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Tell me about inline seater dies - do they really produce less runout?

Charlie, thanks for writing in, thanks for the comparison and feedback on them.

On the repeatability question on the Redding, I use a Forster ultra micrometer seater which I do like. Originally, I had some problem with it being repeatable, what I found is that the thing works best if you approach the setting you want always by turning down instead of turning up i.e. set the seater so that it sets the bullet depth too long and then dial down to the correct depth.

Having worked a bit with mechanical things, I think this is a general characteristics of tools that have threads in them and that is the slight slop they have in them makes them not absolutely repeatable unless you approach the final location with a compression-based direction.
 
There is another issue that should be brought up in any comparison of seating die results, consistency in the length of loaded ammunition, measured from some point on the ogive of the bullet, to the case head. It has been said that as long as on the bullet concentricy is below .002, that differences may not be seen on the target. On the other hand, even with perfectly straight ammunition, variations in seating depth may be a problem. I believe that arbor press dies have the edge in this area. It is my understanding that the editor/owner of this site checks all of his loads for ogive to head length. I think that this is a good idea.
 
Agreed! I have been measuring mine as I use it as an indicator for consistent seating depth. With 175 SMKs, that seemed to be pretty consistent with the Forster, my last 10 rounds that I loaded up and fired only had a one thousands ES in length measuring distance between the ogive and case head. This has improved greatly after I controlled my neck tension.
 
BoydAllen said:
It is my understanding that the editor/owner of this site checks all of his loads for ogive to head length. I think that this is a good idea.

I agree. Works even better if you presort your bullets by bullet base to bullet ogive before seating. Ask Bryan Litz about this sorting method. Better than bearing surface sorting.
 
Thanks!

I’ve read conflicting info about this. Logically, it seems like bearing surface sorting would make the most sense but of course I respect Bryan’s experience, still wonder why this is so – any idea?

Could it be that bullet base to bullet ogive not only gives you bearing surface length, but any inconsistency in bottom of the bullet bearing surface and the base which would affect case volume?
 
http://blog.sinclairintl.com/2010/03/24/bullet-prep-giving-you-the-long-range-edge-part-ii/

"According to Litz, this measurement is in fact sorting the bullets for consistent Ballistic Coefficients (BC). What occurs in the bullet forming process is what determines the bullets physical ballistic qualities. When a bullet is forced into the forming die a few factors come in to place to determine the outcome. These factors include the amount of lubrication used and how it can change the force exerted on the bullet when being formed. If the bullet is forced further than it should into the die, the outcome is a bullet with a short bearing surface, long ogive, and narrow meplat."
 
jlow,
I am shooting the new 105 Berger Hybrids this year for my 1000 yard competition bullets, they vary in length by quite a bit, there pretty good comparing them on a bearing surface comparitor but I still sort by bearing surface and by base to tip length, my groups dropped from 1moa groups at 1K to 1/2 moa just by sorting and by getting my seating depth spot on or tuned for that rifle at that particular distance, they say the hybrid isn't picky about seating depth,...wrong!! .002 one way or another makes a big difference, on sat. I was shooting in the 6" range conditions were not great, my cartridge length measured with a Hornaday OAL tool measured off the base to ojive was 1.8235 I decided to try something different, I seated Sundays first relay rounds to 1.8215 15" group :o second relay back to the 6" range so seating depth DOES matter. I was getting inconsistent seating depths with both my Redding, Forster and Wilson dies with the least from my Forster but it isn't very user friendly on the firing line and I seat long and seat at the bench so the Wilson or inline die is important to me, when I say they were inconsistent I am talking .001 or maybe less but as you can see by my comments above .001 can make or brake these bullets so I had to re invent the wheel so to speak, I took three Wilson seating stems to work and compared them on a optical comparitor :o ALL THREE were different angles!! I also compared the bullets, they have approximately 5 degree angle on there ojive so I reground the stem to 5 degrees and ground it as thin as I dare go so I could get as close to where the lands meet the bullet as possible, I gained about .100 but still lack about that much from being at .237 but it was a lot closer then before and the oal measurements have greatly improved in there consistency. just a side note for you, I know you like everything to be proven beyond a shadow of a doubt it's your scientific background so with that being said, ALL not almost all but ALL seating stems hit the bullet on the ojive but always way up on the nose some where, NOT where we measure from though is it?? we measure with a ojive measuring tool that say on a 6mm is right at .237 yet our seating stems hit at maybe .187 way up the nose makes no sense does it at least from a scientific stand point, just some food for thought and yes I have compared the nose of the bullets and there not all perfectly the same!! I am going to make my own inline die that will seat from .237 one of these days.
Wayne.

