Micrometer bullet seating dies

[nmkid]

Am I correct in thinking that's it's impossible to seat all your bullets to the same length because not all bullets are the same? I guess if a fellow wanted to seat all bullets to the same depth you would have to measure all your bullets. My question was going to be about how accurate micrometer dies are but, started thinking on the first part of the post. No, I don't shoot bench rest and I doubt if I could tell the difference on .001-.003 seating depths on paper. Just an old fart probably overthinking(?) things. Anyway, folks using the micrometer dies...If you make a .001 adjustment on the die does it show up on your OAL?

 

[savageshooter86]

Not always. Depends on brass spring back. I measure every round and seat same COAL. My whidden mic die is pretty close. I need 3 thous more seating, I turn 3 thous on die. Some are about 1/2 thous or 1 thous off. So I sit those aside aND come back to get them exact.

Annealing and sorting bullets help

 

[Sniper338]

^^^

About right.. i dont sort my bullets, but inuse a wilson mic die, fairly dead on too. When i seat them they all tend to measure the exact same most of the time so i roll with that and call it good. Cant tell on paper either.

Neck tension differences i can tell on paper tho!

 

[Lapua40X]

I don't get any better seating depth consistency with my Redding Micrometer Seating die
http://www.brownells.com/reloading/...76348a&gdfms=5BA6C890686E42D6BE7278B711AC5E27
than I get with my Wilson seating die.
http://www.lewilson.com/chambertypebulletseater.html

 

[JohnKielly]

It depends what rabbit hole you want to investigate.

I'm happy to seat off the same ogive point & let the COAL look after itself, but I mostly single load for target sports.

I prefer Wilson stainless micrometer dies for my favourite calibres, because I can adjust them easily, they tend not to rust & I can reset them back to a recorded setting when I change bullets.They have great seating feel too.

I just sold my Redding micrometer .308 yesterday because the tolerances are too close & the plunger tends to bell & chew out the cylinder if you load long bullets or compressed loads.

I've used a lot of standard dies for loads for hunting rifles. I always liked that description minute of whitetail.

 

[Mozella]

Your post implies a couple of questions. Obviously if a batch of bullets isn't the same shape, they won't seat the same; however, I've measured the Berger bullets I shoot in competition and didn't find a bullet-base-to-ogive difference worth sorting on. They are very close in shape measured to the ogive, but they vary in weight more than I would have suspected, so I sort them by weight only.

When it comes to seating bullets, I don't think my micrometer seating die is any more consistent than a standard version. But the micrometer die has one big advantage which is how quickly I can zero in on the correct seating depth. I load several different bullet weights for several different rifles, each with their own preferred CBTO measurement. So I find myself adjusting the seating die frequently. I have a cheat sheet for each combination I load. I consult the data, set the micrometer a couple of thou longer than the target, seat the first bullet, measure it, adjust the micrometer dial appropriately, re-seat the bullet and measure again. Then I seat a second bullet to confirm I have the correct setting and proceed to finish the remainder of the batch of 50, or whatever.

That's not to say a batch of bullets will measure exactly the same because there is not only tolerance stacking involved but the typical way most of measure CBTO with a bullet comparator mounted on a pair of calipers introduces it's own little bit of mystery to the end result. The reading will vary a bit depending on exactly how you hold the cartridge and caliper.

For me, a micrometer seating die is most valuable because it can be so quickly adjusted to hit a desired CBTO distance. That's valuable is you frequently produce different types of ammo for several rifles. Of course, when you're doing load work-up in an attempt to find the optimum jump/jam for a particular ammo/rifle combination, the micro seating die comes in real handy 'cause it's so easy to make a test batch of ammo at 5 or 6 different CBTO values.

Finally, the .001 adjustment you mention won't typically show up as a corresponding change in OAL since bullet length (measured to the tip) is quite variable even with pretty good bullets like Bergers. But since I measure to the ogive, which is much more consistent than over-all length, I can definitely see a .001" difference in CBTO by adjusting my micro seating die by .001".

I don't use magazines for my competition rifles, so OAL is of importance to me only because it's an input variable in Quickload.

 

[Twoboxer]

You can seat ~all your bullets to the same length, but you must choose either overall length or base to ogive . . . but not both because, as you said, bullets will have different shapes.

