Interesting unexpected COAL issue due to Dillon 9mm bullet seating die

[JimGnitecki]

I did just a tiny bit more experimentation tonight which got me some findings that I want to add to the body of knowledge building here.

I have some Federal 147g JHP FACTORY ammo, with both unfired cartridges and cases that were fired in my SIG P210A Target, I took a close look at both.

The tapered crimp diameter of the unfired factory cartridges at the casemouth is very consistently 0.376". That's .002" larger diameter than my .374" taper crimped loads.

BUT, in measuring the wall thickness of the Federal cases, I see that they are pretty consistently .011", which is almost exactly .001" thicker than the .0101" wall thickness of my Hornady cases. .374" + (2 x .0011") = .3762". So, Federal is crimping those factory cartridges to pretty much exactly the same .001" crimp as I am. This makes me think that maybe I am on the right track with my crimping.

By the way, let's make sure you understand what this means: Since the bullet diameter pof .355 plus TWICE the Federal wall thickness (because the case walls SURROUND the bullet) totals to .355" +(2x.011") = .377". But the taper crimped OD is .376", which means Federal is applying .001" crimp across the total diameter, which means .0005" actual crimp on each arc of the wall. NOT .001" crimp on any arc of the wall. So, this is indeed a pretty mild crimp.

Someone pointed out that the 9mm case tapersto a smaller ID as you travel down the case wall, but when taking the ID measurements on both the Federal cases and my cases, I always make sure that I have the caliper jaws in deep enough to go to the depth that the bullet is seated at. So, no, the actual ID is NOT smaller than what I am measuring.

Next, I tried dropping first several of my completed unfired cartridges down the WRONG end of a 9mm go-nogo cartridge case gage. Interestingly, the cartridges drop in until the CASE, not the ogive of the bullet, catches on the case gage. Same with the Federal cartridges. Tis makes sense when you think about it, because the end of the case gage has to be able to handle bullet ODs on the hIGH end of the SAAMI standard, not just average or smaller OD bullets.

But this raises an important point: If you try to literally measure from base to ogive on any tool that uses a gage opening capable of accepting any in-spec 9mm bullet diameter, your efforts will be futile, becsause just as in my testing, the tested cartridges will drop in until their CASES hit the gage.

So, this implies, if I am correct, that the only practical way to measure consistency of bullet seating, using ANY tool you make or buy, is to measure from the base to some consistent diameter point on the ogive that is slightly smaller than the maximum diameter of the bullet, and just make sure that this measurement is consistent, or darn close to being consistent, for all the cartridges you test.

I emailed Hornady though to ask what the slope of the HAP coned ogive is. If they give me that, I can then calculate what the actual true base-to-ogive measurement would be. That, coupled with an accurate plunk and rotate test, provides guidance for calculating the "jump" in whatever firearm you load the cartridges into.


Jim G

Hornady replied. They said that the ogive angle on the 115g .355" HAP is 15 degrees.

Jim G

 

[Otto]

I found some good bullet seating information on the Redding website, that applies to the Redding Competition Bullet Seating die I have ordered:

(the bolding of some of the text is by me, not Redding)

"
There are many factors that can cause bullet seating depth to vary when using our Competition Seating Die. First, make sure you're comparing bullet seating depths correctly. You cannot check bullet seating uniformity by measuring cartridge overall length off the bullet point. You must use a bullet comparator, like our Instant Indicator, to compare bullet seating depths. A comparator contacts the bullet at the bore diameter contact point. This is important, as bullets can vary slightly in overall length.

We have designed the seat stem in our Competition Seating Die to contact the bullet ogive as far down as possible. Our Competition Seating Die features a bullet guide that is only .0005-.001" larger than bullet diameter. This tight fit between the bullet guide and bullet ensures that the bullet is seated straight in the case neck. It also limits how far down the ogive the seat stem can contact the bullet(See also my note below). If the ogive of your bullets aren't uniform, you may notice a slight difference in seating depth. Generally, this isn't a problem as modern bullets are very uniform. In rare instances, when using inexpensive bulk bullets, you may find that the bullets were made on several different machines and then blended.
"

My note: What "It also limits how far down the ogive the seat stem can contact the bullet" means is that the seating insert not only does not contact the tip of the bullet, it actually contacts the bullet at pretty much exactly the point where the the ogive diameter becomes the outer bullet diameter that actually contacts the rifling. This is exactly the point you want to control to create the base-to-ogive length that works best in your firearm's chamber.

