Bob Kingsbury
New member
Lynn
No doub't you have checked this, but if your turning necks, maybe your
seating against a donut
No doub't you have checked this, but if your turning necks, maybe your
seating against a donut
Ogive Variance
- Thread starter Lynn
- Start date
Bob I was born in the morning but it wasn't this morning! I know what a donut feels like and no that is not it. All i'm saying is if you haven't tried moly inside youre necks you might want to give it a try. That or sign up for or Benchrest school in P.A. and lean a lot more. School is April 30th thru May 3rd.
Joe Salt
I tested a RCBS Partner Press and the first two bullets I tried had 1.811 and 1.796 lengths using my comparator zeroed out.
All the bullets in the test were 0.382 bearing surface length.
In the 50 year old Pacific Press I got a low of 1.805 inches and a high of 1.807 inches or 0.002 variance.That is not normaly what I see.
On my Lee Classic Press I got a low of 1.740 and a high of 1.744 but I had 4 rounds at 1.740 inches.These numbers are not useable as the die and shellholder was swapped out and over all length needed to be adjusted on every press.
On the Wilson seater I used a rubber mallet not an arbor press and the first three rounds measure like this 1.757,1.751 and 1.746 with all 3 bullets having a ring completely around them.I am still thinking the variation is in the ogive itself but will buy some moly and see if it does anything.I have the black mica that Sinclair sells and no improvement was seen using it as a neck lube.
Waterboy
I tested a RCBS Partner Press and the first two bullets I tried had 1.811 and 1.796 lengths using my comparator zeroed out.
All the bullets in the test were 0.382 bearing surface length.
In the 50 year old Pacific Press I got a low of 1.805 inches and a high of 1.807 inches or 0.002 variance.That is not normaly what I see.
On my Lee Classic Press I got a low of 1.740 and a high of 1.744 but I had 4 rounds at 1.740 inches.These numbers are not useable as the die and shellholder was swapped out and over all length needed to be adjusted on every press.
On the Wilson seater I used a rubber mallet not an arbor press and the first three rounds measure like this 1.757,1.751 and 1.746 with all 3 bullets having a ring completely around them.I am still thinking the variation is in the ogive itself but will buy some moly and see if it does anything.I have the black mica that Sinclair sells and no improvement was seen using it as a neck lube.
Waterboy
Boyd Allen
Active member
Lynn,
If you have the resources readily available, do me, and possibly yourself a favor and try the following.
Make an insert for your caliper ogive measuring attachment that hits the nose of your bullets at the same diameter as the seating stem does. Use it to measure (to their bases) a group of bullets that are either numbered, or in numbered positions. Record the measurement for each bullet. Next, substitute an insert that hits the bullet where the rifling will make contact. Measure the same bullets and record the measurments for each. Finally, subtract the second measurement from the first for each bullet, and tell us your results.
In effect, this is what Bob Greens tool does without the subtraction. I would be very interested in your results. If the distance between the circles varries then, it would seem to me that relation of the ogive to the rifling would, at a minimum varry by that amount, if neck friction was identical. Given that it is not, the variance that it (neck friction) introduces can either add to or subtract from the ogive variance. In a large sample, I think that it would increase the range.
If you have the resources readily available, do me, and possibly yourself a favor and try the following.
Make an insert for your caliper ogive measuring attachment that hits the nose of your bullets at the same diameter as the seating stem does. Use it to measure (to their bases) a group of bullets that are either numbered, or in numbered positions. Record the measurement for each bullet. Next, substitute an insert that hits the bullet where the rifling will make contact. Measure the same bullets and record the measurments for each. Finally, subtract the second measurement from the first for each bullet, and tell us your results.
In effect, this is what Bob Greens tool does without the subtraction. I would be very interested in your results. If the distance between the circles varries then, it would seem to me that relation of the ogive to the rifling would, at a minimum varry by that amount, if neck friction was identical. Given that it is not, the variance that it (neck friction) introduces can either add to or subtract from the ogive variance. In a large sample, I think that it would increase the range.
Boyd
Here is what I get for each bullet.I will use my comparator first then a smaller comparator next that hits the same place as a seating stem.
1) 0.5865 0.8215
2) 0.5855 0.8220
3) 0.5850 0.8215
4) 0.5865 0.8215
5) 0.5865 0.8215
I also used a couple gizmo's or barrel stubs to check my ogives and the results seemed to get better.I am now thinking the original comparator isn't all that good and the neck tension is allowing the seating stem to dig in.Only the Wilson seaer left a ring on the bulet.
