550b COL settings

[flyrobb]

I have had problems getting consistent COL's with a VERY small sampling of rounds with my 550b. I was setting the COL with a single case verifying with several tests. When I started loading a batch I noticed that COL changed .004 to .005 longer. So it occured to me the difference is a full shell plate vs a single case. I checked this by setting the COL with a full shell plate then took the same round and ran it up the seater die by itself and the COL change from 1.135 to 1.131. A longer COL with a full shell plate vs the single round.

Have you guys experienced the same issue and why would this be the case? I am also now wondering if the powder drop also changes with a full shell plate vs a single round. I have not performed this test yet.

I'm interested in your thoughts and experiences regarding this.

 

[SMSgt]

COL varies. Don't sweat it. It's all dependent on bullet shapes, bullet tip conditions, style of seating stem, etc. A few thousandths variation is common.

 

[ken158]

You are fretting about something you cannot control. If you measure some of your bullets, you will also see that they are not consistent to the exact.

 

[flyrobb]

I agree it's not a big variation and I'm not really worried about it but I'm curious why the difference with a full shell plate vs a single round. Would it be the difference in resistance since you are resizing, charging a case, seating and crimping all at once instead of just seating with a single case.

This is more of a, just want to know thing, than a problem.

 

[ruggyh]

When useing progressive style presses the shell plate should be full while adjusting your dies.

This how the press was intended to be used.

And yes you will get a difference because of the unbalance pressure across the shell plate when using it as a single.

 

[fredj338]

Put 0.004" on your calipers, its nothing. The bullet nose profile can cary more than that. Seating in mxed brass will always have variation but that small means nothing.

 

[pistolpete10]

I think the booklet that came with my 550B said to make adjustments with a full shell plate.

 

[growr]

Nothing to fret over.........

Randy

 

[Nevada Ed]

I have had factory bullets in a box, have different lengths and even a few
that had a cannelure in the wrong spot but when loading, I set my dies at a set OAL, no matter what the bullet length in my pistols, since I am looking for a length that feeds and works with that load.

However, in a revolver I will check the bullet's OAL if it has a cannelure and I am crimping that bullet , to make sure the bullet is in the correct OAL for the crimp to work, in the given area, of the bullet.

Good loading.

 

[minconrevo]

Step one is to remove shell plate and clean it and the press under it. Remember to untighten Allen lock screw first. Next step is to tighten the center bolt holding the plate in place until plate will not turn by hand. Then loosen bolt about 1/4 turn. That's your minimum setting. Retighten Allen lock screw. Take care to keep primer, powder and other debris from under the plate.

 

[RussellD]

I have found using case lube leads to more consistent COAL.

For a benchmark take a box of WWB and measure 10 rounds. Thinking you should see less variation in your reloads.