Jim G

The Redding competition seating die does not make contact with the ogive of a HAP 115gr bullet. The force required to seat the bullet is exerted on the uppermost tip.

 

[JimGnitecki]

The Redding competition seating die does not make contact with the ogive of a HAP 115gr bullet. The force required to seat the bullet is exerted on the uppermost tip.

Hmm, not according to Redding itself. Here's a copy of my email correspondence with them:

James,
They will seat on the ogive



Don Parker
[email protected]
Redding Reloading
1089 Starr Road
Cortland, NY 13045
(607) 753-3331

On Feb 25, 2021, at 9:53 PM, Redding Reloading Equipment: reloading equipment for rifles, handguns, pistols, revolvers and SAECO bullet casting equipment <[email protected]> wrote:

Message Sent From Redding Reloading Equipment: reloading equipment for rifles, handguns, pistols, revolvers and SAECO bullet casting equipment

Thiswas in response to my question below:

Subject: Insert shape in 9mm Comp Seating Die?
Message: In your 9mm Competition Bullet Seating die, does the bullet seating insert bear on the OGIVE of the bullet or the TIP of the bullet? I am asking because my Dillon seating die bears on the tip of my 9mm 115g Hornady HAP bullet, and tip length varies, so I get inconsistent base-to-ogive measurements.


Jim G

 

[fxvr5]

The Redding competition seating die does not make contact with the ogive of a HAP 115gr bullet.

It does on mine. In fact it only contacts the ogive. It does not contact the tip.

The force required to seat the bullet is exerted on the uppermost tip.

Not on mine. The 115 HAP tip does no contact a flat surface.

 

[JimGnitecki]

Otto, if your specific setup DOES bear on the tip versus the ogive, it may be that you have a similar problem to the one I have: the specific combination of seating insert shape and bullet shape is a "bad" one, where the tip is too wide, or the ogive rate of tapering down from the shank of the bullet is too fast. In fact, I THINK I recall reading on the Redding website, maybe in a tech support section or FAQ section, that Redding offers a different seating insert for use with VLD bullets, for this very reason. I'm sorry I cannot recall exactly where I saw that.

Jim G

 

[Otto]

Using a fluorescent marker and ultraviolet light, it's pretty obvious that the seating stem does not make contact with the ogive.
Unlike RCBS, Redding does not make custom stems. You'll have to buy a 9mm stem from Redding and modify it yourself on a lathe to mate perfectly with a HAP.

 

[JimGnitecki]

Using a fluorescent marker and ultraviolet light, it's pretty obvious that the seating stem does not make contact with the ogive.
Unlike RCBS, Redding does not make custom stems. You'll have to buy a 9mm stem from Redding and modify it yourself on a lathe to mate perfectly with a HAP.


View attachment 981355

Otto: First, let me make sure I understand the photo. Is the bright green band where the insert is making contact with the bullet?

If so, Redding is technically correct, as the insert IS seating on the ogive. "Ogive" of a bullet is defined as the entire portion between the shank and the meplat ("tip").

I imported your photo into the Photos app on my MacBook, and cropped the photo down to just basically showing cartridge alone, and then also sharpened the image. I can clearly see that the green band is somewhat below the meplat. So IF the green band is the area of contact, then the Redding seating insert is indeed seating via the ogive.

HAP Bullet Contact With Ogive - Cropped - 1

• JimGnitecki
• Feb 28, 2021

Now on a bullet that has a ROUNDED profile (UNlike the HAP), I would argue that contacting the bullet so close to the meplat increases the possibilities for error since on a rounded bullet the surface area in the portion of the ogive that close to the meplat is going to be affected by its proximity to the meplat, since the "change" from ogive to meplat on a rounded bullet is "pretty blurry".

But on a bullet like the HAP, where the transition is an abrupt change from a 15 degree straight slope to a hollowpoint meplat, as long as you contatc anywhere on the ogive, you should get pretty good consistency.

Still, I would have liked to see the insert contact the ogive a bit lower than it apparently does, just to be SURE of being clear of any transition zone.

I guess I will need to see how well it works in actual use, so will reserve judgment.

But thanks for pointing this out.

PERHAPS one of the reasons the Redding insert grabs this pistol bullet so high on the ogive is because the insert and entire die were designed to seat RIFLE bullets, before masochists like you and me decided to try it for pistol bullets. Rifle bullets tend to have much longer and more slender ogives for ballistic coefficient and other reasons, so a Redding die set up for a rifle cartridge might indeed grab the cartridge significantly lower on the ogive.

Jim G

 

[JimGnitecki]

I just checked the available "play" between the Dillon XL750 toolhead and the XL750 frame. It is hard to measure because the toolhead slips horizontally into the frame via a tongue and groove arrangement that is dimensioned in a way that makes it impossible to slip a regular size feeler gage into it, and very difficult to get just even the corner of a feeler gage into it.


But by using the corner of the gages, i was able to slip a .0015" gage between the toolhead and frame, but not a .002" gage.


So, at least in theory, it is possible for this clearance to contribute up to .0015" of variation to COAL under the right conditions.


"Right conditions" likely means NOT when all the stations are occupied with cases on the upstroke of the platform (because then the toolhead is simply pushed upward removing the clearance, which is also how the individual dies are set up and locked in). But, when NOT all the stations are occupied, and especially when ONLY the bullet seating die station is occupied, the toolhead can be "tilted" upward by the bullet seating load perhaps more than it could be with all the stations occupied.


I thought about clamping the toolhead to the frame to see if it does make a discernible difference, but the rounded contours of the frame, coupled with the tongue and groove setup, make that look impossible, at least on cursory analysis.


However, UniqueTek sells those "clamping kits" online. The kits apaprently equip you to drill & tap the 2 existing holes in the Dillon toolhead to accept small Grade 8 bolts that the kit includes. Then, you can slide the toolhead in, raise the platform to ensure that all the dies in use, and their current cases, are in their fully utilized position, and then bolt the toolhead up to the frame. No movement of the toolhead relative to the frame is then possible.


The kit cost seems like a lot of money when the $37 cost is inflated by shipping, and US to CDN currency exchange, and the credit card premium charge on the exchange rate, but I ordered it and will see if it really does make a difference in actual use.


Recall that I have already discovered that the extreme spread on the COAL is .010", and the HAP bullets themselves contribute .007" of that via tip length variaiton. So, by going to the Redding Competition seating die that seats on the ogivw versus the tip, and installing these clamping bolts, in theory at least I can remove up to .007" + .0015" = .0085" of the COAL variation. As other experienced and wise skeptics have pointed out, "We'll see".


Jim G

 

[JimGnitecki]

The Redding Competition Bullet Seating die arrived today. I pulled the bullet seater out of it and examined it. It has a sloped inner wall and its inner "end" is OPEN, so that a bullet tip can pass upward right through it, forcing the seater to capture the bullet via its ogive - IF the bullet shape is a typically long and narrow RIFLE bullet.

But the Hornady HAP PISTOL bullet has that cone shaped ogive running at a steady 15 degree slope to a rather WIDE hollowpoint. I wondered if the hollowpoint meplat could in fact pass through the center hole at the top of the seater. So, I measured.

Measuring the diameter of that hole in the upper end of the insert was easy. My dial caliper said pretty consistently that the diameter of that hole is apprxoimately .230".

But measuring the HAP meplat (hollowpoint top) diameter is very difficult, because you are trying to measure the diameter right where the 15 degree sloped ogive ends and the hollowpoint begins. If you hold the caliper just a bit higher than the true "knifepoint" intersection, it slides off over the hollowpoint. If you hold the caliper just a bit below that knifepoint intersection, you get a too large reading because you are measuring below the point where the ogive has begun, and where it is therefore wider.

But I persevered, and as near as I can measure, the top of the ogive is approximately .220". So, IF THE BULLET SHANK IS PERFECTLY ALIGNED WITH THE SEATER, the seater will indeed capture the bullet via the top portion of its ogive.

Since the Redding Competition die has a very long "guiding cylinder" that grabs the bullet in its case and reatracts upward with the bullet and case as you lift the bullet into the seating insert, AND since Redding instructs you as part of the die setup to match your case bell OP to that cylinder ID, in theory, if the bullets don't vary much from perfection in terms of diameter (and they don't, per actual measurements), the shank of the bullet should indeed be aligned with the seater.

But, I do obviously wish that the hole in the die insert was larger in diameter, so that I could be sure that the seater grabs the ogive further down the ogive, so that small variances in the bullet do not result in the seater insert grabbing a piece of the wide hollowpoint meplat. I have to examine the insert much more closely to see if it might be possible to drill out that opening so it is wider.

IF that is possible, then I would feel more comfortable about the certainty of catching the ogive versus a portion of the meplat, even if there is slight bullet imperfection or misalignment. Also, grabbing the bullet ogive at a lower point would mean more surface area of contact, which also reduces any effects of minor variances in the bullets.

Hmmm. Need to to study that bullet seater more closely.

Any opinions or suggestions?

Jim G

 

[JimGnitecki]

I emailed Redding and this is the reply I received:

"James,
If the taper portion is only .150-.160” in the stem but .1795” of the bullet is in the stem then we are contacting along the ogive and not the meplat. We do not have any specific stems to a particular bullet and for the 9mm that is the only stem we have. What I have done and has worked very well is to use 4-5 bullets to lap the profile into the stem. Take a bullet and chuck it into a drill. Coat along the ogive with lapping compound and as you spin the bullet, hold the stem to it. The same bullet can usually be recoated about 3 times before the jacket gives way. Replace with a new bullet and repeat. As you progress and it usually takes about 5 bullets you will see the contact portion increase on the jacket of the bullets. As even similar bullets will vary in profile slightly this will lap that profile of that HAP bullet right into the stem.



Don Parker
[email protected]
Redding Reloading
1089 Starr Road
Cortland, NY 13045
(607) 753-3331"

 

[JimGnitecki]

Ok, I might have figured out where the COAL variation is coming from, but it's a combination of good news and bad news:

The Hornady Bullet Comparator arrived, so I inserted the .338" insert (closet insert that is still smaller than bullet diameter), and I set it up on my digital caliper to measure the distance from base of that .338" point on the ogive.

Then I used this setup to measure a sampling of 20 completed cartridges out of 2 boxes of 50 each, selected as follows, in the order in which they were made:

Cartridges number 1, 6, 11, 16, 21, 26, 31,36, 41, 46, 51, 56, 61, 66, 71, 76, 81, 86, 91, 96

The good news is that the extreme spread (ES), IF I disregard cartridges 1, 6, 96, is that the extreme spread was only .0025". Remember, this is in cartridges whose COAL, measured from base to TIP of bullet, varies with an ES of .010". This tells me that the base to ogive (BTO) ES variation is only .0025" for these cartridges which I can probably view as "representative". The range of measurements for these cartridges was .9260 to .9285".

But the bad news is that cartridges 1, 6, and 46 were awful.

No. 1 was .9175

No. 2 was .9230

No. 46 was .9420 !!

The extreme spread here is .0245" (24-1/2 thousandths!!)

But more good news: Notice that these were among the FIRST and LAST cartridges made. I started with my Dillon XL750's stations all empty and ended with them all empty, as I needed to set up the powder drop and bullet seating height for the test, and I don't like to make a bunch of cases with varying degrees of completion, nor leave any on the press, because that's a prescription for later potential errors.

But it looks like the guys that say to never make ammo on a Dillon press without ALL the stations being occupied are correct.

To test this more fully, I also then measured cartrudges 97, 98, 99, and 100 - the very last cartridges made. Two of them too had very extreme measurements.

I can't yet prove, but think I will soon be able to prove, that this is a result of the toolhead "tilting" and moving vertically with the unbalanced loading that results when only 1 or 2 stations are occupied.

I of course suspect now that I have had these extreme cartridges occuring before, but since I had never taken the time to select a large enough number of cartridges to quality check individually, or to even keep track of which cartridges were made first and last, I simply had not yet "found" any of them. I had wondered about some of the ES velocities that the Labradar picked up, but thought they were just the result of a non-ideal load. Up to now, I was testing multiple different amounts of powder in the cartridges. These 100 rounds were the first ones made with ONLY one specific weight of powder in them - the weight that my testing had shown was the most consistent.

During the load development process, I had also as a matter of policy disassembled any of the first cartridges made that were not good enough during the COAL measurement, the gaging with a standard 9mm cartridge gage, or in the plunk & rotate test. I had in the meantime filled all the press stations. So, this length variation problem had not manifested earlier.