Waterbot aka Lynn
Here is what I get for each bullet.I will use my comparator first then a smaller comparator next that hits the same place as a seating stem.
1) 0.5865 0.8215
2) 0.5855 0.8220
3) 0.5850 0.8215
4) 0.5865 0.8215
5) 0.5865 0.8215
I also used a couple gizmo's or barrel stubs to check my ogives and the results seemed to get better.I am now thinking the original comparator isn't all that good and the neck tension is allowing the seating stem to dig in.Only the Wilson seaer left a ring on the bulet.
Waterbot aka Lynn
Boyd Allen
Active member
Subtracting the two measurements for each bullet, it would seem that, for this small sample, that maximum variance of seating depth that could be solely attributed to variations in ogives is .0015. Could it be that modifying the shape of the seating stem, where it contacts the bullet, so that the seating force is more broadly distributed, would help? If you had a Wilson type seater that had been adjusted for a close fit that did not require prying the round from the die, and which had a stem that did not dig in, wouldn't that be the best?
T
tricrown
Guest
Maybe I'm wrong but..
I’m thinking the objective at this point should not be to just have a group of loaded rounds that have the same distance from base to ogive, a very good thing, but to be sorting so as to have a group of bullets that are all shaped as similar as possible so you’ll land up with as little variation in BC as possible.
Granted by measuring all your bullets from ogive to seating stem contact point after sorting for bearing surface you will be sorting, to an extent, some variations in individual bullet shapes. But wouldn’t measuring bullets over a longer distance provide for an even more uniform sorting by shape and thereby more uniform BC?
For instance, take 2 bullets having the same amount of bearing surface. One may have its bearing surface riding say .002” higher than the other. Wouldn’t it be more likely to miss the shape differences in those bullets if you’re only measuring the short distance from the ogive to seater stem contact point, as compared to say measuring from bottom of bearing surface to a point much farther up on the bullet than where the seater stem hits? You can later sort your loaded rounds, which should be much more similar then they would have been without any sorting, for base to ogive measurements.
A mistake I made for a long time, that caused me lots of problems, was to assume that both my Stoney Point comparator set’s tools had the same size opening. They don’t. And each will give different measurements. So I’ve marked one and only use the unmarked one for record keeping.
Bill Slattery Jr.
Edit: Hey Joe, how does sorting with a neck bushing work? You find many fat bullets? Thanks.
I’m thinking the objective at this point should not be to just have a group of loaded rounds that have the same distance from base to ogive, a very good thing, but to be sorting so as to have a group of bullets that are all shaped as similar as possible so you’ll land up with as little variation in BC as possible.
Granted by measuring all your bullets from ogive to seating stem contact point after sorting for bearing surface you will be sorting, to an extent, some variations in individual bullet shapes. But wouldn’t measuring bullets over a longer distance provide for an even more uniform sorting by shape and thereby more uniform BC?
For instance, take 2 bullets having the same amount of bearing surface. One may have its bearing surface riding say .002” higher than the other. Wouldn’t it be more likely to miss the shape differences in those bullets if you’re only measuring the short distance from the ogive to seater stem contact point, as compared to say measuring from bottom of bearing surface to a point much farther up on the bullet than where the seater stem hits? You can later sort your loaded rounds, which should be much more similar then they would have been without any sorting, for base to ogive measurements.
A mistake I made for a long time, that caused me lots of problems, was to assume that both my Stoney Point comparator set’s tools had the same size opening. They don’t. And each will give different measurements. So I’ve marked one and only use the unmarked one for record keeping.
Bill Slattery Jr.
Edit: Hey Joe, how does sorting with a neck bushing work? You find many fat bullets? Thanks.
Last edited by a moderator:
Thanks Lynn
Thanks for starting this thread !
It's great !
I just checked the difference between my seating stems(RCBS, Redding) and they vary greatly from my ogive measurement of my Hornady guage.
Now the question is where can I get a stem that seats the bullet by the ogive measurement ? It seems the manufacturers could sell these as an accessory, or someone could make these as an aftermarket item !
Jim
Thanks for starting this thread !
It's great !
I just checked the difference between my seating stems(RCBS, Redding) and they vary greatly from my ogive measurement of my Hornady guage.
Now the question is where can I get a stem that seats the bullet by the ogive measurement ? It seems the manufacturers could sell these as an accessory, or someone could make these as an aftermarket item !
