Seating Die Marking Bullets

Sniffer

Sniffer

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I have a Hornady 9mm seating die that leaves marks on my bullets when they are seated. This is on a Dillon 650 and the case mouths are flared slightly by the case powder dropper (just enough to allow the base of the bullet to rest there in the seating position)

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I took the die apart and looked at the seating stem and dont see anything abnormal. I think this issue is a component of the lip of the seating stem being focused on a small area on the bullet and causing a mark as it applies enough force to squeeze the bullet into the case.

The seating die is quite straight and as mentioned only a very small / thin area makes contact with the bullet, if the die were shaped like the bullet it would speed this force across more surface area which would eliminate the marks (I know it isn't really possible for the manufacturer to do this due to the large range of sizes / shapes of bullets on the market)

I have read about using lapping compound or similar and using a bullet in a drill to "shape" the die surface where it contacts the bullet to help spread the seating force out / reduce the marks.

Has anyone successfully done this? Did it work? Any other solutions (beyond buying a new die;)).?
 

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Way to much seating presure, flare the case a bit more.

Ive also done this personally by having the seating die screwed to high but the seater bottomed out in the die to compinsate. Basically the case wasn't going far enough into the die body and the bullet was getting pushed into an unsuported case... i bet the mark is on the same side as opening on the shell holder isn't it?
 
OP - you seem to write as if a bit hesitant to alter your seater stem - was an alternative that I read, but never tried - smear release agent on bullet - several goops of epoxy into the seater stem "cup" - use the bullet as a form and set in there to create a "cast fit" to that bullet shape. Once epoxy sets up - basically have a "custom" seater stem for that bullet shape - is about how well can you keep axis of bullet aligned with axis of the seater stem with that epoxy is setting - so that you end up with "straight" seating arrangement. I would think that "keeping it straight" would be about same challenge to abrade that seater stem to fit??

I am not familiar with your tooling, and I have not reloaded for handgun - but I got similar marks on centerfire rifle bullets - in my case, as a result of extra pressure required because the case mouth walls were too thick for the bullet that I was using, and also (I think) the expander ball from the sizing die was a bit too small for those bullets. I must say that I did not see much difference in holes on targets from the bullets with the circular mark on them - and I eventually went to a different brand / different weight of bullet and the issue went away, so I never did go back for detailed investigation. As posted above - is likely that the marks partially caused by excessive seating pressure - probably need to figure out why is that needed - might not be the marks affecting performance, but maybe the cause of the marks are also causing performance change - if you are getting any of that.

I am not so sure about "drilling" as you describe - I am just too wobbly and shaky any more to try that - I would likely chuck that seater into my lathe - use the tool holder to cut or lap to shape - at least I would be more likely to get a concentric result, that way, as opposed to using a drill. Is no doubt that it has been successfully done by hand - if I ever could do that, is no doubt that I can no longer do that any more.

I think that I still get those marks when loading Speer 110 grain #1835 in my 30-30, using the Lee Pacesetter die set - is never intended as a "super precise" loading, so I do not worry about it.
 
Last edited:
LordEvilPepper said:
Way to much seating presure, flare the case a bit more.

Ive also done this personally by having the seating die screwed to high but the seater bottomed out in the die to compinsate. Basically the case wasn't going far enough into the die body and the bullet was getting pushed into an unsuported case... i bet the mark is on the same side as opening on the shell holder isn't it?
Click to expand...

Mark is uniform all the way around the bullet.

I will try more flare.
 
I know it is a pistol and accuracy is relative but would these marks affect accuracy?

I'm guessing it could / would, if the mark isn't uniform all the way around it could cause the bullet to be unbalanced as it spins?
 
I could not help notice in your second picture - if you are worried about bullets being balanced - picture makes it look like a gouge / piece of jacket missing along right side of that bullet? Along the taper between the nose tip and the bullet shoulder?? Is no doubt that you could improve the "looks" by having better fit between your seater and that bullet - but about only you can tell us whether those marks / deformity make a difference on target holes for you??
 
There probably are no problems with your setup or technique, and you have diagnosed the issue and root cause correctly. The bullet is being marked because the seating force is concentrated on the small area of contact between the die and bullet. Die manufacturers cannot match a seater to every bullet shape, so they use a compromise profile. Some brands provide a couple of different seater shapes in each die set to try to compensate for this.

Your options are modify the seater to fit your bullets, change your bullets to match your seater, or live with it.

I shoot many loads that have some kind of visible ring on the bullet from the seating operation.
 
Sniffer said:
I know it is a pistol and accuracy is relative but would these marks affect accuracy?

I'm guessing it could / would, if the mark isn't uniform all the way around it could cause the bullet to be unbalanced as it spins?
Click to expand...

Ummm no, in most cases.

I have a bullet seater that leaves a small ring on my 223rem seater stem. This rifle, a Tikka T3X regularly shoots in less than a half minute of angle, out past 400 yards with bullets ranging from 55-92 grains

I replaced the stem seat head and polished the inside edge before doing so. The ring was still there.

