Bullet seating variations

[long40shot]

Recently I've been measuring base of cartridge to the ogive on my stuff. Lately on my 300wm, I've been loading 185 Berger vlds. I am getting 1 -6 thousandths variation. Could this be due to variations in the bullets? Seater die (Forester comp)? Brass variations? Just trying to narrow it down.

Thanks
Matt

 

[itchyTF]

Neck tension, but that would come under brass variations.

 

[brantfredrickson]

Measured bullet base to ogive for 50 Sierra 175 MK's 30cal with a Hornady OA length gage. Most were .647, five were .654, and four were .652. But I don't think that's your problem. When I experience your type of results I found my primers sticking out of the brass a few thousands which resulted in a cartridge base to ogive variation similar to yours. I was using a lee hand priming tool. Now the primer seater on the Forster Co-ax. I have neuropathy in my hands and can't feel a good primer seating with a hand tool. The Forster primer seating puts the primer .004 below the shell base every time. Not an optimal result, but the best in a bad situation.

 

[Shaggy357]

Is the seating stem, on your bullet seating die, seating on the bullet ogive, or on the bullet tip? Check to see how your bullet fits into the stem...... It's not uncommon to find a few thousandths variation if you are seating by the tip and measuring by ogive, or vice versa.

Steve

 

[KT]

Recently I've been measuring base of cartridge to the ogive on my stuff. Lately on my 300wm, I've been loading 185 Berger vlds. I am getting 1 -6 thousandths variation. Could this be due to variations in the bullets? Seater die (Forester comp)? Brass variations? Just trying to narrow it down.

Thanks
Matt

I would think that you are getting this problem from your seating die (slop in the die) and press (extra pressure at the bottom of the stroke). I use an arbor press with Wilson dies and don't have those problems. An arbor press and inline die will give you the most consistent seating results. You just need to decide on how accurate you want your ammo to be.

Also check to make sure your calipers are still reading correctly. Last thing remember you can minpulate calipers to read differently depending on the amount of pressure you put on them, try and use the same amount of pressure when measuring.

KT

 

[barefooter56]

Recently I've been measuring base of cartridge to the ogive on my stuff. Lately on my 300wm, I've been loading 185 Berger vlds. I am getting 1 -6 thousandths variation. Could this be due to variations in the bullets? Seater die (Forester comp)? Brass variations? Just trying to narrow it down.

Thanks
Matt

Matt,
If this is an older Forster die it MAY be "coil bind" of the spring of the sliding sleeve. Forster now makes a shorter thinner wire spring that solves this problem. Contact Forster for a replacement.

 

[long40shot]

I bought the die around 14 years ago. Not sure if it seats off the tip or ogive.

 

[RemingtonAI]

My Lee and Hornady seating dies are arm pressure sensitive. I think they claim not to be but if you don't do it the same every time, you'll get different results. I was having this problem when my neck tension was slightly more than it is now. Actually the measured "hold" or "tension" is still the same but I just slightly increased how much I chamfer the inside of the neck. This allowed for a noticeable ease in bullet seating and as long as the seat is smooth and soft, I can feel exactly when I am supposed to stop lowering the arm. I found that if I have to apply more pressure to the arm, I wont feel that point as much or at all and tend to continue the arm down further, resulting in a deeper seat. If you cant increase the chamfer due to it already being correct or ideal, I have heard of guys using graphite on the neck to ease seating, as well as just running a nylon brush with carbon on it, in the neck to again ease the seating friction.
I'm not saying your neck tension is too much for the bullet, but it may be too much to feel the exact point where you need to stop applying pressure to the ram in order to get the same exact seating depth. That's what fixed my problem anyways. Good luck. Jesse

 

[Shynloco]

Matt,
I'd suggest you measure your bullets (before seating) as a starting place. To do that, make sure the edges on your comparator are not worn and are consistent all the way around. Next, I was just talking to a good friend who competes and loads bullets. He said he was measuring Berger bullets using his caliper and comparator and out of a box of 500, he ended up with 4 - 5 different groups, thus a variation of ojive. I've experienced similar issues using Sierra bullets. And both of us very much prefer Sierra and Berger bullets. The problem, as we surmise, it that a quantity of bullets come off different machines, are mixed together and thus the difference of measurement, base to ojive. So if you separate your bullets, you'll have better and more consistent measurements of finished casings and then you'll only need to make scope adjustments to make up for the change in POI due to the variations in ojive measurements. Just my two cents.

Alex

 

[itchyTF]

This allowed for a noticeable ease in bullet seating and as long as the seat is smooth and soft, I can feel exactly when I am supposed to stop lowering the arm. I found that if I have to apply more pressure to the arm, I wont feel that point as much or at all and tend to continue the arm down further, resulting in a deeper seat.
I'm not saying your neck tension is too much for the bullet, but it may be too much to feel the exact point where you need to stop applying pressure to the ram in order to get the same exact seating depth.

This surprises me. I can't imagine getting consistent seating results by feel. .005 or .010 ain't much and I doubt I could feel the difference between the two. Maybe I'm just getting old.

 

[jonbearman]

When I seat with my forster seaters I pause at the bottom of the stroke mainly because of the spring. I seem to have a good result like that. The Wilson eliminates all the guess work using an arbor press.

