650 Consistent seating (COAL)

[Sdlrodeo]

My current set up is a Dillon 650 (newer model) with hornady seating die with micrometer seating adjustment. I’m loading HPs so I use the flat seating head (vs the convex for RN). 

 

I notice a variance of about 5 thou. In other words if I set it to coal of 1.120 I get readings from loaded bullets between 1.118-1.123. 

 

Full disclosure i have have been using mixed brass (none that have the ‘shelf’) but I wouldn’t think that would matter since the distance between the shell plate and bottom of flat seating head should be the same on each stroke. 

 

Is is there something I’m missing or Am I achieving a normal coal variance for this machine? Is the mixed brass really the cause?

 

thanks!

[Sarge]

Believe it or not this has been discussed a thousand times on these very forums. Just try searching for oal variance etc.

 

Your assumption that mixed brass won’t contribute is flat wrong. I don’t know why nor do I really care why but sorting by headstamp will tighten up oal. So does using case lube. And so does keeping shell plate full. 

 But then again you can find all of that already by searching.

[Scott Steele]

Believe it or not this has been discussed a thousand times on these very forums. Just try searching for oal variance etc.
 
Your assumption that mixed brass won’t contribute is flat wrong. I don’t know why nor do I really care why but sorting by headstamp will tighten up oal. So does using case lube. And so does keeping shell plate full. 
 But then again you can find all of that already by searching.

^true
I use mixed brass for practice and local matches with that same COAL tolerances you are seeing. As long as they pass the plunk test I'm good.
Plunk test is removing barrel and dropping the round in chamber to hear the plunk.
Once fired brass gives good COAL for matches 1 to 2 hours away.
New brass gives best COAL tolerance and that gets used for anything further than 2 hour drive.
What I get out of the new brass is more consistent chronograph readings with tighter COAL tolerances. Which is what you want at a level II match.


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[jhgtyre]

2 minutes ago, Scott Steele said:

^true
I use mixed brass for practice and local matches with that same COAL tolerances you are seeing. As long as they pass the plunk test I'm good.
Plunk test is removing barrel and dropping the round in chamber to hear the plunk.
Once fired brass gives good COAL for matches 1 to 2 hours away.
New brass gives best COAL tolerance and that gets used for anything further than 2 hour drive.
What I get out of the new brass is more consistent chronograph readings with tighter COAL tolerances. Which is what you want at a level II match.


Sent from my iPhone using Tapatalk

 

Not a bad reloading strategy at all.  When you look at what it really costs to travel to a major match the price of a few hundred pieces of new brass is pretty inconsequential.

[Sdlrodeo]

17 minutes ago, Sarge said:

Believe it or not this has been discussed a thousand times on these very forums. Just try searching for oal variance etc.

 

Your assumption that mixed brass won’t contribute is flat wrong. I don’t know why nor do I really care why but sorting by headstamp will tighten up oal. So does using case lube. And so does keeping shell plate full. 

 But then again you can find all of that already by searching.

 

Understood. I’ll look around more.

 

Seems like the steel would displace the copper/lead of the projectile. Smush it, if you will. 

 

I’ve got a few K of the same brass still on the side. I’ve saved that for Match ammo so I’m going through the last of my pickups for practice ammo. 

[Sdlrodeo]

27 minutes ago, Scott Steele said:

^true
I use mixed brass for practice and local matches with that same COAL tolerances you are seeing. As long as they pass the plunk test I'm good.
Plunk test is removing barrel and dropping the round in chamber to hear the plunk.
Once fired brass gives good COAL for matches 1 to 2 hours away.
New brass gives best COAL tolerance and that gets used for anything further than 2 hour drive.
What I get out of the new brass is more consistent chronograph readings with tighter COAL tolerances. Which is what you want at a level II match.


Sent from my iPhone using Tapatalk

 

Yeah I agree totally as far as price goes.

 

I’m  more curious about the mechanical reasons behind the variance. 

 

I’ll  have to burn through this last batch. So I’ll do the new brass next year for LII. 

Edited April 3, 2018 by Sdlrodeo

[Sdlrodeo]

Ok so after a bit of sitting through the other threads it seems my coal variance is appropriate for using mixed brass. I too am happy with the accuracy I get. 

 

I’m still curious how the Max can grow with a flat seating head. At some point the steel has to hold against the softer copper/lead/brass. Ah the joys of working with metal. Fascinating really. I enjoy all the learning involved. 

[Sarge]

2 hours ago, Sdlrodeo said:

Ok so after a bit of sitting through the other threads it seems my coal variance is appropriate for using mixed brass. I too am happy with the accuracy I get. 