P.S sorry for the long post but I thought you might enjoy it.
 
Wayne, I agree with your approach 100%. The picture below shows the problem you describe. The blue line is where the seater stem contacts the bullet, the red line is where the bullet contacts the rifling. Not the same and that distance can vary from bullet to bullet.

I wrote a short piece about that here: http://riflemansjournal.blogspot.com/2010/09/reloading-measuring-bullets.html

Basically, I was frustrated enough by this that I don't measure anything on bullets. One day I'll attack this problem. I like your approach.


DSCN7675.JPG
 
With high BC bullets, the fly in the ointment is that if you try to measure exactly where the rifling will mark the bullet, there is a wedging effect that causes inconsistency. This can be seen remeasuring the same bullet. I would think that this inconsistency would also come into play if a seater stem were modified to make contact in this area. Another way to approach the problem might be to grind a cutter that is matched to the curve of a particular bullet's ogive, and use that to cut the seater stem cavity. By spreading out the contact area, perhaps greater consistency of seating depth will result.

If my memory serves, in his book The Accurate Rifle Warren Page wrote of using a straight loaded round and some bedding epoxy to custom fit the cavity of a Wilson to a particular bullet, to improve seating consistency. I think that this approach might be tried,with the modification of drilling out the very center of the cavity bedding to allow for the slight differences in tip shape and length.

I think that having a flat bear against a curve results in unit loading that is at the core of this problem. Perhaps increasing the contact area would help.
 
I am no fan of a die not made from the chamber reamer. run out is first started with the chamber being true, next is the sizing die and last on the list is seater. run out should be less than a .001,but does it matter? some testing says no but no run out doesn't hurt. Seating depth is i feel more important, as it varies so does your groups. look for your window. Some may be a few thousands or more. stay in between, i have had no luck it chasing the lands, so i kind of stay put........jim
 
German,
Thank you,
I have read probably most of your articles and refer back to them quite often I am not sure if I have read this one so I am going to right after this post. I will let you know what I think.

Boyd,
I am not sure how wide my seating area is right now but it's fairly wide on purpose, after I polished the stem out then spun a bullet in the stem you can see it is quite wide probably almost as wide as the red mark on Germans bullet, I ask the machinist friend of mine that helped me with the project why he ground such a wide surface area for where the stem touches the bullet and his reply was that I told him too, well I was thinking much less but I will give it a try so far it works fine, I just saw you called on the id so I will talk to you about it on the phone.

Jim,
I had my smith re cut a 6br Wilson die with out 6brx ream and it produced okay results but the seating depth varied a little more then I liked and the runout was as high as .002 not all caused by the seating die but it mostly was as the brass runout rarely is over .0005 after sizing now with just the modification to the stem it is usually not more then .0005 sometimes as high as .001 but that is on the brass in the back of the case that is used for fowlers anyway due to some problem or another anyway, I have only done 150 rounds with this modified die stem but so far I am highly impressed. I think I will take another Wilson die known to have some runout and see if by just doing the stem will make any difference or if this was just a fluke, I will have to have Paul show me step by step how to do all this as I will have plenty of them to do if it does.
Wayne.
 
Wayne, I use a small boring bar,it works great for the VDL type seating stem. Gets the seater steam as close to the ogive as possible.........jim
 
German,
Yes I have read that article many many many! times, it is the article that started my quest to figure this whole thing out, I thought I recognized that Vickerman die photo but didn't want to comment until I read the article first. I was having trouble with seating depth, measured as you do from base to ojive on a .300wm the measurements were all over the place, as usual I am a extremest and nothing short of perfection is good enough, for a hunting round that is ridiculous but like I said,.....anyway after reading your article it got me really thinking, if I can't fix the die I will change how I measure bullets so I used the seating stem from my redding comp die and attached it to my Larry Willis digital headspace gauge tool and that is how I sorted bullets until a couple of months ago and it was a huge improvement over the way I had been doing it. I only compete in 1K bench rest at the moment German and I find any variable to cause problems no mater how small if it is a variable it seems to matter. My new 105 Berger hybrids have varied as much a .020 base to tip I know in your article you said that But the tip is irrelevant to the seating process and thus its irregularity can be ignored. I thought about that for a long time and although I usually always agree with you I thought you were wrong but considered what you first said,.1. What am I trying to accomplish? and decided for your needs you were probably spot on but for my needs trying to get to 5" 10 shot groups at 1K that .020 might change the b.c enough at 1K to give me to much vertical to achieve that and that is why since I have not started pointing or meplat trimming much, ( I will be soon) that I will measure bearing surface with a comparitor I use the Buhay ( Mark King ) and then I sort by bullet length, by doing this I have noticed a noticeable difference in my groups, I am not sure if it is coincidence or not, I was sorting by weight as well but did not notice any difference there, I also haven't noticed any improvement on groups on runout from say .002 to zero runout but I try to keep it as low as possible anyway. I think precision in long range shooting all the little and big things combined and if you ignore any one of them your groups will start to suffer, to what degree will vary but suffer they will IMHO, besides the normal things we have to do to get small groups I think these are the most critical for Long range for short range the list would be different,
#1 Neck tension
#2 exact powder weight ( for the same velocity )
#3 seating depth with bullets of as close to the exact b.c as possible