 

[RemingtonAI]

[Q="itchyTF, post: 36727631, member: 1276608"]This surprises me. I can't imagine getting consistent seating results by feel. .005 or .010 ain't much and I doubt I could feel the difference between the two. Maybe I'm just getting old.[/QUOTE]
I can't "feel" where to stop on the lee die but on the hornady you can feel a detectable little stop. I couldn't tell you what I am hitting or feeling but there's something. Maybe it's just that there is some kind of mechanical friction at that certain point and I have set my die to seat the bullet at the right depth right at that mechanical pause? Dunno but it's consistent so it works for me, for now.

 

[itchyTF]

I've pretty much converted to Wilson seaters with arbor press. Metal against metal, I can feel that!

 

[barefooter56]

I bought the die around 14 years ago. Not sure if it seats off the tip or ogive.

Matt,
The only way to know is to take the seater stem out and check with a couple of bullets. If the tip of the bullet "bottoms out" in the seater stem you will need to replace ( call Forster) or modify the stem by having it drilled deeper. The seater stem should "cup" the bullet nose. the tip should never make contact with any part of the seater stem. Shynloco has a good thought also on sorting your bullets by Base to ogive into groups before seating so you can make the adjustments on the seater you need so all the bullets are the same distance off the lands.

 

[long40shot]

Well, after much thought, I ordered a new Redding comp seater die. I'll see if that makes any difference. If not, I figure since it has a marked adjustment dial, I can tune each round to the same oal. I will try sorting my bullets by measuring base to ogive. Thanks for all the thoughts guys. Keep them coming in!

Matt

 

[CH Luke]

Well, after much thought, I ordered a new Redding comp seater die. I'll see if that makes any difference. If not, I figure since it has a marked adjustment dial, I can tune each round to the same oal. I will try sorting my bullets by measuring base to ogive. Thanks for all the thoughts guys. Keep them coming in!

Matt

+2 for the die and the BTO bullet sort. Start with the longest first. Work your way down. If you are w/i .0005 to .001 you can often close the gap by .0005 by cycling the same setting once more.

I'm pretty OCD on CBTO and will back off the Redding micrometer by .001" after finding each match and can consistently keep w/i .0005" CBTO consistently.

Using the Hornady comparator consistently is another whole set of minor skills.

 

[RemingtonAI]

+2 for the die and the BTO bullet sort. Start with the longest first. Work your way down. If you are w/i .0005 to .001 you can often close the gap by .0005 by cycling the same setting once more.

I'm pretty OCD on CBTO and will back off the Redding micrometer by .001" after finding each match and can consistently keep w/i .0005" CBTO consistently.

Using the Hornady comparator consistently is another whole set of minor skills.

That's why I use the RCBS precision mic to measure CBTO as well as cartridge base to the datum point . It doesn't attach to anything and primers don't affect the measurement. It's by far my favorite and most used tool. You can also take datum point measurements for headspace on a loaded round. Highly recommend it! Jesse

 

[lpreddick]

Recently I've been measuring base of cartridge to the ogive on my stuff. Lately on my 300wm, I've been loading 185 Berger vlds. I am getting 1 -6 thousandths variation. Could this be due to variations in the bullets? Seater die (Forester comp)? Brass variations? Just trying to narrow it down.

Thanks
Matt

this used to just about drive me crazy until i read on this site what was happening to me. i was not annealing my brass and necks developed varying hardness and i could tell there was a difference in resistence to bullet seating and the harder to seat always measured long, easy one would sea deeper. bullets were going into the seating stem since it was easier for them to do that than seat in the case and i could see a ring on the bullets and almost none on ones seating easier. a stem with an internal shape of the bullet"s ogive would be perfect but would have to be bullet specific. annealing has just about corrected my problem. bullet base to ogive variation: i once measured and sorted factory bullets(even benchrest quailty ones varied) but now i usually use custom bullets and variation is almost never found.

 

[Twoboxer]

Just yesterday went through a similar exercise in 30-06 with Lapua cases and Sierra 168s. First loading I got a range of CBTO ~0.008".

Second loading I measured 100 bullets from the same batch for BTO.

Nearly half of them measured .642" (0.6415" to 0.6425"). One bullet was as short as 0.622", and there were reasonable quantities at 0.634" and 0.638". Loaded 35 of the 0.642s and the CBTOs were all within a 0.0015 range.

So, at least in this case, similar bullet BTO lengths fairly accurately projected base-to-seater-stem distance. IOW, eliminating bullet BTO variation eliminated CBTO variation.

 

[BoydAllen]

Here are a couple of things to try. Sort your bullets in to groups that are alike from base to ogive, and then seat them long, and check them for consistency. That way if you need to, you can sort the ammo by head to ogive and do custom seater adjustments for each group to get the end result that you are looking for. On the die, set it up so that the press toggles lightly on the die body, and if the sleeve is long enough so that it is pushed up by the shell holder, trim it a little so that it is pushed up by the case, and of course make sure that your bullet tips are not bottoming in the stem. If your sleeve is a little loose on your cases, try putting some painters tape around the inside of the sleeve, going up about 3/8" carefully applied, with the overlap cut to butt. Do what you have to to get consistent neck to bullet friction.
Variations in seating effort will show up as variations in seating depth.