Bullet seating coal differences

[grizzly63]

Loading some 180 Nos BT into 300WSM and Coal I'm aiming for is 3.070 but a couple of the bullets ended up at 3.090. What is the cause of this. I assume the bullet seating is done off of the ogive so why are some longer? are the jackets not all symmetrical ? Is this a normal thing. I'm using Lee dies which I have had great luck with.

 

[Elktrack]

Loading some 180 Nos BT into 300WSM and Coal I'm aiming for is 3.070 but a couple of the bullets ended up at 3.090. What is the cause of this. I assume the bullet seating is done off of the ogive so why are some longer? are the jackets not all symmetrical ? Is this a normal thing. I'm using Lee dies which I have had great luck with.

That will drive a guy nuckin futs! I’ve dealt with this before and talked to most of my buddies that load and they all have experienced it before. It’s kind of a mystery because there’s so many factors that could contribute. ie,

Consistent speed and same force when seating. Don’t slam the arm down on one and go slow on the next. Be consistent.

Make sure everything is adjusted and tightened properly.

Obviously, check bullets. Most unlikely but could have a variance.

Neck tension is different from one piece of brass to the next.

Inconsistent chamfering.

Slight amount of slop in the seating stem.

Bullet not entering the die concentrically.

Seating over compressed loads.

Obviously you’re paying attention to details or you wouldn’t be concerned about it. I can tell you that I personally have never been able to detect any difference in my loads that have had this issue. I’m not a bench rest competitor chasing teeny tiny groups but I do like small groups and this kinda stuff makes me crazy. It’s even more annoying because I don’t experience it with every single caliber. I’ve got a 22-250 set up that comes out dead nuts exact consistently and I haven’t adjusted those dies for several years.
Measure some factory ammo and you will see the same thing.

I’d love to know what you find out.
Good luck

 

[HiMtnHntr]

Use a bullet comparator and go off of the ogive and you’ll get more consistency.

You can use the comparator to check uniformity of bullets before you load them as well.

Measuring COAL based on bullet tips is far less consistent.

 

[shb]

Measure over all length of 5 bullets , just the bullet, and you'll pull your hair out.

 

[Sheltowee]

Tough for bullet manufacturers to get those little plastic tips consistent down to the thousandths of inches. Compounding that is the propensity for those tips to get slightly dinged during shipment. Hornady and Nosler seemed the most consistent for me, Barnes a lot less so. I don't even bother measure COAL for most of my rifle rounds anymore. As several others have mentioned, buy a set of bullet comparators for your calipers, work from the cartridge base to ogive length (CBOL), go forth and prosper.

 

[N2TRKYS]

Base to ogive is inconsistent, as well. None of it matters. I kept reading about base to ogive measuring was the only way to do it. Well, I learned that that wasn’t true.

I don’t even worry about the ogive measurement anymore. I measure COAL and rock on. Neither of those two types of measurements are perfect.

 

[std7mag]

@N2TRKYS is spot on!

Talking with a custom bullet maker, he claims that getting the ogive consistent is the hardest part.
It varies enough that he will box up different base to ogive measurements for sale.

Of course his buyers have been known to weigh primers.....