9mm seating depth

[Dougs94]

Just got my bullets in the mail yesterday, 9mm, 115g, FMJ. Loaded up the first 100 rounds this morning. I was shooting for a OAL of 1.135. About 75% of the 100 came out at that. A dozen or so came out at 1.142 and another dozen at 1.130. Should I be concerned about the difference in lengths? I tweaked the die and got the long ones back down to 1.135 but the short ones I let slide. Is a .012 fluctuation normal for budget brand bulk bullets? Been loading my own cast for years and always been spot on. Just recently got into the FMJ thing.

 

[Fatboy412]

I'm in for information. I get slight variances also. Just curious what others do about it.

 

[SOLGardener]

Consider that you're talking about a .005-.007" spread. A hair is roughly .003", so your are quite literally a hairs width to your target. The bullets seat based on the nose, so the variance is pretty small. If they seated based on the ogive, it'd be something to address. Just check that the bullet drop fully in to the chamber when on the long measurement.

 

[1006]

First: Your loads sound pretty well put together. Measure some factory loads and compare.



Things to check:
Bullet shape can vary.
Compressed loads can push the bullet up prior to seating.
Dies can become loose.

If you are using a progressive press, the amount of wobble in the shellplate can vary.

I.E. :there is powder or dirt under the plate, one of the stations is not used every time, if the primer ram is not used each time.

 

[Dougs94]

Bullet shape can vary.
This is what i figured. Ran into the same thing with .223s from Wolf. No concerns with a progressive press, everything is one stroke at a time on the ol' Rock Chucker.

 

[gh1950]

Unless you are loading match grade ammo, it shouldn't be an issue.

One thing you didn't address. Are all the casings the same brand?

 

[Dougs94]

Just plinking rounds. All the cases are sorted by headstamp.