I fully understand why Dillon has the clearances it does in its toolhead. First, you have to be able to slide the toolhead in and out for caliber changes. Secondly, the toolhead is able to shift sideways and tilt a bit when an individual case at any of the stations has a slight shape or alignment issue. For example, this ability of the toolhead to move a bit saves the day when a case at the sizing station would otherwise hang up and be crushed, and it's probably rescued more than one cartridge where the bulelt and case were not perfectly presented to the seating die.

But, a s I have stated in my other post about the "bolted-in" Armanov toolhead and its "free floating" die lockrings, it MIGHT be a superior strategy to FIX the toolhead firmly for no movement, and instead allow the sizing die and the bullet seating die to move a bit HORIZONTALLY when the presentation to the sizing die and/or seating die is imperfect. That's why I have an Armanov kit of parts coming from Slovenia (It made it all the way to British Columbia in Canada within TWO DAYS, and just now needs to go the last 60 miles or so!! Why does it typically take two WEEKS from the US to Canada ???)

So based on the above, here is what I am planning to do:

1. Never run the press in produciton mode without ALL the stations being filled

2. Replace the Dillon toolhead with the bolted-in Armanov toolhead, and set up all the dies from scratch using the floating lock rings on at least the sizing die and bullet seating die, and maybe even the crimping die. (I THINK it would be a bad idea to use it on the powder station because the Dillon powder drop stroke is very specifically tied to the mechanical rod from the powder drop mechanism to the FRAME of the Dillon press, so you cannot be sure if you are getting a full powder drop if the die moves)

For you masochistic types who want to see all the data from the test, here it is:

Bullet no. / measured length base0-to-.338 gage


1 .9175

6 .9230

11 .9275

16 .9275

21 .9280

26 .9285

31 .9260

36 .9270

41 .9275

46 .9260

51 .9270

56 .9270

61 .9260

66 .9265

71 .9285

76 .9280

81 .9280

86 , 9280

91 . 9275

96 .9420

97 .9265

98 .9270

99 .9160

100 .9165


I THINK I had these all placed in the ammo boxes in correct order, and transcribed them correctly, but if I made any errors, I apologize.


Jim G

 

[higgite]

FWIW, I eliminate a lot of the COL/BTO variance in the last 4 cartridges in a run by sizing a spare case when seating the bullets. I have an RCBS Pro 2000, but the same principle might apply to your Dillon.

 

[JimGnitecki]

FWIW, I eliminate a lot of the COL/BTO variance in the last 4 cartridges in a run by sizing a spare case when seating the bullets. I have an RCBS Pro 2000, but the same principle might apply to your Dillon.

I like that idea, but then when I get around to USING that spare case in an actual production run, OR just putting it in the sizing die while seating a bullet in the seating die, it will not exert the same upward force - and in fact, being already sized might not exert ANY upward force, so then the seating of that FUTURE bullet becomes variant.

And I hate to waste cases by not using those cases later, as I sometimes take quite a while to get the bullet seating just right, and each attempot represents another wasted case.

That's one other reason to see if the Armanov fixed toolhead with floating dies takes away these "start run" and "end run" issues. I'll see.

Jim G

 

[Walkalong]

The extreme spread here is .0245" (24-1/2 thousandths!!)

How do you manage to get such a large spread?

 

[JimGnitecki]

How do you manage to get such a large spread?

I do not know. But there it is. And it appears to occur only at the start or end of a run of cartridges on the press, strongly suggesting that it is triggered by empty press stations. What else could do that?

Jim G

 

[JimGnitecki]

An idea suggested to me to "paint" the meplat of a bullet with a marker or paint and then pressing it onto a piece of paper did not work well with a marker, but worked fine with black model paint! That coupled with another idea I had to measure at least approximately the diameter of the narrowest part of the cone in the seating insert, ended up answering the question of "Does the Redding die seat the bullet via ogive contact or via tip contact?". It's the ogive, as Redding promised.

Here's how I determined that:

I painted a bullet's tip with black model paint, and then imprinted the paint onto a piece of white laser printer paper. After a few tries, with too much paint, i restrained the amount of paint and I got a very clean image on the paper. The meplat on that bullet is .1775" in outer diameter. Since Hornady bullets are pretty consistent in everything except tip height, I think it's representative.

