Consistent bullet seating depth, and why can't we seat off the ogive?

[thefitter]

... but you might as well get everything as good as possible before setting out for a match. If I have a lousy day, I know who or what to blame and it's not the ammunition!

That right there is the reason I got into hand loading. I have tried to explain this to others but some don't get it.

The way I see it is if I'm going to truly refine my skills I need to evaluate every individual shot fundamentally. There are so many variables simply from an operator stand point that I need to consider, I do not want to have to think "was that a bad load"?

I don't want that excuse to be an option, because then I will always fall back on it.

My first priority is to be a top rate shooter NOT simply a top rate hand loader.

 

[bozo699]

fitter,
With a attitude like that I feel you will go far my friend
Wayne.

 

[Jim D]

Fitter
I just joined this forum because of your thread ! I could'nt take it any longer, as I totally understand your question !

I posted this ? on another site and like you I'm still searching for a seating stem that will contact the bullet "CLOSE" to the ogive.

No luck yet, but I'm like you, still trying !
I've tried stems from different dies, and there is some variation, brand to brand. Even tried seating .20 bullets in a .22 stem, no luck.

All you and I need is a stem that is hollowed out so it contacts the bullet closer to the ogive !

I have standard dies from RCBS, and Redding. I can't believe no one has come up with these !

Example ? A stem that matches a .22 Hornady 50gr. Vmax.

If you find a supplier of such stems, I'm in the market !
And we'll both be better shooters !

Thanks !
Jim

 

[Martin52]

Jim
Go to Forster - they will make a stem for your projectile
Martin

 

[Jim D]

Thanks Martin
That would be a stem for RCBS or Redding, or are you talking Forster dies only ?
Thanks !
Jim

 

[snert]

Maybe this is already covered, if so, disregard: A suggestion. To make up for bullet ogive to base inconsistency, use a turret press, a Redding Comp seating die and Instant indicator next to each other. Set up first "run" to be a bit long for your eventual desired OAL. When "if" bullet "a" is say .016 OAL on instant indicator, and you want .012 (for example) , then simply switch turret, go to Comp die, dial in .004 less and zoom, a .012 measurment. if next cartridge has a bullet that varies to ogive, say .017 on Instant indicator, move turret to comp die, dial in .005 and zoom, you have two cartridges that had varying bullet length to ogive, now exact same oal...

it is a thought. Hope this makes sense...the numbers of course are just examples, but I hope that they help to see that these two Redding tools can make OAL from ogive to base a breeze on a trret press, and bullet variation will make little difference.

Snert

 

[Heavies]

hey Fitter,

does this article from German Salazar explain things?

http://riflemansjournal.blogspot.com/2010/09/reloading-measuring-bullets.html

below is a excerpt from the article.

************************************************
STRANGE
So, if I seat 10 thousands (0.010") into the lands, I should be safe - I hope - as I never seem to get the same seating depth no matter what I try. I probably will first try seating at the lands.

I must be doing something wrong with the seating die. I've thought of going to the Wilson seater with the arbor press but I'm not sure if this will correct whatever I'm doing wrong.

It's really frustrating when one bullet is 1.848" depth, the next is 1.846" and the next is 1.847".
************************************************************************

Also I am not so convinced that all seating depth irregularity is due to the projectile dimensions...IMHO the neck tension and seating force will play a part if you are measuring to within a .001". I sort bullets and will occasionaly get a bullet that seats .004" deeper, I mark these cases and put them aside as I am fairly sure the neck tension is gone...I just don't have a good way of measuring neck tension to be sure.

I have been following this post from the start, and after reading this post and the artical from German, I thought why not measure the bullets with the seat stem?

I run a Redding Comp Micrometer Seater, and the stem is easy to remove. I also just picked up this very cool tool from Innovative Technologies, the digital headspace gauge. (http://www.larrywillis.com/)
normal function of the tool can be read about at the website.

I pulled the seater stem out of the die, and the stem has a c-clip on the top. I used this as a stop and reference to secure it to the tool.

Then I started measuring the bullets and sorting them, most where in a range of +/- .001", I made three buckets one with the most will be used for match. One with -.001" and the one with +.001" will be used for practice, and the ones that were way off will be for foulers.

