once a high level of accuracy has already been achieved though tuning the load to the rifle. It must be capable of 1/2 MOA or better to begin with. You can also use less than the best brass cases such as Hornady, Remington, Winchester, Federal, PPU or similar and have it out perform Lapua, Norma, or RWS, or even improve Lapua brass with these tools and techniques.
i’ll take a little time to explain each tool, what it does, and what benefits it provides beginning with the rear of the case and working forward.
1. Primer pocket uniformer - I used the K&M version, and found that many cases have pockets that are to shallow to seat a primer flush without crushing the primer pellet. After uniforming, primers seat with a consistent feel and are all flush with gentle pressure. I found no impact on accuracy or velocity variance.
2. Flash hole reamer - I used the K&M version, and found that many cases have huge tabs of brass from the flash hole punching process still attached to the inside of the cases. This was not the case with Lapua cases as they are drilled, not punched. I saw no change in accuracy but did note several instances in which reaming the flasholes tightened velocity distributions. This is important for long range accuracy.
3. Neck size die with bushings - I used L. E. Wilson hand dies in a K&M arbor press and found this to dramatically increase case life as compared to full length sizing and often improved accuracy if a high degree of accuracy was already achieved. Some times a 1/2 MOA rifle and load combination was improved to 1/3 or even 1/4 MOA. It is a slower process than full length sizing at first glance but not when you consider that there is no need to lubricate the case or remove the lubrication, and the need to trim the case and resulting chamfer and debur steps are eliminated. I loaded and fired one 204 Ruger caliber Hornady case 22 times before I encountered an increase of resistance to bolt closure that caused any concern, ejection was flawless as well. If full length resizing this case would need to be trimmed, chamfered and demurred four or five times and would have approached incipient case head separation before reaching this many reloads with the shoulder moved back .003”.
4. Shoulder bump neck size bushing die - I used the Forster version for my 204 Ruger only. It provided most of the benefits of neck size only with the added benefit of more reliable bolt closure. I could detect no difference in accuracy or velocity distribution compared to the neck size only. However the case did grow about .001” per firing which would indicate a shorter case life and more frequent trimming, chamfer, and debur. I did not repeat this operation a sufficient number of times to confirm this supposition.
5. Case mouth chamfer - I used the K&M version which has a depth control setting. Bullet seating was noticeably more consistent than several other chamfer tools I use. I couldn’t measure any improvement in accuracy or velocity variation but I really liked this tool regardless and will continue using it.
6. Debur - I used a standard RCBS version of this tool, nothing special here.
7. Bullet seating - I used an L. E. Wilson Stainless Steel chamber seater with micrometer adjustment. This tool definitely seats bullets straighter with measurably less run out. This did not translate to better accuracy at 100 yards but should improve long range accuracy. I used these dies in the K&M arbor press with a force pack measurement and dial indicator which helped identify cases with substandard neck tension. I did not verify that those cases would introduce accuracy or velocity distribution problems but strongly suspect that they would have.
8. Neck turning, I used a K&M neck turn tool but found it to bea waste of effort totally useless unless trying to improve a .2 MOA gun to a .19 MOA gun.
So there you have it, what I found is that I like the arbor press and hand dies and will keep them along with the primer pocket uniformer, flash hole debur tool, and Chamfer tool but I wasted about $500 on neck turning tools.
Bob thanks for taking the time to present such a comprehensive analysis. Is the case chamfer tool that you mention the K&M controlled depth tapered reamer? Been looking at one locally.
7x57 wrote:Bob thanks for taking the time to present such a comprehensive analysis. Is the case chamfer tool that you mention the K&M controlled depth tapered reamer? Been looking at one locally.
7x57 wrote:Bob thanks for taking the time to present such a comprehensive analysis. Is the case chamfer tool that you mention the K&M controlled depth tapered reamer? Been looking at one locally.
I use an ordinary de burrer and sometimes a Redding VLD chamfer tool, but that looks much better. I've never liked the effort needed to get a flat base started in a case that has been only deburred.
Very interesting read Bob, and thankyou for posting the results.
6 months ago I invested in a K&M primer seating kit, and also the case prep kit, but I held off purchasing the neck turning kit. Now after reading your results I am glad I held off.
K&M hand tools seem to be very well made and thought out.
Life is too short to hunt with an ugly dog.
Hunt with a German Shorthaired Pointer.
Yes, if I could do it all over again I would buy the general brass prep kit, and not the neck turn kit. Although there is one thing I'm still wondering about and that is the "dreaded doughnut". I was supposed to run into it and have to ream the inside of the necks but so far it hasn't been a problem. If it were, the carbide cutter mandrel of the neck turner was supposed to take care of it. But I turned the necks to uniform them at the start and never touched them again. If I do run into this problem, I'll update my findings.
