Seating depth

[big5ifty]

The OP hasn't replied yet to the question, but if it is a Forster seater, there may be a gotcha.

There is a spring in the die that the die chamber rides against.

I found that I was getting the same big variation in seating depth because my die was incorrectly setup. The spring was not compressed enough, and seating was happening against die chamber contact, not stem contact. The spring pressure is probably constant, but a small variance in neck tension can result in seating depth variation if seating is happening without the spring fully compressed.

Set the die to take up the slack in the spring, and the seating depth should be constant.

If you setup exactly according to the instructions it should work properly.

 

[bulldog284]

the dies I’m using are Redding competition micrometer adjustment and the bullet’s are either lapua Scenars or Berger and some Sierra. Lapua cases .
I can eliminate the primers I have checked many of times and they are not sticking past the base,
thinking now after reading your post it could be an annealing problem or neck thickness maybe .

 

[Kracken McGraw]

If you setup exactly according to the instructions it should work properly

After you compress the sleeve and spring against the shell holder, how many turns do you back your die out? I’ve been backing mine out two full turns and haven’t noticed a problem.

 

[JFrank]

the dies I’m using are Redding competition micrometer adjustment and the bullet’s are either lapua Scenars or Berger and some Sierra. Lapua cases .
I can eliminate the primers I have checked many of times and they are not sticking past the base,
thinking now after reading your post it could be an annealing problem or neck thickness maybe .

We had a similar problem with a Redding seater, odd to describe but the top section was adjusted to far down and bottoming out so even though we were making adjustments the bullets weren’t seating consistently. Anyway we disassembled the die and realized what the hell was happening.

 

[Jeff Porter]

Also - Forster seating cup will split giving you erratic seating depths. Look closely at the honed area for a crack.

 

[Papa Charlie]

I fought this same issue for a long time. I solved the majority of it by refining may case preparation and my seating procedure. Yes I get an occasional round that falls outside of the 0.001" limit I have set, but they are identified and set aside for sighters. Neck tension, in my humble opinion has the largest impact on seating consistency. To address this I go through a lot of steps. Maybe some steps are not required, but I feel that making the best effort I can to make every round identical every single time is well worth it to try and avoid those moments in a match. I wish I could say that I never make a mistake or get a flyer. But that is not the case. I can screw up absolutely perfectly. But I want to ensure that I try and eliminate things I have control over to reduce those.

 

[big5ifty]

After you compress the sleeve and spring against the shell holder, how many turns do you back your die out? I’ve been backing mine out two full turns and haven’t noticed a problem.

I can't remember exactly how far it needed, but the sleeve is close to the end of it's travel.

 

[bulldog284]

Today I’m going to re adjust my seater die by bottoming out the skirt then turn the die 2 full turns out and see how that goes.

some very good ideas you have given me to check out your guys are a wealth of knowledge
thanks Darin

 

[KMart]

The OP hasn't replied yet to the question, but if it is a Forster seater, there may be a gotcha.

There is a spring in the die that the die chamber rides against.

I found that I was getting the same big variation in seating depth because my die was incorrectly setup. The spring was not compressed enough, and seating was happening against die chamber contact, not stem contact. The spring pressure is probably constant, but a small variance in neck tension can result in seating depth variation if seating is happening without the spring fully compressed.

Set the die to take up the slack in the spring, and the seating depth should be constant.

If you setup exactly according to the instructions it should work properly.

I started taking those springs out of Forster dies years ago. The die works fine without it. Then, the only resistance you feel is the bullet/case neck interface when seating. Go slowly with your press handle until it bottoms out, and you can feel every little hump and bump and you will get consistent seating depth.
If you feel different seating pressures, there is inconsistence in the bullet/case neck interface. Then you will see more variation in seating depth. .001" is not a long distance.
The spring is only in there to return the chamber of the die to the down position. I have not had problems with the chamber remaining in the up position without the spring in place. As with any die, it doesn't hurt to take the seating die apart and clean it on occasion.

I have at least 10 Forster seaters. And 10 springs setting around with no purpose.

 

[Dave M.]

Do you have any idea how minor .0003 is?

I had to reread the OP…I thought he stated 3-4 thou…….but instead it was 3-4 ten thou. About one quarter of the thickness of a human hair.