Bullet seating problems

[Craig28]

I've been having trouble getting bullets to seat to consistent lengths with my hornady new demension dies in .308 and 7mm STW.

I was working up some 168 grain speer match loads for my .308 tonight. My goal was to seat them at 2.910" which is roughly 20 thousands off the lands. I seated the 1st and the 2nd rounds to 2.912". The 3rd seated 2.915" and the 4th seated at 2.916" with the die locked down to the same settings. Not the end of the world... The 5th seats at 2.911". The sixth(next row of loads) seats at 2.910" dead on. The 7th seated at 2.924" which was strange (I had 3-4 out of the batch of 25 seat to at least 2.920" on the first seating). I was loading some barnes 150 ttsx's in my STW and was having similar problems (with less variation in OAL however). Same thing with some 155 grain A-maxs in my .308 but again with less variation than the speer 168s tonight. Perhaps ogives can vary in size, but I've been trying to figure out if something is wrong with my press/dies or if I'm doing something wrong. I tend to seat my bullets 2 thousandths over my goal and seat other bullets using those settings. Then I go back measuring to find the long ones and reseat them to the desired depth. So I end up seating bullets in 2 if not 3 different tiers to get them all as close to my desired seating depth as possible if that makes sense.

If anyone can chime in on what could possibly be going wrong, I'd appreciate it. I'll provide more info as needed. I'm using a redding big boss press. I take the time to weight sort my bullets and weigh each charge. It's frustrating to reach the last step and my bullets won't seat consistently.

 

[243winxb]

Bullet base to ogive needs measuring first.

Seating stems must contact bullet ogive, not bullet nose.

Try a Lee Dead Length bullet seater. The base of the die contacts the shell holder, removing slop from the press linkage.

 

[243winxb]

hornady new demension dies

The sliding sleeve may be an issue? Degrease/clean the die.

 

[JFrank]

In addition to the excellent post by @243winxb inconsistencies in neck tension can result in variations in seating depth gone unnoticed when using a ram press with the extra leverage.
Personally I don’t weigh Bullets anymore but I do measure them BBTO then seat and confirm by CBTO , I also don’t use off the rack Bullets and expect them to react /seat as perfect as a custom or even a Berger.
Clean and inspect your die, mark a bullet with a sharpie and see where the seating stem is making contact and hopefully not on the meplat.
Btw- those new dimension sizing dies were quite possibly the worst I’ve ever used but the seater worked as well as any .

 

[Woolecox]

In addition to what everyone else has said, bullets can vary several thousands if measured from the tip to the base. Get a bullet comparator and measure from the ogive.

You can also use a bullet pointer for better BC and more consistent length. Whidden makes a good one. I point all my match loads. You can also use a meplat tool to uniform the length if you want to keep the tip open.

https://www.midwayusa.com/product/1012887559/

If you ignore the variations, chances are they will shoot just fine anyway.

Let us know.

 

[edwardware]

My goal was to seat them at 2.910" which is roughly 20 thousands off the lands. I seated the 1st and the 2nd rounds to 2.912". . .

With those lengths, I assume your measuring to the tip. . . you can't do that and achieve any consistency.

Base-to-tip and base-to-ogive vary, especially in open-tip bullets- and you should be measuring to ogive, with a comparator.