I also think if your jamming that maybe your seating depth is not nearly as critical as if your jumping them. Incidentally in the beginning of this post I mentioned I was having trouble with seating depth variance in my .300wm that started this whole thing,....it was a neck tension variance problem more then any other factor, once I got that resolved, most of the problem went away. I am sorry for such a long post but I thought you might find it interesting, these statements of course are only my findings and opinions which of course aren't proof of anything but they are honestly what I believe have helped me achieve my goals and I am getting better all the time from my own discoveries and the help from good friends and people like you German, thank you for all you have done and continue to do for the shooting world.
Sincerely, Wayne Bezona.

P.S, I think the K&M arbor press with force seat measurement system is the single most important investment you could ever make for long range shooting as you can monitor and sort by seating force, remember my #1 thing,... neck tension, I truly believe this is the key.
 
Wayne, if you can write an article about your bullet sorting process with some good digital pictures of the setup, I'd love to put it on the site; it sounds like a well thought out approach but without some visuals I'm not following it entirely. I think it would make a great article.

I agree with your three or four part list and the order of importance - how we get there can vary a bit, but we're going down the same path.

Thanks to all for getting a good dialogue going on this topic, very interesting stuff.
 
Hi Wayne,

Sorry for the late response but I was tied up with another of my hobby i.e. building a new computer! Thanks to every one for writing in and the great and interesting info.

Would agree with you about importance of consistent seating depth, I have similar experiences. However, I do have to question the experts here about the utility of trying to seat bullets consistent to the last thousands or more in terms of accuracy.

It is not that I don’t believe that it might affect group size/MV etc, but I think with spizer bullets, especially with the VLDs, the angle of the ogive is so steep that slight difference in “seating depth” as measured by the comparator may not actually transcribe to real seating depth i.e. the exact location of where the base of the bullet sits and how it affects case volume. How it relates to the lands is yet a different question/animal.

This is because I think the general assumption that if you seat the bullet to the same depth as measured by the comparator will give you a similar accuracy in terms of where the base of the bullet sits in the case may be incorrect. Even a slight difference in the diameter of the ogive where the seater is pushing down will affect how far down the bullet is pushed and thus where the base end up? So in some ways I agree with BoydAllen’s comment that “having a flat bear against a curve results in unit loading that is at the core of this problem”.

I think grounding the stems to the same angle as the ogive is interesting and my help some but still wondering about the above...
 
I have had success useing both type of seaters and all threaded dies i buy are Redding. I like reloading equiptment and like to buy and try things that are different but produce the same results. As stated earlier if you are going to reload and have a place at the range to do it a arbor press and hand dies are very conveinant. As far as getting a case out of your hand die this is my favorite tool to use. It works perfect and the second picture shows what end i use to pop it out.
 

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dtucker said:
I have had success useing both type of seaters and all threaded dies i buy are Redding. I like reloading equiptment and like to buy and try things that are different but produce the same results. As stated earlier if you are going to reload and have a place at the range to do it a arbor press and hand dies are very conveinant. As far as getting a case out of your hand die this is my favorite tool to use. It works perfect and the second picture shows what end i use to pop it out.

Dan,
On the dies I have had custom made the cartridges don't stick hard enough that you can't get them out with your thumb nail, I keep my left thumb nail just long enough to catch the rim on some of the factory dies I have had this sticking problem and use a brass tool I built but I really like your idea,..thanks.

jlow, your thoughts on ojive to base measurement being different does throw another factor in I never thought about in case volume, I don't think I would be affected by the way I sort but for those that don't sort velocity and pressures could be affected some, how much I have no idea, however as far as pressure I could ask some of the mindless drones in QC at work if they have noticed any difference in pressure curves in our pistol ammo with a say .002-.003 difference in seating depth, I would be interested in knowing myself.
Wayne.
 
Thanks Wayne, would be interested in more feedback. One reason I am keyed in on this is that I handload 175 SMKs loaded only slightly longer than mag length for an AR-10 and seating depth has a pretty profound effect on groups size and MV consistency for me. Since I am nowhere close to the lands with these rounds, my thoughts are they are affecting case volume.
 

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