Why does my OAL change when using a progressive press, (Dillon 550C)

[Rustynails]

Ok, I just started using my new Dillon 550C and started to notice the OAL changed when running the machine as a progressive machine. By this I mean when I start at station 1, then 2, 3,and 4 my OAL is 1.130. However if I just run one case at a time I get 1.127 which is the OAL that I set up the machine to. I am using the LEE Deluxe Pistol Die Set for 9mm Luger. I cleaned the full length sizing die and double checked the die setup. Something is pulling the bullet on the down stroke at the 3rd stage of bullet seating. I am using the Lee carbide factory crimp die in the last stage. I am also using the Lee 356-125R cast bullet ww.

[C-dubb]

When you set your seating die, you must have brass in all of the shell holder spots on your press. If not, the head tilts differently and will mess with your OAL. At least that's what I've experienced.

[Rustynails]

When you set your seating die, you must have brass in all of the shell holder spots on your press. If not, the head tilts differently and will mess with your OAL. At least that's what I've experienced.

Thanks C-dubb, I'll go try it now.

[Rustynails]

It didn't work. I set it at 1.127 but they came out at 1.130. I then took each one and put them back through stage 3 (the seating stage) and they came out at 1.127. Why does it work if I do one at a time, but not when I use the press as a progressive press. This is crazy.
It has to do with stage one causing some problems when a bullet is in stage 3?

[Camper64]

You might have your decap/sizing die set too deep and with brass in stage one it prevents you from doing a full pull.

[Rustynails]

You might have your decap/sizing die set too deep and with brass in stage one it prevents you from doing a full pull.

Okay Camper64, I'll try that and see what happens.

[BK7saum]

There is play or deflection of the subplate/ram due to uneven pressure whether the shell plate is full or only running one cartridge. 0.003" is insignificant. You need to set up the seating depth with a case on each previous station if you want as close as possible. Just an artifact of setup and progressive presses in general.

[M-Tecs]

http://armsvault.com/2008/08/dillon-...mp-kit-review/

UniqueTek’s toolhead clamp kit is designed to minimize this occurrence by rigidly holding a Dillon’s toolhead in place, and thus eliminating any possible vertical movement of the toolhead assembly as cartridge cases on the shellplate are being ran up into the dies. Any vertical movement of the toolhead assembly will likely cause OAL and crimp dimensional variations in reloaded rounds.

They used to sell shim kit and various other screw kits to address this. Currently there are a bunch of companies that make thicker tool heads to help with this.

[onelight]

I would fine tune for how I am using it if running 1 at a time adjust it for that if running all four stations adjust it that way.
One of the things I like about the Lee bullet seating die is easy to set.

[Rustynails]

Thanks for the good information. I will adjust it again with all cases in the previous spaces. Then, if all else fails, I will just set it for the oal O I want when I run it as a progressive press, 500 more rounds to go for now. I'll check out the tool head clamp kit too. I'll see how it goes tomorrow. It's been a long day. Thanks again to all.

[David2011]

While you’re tweaking the dies you might consider loosening all of the locking nuts before raising the cases into the dies. That will help center the dies in the toolhead. Tighten the nuts with the cartridges in the dies.

[Rustynails]

Great advice from all! I adjusted all dies with cases in each station and it is running true, consistent OAL while running the progressive press.

[Sig556r]

Nice info, I have the same issue but thought OAL difference between running single & progressive is too minute for my application. Will try to adjust my 500b setup with brass in all stations.

[onelight]

Lee die setup instructions are slightly different than some others. Lee has you set the sizing die to touch the shell holder with the ram full up then lower ram screw in die another 1/4 to 1/3 turn , this effects the adjustment on the rest of the dies and may not be best on a 550 Perhaps someone with 550 and Lee sizer will chime in dillons die setup instructions may be better on a 550.
On Lee presses that use the safety prime the Lee die instructions help set the position of the primer ram to load a primer , you of course don’t need this.

[str8wal]

Great advice from all! I adjusted all dies with cases in each station and it is running true, consistent OAL while running the progressive press.

Outstanding, but .003" with 9mm is well within my close enough tolerance

[country gent]

There is clearance in all the joints of the mechanism you may be getting a little more "compression" from a full shell plate due to the added pressure force pushing the tool head down. .003 difference between links handle ram wouldn't be a lot.

[onelight]

There is clearance in all the joints of the mechanism you may be getting a little more "compression" from a full shell plate due to the added pressure force pushing the tool head down. .003 difference between links handle ram wouldn't be a lot.

Good point I hadn’t thought of that . I know that you have to have some play in the shell holder so it can rotate so if it is not loaded the same each time it’s not as consistent. It rocks

[Conditor22]

You can get aftermarket turrets for Lee Loadmaster that contact the shell plate in 5 locations and eliminate OAL differences in loading.
I don't know if this is available for Dillons.

[kmw1954]

Another issue I haven't seen brought up is bullet ogive. I load plated bullets from a couple different suppliers and at times can get as much as .005" variation just because the shape of the bullet varies that much. At first it was driving me crazy but now that I understand it, not so much. Also the brass which is being used can cause some variance. Thicker tighter brass causes more resistance and will flex progressive heads differently.

[HCH]

Great advice from all! I adjusted all dies with cases in each station and it is running true, consistent OAL while running the progressive press.

Glad you got it running, but did you find out what the problem actually was?