Sorting your bullets by ogive lehgth

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Fla mac

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Sorting your bullets by ogive length

Ok, here is a question about different ogive lengths. I make my own 118gr.,30 cal. bullets (.925 J4 jackets). I sort my bullets by ogive length (.235” to .255”) in groups of + .002”. Am I doing work that doesn’t need to be done, or will the ogive length change your zero using the same load numbers? I know that some of you bullet makers have some work on this.
john
Mims, Fl
 
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Personally, for point blank BR, you are picking fly poop out of the pepper. If you are truly using BR custom bullets, you would not have the variance of .020 in ogive point on the jacket that you describe. Now, machine made, multiple machine point-ups, I can see that variance. But why are you trying to shoot BR with those kind of bullets?

Bring it on Peter..........

David
 
It looks to me that length from base of the bullet measured with an ogive checker would give a result that didn't mean much especially when the bullets are all made at the same time with the same bullet die setup. All bullet seaters seat the bullet from somewhere on the tip. It looks like that distance from where the seater stem touches the bullet to the ogive would be the same for all bullets made on that die setup. A pretty simple test would be to take some of your bullets from both ends of the ogive lengths, seat them in sized cases and use the ogive checker to check from base of the case to the ogive of all the bullets that you seated. See if you are still getting the same .020" variation. I don't make .30 caliber bullets, but have made quite a few 6mm bullets. If I was getting .020" variation in ogive length, I'd be looking for a loose die or something moving that shouldn't be moving.
 
What Berger did was make the height of the lead line, inside the bullet, where the top of the seated core is, a constant measurement from the base of the bullet. It is most decidedly not the same thing as measuring from the base of the bullet to some diameter on the ogive.
 
Boyd Allen said:
What Berger did was make the height of the lead line, inside the bullet, where the top of the seated core is, a constant measurement from the base of the bullet.
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Boyd, this has been standard practice for some of us .30 cal. bullet makers for quite a while.

Good shootin'. -Al
 
Each time I make bullets I only make about 250 to 300. In a bullet making session the ogive length only changes about +or- .004”. The .020” variation would be from one time to another of bullet making. I know why I get + .004” variation, because I lube the cored jackets with my fingers just before I point swage. The .020” variation is from setup to setup (I don’t reset my dies each time I make bullets). I just wonder if the ogive length will change the shooting characteristics of a bullet that measures .235” and one the measures .255”.

john
Mims,Fl
 
Thank you Pete, someone who understands about whats going on with Ogive length! And yes John the long and short ones do shoot different.

Joe Salt
 
I measured the ogive to base length with a Davidson ogive checker on 25 68gr bullets that were made at the same time on Rorschach 6mm dies. Subtracting the .750" length of the ogive checker, I came up with a median of .32004" in length from the base of the bullet to where the ogive checker measures. The standard deviation was .00106". Lube was done with 6 gr of lube to a bucket of jackets applied in a Lyman vibrating tumbler. These bullets were made March 7, 2012. I made the same measurement on some 65 gr bullets that were made in June 5, 2003 out of the same dies, different lot of jackets and different die setup. These had a median of .31388" in length and a standard deviation of .001536". These were measured with a Brown & Sharpe dial caliper with the Davidson ogive checker installed on it.

Dial calipers are not very accurate measuring devices and are not 100% reapeatable no matter how good they are. I could measure the same bullet and get different readings within a thousandth or two. I wouldn't put too much faith in measuring bullets with an ogive checker as it's just a relative measurement, but I would keep bullets made at one time separate from bullets made at another time and mark the packaging that they are in with a lot number. I use the date as the lot number on the bullets I make. I make them for myself and not for sale. Making bullets isn't something that I'd want to do for a living for sure.

When you measure bulk bullets made by some of the larger bullet manufacturers and sort them into different ogive lengths, I believe what you are doing is separating the bullets out into lots based upon which die made them. To my understanding, some of the large manufacturers use several different dies making the same or similar ogive and instead of keeping the bullets separated as to which die made them they all go into the same bulk lot. In that case, measuring ogive to base length is just sorting the bullets back into the die that made each bullet.
 
A 68gr 6mm bullet made from a .825 jacket will seat the same in relation to the lands as a 62gr bullet/.750 jacket made in the same point die using the same seating die....if the stem contacts the ogive.
 
Mike,
The problem with steel dies is that it takes more lube to point your bullets than using carbide dies. If you do not put enough lube on you jackets you will stick bullets. When lubing with your fingers you may apply more lube on one bullet and less on another. This is why your ogive length will change. This is why I sort by +or- .002".

john
Mims, Fl
 
Fla mac said:
Mike,
The problem with steel dies is that it takes more lube to point your bullets than using carbide dies. If you do not put enough lube on you jackets you will stick bullets. When lubing with your fingers you may apply more lube on one bullet and less on another. This is why your ogive length will change. This is why I sort by +or- .002".

john
Mims, Fl
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John, have you tried lubing with a dedicated tumbler and just adding more lube than what's necessary for carbide dies. I'd think the more uniform you can get your jackets lubed the more uniform your bullets will be. Sticking bullets in a point up die is no fun and sometimes can be hard to get out.
 
As I understand it, different lots of jackets vary slightly in their thicknesses. and for the lead line to be at the same distance from the bullets' bases. core weight is adjusted...thicker jackets, lighter core, lighter bullet...slightly...thinner jackets, heavier core, slightly heavier bullet. Instead of adjusting the level of the lead line and holding the bullet weight constant, the height of the lead line is held constant, and the weight of the bullets is allowed to vary slightly from lot to lot.....because the height of the lead line matters to accuracy, and having different lots of bullets all the same does not. This was discovered in the testing process for the new bullet.
 
I don't think that they do. I believe that the adjustment is made when the jacket lot changes, but of course that would be a question for Eric.
 
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Fla mac said:
Mike,
The problem with steel dies is that it takes more lube to point your bullets than using carbide dies. If you do not put enough lube on you jackets you will stick bullets. When lubing with your fingers you may apply more lube on one bullet and less on another. This is why your ogive length will change. This is why I sort by +or- .002".

john
Mims, Fl
Click to expand...

John:
I would hold your length to +.001 for long range. the +.002 should not impact the short range shooting, I can tell you that .oo2 will hold waterline at 1k yards or about 2 to 3 inches and that is out of a sling.
 
All,
After doing some work on reloading bullets of different ogive lengths, I found that you have to work with each ogive length to get the right OAL roung lenght. It is not the difference between one ogive length and the next. I start at just coming in contact with the lands and add .010".
john
Mims, Fl
 
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