Dillon 550 sizing and seating on Rifle

[AllenOne1]

Considering loading precision rifle rounds on a Dillon 550. Proposed order of operation, station 1 sizing die, station 2 mandrel die, station 3 powder funnel, station 4 seating die.

I use a universal decapping die and prime off the press so those steps aren't going to be moved to the 550.

Is anyone sizing and seating on the same tool head? If so what results or issues have you seen?

 

[DownhillFromHere]

I use a 550 this way for precision loading:

1. Anneal (AMP)
2. Tumble in corncob/polish media
3. Resize/deprime (station 1)
4. Mandrel (station 2)
5. Run brass through separate tumbler to remove lube
6. Prime with hand primer
7. Powder - charge all cases with Dillon drop measure/trickler/ FX-120i (yeah yeah an autotrickler would be faster)
8. Seat bullets (Seat die in station 3)

With this approach, I'm getting +/- .001" CBTO and <.002" TIR with RCBS Matchmaster dies.

I'm experimenting a little with swapping steps 3 and 4 4 and 5- do the mandrel AFTER lube removal. This was suggested by another Hide poster as eliminating any neck dings from tumbling. Jury still out on that... the listed steps get me ES/SD values around 25/7 so I'm not sure running the brass through the press again is worthwhile.

 

[memilanuk]

Is anyone sizing and seating on the same tool head? If so what results or issues have you seen?

Long ago, before the whole 'two tool head' thing caught on, I seem to recall David Tubb using one tool head on a 550 for his match ammo. IIRC, the 'trick' was that he alternated inserting cases, so as to spread the load out across the tool head. Bear in mind, this was before using expander mandrels was common, or even frozen tool heads.

The order went some thing like this:

Station #1: F/L sizing die, with expander
Station #2: Powder die / funnel ( think he was using a Prometheus, even back then)
Station #3: skip
Station #4: Bullet seater die

The process was to put a case in station #1, size / decap / prime, then rotate the shell plate but *DON'T* put a case in #1. Raise the ram, charge the case, lower the ram, rotate the shell plate to #3 (empty), and put a case in #1. F/L size, decap / prime, then sit a bullet in the mouth of the charged case @ #3, rotate the shell plate and again, don't insert a new case in #1 yet. At this point you should have a sized / primed case in station #2, ready for powder, and a sized / primed / charged case in #4, ready for seating.

The concept is this: isolate the 'high force' operation (sizing / expanding) from the 'low force' operations that require some amount of 'feel'. With the original tool head, there was a chance for the force of the sizing die operation to load the tool head ever so slightly, possibly affecting the consistency/runout of the seating operation. So nothing else is done while sizing. Seating (and powder, even with the press-mounted thrower) require very little to no force, but a fair amount of 'feel'. Separating them from the sizing/priming process increases the consistency of both, and adds relatively little to the overall time.

The way you're proposing could work similarly... but again, I wouldn't necessarily recommend F/L sizing in the same stroke as bullet seating, not if you're trying for 'precision' ammo.

All that said, I used to have a good friend who couldn't *stand* the drudgery of weighed powder charges, even from a Chargemaster, and kept going back to using the Dillon APM on a 550, then a 650, and for some stuff (.223) a 1050 - and routinely beat the pack by a good margin. He didn't always win the match, but it probably wasn't because of his ammo.

 

[KnowNothing256]

Considering loading precision rifle rounds on a Dillon 550. Proposed order of operation, station 1 sizing die, station 2 mandrel die, station 3 powder funnel, station 4 seating die.

I use a universal decapping die and prime off the press so those steps aren't going to be moved to the 550.

Is anyone sizing and seating on the same tool head? If so what results or issues have you seen?

One issue you're going to have is that you still have lube on your loaded rounds. Opinions vary extensively as to whether this matters, or how much; however, people have reported that you'll see pressure signs earlier than you should (case slipping in the chamber under pressure) and potential accelerated chamber fouling (lube converts to carbon when temp spikes during combustion).

 

[DownhillFromHere]

... people have reported that you'll see pressure signs earlier than you should (case slipping in the chamber under pressure)

Good catch. I certainly found this to be true. Early on, I tried to wipe lube off cases by hand. Of course, this got tedious fast, and I ended up with cases with a bit of lube left on them. Early pressure signs ensued.

I now use a separate tumbler with old/used corncob media to clean lube from resized/unprimed cases. While I have to check each case to ensure the flash holes are clear, there is an added benefit of having some film from the media applied to inside of case neck --> easier, more consistent pressure in bullet seating --> more consistent ES/SD.

 

[KnowNothing256]

Good catch. I certainly found this to be true. Early on, I tried to wipe lube off cases by hand. Of course, this got tedious fast, and I ended up with cases with a bit of lube left on them. Early pressure signs ensued.

