Reply with quote #1
I have 5 Dillon presses 1 450B, 2 550s, and 2 1050s.
I reload precision longrange ammo on the 550s and had problems two case head seperations)at the F-class Nationals. After an extensive review of my loading I found the problem and thought I should share it with others who load with a progressive press.
My two Dillon 550s were made about 10 years apart from each other. I have been loading ammo with both for years with little or no problems. I have one set up for large and one set up for small primers. Recently, I used the tool head set up for one loader on the other press. I assumed there would be no problems. How wrong was I. The stroke of one loader was approximately .005" longer on one press than the other. This over sized my cases by about .0035". This was hardly noticable during the loading process but was quickly found out when the cases had case head separations after 3 reloadings. This particular case 6mmBRX normally is reloaded between 16 and 20 times.
If you reload on any press and use dies that were set up for another press, make sure you check that they are sizing those cases where they are supposed to be sized.
The changes in one loaders dimentions can be very suttle but the consequences be very devestating. I ruined about 200 pieces of twice fired brass.
All due to operator error.
Reply with quote #2
Nat, thanks for the heads-up. I will forward this info to my friends, since our club has two 550s and there's at least 10mm and 45ACP that have both large and small primer brass (although one or the other is much more prevalent).
I'm afraid that if toolheads are used interchangeably, there may be some *under sizing* issues and thus (large batches of) ammo won't chamber properly.
I hadn't thought of this issue either, although with single stage presses I adjust and dedicate dies for only one press.
Reply with quote #3
Another example of this. Last year I switched a full-length sizing die from an RCBS Turret press to a Rockchucker. The die was set to give about 0.002" shoulder bump when used on the Turret. When I put the die on the Rockchucker, which has less flex/deflection, it was pushing back the shoulder over .010". I had to back off the die quite a bit to end up with the same results.
Nat's example is why I measure every loaded case when it comes out of the bullet seater.
Reply with quote #4
Even "Gump" would have checked this before proceeding.
I feel like a real dummy.
I hope no one else makes this mistake. I talked with Dillon today and suggested if this information is not in their directions then it should be added to them.
I susspect it fell on deaf ears.
Reply with quote #5
Thanks for sharing Rustystud. SPM
Reply with quote #6
Thanks for the FYI. I also use two 550Bs for large and small primers. I have several rifle caliber tool head setups from before I bought the second press 8-10 years ago and will check the settings. Who would have thought-WWHT<
Old Doug Griffin, GA