OAL variations

[WDN41]

I'm using a basic Lee press and dies.
After seating the bullet, I'm having variations on OAL.
These variations range from a minus .005" to a plus .007".
I've followed the Lee instructions and don't understand why
these variations persist.
Any suggestions as to what may be causing this?
I've checked for dirt and crud everywhere.
Could it be the measuring tool? (Harbor Freight)

[boyguan]

I'm using a basic Lee press and dies.
After seating the bullet, I'm having variations on OAL.
These variations range from a minus .005" to a plus .007".
I've followed the Lee instructions and don't understand why
these variations persist.
Any suggestions as to what may be causing this?
I've checked for dirt and crud everywhere.
Could it be the measuring tool? (Harbor Freight)

What bullet are you using? Sometimes it’s a crap bullet. My Lee seats different for me too but I never cared how much unless it’s for my precision rifle reloads

[fawndog]

They don't seat by the tip.

[highpower790]

Take measurement from base to ogive,not tip.

[eric n]

Bullet manufacture variation
Dirty shell holder
Neck tension
Die(tip hitting top of stem instead of ogive)
Seating technique (slow and steady, not jamming as
fast as you can. )
Those are the things to start ruling out. Usually sorting bullets base to ogive will cut the variance. If you still have variance, look at neck tension.
Measuring your calipers against a standard would be prudent as well.

[CK_32]

OGIVE.

[divingin]

What caliber, and what components?

As said above, OAL is a rough estimation of where important things are falling. If you use a bullet comparator (Hornady/Stony Point, Sinclair, etc.), you can get a measurement from the bullet base to the ogive (the point of the bullet where it's wide enough that it hits the rifling.) Comparing that measurement to the OAL of the bullet will give you differences in ogive to tip. You may see your .003" to .007" variation in bullet to bullet comparisons.

Your seating die, if you look at the stem, does not seat from the tip, but rather it contacts at an approximation of the ogive, and seats that to the same depth every time. Any difference in ogive to tip will show up as a cartridge OAL discrepancy.

So, as previous posters have said, use the cartridge base to ogive as a measurement for length; it's a more important measurement in terms of accuracy.

Use cartridge OAL if you need to fit the cartridge in a magazine (in which case you're probably not going to be fiddling with seating depths anyway.

[mjmagee67]

What are you reloading? Pistol? Thats good enough. Rifle? What components? Are you measuring off the tip or ogive?

[longrange1]

my question is how are you getting your OAL measurements?
are you measuring off the tip of the bullet to the base of the case or off the ogive of the bullet to the base of the case?

[WDN41]

I am reloadinf .380, measuring form the tip of the flat nose bullet to the base. Pardon my ignorance, but I do not know how to measure from or to the ogive. The major problem is that some of the longer rounds will hang up in the magazine.
I am having better luck now that I've modified my stroke on the lever to a steady and slower stroke, as suggested by Eric N, which, thus far has given me more consistant measurements
Thanks to all who have taken the time to respond

[DueceMcGurk]

Measure 20 bullets OAL. Mean, std deviation.

Don't know what you are loading so can't help beyond that.

[tonyjr]

On my 380 [ mustang II ] , some of the cases were sized /
belled to much causing the case to hang up on magazine .

[kcstott]

you're worried about +/- .005-.007" in a .380 acp? there are bigger things in life to worry about. that tolerance is fine for handgun loads. If they hang up in the mag seat them deeper and be done but this is not something to be overly worried about.

[J-cat]

The reason you’re getting oal variance is because there is variance in every aspect of reloading. For example, primer sticking out just a hair will throw the reading off. The flatness of the casehead or lack thereof will throw the reading off. This is an auto pistol and cases get beat up. Defects in the casehead throw the reading off depending where the jaws of your caliper contact the case.

Then there are the bullets which are made in bulk on multiple machines. They all end up in one box and have slightly different nose profiles. The seater stem indicates off the side of the nose, not the tip of the nose, therefore any variance in the shape of the nose will throw off the oal.

Then there is seating pressure. The harder the bullet is to seat, the longer the oal. Variance in seating pressure from case to case creates variance in oal.

The first thing I would do to diagnose your issue is load up new brass, taking care to seat the primers below flush.