This is one that was on the money.

This one was one of the out casts .003" off

Interesting thing... the ones with the most consistency weighted in at 106.9, almost all of them. The + or - were between 106.8 and 107, and the long ones were 107.1.

Loaded up about 25 rounds and pulled the stem out again to check OAL. Pretty much dead on the money. a few were .0005 to .001 off, but I think that is pretty darn good. ;D

Now the bullets are seated at a consistent ogive to lands, AND at a consistent depth in the case. Will this give me better consistency overall?


Want are your thoughts on this?

 

[bozo699]

Now the bullets are seated at a consistent ogive to lands, AND at a consistent depth in the case. Will this give me better consistency overall?


Want are your thoughts on this?

Heavies,
My thoughts on this??? I think your a genius, I have this Larry Willis tool and it does a excellent job on setting up a die for shoulder bump, which is the sole purpose why I bought it and it does a decent job of measuring coal but I hadn't found a good way to just measure bullets,...until now, that's just down right ingenious. Thank you I will give it a try tomorrow, this should be the answer to your problems fitter, $90 of the best spent money on re loading equipment to date.
Wayne.

 

[Heavies]

Now the bullets are seated at a consistent ogive to lands, AND at a consistent depth in the case. Will this give me better consistency overall?


Want are your thoughts on this?

Heavies,
My thoughts on this??? I think your a genius, I have this Larry Willis tool and it does a excellent job on setting up a die for shoulder bump, which is the sole purpose why I bought it and it does a decent job of measuring coal but I hadn't found a good way to just measure bullets,...until now, that's just down right ingenious. Thank you I will give it a try tomorrow, this should be the answer to your problems fitter, $90 of the best spent money on re loading equipment to date.
Wayne.

No problem! I just hope this theory pans out. I haven't had time to test this yet, and Ill probably never be able to test this out to the fullest.

I was following this thread, the one on consistent shoulder bump, and the Larry Willis tool. Bing, the idea popped. Purchased the tool; kill two birds with one stone. ;D

 

[jo191145]

Heavies, Maybe I'm missing something. Forgive me if I'm misreading your post.

Sorting bullets with the seating stem is not the issue.
What does your stem sorted ammo measure when using a larger diameter comparator that is located at a datum point further down the ogive?
Thats the question.
The OP is trying to find a way to seat bullets within .001" at the rifling/comparator datum. The problem is the seater datum is much farther up the ogive. Any variations in ogive between these two datum points shows on the comparator.
Sometimes its good to be just a short ranger. Dem widdle bullets we use are usually spot on.

In Germans article he states he's found no way to measure between these two points. No offense to German but everytime you seat a bullet and measure with a comparator your in essence measuring between those points. Of course German wants to measure before seating.
Fully understandable. I can't think of an easy solution to that one either ;D
I know what he meant.

If you measure COL with the seating stem you should always get a consistent measurement sorted or not. Your using the exact datum point the die used to seat.

Ron did a fine job explaining why seating off the rifling/comparator datum point won't work to well.

If anyone really wants to try seating off the rifling/comparator datum point (or at least much closer to it) get a plug one or two sizes bigger than standard.
Probably, most likely need to modify it a bit. I offer no quarentees larger plugs will function in any specific die.
Good Luck.

 

[Jim D]

Exactly Jo
The stem in the previous post gets no where near the Ogives contact point with respect to rifling.

I guess we are not all on the same page, no disrespect !

My dies produce consistant OAL, but because of variations on the bullet ogive, distance to the lands varies.

In my mind, which is feeble ! If the the stem fit down further, it would help eliminate this variation.

When I seat my bullets, I want all of them to seat the same in relation to the rifling...


Jim

 

[Jim D]

I will check into Forsters as reccomended !
Thanks Martin !
Jim

 

[Heavies]

Ahh jo,

You are exactly right! ;D

I'll have to reevaluate this theory. That is why I love this forum, so many great minds in one place!

What does your stem sorted ammo measure when using a larger diameter comparator that is located at a datum point further down the ogive?

If you measure COL with the seating stem you should always get a consistent measurement sorted or not. Your using the exact datum point the die used to seat.

