Seating depth inconsistency- Redding comp

[ColeT96]

I set it to just barely having the slightest cam over and wala perfect. I wonder if how it was I backed it off the shell holder too much where tension was very inconsistent

 

[MagnumManiac]

I set it to just barely having the slightest cam over and wala perfect. I wonder if how it was I backed it off the shell holder too much where tension was very inconsistent

How have you prepared the die?
Did you disassemble it and do as the instructions say?
I find all new Redding Comp seaters need some attention to detail to get them operating smoothly. Thoroughly cleaning them after disassembly is the first step, squeaky clean to begin with…

Cheers.

 

[LaHunter]

Here I am again. When seating I will get my first one fine tuned in. Then the next on is .003-.006 long. I adjust and some are right and some seat too deep. Once first brass set with bushing die. I loaded some a couple weeks ago and perfect. I was running a small cam over. I backed it out this time per set up manual.

Also, I have not cleaned or oiled this die. It does have the correct stem in

If you have used a cam over with the Redding Comp Seating Die, there is a chance you may have damage it. This die is not made for cam over.
Also, you have to remember, the seating stem and the comparator (assuming you are using a comparator) do not contact the bullet at the same location. If you are +/- .003, depending on the bullet, that may be about as good as you can get. If you are measuring cartridge base to bullet tip, then you will always have a lot a variation.

 

[ColeT96]

I cleaned it by wiping down earlier. Definitely a tad sticky. Have no oil to wipe down in. Slightly better results but I backed off to no cam over. The very slightest cam over is dead nuts time after time

 

[MagnumManiac]

Well, if you have not disassembled the die and wiped it down with solvent to remove the rust inhibitor, then it will function poorly.
The only part that gets lube, not oil, is the sleeve, everything else, including the threads stay 100% dry without lube of any kind.
Also, if the stem sticks in the sleeve, the sleeve AND stem are trashed because a burr will have formed creating damage.
Never use cam over on a Comp die, even slightly.
Lucky you're not using a Forster die, cuz the stem would have been ruined the first time you cammed over…

Cheers.

 

[MarkInPA]

Well, if you have not disassembled the die and wiped it down with solvent to remove the rust inhibitor, then it will function poorly.
The only part that gets lube, not oil, is the sleeve, everything else, including the threads stay 100% dry without lube of any kind.
Also, if the stem sticks in the sleeve, the sleeve AND stem are trashed because a burr will have formed creating damage.
Never use cam over on a Comp die, even slightly.
Lucky you're not using a Forster die, cuz the stem would have been ruined the first time you cammed over…

Cheers.

Seating bullets on compressed loads with this die will also ruin the stem. I learned from experience.

 

[Opa-lopa]

Ya know, you guys can chase neck tension & free run to the rifling all you want, IMO, it's peanuts compared with shot-shot engraving pressure changes. Go see: https://storage.googleapis.com/wzuk...ach to Estimate Muzzle Velocity Variation.pdf

 

[Eric H]

I've used the Sinclair mandrels to adjust bullet tension so all bullets will have the same tension. It helps to use brass that has about the same amount of firings or recently annealed. Some bullets are all over the place with their BTO and when I run across them I will in seat long and gradually work down to desired BTO.

 

[MagnumManiac]

Ya know, you guys can chase neck tension & free run to the rifling all you want, IMO, it's peanuts compared with shot-shot engraving pressure changes. Go see: https://storage.googleapis.com/wzuk...ach to Estimate Muzzle Velocity Variation.pdf

No thanks.

 

[LRNut]

I meant to comment last week but forgot. Are you sure your primers are seated flush or deeper? They might look okay, but you can't see .001 to .003. Try measuring a case without a primer, then seat a primer and measure again. Or, if a load comes out long you can seat your primer with a hand seater and then see if your ogive to base has been reduced. If so, the primer was the culprit.

 

[Varmint Hunter]

I meant to comment last week but forgot. Are you sure your primers are seated flush or deeper? They might look okay, but you can't see .001 to .003. Try measuring a case without a primer, then seat a primer and measure again. Or, if a load comes out long you can seat your primer with a hand seater and then see if your ogive to base has been reduced. If so, the primer was the culprit.

Good point

When you measure the CBTO with a comparator, one of the jaws will lay across the primer/case head. If you hold it up under a light, you can easily see if the primer is proud of the primer pocket.

 

[Phil Rizzo]

Ya know, you guys can chase neck tension & free run to the rifling all you want, IMO, it's peanuts compared with shot-shot engraving pressure changes. Go see: https://storage.googleapis.com/wzukusers/user-33607572/documents/04a9d38d49f84120ac955d29481d306f/Using an Error Budget Approach to Estimate Muzzle Velocity Variation.pdf

Seating depth doesn't matter.
Neck tension doesn't matter.

Next will be powder and charge weight.?…? Primers?

 

[DeadEyeDeadly]

I've been looking for an area on this forum to post about a handy measuring tool that I've used for many years. While not a precise device or relevant to the subject being discussed, someone may find the info useful. So here goes ...

I stole mine from my wife's sewing box, but one can be purchased at Walmart or online for a few bucks.