Length of loaded round variation?

[PaperSniper999]

Something came up yesterday that I haven't seen and wonder if the fine folks here might have an opinion based on their experience.

I seated Hornady 52 grain V-Max bullets in 1.54 inch trimmed Lapua 6mm BR brass after FL sizing and stepping down form 6mm to 22 cal in a Redding FL sizing die with a 0.249 neck bushing.

I seated about 36 bullets using a Wilson seater die. Mine is not the micro-gage equipped one, but the regular one with the screw adjustment for seater stem length. Anyway, I had it adjusted for a 1.734 length to ogive, or about 2.13 cartridge overall length. The Wilson seater die normally seats them consistently as far as the LTO measurement goes. There is of course some variation in the OAL measurement due to minor variation in the bullet's tip.

Odd. I have had small variation before, but the odd-ball rounds were longer.....1.740 +- about 2 thou. This is about 5 thousandths off my criteria. Also, those long ones were not all seated at the end or beginning of my reloading, but pretty much randomly.

I was very careful and tried to reseat each long round after it measured short, but re-seating made no difference. The only thing I can think of that is logical is that some of my bullets had the ogive further toward the tip of the bullet. I use Hornady and Sierra bullets a lot, and have not noticed this variation before.

Ideas?

 

[Innovative]

papersniper999 ........

I have an article about this exact situation on our website. You discribed it very well. The bullet ogive can be different between bullets. It's fairly rare with quality bullets, but I've even seen it happen with 69 gr SMK bullets. This happens quite often when switching to a different lot of bullets.

Remember, the bullet is usually seated from a different location on the ogive than where you're measuring. The most relevant part of the ogive is 'lower on the bullet' where it contacts the rifling.

- Innovative Technologies

 

[NorCalMikie]

Might be the bullet tip bottoming out in the seater stem?? Had the same problem with Bergers. The tip would touch the top inside of the stem and the seating depth would change. Drilled out the seater stem a 'little deeper' for tips of the VLD bullets and that cured the problem.

 

[fdshuster]

PaperSniper999: When opening a new box,,of the same bullets) and if they are of a different lot number, I will always use a bullet comparator, and may even take a 'new' throat seating dimension. I've even found several thousandths difference between bullets randomly selected out of the same box/lot number. I've been told that there may be several sets of different machinery making the 'same' bullet, and at the end they will be mixed together. When one of the major manufacturers were questioned about this 'mixing up', they said their testing showed it did not matter, in their opinion. For the smallest group sizes possible,off the bench, I will sort. For varmint type loads I do not.

 

[jb1000br]

New brass,necks) tend to be sticky when seating...I'm guessing variable seating force due to friction between the bullet and neck is causing the stem to indent the bullet on the ogive where it is 'pushing'

The long rounds will be the ones with the dents from the seater plug in them...

With one firing on the cases and a good tumble, they will be fine if I had to bet. To make this easier, NECO, dry moly neck lube works wonders on consistent overall length.

YMMV,
JB

 

[Innovative]

The stem of the bullet seater should not mark your bullets. It's an easy job for most shooters to match the bullet shape to the seating stem. This can be done with a drill gun spinning a bullet with some valve grinding compound. The more contact surface your the bullet - the better.

If you're getting marks on your bullets from seating, this will help keep your OAL more consistent. It also helps to clean the inside of your necks with a brush.

- Innovative Technologies

 

[PaperSniper999]

Might be the bullet tip bottoming out in the seater stem?? Had the same problem with Bergers. The tip would touch the top inside of the stem and the seating depth would change. Drilled out the seater stem a 'little deeper' for tips of the VLD bullets and that cured the problem.

That's an idea, but probably not with this particular 'short' bullet. However, it's worth filling away for future reference.

 

[PaperSniper999]

The stem of the bullet seater should not mark your bullets. It's an easy job for most shooters to match the bullet shape to the seating stem. This can be done with a drill gun spinning a bullet with some valve grinding compound. The more contact surface your the bullet - the better.

If you're getting marks on your bullets from seating, this will help keep your OAL more consistent. It also helps to clean the inside of your necks with a brush.

- Innovative Technologies

Hmmmm, another good idea. The seater stem on my Wilson die never leaves marks, but should marks be left with any die you raise a good point.

Here's what I decided to do after talking the the folks at Wilson: send the die to them with three of my fired cases. I noticed that sometimes when I put a case into the die that it did not seem to go all the way in. They suggested honing the die body to match my cases would lessen that, and also insure a more uniform seating of the bullet. Sounds logical so off to Wilson the dies went late last week.

Hopefully I will remember to report my results here when I use my die next.....................

 

[NorCalMikie]

Around the first part of last year my shooting buddy ran into the same problem with a batch of Bergers. Come to find out there were bullets in the same box that were pressed with 'different' dies. Took a bit of figuring out but Berger replaces all the bullets. :thumb: