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Need help with inconsistent bullet seating depth

Ted Bell

Ted Bell

"Living the dream"
Minuteman
Mar 10, 2010
29
17
I'm having a hard getting consistent bullet seating depths and was looking for any advice or suggestions. I'm reloading 6x47 Lapua on a Redding T7 with Whidden custom dies. New Lapua brass, and bullets are Berger 105gr Hybrids, all from the same 100 count box. I'm measuring them with a Hornady Lock n Load Comparator on a set of calipers, with the comparator insert that gets me closest to the ogive without sliding over it. I'm making sure to use the same speed on the upstroke, the same pause at the top, and the same speed on the downstroke from cartridge to cartridge. However, just using my last six rounds as an example, the cartridge length (case base to the compartor's position slightly above the bullet ogive) was two at 2.050, three at 2.051, one 2.052, and one 2.053. Any advice or suggestions would be most appreciated.

Thanks,
Ted
 
Ted Bell said:
I'm having a hard getting consistent bullet seating depths and was looking for any advice or suggestions. I'm reloading 6x47 Lapua on a Redding T7 with Whidden custom dies. New Lapua brass, and bullets are Berger 105gr Hybrids, all from the same 100 count box. I'm measuring them with a Hornady Lock n Load Comparator on a set of calipers, with the comparator insert that gets me closest to the ogive without sliding over it. I'm making sure to use the same speed on the upstroke, the same pause at the top, and the same speed on the downstroke from cartridge to cartridge. However, just using my last six rounds as an example, the cartridge length (case base to the compartor's position slightly above the bullet ogive) was two at 2.050, three at 2.051, one 2.052, and one 2.053. Any advice or suggestions would be most appreciated.

Thanks,
Ted
Click to expand...
I bought an RCBS micrometer it seems more accurate than the Hornady comparator. Still it seems pretty much what I end up with on my reloads. I use the redding seater and seat long and bring it down. I still get a discrepancy and that helps. Not sure if this helps but .001-.003 isn't that bad.
 
I had the same issue with my 6cm. It was the Whidden dies couldn't get any consistency so i sold the dies and went back to REDDING Comp dies set. I use the 2 dies set, FL die and micrometer seating die
 
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Have you measured your bullets (oal) before you seated them. A dollar bill to a hole in a donut says that's where the variation is. Base to ogive may be the same with shorter or longer oal.
 
I just measured six bullets, and the length to ogive was 3 at 1.075, 2 at 1.065, and 1 at 1.060, so there is some variation there. However, I'm trying to figure out how a variation in bullet length-to-ogive would matter - if the two contact points when seating a bullet are the press ram at the base of the case and the die at the bullet tip to shoulder pressing the two together (i,e, you're holding the bottom of the case and the top of the bullet and squeezing them together), shouldn't any variation in bullet base-to-ogive just result in a variation in how far down the base of the bullet sits in the case, not in a difference in the shoulder-to-cartridge-base distance? I'm thinking that the ram (i.e. base of the case) to bullet contact point in the die (which should be bullet shoulder) should be a constant, and any difference in bullet length or case length just results in a difference in how much the case and bullet overlap, not in a difference in the cartridge overall length.

Thanks,
Ted
 
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Check your seating stem. Mark the inside of the seating stem with a sharpie and put a couple of Bullets in and see where the sharpie transfer onto the bullets and compare. Post pictures of the results.
 
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The base to ogive measurement is the most important. If the bullets differ in ogive, the OAL will differ by the same amount. This assumes the seater die engages the ogive and not the tip of the bullet. .001-.003 is a fairly common ogive variation on bulk bullets but I've not seen much variation at all with Bergers. JMHO.
 
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is this new brass?
how much neck tension are you running?
is your T7 head a little sloppy?
are you using the hornady lock n load quick change bushings?

ive been running off the shelf whidden dies for 7yrs through 4 different cartridges and have never had and issue with any of them.
 
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Mine wasn’t a Custom Whidden, but I was on the same page. Before troubleshooting the entire chain I tried with a Forster micrometer seater and never looked back...
 
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BLDTYLRY said:
Check your seating stem. Mark the inside of the seating stem with a sharpie and put a couple of Bullets in and see where the sharpie transfer onto the bullets and compare. Post pictures of the results.
Click to expand...

It's easier just to unscrew the die and pull the seating stem out to stick a bullet in there. Then you can see exactly what is going on and you won't lose the setting on most dies when doing that.
 
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Ted Bell said:
I just measured six bullets, and the length to ogive was 3 at 1.075, 2 at 1.065, and 1 at 1.060, so there is some variation there. However, I'm trying to figure out how a variation in bullet length-to-ogive would matter - if the two contact points when seating a bullet are the press ram at the base of the case and the die at the bullet tip to shoulder pressing the two together (i,e, you're holding the bottom of the case and the top of the bullet and squeezing them together), shouldn't any variation in bullet base-to-ogive just result in a variation in how far down the base of the bullet sits in the case, not in a difference in the shoulder-to-cartridge-base distance? I'm thinking that the ram (i.e. base of the case) to bullet contact point in the die (which should be bullet shoulder) should be a constant, and any difference in bullet length or case length just results in a difference in how much the case and bullet overlap, not in a difference in the cartridge overall length.

Thanks,
Ted
Click to expand...
You are correct. Those two points should be mechanically the same every time.

If there’s slop in the turret this could cause the effect.

Your neck tension can cause this effect as well, new brass, ultrasonic brass, anything that makes it grippier.

But if the variation is in between where the seating stem contacts and the comparator contacts then the seating stem could all be right but the numbers you read are wrong doe to that bullet to bullet error. A bob green comparator will allow you to sort out and make lots around those differences.
Probably not what you’re wanting to do though.

Split the seating die in half, make sure the bullet tip isn’t bottomed out in the stem. It shouldn’t rock when inserted.
 
In my process I use a Forster micrometer seating die, and use both an rcbs precision mic and a hornady comparetor to measure headspace and length to ogive. I've found using these all together helps a lot. I love the forster micrometer die because you can dial very tight tolerances.

1. I will usually set it about 5 thousands longer than I want.
2. measure with the comparetor to get the exact distance i need to go.
3. then i'll seat the rest of the way based off the measurement above.

I also agree it could be the seating stem with the bullet combination. some companies offer different stems for different bullet designs.
 
It is new Lapua brass, sized for .002 neck tension. I took the seating die apart, no issues there - the die stem is clean, and no issue manually fitting it to the bullets - plenty of room for the nose. I took the turret off my press, cleaned all the mating surfaces thoroughly, regreased it, and reinstalled it, following Reading's instructions and torquing it to 45 in/lbs. That helped a little - I'm down to about a .002 inch variation on a run. If I had to guess, the difference is from the slight bit of flex in the turret head when the round/ram presses against the die at the top of the stroke. Might have to add a Forster Co-Ax to my collection of presses.

Thanks,
Ted
 
I agree, unless you are pointing the bullets and sorting by length lots .001 - .002 is fine.
 
The diameter of the seating stem and of the comparator are 2 different measurements. Because of this, there will be variance if you leave the seating die set at one depth. The only way to get all the bullets seated to exactly the same depth is to seat long, measure, adjust the micrometer, and seat again
 
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Check to make sure your primers are seated past flush. I had this issue and was getting inaccurate readings because my caliper was on my primer and not the case. Just something to consider.
 
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Recomend you sort bullet ogive with the same comparator,sort them in groups by Ogive length and weight.When you do you should be getting same Ogive reading .OAL'S will vary because bullets are not always same oal even when they have same Ogive length.More important Ogive length than oal.
 
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Sharpshooter3 said:
Just a thought did you try to measure the bullets with the comparator before you seated them?
Click to expand...
This is a good/valid point. I think you will find that much variation in bullet (alone) length. Having said that, the seating stem (assuming you have a VLD seater stem....) should be seating bullets/loaded cartridges to the same OAL. I'd look into your neck tension if I were you. When I hand load (non-progressive) I do see variation of at least .002". I used to adjust my die, but found I was just chasing OAL all around the place.
 
GIXXER2000 said:
I had the same issue with my 6cm. It was the Whidden dies couldn't get any consistency so i sold the dies and went back to REDDING Comp dies set. I use the 2 dies set, FL die and micrometer seating die
Click to expand...

This. I had Whidden 243 and 6.5 Creed dies that gave me fits between the sizers and the seaters. I’ll never own another set. Redding’s have always worked wonderfully for me and recently I’ve been using some Forsters with good luck so far.

I’d return them and get another set of dies.
 
Ted Bell said:
I'm having a hard getting consistent bullet seating depths and was looking for any advice or suggestions. I'm reloading 6x47 Lapua on a Redding T7 with Whidden custom dies. New Lapua brass, and bullets are Berger 105gr Hybrids, all from the same 100 count box. I'm measuring them with a Hornady Lock n Load Comparator on a set of calipers, with the comparator insert that gets me closest to the ogive without sliding over it. I'm making sure to use the same speed on the upstroke, the same pause at the top, and the same speed on the downstroke from cartridge to cartridge. However, just using my last six rounds as an example, the cartridge length (case base to the compartor's position slightly above the bullet ogive) was two at 2.050, three at 2.051, one 2.052, and one 2.053. Any advice or suggestions would be most appreciated.

Thanks,
Ted
Click to expand...

So, what is the problem?
 
I don't see how different measurements of the OAL of the bullet can cause a difference.

If the die is pushing the ogive down into the brass, a longer bullet will simply be shoved further in, and there will be more bullet in the brass, but the COAL should be the same.
 
Sogan said:
Are you saying that those seating depth differences arnt much to worry about?
Click to expand...

Yeah. Measure ten bullets with your gauge so you have a starting baseline. You want the AVG and SD for your bullets as well as as CBTO to get a tolerance baseline. Also, I want to emphasize your comment about primers flush or sunk. But overall the AVG and SD in the OP post is not material.
 
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Jammer Six said:
I don't see how different measurements of the OAL of the bullet can cause a difference.

If the die is pushing the ogive down into the brass, a longer bullet will simply be shoved further in, and there will be more bullet in the brass, but the COAL should be the same.
Click to expand...
The importance lies in the position the ogive is with the lands. When one is chasing the last bit of accuracy with respect to distance to the lands, and is desiring a .020-.010" distance and the bullet oal and/or position of the ogive is changing by up to .025", can you see where this may be problematic?
It's best to have the ogive in the exact same location every round, oal be damned. Therefore, having the seating die seat the projectile off the ogive and not the tip is key.
I'm playing around with Nosler RDF's right now and it's driving me batty. Where Hornady ELD-x is varying at most .002", the RDF's are varying as much as .022" on the oal, and .014" on the ogive to base.
 
Jammer Six said:
I don't see how different measurements of the OAL of the bullet can cause a difference.

If the die is pushing the ogive down into the brass, a longer bullet will simply be shoved further in, and there will be more bullet in the brass, but the COAL should be the same.
Click to expand...

Yes but we dont care about OAL (over all length) except for making sure they fit in the magazines if you have that requirement.

As soulezoo mentioned, the ogive is where we place our attention (CBTO- case base to ogive)
The barrel doesnt touch the bullet at the tip, it touches it right in front of the bearing surface (full bullet diameter). The tip of the bullets varies far far more than the portion thats pushed down in the case which is why the OALs rarely match even when the CBTO is the same. We want the ogive measurement to be consistent- We want where the bullet touches the barrel to be the same.
1543856134354.png

1543856067141.png



Now, does the OPs .002 diffrence now come into play with the actual .244 bullet diameter being different or is the difference between that point and where the comparator contacts as shown in this image by the green critical distance measurement?

1543856228896.png
 
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Those are some really good pics and should hopefully clear up some of the confusion.
 
And doesn't the die use the ogive?

It seems to me that the die is pushing the same point on the ogive to the same length every time-- it's just that sometimes it pushes more base into the brass than others. (It sets the BTO every time, using the contact point on the ogive.)

So the only thing a variance in bullet length changes is how far the bullet base gets shoved into the brass.
 
Your getting 3thou difference measuring from base to ogive,Right?
If so what is the problem?
If you take that box of bullets and measure every bullet from the bottom of the bullet to the ogive you will see where your 3 thou is coming from.
 
Brux said:
Your getting 3thou difference measuring from base to ogive,Right?
If so what is the problem?
If you take that box of bullets and measure every bullet from the bottom of the bullet to the ogive you will see where your 3 thou is coming from.
Click to expand...
3 thou is a very small amount. I understand wanting them perfect. I do too, but it’s not very practical to assume that these bullets are made identical when thousands are made at a time. I wonder what the acceptable bullets tolerances are to make it out the door with QC.
 
Jammer Six said:
And doesn't the die use the ogive?

It seems to me that the die is pushing the same point on the ogive to the same length every time-- it's just that sometimes it pushes more base into the brass than others. (It sets the BTO every time, using the contact point on the ogive.)

So the only thing a variance in bullet length changes is how far the bullet base gets shoved into the brass.
Click to expand...
The ogive is the entire curavature from the exact point it transitions from the bearing surface to the meplat.

So, yes, the stem seats on ogive but if you were to try and seat it at that exact outermost diameter you would have a very hard time doing it well as it would have the propensity to slide about. The stem is a bit smaller so that there is enough bullet for it to not only be in contact with but also push solidly against and hopefully in such a way, over enough surface area, so that it doesn’t make the bullet or disturb it in anyway that could effect its aero dynamics.

Take the top half of your seating die out and stick a Bullet in it and check for yourself. Or better yet look at the ring on your bullets where it makes contact. Or look at the picture in my previous post, you can see a pinky fingers width above “the start of bullet ogive” line on each bullet there is another line. That’s where the stem is contacting.

Edit:
AE1B9FFC-9373-4D8F-9EB2-BED1E1ED5698.jpeg
 
I see. I should have said "the die seats at the same spot on the ogive", then, and the die should be set to generate the same base-to-contact-point each time.

So that shouldn't change, and if the bullets are different lengths, what would change is how much bullet gets shoved into the brass.
 
To me where the die is hitting the bullets is not the same where the comparator is hitting so I could see the 1 to 3 thou difference when measuring. I’m sure if you measure the same spot your die is seating the bullets then you could be getting closer results.

Is really chasing a thou going to make that big of diff? I only ask cause I am afraid to go down the rabbit hole. I do reload and do my best to prep my brass the same and have a fd-120i scale for consistent powder throws but that’s about it.
 
In my experience I have found the Hornady comparator gauges aren't the most consistent things in the world. If you take a measurement and then spin the cartridge a little and repeat you will find that you can sometimes get several different measurements that vary by a few thousandths. Also if you tighten the comparitor body onto your caliper arm too much it will actually cock the comparator off a little bit. I don't get hung up on being at lets say exactly .020 off the lands, if i'm .018 to .022 im not going to stress about it as long as all my loads are coming out within 1 or 2 thousandths of EACH OTHER at CBTO. I load up a dummy round using the comparitor gauges to get as close to my desired CBTO as possible (spin and recheck in the comparator a couple of times). After that I use a gauge that I bought from http://www.larrywillis.com/ for comparison of the rounds coming off my press which I have found to be far more accurate.
COAD-06.jpg



I also use that gauge to measure shoulder "bump back" when resizing as I find it to be extremely accurate for that as well. As a couple of others have already mentioned both of these methods are subject to error if your primers are not seated below flush so use a primer pocket uniformer and get those pockets as deep as they should be. Another thing I have noticed is that my Redding competition dies are so sensitive that my seating depth will change as much as .001 with temperature changes in my reloading area, so if i'm reloading throughout the day I may have to make small adjustments here and there.
 
spife7980 said:
The ogive is the entire curavature from the exact point it transitions from the bearing surface to the meplat.

So, yes, the stem seats on ogive but if you were to try and seat it at that exact outermost diameter you would have a very hard time doing it well as it would have the propensity to slide about. The stem is a bit smaller so that there is enough bullet for it to not only be in contact with but also push solidly against and hopefully in such a way, over enough surface area, so that it doesn’t make the bullet or disturb it in anyway that could effect its aero dynamics.