Jim
J
Jess
Guest
Bullet Seating
Tricrown, I agree with you considering consistency. My primary concern is to that I have groups of 5 for record strings. To add to my earliar post, back a couple of years ago when I was working with this problem I did some testing in a laboratory, because that is what I do. Using a programmable apparatus that employs a load cell to record the force of resistence, I seated test lots of ammo. Once the bullets were seated, corrulation with the resulting ogive to base (otb) readings it was determined all of the bullets with elevated seating force resulted in a higher otb reading, i.e.longer dimension. Performing the same test with the model railcar blackening graphit that you can get from MSC the seating forces seemed to equal out somewhat. So I now batch my brass by what the first seating operation produces with sacrificial measured bullets, then I pull these bullets polish the insides of the necks, resize and reseat with my match bullets, if I have an odd ball at this point its a sighter. My theory is that the seating friction is unpredictable unless the necks are polished and lubricated however and this process starts all over again when the brass is annealed, the friction is always present to some degree, I believe some smart guy once said that for every force there is an opposing one. LOL
Tricrown, I agree with you considering consistency. My primary concern is to that I have groups of 5 for record strings. To add to my earliar post, back a couple of years ago when I was working with this problem I did some testing in a laboratory, because that is what I do. Using a programmable apparatus that employs a load cell to record the force of resistence, I seated test lots of ammo. Once the bullets were seated, corrulation with the resulting ogive to base (otb) readings it was determined all of the bullets with elevated seating force resulted in a higher otb reading, i.e.longer dimension. Performing the same test with the model railcar blackening graphit that you can get from MSC the seating forces seemed to equal out somewhat. So I now batch my brass by what the first seating operation produces with sacrificial measured bullets, then I pull these bullets polish the insides of the necks, resize and reseat with my match bullets, if I have an odd ball at this point its a sighter. My theory is that the seating friction is unpredictable unless the necks are polished and lubricated however and this process starts all over again when the brass is annealed, the friction is always present to some degree, I believe some smart guy once said that for every force there is an opposing one. LOL
Tricrown: Yes I do find a fat one now and then, but ran into it more when I was shooting 240 sierras not so much with the 210 Bergers.
Jess: I've done that also Pulling bullets Then re-seated them and got some great groups. There are a lot of little tricks out there that have been tryed that work just have to find which ones work for you!
Joe Salt
Jess: I've done that also Pulling bullets Then re-seated them and got some great groups. There are a lot of little tricks out there that have been tryed that work just have to find which ones work for you!
Joe Salt
D
dk hunt 14
Guest
arbor press
Lynn, The arbor press puts the bullets in with slower more even pressure than a blow from a mallet. When i got my first Wilson seater i didn't have an arbor press and used a block of wood. Left very ugly rings around the front of 240 Sierras. I use a lot of neck tension also. Matt Kline
Lynn, The arbor press puts the bullets in with slower more even pressure than a blow from a mallet. When i got my first Wilson seater i didn't have an arbor press and used a block of wood. Left very ugly rings around the front of 240 Sierras. I use a lot of neck tension also. Matt Kline
O
oneflyer
Guest
Lynn
Talk to Kathy she's the shooter in the family.
Talk to Kathy she's the shooter in the family.
G
gonehunting378
Guest
ouch
O
oneflyer
Guest
Tom
It hasn't even started yet-remember whose gun he's shooting this year!!!!
It hasn't even started yet-remember whose gun he's shooting this year!!!!
Hasn't even started, and your beating up on me already! Maybe I should let them talk to Kathy because I'm starting to get confused. Just have to try my theory and see what happens. And good luck to you oneflyer hope we get the same relays, at least the first two. As long as we keep the two Matt's and Dan out we'll be OK.
Joe Salt
Just have to try my theory and see what happens. And good luck to you oneflyer hope we get the same relays, at least the first two. As long as we keep the two Matt's and Dan out we'll be OK.Joe Salt
O
oneflyer
Guest
Relays
As long as we get a relay with only the two of us. that way I'd be guaranteed at least a 2nd. That's assuming I'd get all 10 on.
As long as we get a relay with only the two of us. that way I'd be guaranteed at least a 2nd. That's assuming I'd get all 10 on.
G
gonehunting378
Guest
if you guys were the only two on a relay you could pull one out of the capehart playbook. just look at joe and ask him "witch one of you #*&!'s is shooting for second place?"