Go back, re-read, and try comprehending my post.
I did not suggest a single thing about ogive radius variances, nor the virtues of qualifying ogives.
What is wrong with you?
Seating Die design
- Thread starter PhilKeil
- Start date
I did not suggest a single thing about ogive radius variances, nor the virtues of qualifying ogives.
What is wrong with you?
O.K. let me explain piece by piece so you can understand , If you contact the ogive with a SEATER STEM that is working off the ogives and we already have established the ogives are not the same even in the same lot of bullets unless you separate them and readjust for the differences your seating depth will vary. Which is why I made a seater that works off the reamed throat the contact point with throat will always be the same no matter what ogive is used or whether jumping or jamming. the relationship from bullet to throat will not vary due to ogive differences. I don't know what type of shooting discipline you are shooting but as you said SEATING ACCURACY is VERY IMPORTANT For Bolt Guns . In benchrest .001 will make am big difference unless Mr. Boyer is wrong which with his record I kind of think he has it figured out...and yes if seating with a throat angle there is enough force to stick on angle, contact area is much narrower. Hence the need for an ejection pin... Hope you get it now have a nice day.....
Ned Ludd
Silver $$ Contributor
Ogive variance can be addressed to a large extent by using a tool such as Bob Green's Comparator, which allows one to sort bullets by the most critical dimension (i.e. length variance between seating die stem and caliper insert tool contact points on the bullet ogive). Sorting bullets by this critical dimension prior to seating has so far proven to be simpler than designing a seating die stem that contacts the bullet much farther down the ogive.
greensrifles.com
As far as designing a seating die stem that seats further down on the bullet ogive closer to point that will first contacts the rifling, there are several engineering caveats. I'm not saying it couldn't be done, but in order to keep the die cylinder tight around the bullet, the closer you get to the point on bullet ogive that first contacts the rifling, the thinner the metal of the stem would have to be. In fact, right at the contact point the lip of the stem would have to be quite thin, which might cause structural integrity issues. Additionally, because the clearance between the bullet ogive and the die cylinder wall becomes smaller and smaller as you approach the point on the bullet meplat that first contacts the rifling, the less forgiveness there would be in terms of creating a die stem that would work well across a wide range of different bullet ogive radii. A cross sectional image of a typical seating die showing exactly where a bullet sits in the die cylinder when the ram/seating die stem is at the bottom of its travel would give a much better idea of how much room there is to work with, but I don't have such a cutaway image available.
Welcome to Green's Rifles
Complete Bench & Varmint Rifles Precision Barrel Installation Superior Custom Dies and Tooling Specializing in craftsmanship
As far as designing a seating die stem that seats further down on the bullet ogive closer to point that will first contacts the rifling, there are several engineering caveats. I'm not saying it couldn't be done, but in order to keep the die cylinder tight around the bullet, the closer you get to the point on bullet ogive that first contacts the rifling, the thinner the metal of the stem would have to be. In fact, right at the contact point the lip of the stem would have to be quite thin, which might cause structural integrity issues. Additionally, because the clearance between the bullet ogive and the die cylinder wall becomes smaller and smaller as you approach the point on the bullet meplat that first contacts the rifling, the less forgiveness there would be in terms of creating a die stem that would work well across a wide range of different bullet ogive radii. A cross sectional image of a typical seating die showing exactly where a bullet sits in the die cylinder when the ram/seating die stem is at the bottom of its travel would give a much better idea of how much room there is to work with, but I don't have such a cutaway image available.
Ned, Being I have made a few of these already the bugs have been worked out and they work fine. But if sorting is something that people enjoy all the best to them....Ogive variance can be addressed to a large extent by using a tool such as Bob Green's Comparator, which allows one to sort bullets by the most critical dimension (i.e. length variance between seating die stem and caliper insert tool contact points on the bullet ogive). Sorting bullets by this critical dimension prior to seating has so far proven to be simpler than designing a seating die stem that contacts the bullet much farther down the ogive.