I now use a separate tumbler with old/used corncob media to clean lube from resized/unprimed cases. While I have to check each case to ensure the flash holes are clear, there is an added benefit of having some film from the media applied to inside of case neck --> easier, more consistent pressure in bullet seating --> more consistent ES/SD.

If you put a decapping die on your loading tool head, you can probably skip the flash hole check

 

[AllenOne1]

One issue you're going to have is that you still have lube on your loaded rounds. Opinions vary extensively as to whether this matters, or how much; however, people have reported that you'll see pressure signs earlier than you should (case slipping in the chamber under pressure) and potential accelerated chamber fouling (lube converts to carbon when temp spikes during combustion).

I wipe the lube off by hand with my current process so that just moves that to the end of the process as I box up the loaded rounds.

 

[TylerN]

Considering loading precision rifle rounds on a Dillon 550. Proposed order of operation, station 1 sizing die, station 2 mandrel die, station 3 powder funnel, station 4 seating die.

I use a universal decapping die and prime off the press so those steps aren't going to be moved to the 550.

Is anyone sizing and seating on the same tool head? If so what results or issues have you seen?

I loaded thousands of rounds this way and can state it will work well. The biggest downside I found was that excessive case lube would cause powder to occasionally jam up the powder funnel which would usually mean the powder dumps all over the place on the downstroke. I found using die-wax and carefully applying just a little bit to the body minimized the chance of this happening.

Since then I've moved to using two tool heads since I was already depriming separately on the 550 with a different tool head. Since I was running my brass through the 550 twice anyways I didn't have a process advantage. I've found the two tool head setup more efficient. I don't have to be as careful with lube application and I don't need to spend time wiping lube off the loaded rounds by hand.

 

[TylerN]

If you put a decapping die on your loading tool head, you can probably skip the flash hole check

That is what I do to prevent corn cobb or whatever media stuck in the flash hole.

Tool head #1:
- Station 1: Full-length neck/body sizing die with decapping pin.
- S2: mandrel

Clean with the ultrasonic every time. Occasionally tumble to polish up the brass. Anneal every time; usually all the stuck media falls out after annealing.

Tool head #2:
- S1: decapping pin to knock any stuck media out of the flash hole.
- S2: undersized mandrel; usually 0.0005" under my sizing mandrel to round out any dents, dings or burrs that might have occurred in handling and cleaning.
- S3: powder funnel
- S4: Seating die

 

[AllenOne1]

I loaded thousands of rounds this way and can state it will work well. The biggest downside I found was that excessive case lube would cause powder to occasionally jam up the powder funnel which would usually mean the powder dumps all over the place on the downstroke. I found using die-wax and carefully applying just a little bit to the body minimized the chance of this happening.

Since then I've moved to using two tool heads since I was already depriming separately on the 550 with a different tool head. Since I was running my brass through the 550 twice anyways I didn't have a process advantage. I've found the two tool head setup more efficient. I don't have to be as careful with lube application and I don't need to spend time wiping lube off the loaded rounds by hand.

Were you originally using a spray lube?
I'm using a die wax and it doesn't take much. I'm running a single stage press right now and getting really good results so I'm a little bit scared to switch to the 550. Sizing while seating worries me the most but if I seat in a separate operation I really don't gain anything. Hate to spend the money to set it up just to find out it doesn't work as well as the single stage.

Right now I'm decapping on a Hornady progressive (fast), priming on a CPS, sizing on the single stage, wiping off the lube, expanding with a mandrel on the single stage, adding powder in the tray and seating on the single stage.

I usually break it up into small chucks on different days so it seems like it goes pretty fast, this would move most steps into one session.

Worth it? idk

 

[KnowNothing256]

Were you originally using a spray lube?
I'm using a die wax and it doesn't take much. I'm running a single stage press right now and getting really good results so I'm a little bit scared to switch to the 550. Sizing while seating worries me the most but if I seat in a separate operation I really don't gain anything. Hate to spend the money to set it up just to find out it doesn't work as well as the single stage.

Right now I'm decapping on a Hornady progressive (fast), priming on a CPS, sizing on the single stage, wiping off the lube, expanding with a mandrel on the single stage, adding powder in the tray and seating on the single stage.

I usually break it up into small chucks on different days so it seems like it goes pretty fast, this would move most steps into one session.

Worth it? idk

That is way more single-stage steps than I would’ve expected.

Man you’re gonna get a ton of time back, esp if you add a case feeder.

 

[TylerN]

I was using Redding die wax. Use it sparingly and maybe clean out your funnel every few hundred rounds to prevent it gumming up.

Once you build the muscle memory with the 550 you won't want to go back to single stage. You can load rounds that perform equally as well in less time. It's 100% worth it.