Then, I remembered that I have a fairly large set of drill bits with relatively small increments in size from one bit to the next. I found 2 bits whose shanks were useful for this experiment.

One of the shanks, .203" in diameter was small enough to go through the narrowest part of the cone in the insert, and continue on into the lengthy "tunnel" beyond that narrow point.

The other bit shank, one size up at .218" diameter, was a little too large in diameter to even get close to that narrow point. This 2nd drill bit proved to be unnecessary.

Since the meplat diameter is .1775" and the narrowest seating cone diameter is larger than at least .203" (since the .203" bit shank went through with no contact at all), the Redding seating insert does indeed catch the bullet by its ogive, and not by its tip.

So, if I can resolve the toolhead movement issue I identified earlier, via the Aramov bolted toolhead and floating die lock rings, I should be able to get the base-to-ogive extreme spread to .0025" or BETTER.

Plus, I'll be able to adjust the die far more easily and consistently to attain different amounts of bullet "Jump" to the rifling, via the micrometer adjustment on the Redding die.

This sounds promising to me.

Jim G

 

[Walkalong]

strongly suggesting that it is triggered by empty press stations. What else could do that?

That does make a difference, especially if you size while loading, but even then I have never had that large of a spread. I can only assume the seater stem is a poor fit.

 

[JimGnitecki]

That does make a difference, especially if you size while loading, but even then I have never had that large of a spread. I can only assume the seater stem is a poor fit.

Yes, the Dillon seater stem is a very poor fit for this specific bullet. It is clearly grabbing the tip instead of the ogive, and that means at least an ES of .007" in COAL by itself, because that's how much the bullet tip (not ogive) height varies. Given the actual total ES of up to .010" I have experienced, and the .0025" ES I get by measuring from base to .338" on the ogive, it is clear I need to change from that Dillon insert to the custommade insert that one of our forum members has made for me and has mailed to me, or to the Redding Compeition Bullet Seating die, as each of those seats on the ogive.

The Redding die has the advantages of
(1) micrometer adjustment that enables ACCURATE varying of the base-to-ogive measurement, and thus accurate variation of the bullet "jump" to the rifling, and
(2) Very precise control of coaxiality of the case and bullet, via the very snug and deep "tube" surrounding the case and bullet during the entire bullet seating process.

The custommade insert for the Dillon die, from my forum friend, has the advantage of costing MUCH less, and also being specifically shaped to match the slope of the ogive. This ensures that contact between the insert and the ogvie will be over a much broader total area versus one thin line of contact around the circumference of the insert's internal diameter. In theory at least this prevents marking of the bullet at the line of contact, and smothers the effects of minor bullet variances.

In fact, Redding Customer Service says (see post #60 above) that I can use lapping compound, a bullet in a drill press, and a drilled block of wood to lap the Redding insert to exactly match the bullet to THEIR insert (the wood is to keep the insert exactly upright while it is being lapped to the bullet shape). Since this process is fairly ripe for errors in setup and/or technique, and will require multiple bullets (the lapping compound apparently wears the jacket off if you don't replace "the lapping bullet' often), I'll probably not undertake this unless the Redding insert as delivered still produces more BTO variation than I want.

In fairness to Dillon, I don't think the "truncated cone with hollowpoint on top" is necessarily a bullet shape that the Dillon folks anticipated when designing the die.

Jim G

 

[higgite]

I like that idea, but then when I get around to USING that spare case in an actual production run, OR just putting it in the sizing die while seating a bullet in the seating die, it will not exert the same upward force - and in fact, being already sized might not exert ANY upward force, so then the seating of that FUTURE bullet becomes variant.

And I hate to waste cases by not using those cases later, as I sometimes take quite a while to get the bullet seating just right, and each attempot represents another wasted case.

That's one other reason to see if the Armanov fixed toolhead with floating dies takes away these "start run" and "end run" issues. I'll see.

Jim G

I just use the same case over and over and it works. Quit thinking of reasons not to try it and just try it. At least you'll know if it works for you or not.

 

[JimGnitecki]

I just use the same case over and over and it works. Quit thinking of reasons not to try it and just try it. At least you'll know if it works for you or not.

I WILL try it!

Jim G