Bullet measurements

[DennisH]

I tried searching and didn't find out exactly what I am looking for.

Most seasoned shooters are accurately sorting their bullets by base to ogive length. They don't worry about weight.

What is your opinion on this? Or how does this increase accuracy?

One well known shooter measures the bullet as per the above and trim's the meplat. That's it.

Dennis

 

[Hoier]

I guess I'm weird but I just measure by weight. And soon I'm gonna be pointing also.

 

[tenring]

The advantage is that you attempt to match bearing surfaces that are identical. That affects time the bullet is in the barrel and thus velocity and pressure.

 

[brno308]

The advantage is that you attempt to match bearing surfaces that are identical. That affects time the bullet is in the barrel and thus velocity and pressure.

Correct. The difference in weight could be anywhere and that is not going to help much. Sort by base to ogive and forget weight.

 

[DanConzo]

Base to orgive is a good measurement, but also measure the actual bearing surface as tenring said and weighing them won't hurt especially if you are shooting mid to long range. Measuring the diameter of the bearing surface is beneficial too, most slide the bullet thru a neck sizing bushing of proper id or mike it w/ a comparator micrometer or a micrometer (.0001"). Close overall length may help also. Bullet to bullet consistency is the way to go.

 

[Erik Cortina]

Base to orgive is a good measurement, but also measure the actual bearing surface as tenring said and weighing them won't hurt especially if you are shooting mid to long range. Measuring the diameter of the bearing surface is beneficial too, most slide the bullet thru a neck sizing bushing of proper id or mike it w/ a comparator micrometer or a micrometer (.0001"). Close overall length may help also. Bullet to bullet consistency is the way to go.

Please explain the following ways to sort.
How does base to ogive sorting help?
How dose bearing surface sorting help?
How does weight sorting help?
How does diameter sorting help?

 

[DanConzo]

Base to orgive-Help maintain prior proven distance of bullet to land engagement.
Bearing Surface-Consistent time in barrel to maintain close to the same pressure and velocities.
Weight-Assures there are no voids in bullet core which would upset the bullet in flight.
Dia of Bullet-Keeping diameters close also keeps pressure and velocity close in a proven load.
Erik-This is what I could think of in a hurry, most of this I would think would maintain barrel harmonics also.

 

[Hoier]

The main reason I sort by weight is to catch the ones that are way out. But since I started shooting lapua and Berger that number has dropped drastically.

 

[Erik Cortina]

Base to orgive-Help maintain prior proven distance of bullet to land engagement.
Bearing Surface-Consistent time in barrel to maintain close to the same pressure and velocities.
Barrel does not contact the base nor the ogive at the place you are measuring, nor does the seater seat from the same place on the ogive, so this does not work.

Weight-Assures there are no voids in bullet core which would upset the bullet in flight.
True, but it's mainly to find the outliers. That ONE that is way off.

Dia of Bullet-Keeping diameters close also keeps pressure and velocity close in a proven load.
The bullet will be deformed as soon as it enter the rifling, I don't believe this is enough to make a difference.

Erik-This is what I could think of in a hurry, most of this I would think would maintain barrel harmonics also.

 

[DanConzo]

Of course the barrel won't contact the base (bottom of a boattail) of a bullet. The front part of the bearing surface (which is in this measurement) will contact the barrel first as will the rest of the bearing surface behind that, this is the measurement the most of use as the seating depth relative to the lands. It's true the seater stem doesn't seat on the front of the bearing surface but above it on a smaller orgive but it also maintains the seating depth very close. I agree w/ you about the bullet weight, but it sure doesn't hurt (if time permits) to weigh and maybe the one that got away doesn't. Of course the bullet will deform as it enters the rifling but the pressure will still vary in accordance w/ the bullet diameter.

 

[DanConzo]

I had a friend now deceased, that did make and sell a hand type bullet seater that did seat the bullets off the bullet diameter orgive (top of bearing surface) in the 1970s, his name was Bill Theis (a founder of the Pa 1000 Yd Club), and he shot very well, perhaps even ahead of the times.

 

[DanConzo]

Erik-If a person had 18 selected bullets (everything he might do to select them) for a 10 shot match ready and the extra time to weigh them, I may be wrong but I think most competitors would probably weigh them and segregate the 10 best of those by weight for the record string. I know I would but maybe I'm wrong.

 

[DanConzo]

Erik-Would you please ask Lapua, being you have a relationship w/ them these questions and let us know especially Dennis the answers fom their tech assistance. Thanks

 

[DanConzo]

Sierra Bullets, Jim Hull explained bearing surface importance to me and others in 1982 @ the NRA Convention in Philly. In their manuals they always point out weight tolerances. jacket thickness, and bearing surface diameters. Just about every manual shows Quality Control measuring the diameters w/ a Comparator Micrometer. And of course their shooting tunnel. Martin Jim Hull also went into annealing case necks extensively. He probably couldn't wait for the show to be over. We drilled and grilled him. About 60% of the Pa 1000 Yard Club was there during that week.

 

[DanConzo]

I hope you got something out of this Dennis. I guess some don't want to contribute. Good luck.

 

[Erik Cortina]

I have not been following the thread.

DonConzo, I'm not going to bother Lapua with things I have already tested myself. I have never measured bearing surface or shank diameter and my guns sometimes still surprise me because of how good they shoot at 1,000 yards.

I will tell you for sure that base to ogive and bearing surface measurements don't matter.

Happy shooting and may all your groups be one hole.

 

[DennisH]

I mainly started this thread because John Hoover sorts bullet bearing surface only. This got my interest as he doesn't worry about weight.

Several sort by weight only.

Some drop the bullets out of the box into a cleaning solution, clean, dry, then load! No measuring of any kind!

I respect all opinions above.

I guess if you use a quality bullet, clean it and shoot it!

Dennis

 

[DanConzo]

Dennis-The Hoovers also point their bullets also, and of course sort by bearing surface, John and Diane shoot consistently very well and have for many years and mostly use Sierra Matchkings and older boxed Win brass.

Erik-Lapua states that they tightened up their new Scenar L bullets on dimensions of the length from base to ogive, jacket wall thickness and improved concentricity and weight. It must mean something if they state this. I'm glad you have good accuracy with your loads.

 

[DennisH]

they tightened up their new Scenar L bullets

I have good luck with them, wish they were a little cheaper, but they are good bullets.

 

[gunner69]

The advantage is that you attempt to match bearing surfaces that are identical. That affects time the bullet is in the barrel and thus velocity and pressure.

Correct. The difference in weight could be anywhere and that is not going to help much. Sort by base to ogive and forget weight.

Agreed. Pressure will impact your bullet far more than .05 grains of weight difference.