The UK's Finest Independent Forum for Shooters and Gun Owners. Est 2010.

What's the best way to ensure correct seating depth / COAL ?

We currently do it by trial and error: setting the die to seat the bullet a little off the desired COAL and then slowly homing in on the desired length by iterations of seating a bullet, measuring COAL, adjusting the die and so forth until we get it correct. At that point we lock the die off and churn out the rounds...

Is there a better way? What about those micrometer adjustabubble dies from the likes of Forster ? Can they just be dialled in to the correct length and eliminate the trial and error?

Make up a dummy round for each load and use that for setting the dies in future.

dromia wrote:Make up a dummy round for each load and use that for setting the dies in future.

I'll go along with that, that's what i do..

bhodge wrote:

dromia wrote:Make up a dummy round for each load and use that for setting the dies in future.

I'll go along with that, that's what i do..

Same here

I do that too. Make a point of marking it with some paint or similar. I once took mine to the range and tried to fire it. :)

And me.
ukrifleman

There's a handy list of thread pitches for die manufacturer's bullet seater stems:



Some simple maths will get the bullet within a couple of thou & a final tweak after measuring will do the job.

meles meles wrote:What's the best way to ensure correct seating depth / COAL ?

We currently do it by trial and error: setting the die to seat the bullet a little off the desired COAL and then slowly homing in on the desired length by iterations of seating a bullet, measuring COAL, adjusting the die and so forth until we get it correct. At that point we lock the die off and churn out the rounds...

Is there a better way? What about those micrometer adjustabubble dies from the likes of Forster ? Can they just be dialled in to the correct length and eliminate the trial and error?

2 different ways of answering really, COAL to get a fit into a mag etc or the way in which you want to achieve a particular bullet 'jump' with a measured bullet type and the jump to the lands in something a little more accurate. (If that makes sense)

If your just making rounds to fit into a mag then set it up as you say and measure the overall length, trial it in the rifle as a dummy round and bobs your uncle (or whatever the badger equivalent is)

If however you're trying to achieve a best bullet jump to achieve a tuned length in a particular rifle then being able to fine tune the seater die makes life a whole lot easier, set the die up and dial it in and check your measurements. If you want to set as an example a 20 thou jump then the micrometer dies are excellent, especially when you then want to try it with a 25 or 15 thou jump, dial it in, seat and measure it and job done.

Or the simple answer, yes, they're really good whatever you want to achieve