COAL drift?

[njl]

When I setup my RL550b, I adjusted each die while a single round went from station to station. I adjusted it for a COAL of 1.150 (9mm, 124gr PD, Win brass).

Today, I adjusted the powder measure and loaded up 30 rounds (3 different charges of 10).

The first thing I noticed was Dillon shipped my small powder bar adjusted kind of on the high end. >8gr of universal clays in a 9mm case makes a bit of a mess. The second thing I noticed is universal clays is a PITA to clean up off the bench and press. I ended up using rolled up bits of tape to pick up the grains.

Anyway, after loading my first 10, I was a little disappointed when I measured them and found they were all around 1.157". I measured my dummies loaded individually while calibrating the other night, and they were still 1.150 and 1.151. I found that if I loaded 1 round at a time, I could maintain 1.150-1.151, but if I used the press as intended, the best I could do (really putting my weight into each downstroke) was 1.154. Is this expected?

Also, when throwing a bunch of powder charges (a few to let the adjustment settle, then 5-10 to actually measure the charge being thrown), that case which gets belled 8-14 times seems to get extra belled. Do you use a non-live case for this and figure its going to be your dedicated powder measure case for the caliber being loaded?

These first 30 took forever, mostly because I was fighting with the powder measure and cleaning up spilled powder. I see now why some people might buy the deluxe quick change kits.

[barney88pdc]

Put a round in each station when you are adjusting the seating die. You will get vaired OAL loading one round at a time versus a round in every station. Also continued throws will bell the case "extra". That is why I will put a case still w/ a spent primer in that station to check the charge. Once the charge is right you want to run that case through the sizing die in station 1 so that you do not have any setback issues with that round due to over belling. Also on your stroke you want nice steady consistant pressure. Do not press the handle like a mad man the more consistant you are the more consistant the rounds will be.

Edited March 3, 2009 by barney88pdc

[G-ManBart]

Generally, you're going to find that the first couple of rounds loaded will be slightly different from the following rounds, but it will stay consistent once you're loading with all the stations full. Normally the last one or two will be slightly different as well. Since it's only a couple of thousandths it shouldn't really make any difference in how they run in the gun. It usually isn't even enough difference to notice any change in how they chronograph since there's enough variation present before the slight OAL difference that you won't be able to see it in the chrono results. Give yourself plenty of fudge factor for the power factor and all will be well.

I keep a clean case with a spent primer in it for throwing charges when I'm making an adjustment as they do get belled considerable more than just running them through once. R,

[Flexmoney]

Anyway, after loading my first 10, I was a little disappointed when I measured them and found they were all around 1.157". I measured my dummies loaded individually while calibrating the other night, and they were still 1.150 and 1.151. I found that if I loaded 1 round at a time, I could maintain 1.150-1.151, but if I used the press as intended, the best I could do (really putting my weight into each downstroke) was 1.154. Is this expected?

Sure it's expected, when you realize the mechanics involved.

Think about this...a teeter-totter on a play ground that has a kid sitting on just one side. You can take a measurement from the ground to that kid's head, right? Now, what happens when you put a second kid (similar weight) on the other side of the teeter-totter? Your measurement to the head of the first kid is going to change, right?

That is pretty much what you have going on with the shell plate on your press. It has a fulcrum point in the middle.

When setting up your dies, you will need to load up each station as if you were producing ammo. That will get you your consistency.

[njl]

Sure it's expected, when you realize the mechanics involved.

Think about this...a teeter-totter on a play ground that has a kid sitting on just one side. You can take a measurement from the ground to that kid's head, right? Now, what happens when you put a second kid (similar weight) on the other side of the teeter-totter? Your measurement to the head of the first kid is going to change, right?

That is pretty much what you have going on with the shell plate on your press. It has a fulcrum point in the middle.

When setting up your dies, you will need to load up each station as if you were producing ammo. That will get you your consistency.

That does make sense, and I kind of figured that'd be the explanation. I'll have to watch again, but I don't think there was any mention of this or the suggestion to load up the shell plate (I suppose at least stations 1-3) when calibrating the seating die. I guess at the same time, my resizing die probably isn't getting all the way down after the first case is resized, and even the belling and crimp could be a tiny bit off. I didn't have any trouble placing bullets on the shells in station 3, so I guess the powder die is ok as is. I didn't even think to measure the crimp on last night's loads.

[lcs]

Even when you have learned all the "tips and tricks" of setting up your press, you will see variation.

Whatever your target COAL is, your going to see a plus or minus .003. Your never going to be "exact" all the time. Just the nature of a progressive press, variance in brass, bullets, and even the amount of powder if running compressed loads.

[Flexmoney]

+1

As FullRace says...you are always going to have some variables...even once you get the settings where you want them.

BTW...how did you come up with 1.150 as a target OAL ? That might be a bit long unless you are running in a 1911 based gun.

I won't load that long for my Glock, for example. As, that length is starting to reach the limits of what will feed in full Glock magazines. (I recall that Winchester factory 115g FMJ's would measure out to a bit longer than that, but they are a pointy bullet.)

The axiom that I go by...for our game...is to set the OAL for maximum feed reliability in the gun the load is for...then adjust other parameters to suit (even if that would mean changing powders).

[njl]

BTW...how did you come up with 1.150 as a target OAL ? That might be a bit long unless you are running in a 1911 based gun.

I won't load that long for my Glock, for example. As, that length is starting to reach the limits of what will feed in full Glock magazines. (I recall that Winchester factory 115g FMJ's would measure out to a bit longer than that, but they are a pointy bullet.)

My load manual said to do 1.135 COAL, but also said not to go under the specified COAL. I measured a few of the factory rounds I've been using (Blazer, Federal AmEagle), and they were 1.150...so I decided to go with that. Maybe I should have split the difference?