Take the top half of your seating die out and stick a Bullet in it and check for yourself. Or better yet look at the ring on your bullets where it makes contact. Or look at the picture in my previous post, you can see a pinky fingers width above “the start of bullet ogive” line on each bullet there is another line. That’s where the stem is contacting.

Edit:
View attachment 6980411
Click to expand...
 
If neck tension is light and charges are getting compressed, the bullet can and may back out somewhat. The solution to that is to increase neck tension.

I only worry about cartridge dimensions if there's a problem on the target.

Sometimes I find that the "best" practices may only be attainable at great effort and may not bring a comparable improvement to accuracy. IMHO, simplest measures are best, they allow more reliable consistency. If the target doesn't demand the process, skip it.

Greg
 
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JimLee said:
In my experience I have found the Hornady comparator gauges aren't the most consistent things in the world. If you take a measurement and then spin the cartridge a little and repeat you will find that you can sometimes get several different measurements that vary by a few thousandths. Also if you tighten the comparitor body onto your caliper arm too much it will actually cock the comparator off a little bit. I don't get hung up on being at lets say exactly .020 off the lands, if i'm .018 to .022 im not going to stress about it as long as all my loads are coming out within 1 or 2 thousandths of EACH OTHER at CBTO. I load up a dummy round using the comparitor gauges to get as close to my desired CBTO as possible (spin and recheck in the comparator a couple of times). After that I use a gauge that I bought from http://www.larrywillis.com/ for comparison of the rounds coming off my press which I have found to be far more accurate.
View attachment 6980454


I also use that gauge to measure shoulder "bump back" when resizing as I find it to be extremely accurate for that as well. As a couple of others have already mentioned both of these methods are subject to error if your primers are not seated below flush so use a primer pocket uniformer and get those pockets as deep as they should be. Another thing I have noticed is that my Redding competition dies are so sensitive that my seating depth will change as much as .001 with temperature changes in my reloading area, so if i'm reloading throughout the day I may have to make small adjustments here and there.
Click to expand...

That's what I use. Damn fine tool!
56557166884__BDF1DADA-1897-466E-A0E8-D84DC340595D.JPG
 
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Ted Bell said:
I just measured six bullets, and the length to ogive was 3 at 1.075, 2 at 1.065, and 1 at 1.060, so there is some variation there. However, I'm trying to figure out how a variation in bullet length-to-ogive would matter - if the two contact points when seating a bullet are the press ram at the base of the case and the die at the bullet tip to shoulder pressing the two together (i,e, you're holding the bottom of the case and the top of the bullet and squeezing them together), shouldn't any variation in bullet base-to-ogive just result in a variation in how far down the base of the bullet sits in the case, not in a difference in the shoulder-to-cartridge-base distance? I'm thinking that the ram (i.e. base of the case) to bullet contact point in the die (which should be bullet shoulder) should be a constant, and any difference in bullet length or case length just results in a difference in how much the case and bullet overlap, not in a difference in the cartridge overall length.

Thanks,
Ted
Click to expand...
You are absolutely correct. That variation in bullet to neck contact under tension is exactly where it matters. Like a slingshot or a bow, a nice clean & consistent release of the projectile is required for consistent impact. No different here.
 
OP posted his inquiry over two years ago and nobody bothered to ask if he used the correct Hornady insert. You know, the one that says 24 on the side, lol.
 
I would bet good money it is in the bullet.

First pull your seating plug. Put a bullet in it. Mark where the bullet touches the seater. Find a comparator bushing about that diameter. Measure 10 loaded rounds with the smaller insert. If variation goes to near zero, it is in the bullet. At the tip, buller taper can vary quite a bit. This generally is ok for accuracy.

If it is still there, look at your neck tension.
 
Had the same problem as the o/p, I'm a tightass on most things and enjoy making do with things on the cheap. That said I use basic R.C.B.S. dies, I sent the seating stem and 3 bullets to them and they machined a custom stem for the bullets and problem was solved. Now my c.b.t.o. is within a .001. Now it seems to me that a guy could do a couple coats of car wax on the bullet your using and do a custom stem with j/b weld.
 
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