Load WorkUp with MIXED BULLET OGIVES.....?

[daniel brothers]

I've been working up a load for long range coyotes with my 22-243 AI, with 80 gr Amax bullets... and got her shooting really good... BUT... I went into some more boxes of bullets and found them to have a scattered range of ogive to base measurements. Of the 400 I measured, they range from .614-.642. The largest two quantities are in the .622-.628 range and the .632-.639 range. The bullets I had been shooting were in the .633 range. I even have a bag of 300 that I bought from a guy that seem to mostly range between .612-.620... I stopped going through that bag for now. I called Horny about it and they said they had no bullets to trade out with me....and couldn't... if I didn't have the lot numbers, which I only had on two boxes, which does me no good.

Anyways... I've worked up a load with the bullets in the .636 range and got it shooting great... BUT WHAT DO I DO WITH THE OTHER BULLETS....?

I only have about 100 bullets in the .632-.639 range, and really do need to shoot those other ones as well, since the source of bullets right now is as scarce as Obama telling the truth.

If I load the other bullets to the same seating depth, then the pressure and fps is different... WHO HAS SOME HELPFUL THOUGHTS....?

Thanks...Dan

 

[mikecr]

I think your worries are unwarranted. IMO, ogive to base measurements are meaningless.
So I'm predicting they will all shoot the same, provided you seat ogives the same w/resp to land contact.

Try it

 

[Lapua40X]

I think your worries are unwarranted. IMO, ogive to base measurements are meaningless.
So I'm predicting they will all shoot the same, provided you seat ogives the same w/resp to land contact.

Try it

+1 -

Relax - You're shooting coyotes not national match championships.

 

[daniel brothers]

are you saying that the ogives don't matter as long as you seat them the same...if so... then what is the point of measuring the ogive to base...?

I do know that the seating stem contacts the ogive at a different spot, which seats the bullets to a different depth, which throws off the whole seating purpose.


This whole rig is for the purpose of shooting coyotes way out there... not for dogs under 400 yds... that can be done with factory rifles.

 

[Bart B.]

As bullet jacket metal ain't absolutely uniform in its metalurgy, there's gonna be a small tolerance in how they're formed in the dies making them. A 1 to 2 thousandths spread is normal and such bullets win matches and set records all the time.

Note also, the bullet's jump to the rifling on rounds headspacing on their shoulder is controlled by the distance from the case shoulder to the rifling contact point on the bullet ogive. While a batch of ammo may have zero spread in case head to bullet ogive reference, case headspace may well have a spread of 2 thousandths because brass cases are like copper bullet jackets. With the case shoulder hard into the chamber shoulder (and it's usually set back a thousandth or two from firing pin impact), whatever spread there is in case headspace gets transferred to the bullet ogive refernce point in the chamber throat.

 

[daniel brothers]

These first two pictures show that the .636 ogive and seating depth is pretty close to being the correct load at 100 yds.

This third pic shows the group getting bigger with a ogive of .622... which is bigger than I'd like.

 

[daniel brothers]

this is the first time I tried for a longer range... gotta figure out how those two climbed up there

 

[mikecr]

are you saying that the ogives don't matter as long as you seat them the same...if so... then what is the point of measuring the ogive to base...?

You tell me. Just what does ogive to base distance mean? Why are you doing this?

I do know that the seating stem contacts the ogive at a different spot, which seats the bullets to a different depth, which throws off the whole seating purpose.

How do you know any of this? Are you measuring cartridge base to ogive(CBTO) to verify they are different?
You should be making them all the same. That's the 'whole purpose' of seating in a sense.

The same attribute that changes stem contact datum(ogive radius), also affects distance to lands, which is then normalized back to intent, with different seating depth produced by the new seating stem datum.
For example; a lower ogive radius causes seater stem to contact the nose closer to it's tip/meplat. The same condition would also cause the ogive to be closer to lands. But, because the earlier stem contact will cause the bullet to seat deeper in a neck, the ogive will move away from land contact -compensating.
Aren't we lucky!
In other words, ogive radius variance does not mean varying ogive distance to lands as seated, it only means varying bearing seated in necks, and not enough to worry about IMO, given that 'some' of your ogive to base variance is in bearing, gripped by the neck anyway(and is likely less by as much, to again compensate).

You should keep trying.

 

[daniel brothers]

Okay.... let me try to explain... while trying to understand this whole thing at the same time.

I just seated two rounds to the same depth, into two cases.

One bullet, which measures .618 from ogive to bullet base. It's overall length from bullet tip to the bottom of the loaded shell case, measures ....2.751. When measuring this same round from base of shell case to ogive, with Horny's Comparator, it measures 2.215.

The second bullet from base to ogive measures .639... it's overall length is...2.761....and the ogive to shell case bottom measures 2.240.

This means to ME.... that the overall length of the loaded round is only .010 difference.... but... the over all length of shell base to ogive is .025 difference.