Yes, I'll have to see how much variation exists there, but Even using the comparator, you would be getting the wrong reading, the only way to get to dead on would be to use the barrel to mark each bullet, to give the exact point, on each bullet, were the rifling meets the ogive, and then seating at that point.

brings us to ...

Ron did a fine job explaining why seating off the rifling/comparator datum point won't work to well.

I have tried this as well. The seater stem has to match the couture of the bullet to a tee, and again, slight variations in the tips make the effort futile. If I'm using anything but minimal tension, either the bullet get stuck in the seater, or the bullet gets damaged.

I guess we are not all on the same page, no disrespect !

Jim,
None taken. That is why we do this, and come together to tackle a problem. I should be apologizing. My theory was for a different type of situation completely. Haha;D


Sorry for the misunderstanding, and Thanks guys, for the feedback!

 

[jo191145]

Heavy
No need to apologize. I agree, its nice to see people try to wrap thier head around these questions, me included ;D Especially new shooters like fitter.
The attention to detail and critical thinking ability will do him well.
Keeps us all sharp.

Yes I use the term comparator/rifling datum point loosely. To have the ability to make the comparator exact with the point of contact with the freebore in a specific bore is above my pay grade ;D
Someone pointed out pages back even if your capable of such a feat, as soon as the throat begins to wear that diameter number will change.

IMO having a plug fit the exact contour of a bullet is impossible. There will be variations in the lot which has led us here.
The next lot will be even more different.
Seating from the rifling/comparator point can only happen with very minimum tension. Maybe not even then. Never tried going that low.

Heres my method FWIW
Trust your comparator. .002" variations throws up a yellow flag.
Slow down, continue loading and try to discern the problem. Can be operater error at times
.003" gets a red flag. Stop everything and find out whats happening.
Could be bullets, could be bad mate between plug and bullet.

I surely like all the little 68gn 6mm bullets I shoot. Let the target tell you the correct seating depth. Set the die for it and pull the handle. Individual measuring would become quite boring.

 

[Heavies]

Heres my method FWIW
Trust your comparator. .002" variations throws up a yellow flag.
Slow down, continue loading and try to discern the problem. Can be operater error at times
.003" gets a red flag. Stop everything and find out whats happening.
Could be bullets, could be bad mate between plug and bullet.

Thank you Jo. Even though I used the seat plug to recheck the measurement, a few were .0005 to .001 off. I'd attribute that to slop in my press. Good idea to cull those that fall out in the .002+.
Reduce those flyers.

Maybe I'll just soft seat em all. Then I wouldnt have to worry about the seat depth.

 

[BoydAllen]

1. The ogive is the entire section of the bullet from the front of the full diameter portion (shank) to the meplat (very end of the bullet). Anyone uses the term differently has gotten it wrong, and should conform to a long standing industry wide definition. The initial reason for tools that measure off of this part of the bullet, was that it was recognized that bullet tips are irregular,and therefore setting up a die based on one bullet's tip, might not give the same relationship to the origin of the rifling as a another bullet, even though they came from the same box. For this purpose, it is not all that important that the tool even be the same caliber, as long as it is noted. it is only later that information generated by these tools has been put to more sophisticated use. Using the term "ogive length" simply refers to measuring from some point on the ogive, rather than the tip of the bullet, but does not imply that the point is the same place as where the bullet would be engraved. A barrel stub, that has been short chambered with the throat and part of the shoulder of the chamber being loaded for is the preferred tool for this measurement, but of course is only correct for a new barrel, since throat wear will change the actual barrel. Nevertheless, this sort of tool,sometimes referred to, in Benchrest parlance as a "gizzy" can be of real use in comparing the profiles of different bullets, and to get a real fix on shoulder bump.

2. If one were to make a seating stem that only touched right where the rifling engraves a bullet, IMO, it would not be able to do a good job of establishing angular alignment with the CL of the case, especially with short flat base bullets.

