9mm OAL not consistent

0.005" is pretty common with 9mm depending on what bullets/brass combo your using. If you measure off the ogive you will be within 0.002"-0.003" or less. On AP presses it helps to keep all stations full and doing equal work. Mixed brass will give you a larger spread.

I do the crimp as separate step, gives me the best results.

Check the fit of your bullet profile with the seating stem. I've had bullets that don't fit the seating stem very well that end up resulting in varied OAL's. You can remedy this with hot glue and making a custom fit stem to the bullet profile..

It really helps to sort your brass for headstamp with 9mm, say your seating a bullet for a Remington case which is thinner and springier than a PPU and not as hard, The bullet seated in the Remington brass will seat deeper due to less case resistance than the PPU will. That will play hell with a progressive.

On a single stage you would think they have to be all the same no matter what, but the difference in the case brass alloy will change things regarding how the bullet seats.
There is nothing wrong with PPU cases as long as they are all PPU they will be fairly consistant.

You could also be flattening the nose of the bullets on some of the stiffer cases also, which changes the ogive location on each round loaded.

I sort all my 9mm brass because of this and chase the minimum taper crimp I can get away with.

That’s a pretty large variation in seating depth for a single stage. Even my LNL AP does much better at +-.003”, with mixed brass and not being fussy about anything. I’d check to make sure everything is tight, seating die, stem, etc, and that the seating die is clean. When I did load lubed lead, the die would need to be cleaned quite often. The seating stem can be and issue but even if I have the wrong stem in I don’t see that much of a variation. Also make sure your primers are flush or below the case head. If they’re a bit proud and not consistent, that can contribute to COL variations. Good luck!

try rotating the bullet 90 degrees just after the bullet is started into the case. and another 90 degree rotate a bit farther.

luck,

murf

Fill in the seat plug with JB Weld epoxy then file it flat once it hardens. It will slightly flatten the tip when seating round nose, but doesn't effect anything in any sort of meaningful way.

OAL should be dead on every time after doing so.

Strange. I measured 25 9mm 124gr coated bullets straight off the Dillon and saw a total spread of 0.006".
You say .020-.025".

What bullets are you using?

Figuring out your problem shouldn't be hard, but you need to eliminate one variable at a time. Just think of all the variables that could cause OAL variations.

I assume your seating die indexes off the nose of your bullets. Is there any potential for variations in bullet ogive to cause the seating die to contact the bullet at different points in reference to the base of the bullet? If so - eliminate that variable. For example, using flat-nosed JHPs in my dillon die (with an insert you can flip between round nose & flat nose), I know for a fact it's always contacting the bullet at its tip, with ogive completely out of the equation. With round nose bullets, and the round-nose die interface, if the curvature of the die contact point is narrower than the bullet, then minor variations in bullet profile can cause inconsistent OALs. Same if the ogive is a hair off-center. Using flat-nose bullets w/ the flat-nose interface eliminates all these issues (just make sure it is interfacing on the tip of the bullet & not riding down the shoulder).

Once you're sure that's not a problem, look at cases. You could get all kinds of variation from not-so-easy to investigate factors (rim distortion, differences between factories, etc. So for purposes of eliminating this variable, why don't you use a small batch of all-new brass from a reputable manufacturer? Doesn't have to be much, just enough to make for a meaningful sample size. Then inspect each case well to make sure they're all identical.

At this point you should have consistent brass, and consistent contact between your bullets & bullet dies. So churn out some rounds. Still have a significant OAL variation? If so, you now know it's the process, not the parts. So what could it be? Movement of the shell plate / collet? Insufficient neck tension? Variations in the force / speed you apply to the press? Movement of the dies? Start out not crimping at all (if you do), as this could introduce a variation. If everything is perfect then finalize by crimping and see of things change.

Looks to me like if the seater ram fits the bullet they would all seat to the same depth. The ram comes up, the bullet seats. Solid mechanical all the way. I would check the seating die and the bullet shape. I have not seen much variation in OAL for my 9mm loads once I set it.

I am sure you can load good loads with your equipment if you are careful and tune it in. I had some money to burn and was having a problem seating wadcutters in .357. I bought a used Redding competition seating die on Ebay for my .357. I liked it so well I ended up buying one for the 9mm too. And got lucky and found a fairly cheap used one for my .41 Mag. I like the Redding competition seating dies a lot better than the Lee seater it replaced. I thought the dies were a better upgrade for me than a new press. (I use an early Lee classic press)

There is a used 9mm Redding competition die on e-bay right now.

Maybe there is something going on with the shell holder or the fit of the case into the shell holder?

Waterboy3313 looking to the press or the die as the problem is the wrong answer. 95% of what you are seeing is inconsistency in the overall shape of the bullet and where it is making contact with the bullet..

Try this. Take the seating stem out of the die and then grab a handful of raw bullets that you are using. Then place the stem on top of the bullet and measure the whole stem length and the bullet held together as one piece.. Do that to the whole handful and see if you come up with the same inconsistency as what you loaded..

@Waterboy3313
You can take your seating die apart and not only clean with carb or brake cleaner, color a bullet at the ogive area with a sharpie to identify where the seating stem is making contact.
I feel comfortable saying that your press is not the problem

Variation in ogive of bullet changes relationship to seating punch. Bullets sre made on multiple machine and there will be some variation in tooling.

I sort brass by headlamp. It makes the OAL very consistent

Out of a handgun or a AR9 will it matter? I mean honestly is 010-.015 going to make a difference? What kind of shooting are you doing that its going to matter? Just asking.