I'm fairly new to reloading handgun ammo and am trying to work out the kinks. One of them is that I get inconsistant seating depths when seating the bullets. Here are the particulars:
bullet: 115gr RN x-treme (plated)
powder: W-231 @ 3.8gr
dies: Hornady Custom Grade Titanium Nitride
I set the seating die to seat the bullets at 1.155 (OAL is 1.169). After seating 5 bullets I check each one with a caliper. Most seat depths are ~1.155 + or - a thousand or two. However, every once and a while one will seat @ ~1.165. See pics. I check for grit in the shell holder, make sure the seating adjuster isn't walking, insure the primer is fully seated so its not messing with the caliper, - but all is good and there is no slop in the press. And the caliper is good too - no slop in it. Out of 100 rounds loaded today 80 were between 1.153 and 1.158 and 20 anywhere from 1.150 to 1.165.
but some are longer or shorter:
View attachment 1000058
A progressive press (Dillon) may have up to .010" variation in col. If a die contacts the shell plate, it may acts as a stop. The deck height (.125") may not be the same at each station. Each round from that station may have a different oal.
Two suggestions that will really help...
All the best.
- Place the Dillon calendar so that it's behind you.
- Consider using a case lube.
Why would a seating die contact the shellplate...?
Even the sizing die on a "straightwall" case won't (shouldn't) touch the shellplate.
While the deck height may not be the same at each station, the seating station would always be the same, as the round is only seated at THAT station.
Change to "Any Die".If a die contacts the shell plate , it may acts as a stop.
Even the sizing die on a "straightwall" case won't (shouldn't) touch the shellplate.
While the deck height may not be the same at each station, the seating station would always be the same, as the round is only seated at THAT station.
Not so for presses that rotate a different “deck” into position under the seating die with each pull of the handle.While the deck height may not be the same at each station, the seating station would always be the same, as the round is only seated at THAT station.
The shell plate gives instead of pushing the case all the way in the resizing die.
From my new RCBS 2021 9mm die set instructions.
One of them is that I get inconsistant seating depths when seating the bullets
Also, on the machine I use, when sizing ( let's use .223 as an example) the sizing die does not completely contact the shellplate.
If it does, then I get too much "bumping" of the shoulder.
The RCBS carbide dies & instructions seem to have changed over the years.
I have experienced this myself loading 9mm. When I load 44 mag or special this does not happen! I use a lee 4 hole turret press (love it by the way) all my dies are also lee. I have wasted so much time measuring every damn 9mm because of this issue. I have come to a point that I "almost" dont care anymore with 9mm being off a little. If it don't visibly look off I'll let it pass. Havent had a problem, but I too get a flyer every now and then. I dont think there should be any issue other then the occasional flyer (if that even causes that) with 9mm, a little to deep or not deep enough isn't gonna blow up a 9, so at least it wont kill us... Frustrating for sure though. I hope there is a sure answer in here.A second pull/try does not seat it any deeper, nor does spinning it 90 degrees. It's quite strange. Right after one that seats long, the next several will be right back at ~1.155. I'll crank mine down to ~1.130 as Walkalong suggests.
I use berrys and also have this issue with 9mmIt's most likely the bullets. I just got a shipment of Berry's that have a different ogive reading than the lot I boughts 6 months ago, and there is variation between those.
I've only done round nose so far.Jim, do you have this problem with flat points or only round nose?
Concerning mixed brass and different case lengths, should that really matter? I would think the only factor involved is the seating plug itself. When set to a certain depth, does it matter how much of that depth is the length of the brass? It would seem to me that if one shell case is a bit longer than another, the bullet will just seat deeper into the longer case when the press arm is lowered all the way. But the OAL should be the same if everything on the press is tight and the seating die ring is tightened. Still scratching my head.Different dies= Different results. In 45acp range brass, the neck tension can be very different, but has no effect on finished col.
9mm Luger
I found range brass trim length is loadable with .012" difference between shortest to longest. When New RCBS dies are adjusted correctly.
One brass was longer then .754" SAAMI maximum by .002" , but chambered & fired ok. Then it got trimmed.
No sorting range brass for me, but each gets checked closely. No maximum loadings. 700X- 3.2 grs- Lee 356-120-TC cast bullet. Sized to .3568" Wspm primer. OAL 1.045"
But the OAL should be the same if everything on the press is tight and the seating die ring is tightened. .
The amount of taper crimp will be different with untrimmed brass. But online, no one trims 9mm brass, so they say. If i find brass that is over SAAMI maximum, its getting trimmed.Concerning mixed brass and different case lengths, should that really matter? I
https://support.leeprecision.net/en/knowledgebase/article/seating-depth-variationsAnother possible cause for bullet seating depth variation is seating and crimping at the same time when trying to apply a firm crimp to untrimmed cases. Variation in case length also causes variation in the amount of crimp applied. Long cases get a heavier crimp than short ones. When seating and crimping at the same time, the crimp is formed as the bullet is seated into the case. The crimp will form sooner on a long case, and therefore the bullet will not be seated as deeply. The solution is to seat and crimp in a separate step and/or trim cases to a uniform length.