3. if you use something like a 17 caliber ogive length attachment (closest easy approximation of where the seating stem will contact a larger caliber bullet) , and another that is the same as the caliber of the bullet, to measure a set of bullets, that you keep in order, you can make a table in which the last value, for each bullet is the difference in the two measurements. It is this difference that, even is a press with no slack, using an otherwise perfect seater, will at a minimum, give you a variance in seating depth equal to the variance of these values. (because the curves of the bullets' ogives are not the same)

4. The next step would be to establish how much difference matters at the target, by actual testing.

5. Measuring each loaded round, from base of case to a point on the bullet near where the rifling will engage, as a last quality control step. to catch any that are too different from the average value, is always going to be a good idea.

6. As far as accuracy goes, some things have a bigger effect than others. In order to truly see the differences that may be the result of smaller issues, all of the larger ones have to be resolved first. One of the advantages of a really accurate rife, shot off of of a high quality bag/rest setup, over flags, is that you can more readily discern differences in accuracy that are the result of smaller factors. With anything else, what you may be doing is looking at a group that falls within the accuracy limits of the system, and attributing the differences between it and a previous group to something that did not really cause the difference. This is common. I have done it myself. Larger samples are the answer.

 

[normmatzen]

I'm from California too. In fact I was born in Petaluma, for what it's worth.

But, to the subject at hand. I, too, am an engineer and strive for non-anecdotal evidence of facts. But, I like to keep things simple as well.

I have only been hand loading for 2-3 years as well and do it both for hunting rounds as well as for my 243 WIN long range bench rest gun. For the 243, I use a Forster precision seater die. For cartridge length, I use a Hornady comparator on a digital caliper. I used the comparator to set up a ladder to determine the jump my barrel likes.

I had been having a problem in getting consistent lengths, the variance was 2-5 thou. My mentor in Australia was having the same problem, so we tweaked the die spring till the inner sleeve went into the die. Problem solved! In fact, Forster noted the problem as well and has changed the spring.

Anyway, now I get consistency of less than 0.001" in cartridge length as measured by my Hornady comparator and set by my improved Forster seater die.

This consistency says one of a couple things, either the Forster die and the Hornady comparator gauge to the same place on the ogive, or the 107 SMK I am now using have a very consistent ogive shape. Any way, I am convinced my jump stays VERY accurate.

Any variation of where, with reference to the base of the bullet, the ogive begins, or exactly how long the bullet is, is of no significance to me because I want the jump to be VERY accurate as the velocity varies significantly with jump as well as the performance with respect to the "sweet spot."

 

[BoydAllen]

Norm,
Good post. So the way that the Forster seater came, the sleeve return spring was too long, and would coil bind as the bottom of the sleeve approached the bottom of the die body, not letting the shell holder touch the die body? What did you do, reduce the number of coils, so that the shell holder could touch the die body? Just trying to get a fix on what you did. This is useful information, and I want to fully understand what you did.
Boyd

 

[normmatzen]

Boyd,

We took the spring and ground down each end a bit by holding it against the side of a bench grinder wheel. The original spring had no real taper ground into the ends of the wire, so we tapered it plus a bit. We stopped when the inner sleeve would enter the outer sleeve by 0.010-0.020".

Then we ignored the Forster instructions and lowered the die in the press till there was just enough room between the ram and the die to get a bullet in. This way, we could easily feel the amount of force it takes to seat the bullet, and the bullet seating depth is set by the die, not how springy the press is. My friend and I both have the LEE breech Bloc aluminum "O" press. Before we did this mod, I put a torque wrench on the lever clamp bolt to be able to limit the torque I applied. Now, I can pull as hard as I want without changing the seating depth. And, now the Forster is EXTREMELY consistent! I do not measure each load anymore, just 1 in 15 or so just for QC! And, it is rare to have the depth vary even as much as 0.0005". This tells me Forster makes a fine product!

You can obtain one of the new springs from Forster if you want. I hear both the length and wire size has been changed, so I think I will change it to keep it to Forster's specifications.

 

[boogershooter]

I guess that if your rifle shoots well with light neck tension and "jammed" length you dont have to worry about this topic much huh? I am not so lucky. But good topic, as I have often thought of the same thing, but I have noticed when I seat with my Wilson the point of contact is pretty far down off the tip of the bullet. However they ogive measure a little different from one to the next.