Welcome to Green's Rifles
Complete Bench & Varmint Rifles Precision Barrel Installation Superior Custom Dies and Tooling Specializing in craftsmanship
As far as designing a seating die stem that seats further down on the bullet ogive closer to point that will first contacts the rifling, there are several engineering caveats. I'm not saying it couldn't be done, but in order to keep the die cylinder tight around the bullet, the closer you get to the point on bullet ogive that first contacts the rifling, the thinner the metal of the stem would have to be. In fact, right at the contact point the lip of the stem would have to be quite thin, which might cause structural integrity issues. Additionally, because the clearance between the bullet ogive and the die cylinder wall becomes smaller and smaller as you approach the point on the bullet meplat that first contacts the rifling, the less forgiveness there would be in terms of creating a die stem that would work well across a wide range of different bullet ogive radii. A cross sectional image of a typical seating die showing exactly where a bullet sits in the die cylinder when the ram/seating die stem is at the bottom of its travel would give a much better idea of how much room there is to work with, but I don't have such a cutaway image available.
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included a photo of one die. 
You said it better than me.
I tried to build one once and found exactly what you said. The metal becomes very thin. I figured part of the problem was my choice of materials (brass). But in the end it did fix the problem I was having at the time.Ogive variance can be addressed to a large extent by using a tool such as Bob Green's Comparator, which allows one to sort bullets by the most critical dimension (i.e. length variance between seating die stem and caliper insert tool contact points on the bullet ogive). Sorting bullets by this critical dimension prior to seating has so far proven to be simpler than designing a seating die stem that contacts the bullet much farther down the ogive.
Welcome to Green's Rifles
Complete Bench & Varmint Rifles Precision Barrel Installation Superior Custom Dies and Tooling Specializing in craftsmanship
As far as designing a seating die stem that seats further down on the bullet ogive closer to point that will first contacts the rifling, there are several engineering caveats. I'm not saying it couldn't be done, but in order to keep the die cylinder tight around the bullet, the closer you get to the point on bullet ogive that first contacts the rifling, the thinner the metal of the stem would have to be. In fact, right at the contact point the lip of the stem would have to be quite thin, which might cause structural integrity issues. Additionally, because the clearance between the bullet ogive and the die cylinder wall becomes smaller and smaller as you approach the point on the bullet meplat that first contacts the rifling, the less forgiveness there would be in terms of creating a die stem that would work well across a wide range of different bullet ogive radii. A cross sectional image of a typical seating die showing exactly where a bullet sits in the die cylinder when the ram/seating die stem is at the bottom of its travel would give a much better idea of how much room there is to work with, but I don't have such a cutaway image available.
Looks nice. It appears you use it with a arbor press correct?
BoydAllen
Gold $$ Contributor
This is only an issue if you need the seater stem bore to be a little over bullet diameter. If you are seating BT bullets, they can be relied upon to stay well enough aligned after placement in the case mouth so that you do not have to have this feature. A friend who likes new toys bought one of the 21st Century seaters and was having a terrible time with it, trying to seat FB varmint bullets. I explained to him that it was probably not designed with those in mind and that he should use something else for those applications. I think that it is a great design for BTs. If I wanted to play with one for FB bullets I would use something else to barely start the bullets and finish with the 21st.
I think and feel part of the problem I am wanting to fix is I am trying to use commercial bullets. The tolerances are not there. Some brands from my limited experience are a little better but they are all mass produced. What is driving me fits is is 1 brand (well known and respected) I am curently using has as much as .020 +difference in the length of the nose where the conventional seating stem would contact. This is causing huge inconsistent jumps.
My son bought some custom lathe turned solid bullets and i spent some time yesterday measuring and they are all within .001 maybe less due to my possible technique.
I Also checked some JLK i have they were all very close. I feel the custom offerings from Barts and others are well worth it.
For the application /discipline I am working towards I am thinking to use a custom lathe turned sold. The selection I would like to use would require a fast twist barrel. Might be cheaper in the long run to just switch barrels and use the custom bullets.
But I am a glutton for punishment I guess, but I like to solve the engineering puzzle as Mr. @Ned Ludd laid out.
My son bought some custom lathe turned solid bullets and i spent some time yesterday measuring and they are all within .001 maybe less due to my possible technique.
I Also checked some JLK i have they were all very close. I feel the custom offerings from Barts and others are well worth it.
For the application /discipline I am working towards I am thinking to use a custom lathe turned sold. The selection I would like to use would require a fast twist barrel. Might be cheaper in the long run to just switch barrels and use the custom bullets.
But I am a glutton for punishment I guess, but I like to solve the engineering puzzle as Mr. @Ned Ludd laid out.
Yes , but did a couple for reloading presses
Cool thanks
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