Thanks. Yes just a few days ago.
I'm loading 110 Hornady FMJ. They are flat based, and look like a 115 grain 9mm FMJ, just smaller diameter.
A couple things. Yes, there is something wrong with the die, and yes you need to change your technique to get OAL plus or minus 0.001”.
First, pull your Lee die apart and look at the face of the surface that seats the bullet. Lee usually uses a concave / curved surface. Grind the concave surface flat and square to its side. Reset your die to correct OAL using a round you’ve already made and are happy with.
And / Or
Add a step to your technique, if using a single stage press. Put the charged case with bullet sitting on top into the shell holder. Drop the handle lifting the ram part way to seat the bullet part way. Lift the handle a little to drop the ram some, spin the case in the shell holder some and then seat the bullet the rest of the way.
The reason you are getting varying OAL, is the bullets are not being initially seated straight, and the concave surface of the Lee die limits how much the bullet can right itself as it slides into the case mouth. The hitch step in technique should be done anytime you want the best chance of getting the bullet concentric and parallel to the centerline of the case. So bench rest type accuracy. This hitch step gives the case and bullet tip a chance to get a different surface to bear on for the final seating. Once this becomes your routine, it adds about a second to each bullet seat time.
Similar to what WestKentucky said, two stroke seating approach, but spin the case some in the middle of your two stroke.
Shh. Don’t tell anyone you’ve learned the secret of why $100 precision seating dies are a waste of $100.
I’ve ground the concavness out of Lee dies for the simple fact that they were changing the shape of the bullet nose. I would bet if you look close, the nose on your JHP bullet tips are being distorted slightly because the concave curve is not an exact match to your bullet nose.
Long post, complicated answer, but that’s learning. If you incorporate both above, grinding and hitch step, all of your 30-30 rounds OAL will be plus or minus 0.001”.