I finally machined out the seat head until it was only bearing on the tip of the bullet. Didn't make any difference to accuracy at all.

OP, if your bullets are seated true to the center of the axis of the cartridge, with minimal .002 run out, that mark on the ogive won't have any affect of consequence.

Now, what you really have to worry about is whether or not the bases of your bullets are being deformed as they are forced into the case mouths.

Many shooters don't bother to slightly bell the case mouth and shave a bit off the base of the bullet when seating. This does cause some issues with accuracy. Not so much with pistols but it's quite noticeable with rifle loads.
 
^ to reinforce that, I did some testing years ago where I purposely damaged some bullets to gauge the effect. Damage to the tips caused very little if any accuracy loss at shorter ranges (under 200m) while damage to the base caused big changes in group size.

I have never seen the OPs issue caused by anything other than insufficient flare. Sure he could modify his die, or he could just make it easier for the bullet to go in by lowering the resistance being produced by the case. I went through this a couple times when learning the ins and outs of my Dillon.
 
Potashminer said:
I could not help notice in your second picture - if you are worried about bullets being balanced - picture makes it look like a gouge / piece of jacket missing along right side of that bullet? Along the taper between the nose tip and the bullet shoulder?? Is no doubt that you could improve the "looks" by having better fit between your seater and that bullet - but about only you can tell us whether those marks / deformity make a difference on target holes for you??
Click to expand...

For some reason that picture does make it look like there is a gouge or similar but it must be a reflection or something - there are no gouges etc except for the ring from the seater.
 
Potashminer said:
OP - you seem to write as if a bit hesitant to alter your seater stem - was an alternative that I read, but never tried - smear release agent on bullet - several goops of epoxy into the seater stem "cup" - use the bullet as a form and set in there to create a "cast fit" to that bullet shape. Once epoxy sets up - basically have a "custom" seater stem for that bullet shape - is about how well can you keep axis of bullet aligned with axis of the seater stem with that epoxy is setting - so that you end up with "straight" seating arrangement. I would think that "keeping it straight" would be about same challenge to abrade that seater stem to fit??

I am not familiar with your tooling, and I have not reloaded for handgun - but I got similar marks on centerfire rifle bullets - in my case, as a result of extra pressure required because the case mouth walls were too thick for the bullet that I was using, and also (I think) the expander ball from the sizing die was a bit too small for those bullets. I must say that I did not see much difference in holes on targets from the bullets with the circular mark on them - and I eventually went to a different brand / different weight of bullet and the issue went away, so I never did go back for detailed investigation. As posted above - is likely that the marks partially caused by excessive seating pressure - probably need to figure out why is that needed - might not be the marks affecting performance, but maybe the cause of the marks are also causing performance change - if you are getting any of that.

I am not so sure about "drilling" as you describe - I am just too wobbly and shaky any more to try that - I would likely chuck that seater into my lathe - use the tool holder to cut or lap to shape - at least I would be more likely to get a concentric result, that way, as opposed to using a drill. Is no doubt that it has been successfully done by hand - if I ever could do that, is no doubt that I can no longer do that any more.

I think that I still get those marks when loading Speer 110 grain #1835 in my 30-30, using the Lee Pacesetter die set - is never intended as a "super precise" loading, so I do not worry about it.
Click to expand...

Only issue with this idea is that I load several different 9mm bullets (flat nose, hollow point etc)
 
If you buy a Dillon seating die you can flip or switch out the insert for different profiles. I'm still very confident your issue will be solved by adjusting your die.
 
Sniffer said:
Only issue with this idea is that I load several different 9mm bullets (flat nose, hollow point etc)
Click to expand...

Good point - as mentioned, I never did load for hand gun - only centre fire rifle - and I only have one seater cup for each seater die. But looking in books - hard to imagine how handgun re-loaders could do that - say using wadcutter bullets, semi-wadcutter bullets and round nose - not likely even noticed with "hard ball" types - but I suspect might show up with the lead cast bullets? - I would suspect they need different shape seating cup for each? Likely, as posted above - addressing whatever is making you have to use excess seating pressure, would reduce the markings on the bullet shape - but in the end, might want to find out for you, if that is a "looks" (cosmetic) thing, or an "accuracy" (results) thing.
 
I would not leave it the way it is. Try more flare. The close up photo looks like the bullet jacket is scraping. Looks like a piece of brass or copper is even pinched in between the bullet and case. I have zero troubles with that bullet and Lee dies. I flare mine enough so the bullet sits square before being seated. Then hit it with the Lee crimp die.
 
Lead hammer said:
I would not leave it the way it is. Try more flare. The close up photo looks like the bullet jacket is scraping. Looks like a piece of brass or copper is even pinched in between the bullet and case. I have zero troubles with that bullet and Lee dies. I flare mine enough so the bullet sits square before being seated. Then hit it with the Lee crimp die.
Click to expand...

See post 14.

I will try more flare when I load next, and I do a light crimp (barely perceivable but it makes the edge of the case less "square" which should help with feeding / reliability).
 
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