To do this set your micrometer to seat long. Seat your bullet then measure its length (either COL or BTO). Figure out how many thousandths long it is, adjust your micrometer accordingly, and seat the bullet again. Reset the micrometer long before seating the next bullet.

This has to be done with each bullet because the seating plug doesn't use the bullet's tip, nor does it use the ogive, to push the bullet in. Instead it uses a third point of contact that will change slightly depending on the shape of each specific bullet.

If you are seating a specific distance from or into the ogive, choose BTO to measure so they are all the same. If seating to magazine length you might want to choose COL.

 

[tenring]

For competition, I measure only base to ogive with the Davidson nose pieces and base. I set my Whidden seater about .005" above my desired depth, measure every round and place each in a cartridge tray each line another thou. Seat 10 at a time, moving depth down by .001" each time. Works perfect. But then, compressed loads push the bullet back up slightly.

 

[nmkid]

I measure off the ogive as accurately as I can. However my old fingers and a comparator don't always get along.

 

[USMCDOC]

Been soft seating for years, so i let them find where they want to be on their own.. i know, a lot of you don't like that idea, but it is that i have been doing it, only twice have i ever had a problem where i needed to unload

 

[jr600yd]

Another question? Since most barrels have a .005-.010 spread in seating depth is that .001-.002 difference really worth it if your not shooting benchrest?

 

[mikecr]

Since most barrels have a .005-.010 spread in seating depth

What do you mean by this?

 

[savageshooter86]

What do you mean by this?

Think referring to seating depth window where load still shoots good

 

[ireload2]

Seating "depth" into the case neck is not really a functional dimension other than providing grip on the bullet shank.
The base of the bullet does not have any mechanical interaction with the case.
Rather the functional dimension is somewhat controlled by the datum on the case shoulder to the origin of the rifling or it is controlled by the location of the case head to the the origin of the rifling.
I say "somewhat controlled" because your case can vary from the head to the shoulder. A plunger ejector might push the case forward.
A rifle with a blade ejector or no ejector will not push it forward but will allow it to be positioned by the shoulder, the bullet and the bolt face.

It is possible for the case head, the case shoulder and the bullet to all have some clearance resulting in the loaded rounds floating back and forth.
Or you can control the shoulder position to control the case location at the shoulder. The bullet position is controlled by seated length or the shoulder or both.

Most of the Wilson dies used by a preponderance of bench resters have no micrometer on the die but are usually adjusted with a micrometer or .001 increment shims.

The benefit of the micrometer die is mostly convenience of adjustment since the die cannot tell you the position or length of anything. A diligent handloader will measure the OAL or seated length to the ogive with some other tool, or he will not measure it at all.

 

[500Stroker]

Am I correct in thinking that's it's impossible to seat all your bullets to the same length because not all bullets are the same? I guess if a fellow wanted to seat all bullets to the same depth you would have to measure all your bullets. My question was going to be about how accurate micrometer dies are but, started thinking on the first part of the post. No, I don't shoot bench rest and I doubt if I could tell the difference on .001-.003 seating depths on paper. Just an old fart probably overthinking(?) things. Anyway, folks using the micrometer dies...If you make a .001 adjustment on the die does it show up on your OAL?

To answer your original question, yes, you can reliably change your OAL by .001 using a mirco adjustable seating die. And keep them all at the exact desired OAL length.
I use a Wilson micro seating die that was custom cut by Wilson from my 6BRX fire formed brass.
.001 adjustment of the die will change the OAL by .001

 

[nmkid]

Thanks all!!!!!

 

[jr600yd]

My error, yes I was asking about a seating depth window of 5-10 thousands?

 

[dcali]

There is some variability, but it's not much - maybe a coule thous in my experience (you should be measuring base to ogive, not overall length). But yes, you can see the average seating depth move .001" if you adjust your die .001". It's very convenient when loading for a seating depth test. Typically, I test every .004" or so. You can see a difference in a good accurate rifle.

 

['Freak]

I added the micrometer adjust stems to a couple regular ol’ Redding seater dies. I don’t get the case and bullet guiding sliding sleeve of the Comp seaters but the micrometer do make seating depth tweaks a lot easier.