So if the ogive is the part of the bullet that touches the lands... then one bullet has to travel .025 more than the other one... which is the whole point of seating depth.

If I'm missing it, then I'm open to correction since I've always been a bowhunter since birth, and have now gone crazy about long range coyote killing out west.

 

[daniel brothers]

I think your worries are unwarranted. IMO, ogive to base measurements are meaningless.
So I'm predicting they will all shoot the same, provided you seat ogives the same w/resp to land contact.

Try it

So Mike... what your saying here is to simply seat the skinny and fat ogive bullets to the same seating depth using the shell case to ogive measurement depth... while not paying attention to the overall bullet tip to shell case bottom length.

By changing the depth, doesn't it change the pressure and velocity...?

 

[Johnboy]

I am sorry but you have taken to much thought into this, like I on other subjects. What all are trying to say is, either measure all your bullets and sort them into groups +/- a thou. at the ogive and make groups. Then load the bullets to the over all length you are wanting to load at. Or you can just load based off the ogive of each bullet to the over all length you are wanting to load at, maybe even do both if you really want to get that deep into you loading.

 

[daniel brothers]

I did measure all these bullets to the one thou... and I have 20 bags of different length bullet base to ogive lengths.

I guess the only thing I can do is adjust the seating depth of loaded rounds by measuring from shell base to ogive.

It still seems like the fps and pressure will be different.

I'll test some to see what happens.

 

[mikecr]

Yes what you want is same ogive datum(from your comparitor) to cartridge base(CBTO) that has shown most accurate in your barrel. You must match CBTO for any accuracy.

I don't understand the differences from your measured results. The seater should seat all to within 1-2thou of setting, as measured CBTO.
This, regardless of your base to ogive measure(which does not measure ogive radius, or isolate bearing form base, or ogive datum to bearing, etc).
It should not take a lot of effort on your part unless there is an equipment issue. I wonder if your bullet tips are bottoming out in the seater stem..

Hell I can take any different bullets in cal(different makes & weights) and seat them to the same CBTO with hardly a tweak of my seater die. And they shoot good there too, as I have already established this as best distance to lands(DTL).

I'm not trying to be a pain. I'm just trying to get you to same DTL, with all bullet batches, so that you can do some quality testing of them. And then I think you'll be fine.

 

[daniel brothers]

I don't think the bullet tips are bottoming out in the stem, only because I can see a very slight ring on the bullet where the stem is making contact.

What got this whole thing started was when I opened the third bad of bullets and continued seating them the same, but found out that the full measured lengths were way off... like .010-015 off. So I then started measuring the base to ogive, and found out that they were ranging super high to super low in lengths. I even shot some groups with the crazy miss-match, and they opened up to about a inch, which made me stop and redo this whole thing of checking them all.

Heck... I just got some boxes of Berger .22 90gr VLD bullets, and found out that half in one box measured consistently to .660 and the other half were .670. So I opened up a brand new box I bought in Wy last fall on my monthly coyote hunting adventure, and found them to consistently measure .706. I have a few more boxes of them coming from some friends, and I guess I'll have to open them up and see what their average is.

I just reloaded two rounds, one with a 616 ogive bullet and a .636 bullet... and yes... they both seated within 2 thous..... but there ogive to shell base was .020 apart.

So even if the seating depth from a loaded tip to base is close... doesn't this ogive to case base being off this much make a difference in contacting the lands properly...?

Wouldn't pulling the .616 round out .020 to match the other rounds, throw everything off...?

 

[mikecr]

There is some discrepancy in the measure here, and I'm struggling to see it..
When you say a bullet represents a '.616 ogive', this is not the ogive itself(nose length), but a datum on the nose to bullet base.
And seated DTL and CBTO are independent of bearing or base lengths.

Do these bullet lots vary in diameter?
About how high on the nose is the contact datum of your Hornady comparator?
Could you take a comparison measure between the lots CBTO to a lower point on noses, just to see what the seater is seeing.

 

[BoydAllen]

What you may have here is an example of extreme variance in the distance from where the seater stem contacts to where your comparitor makes contact. If this is the case, and you think that your comparitor hits bullets about where the rifling would touch, I would figure out what the most accurate seating depth is, measured case head to ogive, seat everything longer than that, sort the rounds into rows of each measurement, and adjust your seater for each row, to produce the desired comparitor contact to case head measurement. I agree that this will result in some difference in case volume, but I think that the relation of the bullet to the rifling is likely to be more important. If you really want something else to do, sort your cases by volume, and use the ones that have the least volume with the longest die settings, and those with the most with the shortest. By then it will be next year, and you had better hope that you took good notes so that you can know what you are testing. ;-) On the other hand, you could size your cases to a uniform .001 neck tension, load them all a little long, and soft seat the bullets as you chamber the rounds, and adjust your powder charge for the best accuracy with this seating. Just remember not to try to unchamber a loaded round. Shoot it.

 

[snakepit]

huh