 

I’m still curious how the Max can grow with a flat seating head. At some point the steel has to hold against the softer copper/lead/brass. Ah the joys of working with metal. Fascinating really. I enjoy all the learning involved. 

I’m not following you steel questions? What steel are you talking about?

[Tom S.]

The variable isn't the seating die or even the length of the case, it's the rim of the cartridge and how it sits in the shell plate. If the case sits higher in the shell plate due to the way the rim is cut, the OAL will be shorter. If it sits lower the OAL will be longer.  This can also effect primer seating depth.

[Sdlrodeo]

2 minutes ago, Tom S. said:

The variable isn't the seating die or even the length of the case, it's the rim of the cartridge and how it sits in the shell plate. If the case sits higher in the shell plate due to the way the rim is cut, the OAL will be shorter. If it sits lower the OAL will be longer.  This can also effect primer seating depth.

Ahh. I understand what you’re saying. I’m not home right now but I’ll definitely have to look at that. However I seem to remember a bit of slop in the shell plate with all of my cases. If there is slip, the case ‘should’ sit on the bottom ledge of the shell holder. But interesting point if it stops on top of the ledge going into the case groove. 

[Sdlrodeo]

33 minutes ago, Sarge said:

I’m not following you steel questions? What steel are you talking about?

 

Im talking about the components in the press being made of steel (seating die and shell plate) which are much harder than the bullet components. I would think due to the differing hardnesses and using a flat seating head the COAL could not possibly be longer. (Alas sometimes it is) If anything the bullet tip would be smushed (because copper and lead are softer than steel) if there were resistance from the bottom (like hitting a shelf in the case with a long bullet?) keeping it from being seated to the set depth. 

 

 

[Sarge]

3 minutes ago, Sdlrodeo said:

 

Im talking about the components in the press being made of steel (seating die and shell plate) which are much harder than the bullet components. I would think due to the differing hardnesses and using a flat seating head the COAL could not possibly be longer. (Alas sometimes it is) If anything the bullet tip would be smushed (because copper and lead are softer than steel) if there were resistance from the bottom (like hitting a shelf in the case with a long bullet?) keeping it from being seated to the set depth. 

 

 

Oh. Here is what’s happening.

One-Any variance in the case will cause different resistance and hence, seating depths. Not using lube will make said difference MUCH more pronounced. 

Two- if the shell plate has an empty slot there will be more “float” in the toolhead and/or more “movement” in the shell plate. Especially if the plate is loose. I use the bearing kit and keep mine pretty tight.

Three- stopping and starting the press to keep checking things causes oal problems because you have no rhythm while pulling the handle. The press is meant to be run at speed.

SO, make sure the shell plate is nice and snug, lube 100 brass of same headstamp, start pulling the handle, remove the first 2-3 off the press from the bin, resume pulling the handle until primer alarm sounds then STOP. Measure the rounds in the bin. That is as good as oal consistency will get on a 650. If it’s not within a few thou one way or the other keep refining the process and it will improve.

[lgh]

4 hours ago, Sarge said:

Your assumption that mixed brass won’t contribute is flat wrong. I don’t know why nor do I really care why but sorting by headstamp will tighten up oal. So does using case lube. And so does keeping shell plate full. 

I agree with Sarge. If you need to tighten up COAL, these things will certainly help. And keep the shell plate tight. At least for a lot of people it does. It also helps when trouble shooting to have the same headstamp rather than find out x hours later that it actually matters.

 

You might measure dimensions of different headstamp brass, run some stats on batches of ten, and you will see that all brass is not the same. No surprise then that they don't act the same.

[Sdlrodeo]

Thanks for the good info. I’ll finish up my mixed range brass and then try a batch of the same headstamp. However, i’m Actually pretty happy to hear that most folks don’t see much difference in performance when there is a +/- .003-.004 variance in coal. I had the assumption that there is going to be some variance in a machine that is built to run at speed. Glad to hear I’m not alone.

 

[stick]

I just started sorting brass by headstamp again.  My COAL is very consistent since I'm using the same headstamp.  With mixed brass, I was seeing a variance of .02 to .05. I don't notice a difference in the rounds.  personally, I don't think .02 to .05 increase or decrease will make a difference. 

[lgh]

1 hour ago, Sdlrodeo said:

happy to hear that most folks don’t see much difference in performance when there is a +/- .003-.004 variance in coal.

I can't say I've noticed a difference in accuracy but I never really checked. The difference I did notice was when the variation caused chambering problems and light strikes and I had to trouble shoot the issue. PITA.  Then I had to pull the bullets. PITA. If you run them on the short end (for your chamber), it won't matter, at least for chambering.

[Sdlrodeo]

1 hour ago, lgh said:

I can't say I've noticed a difference in accuracy but I never really checked. The difference I did notice was when the variation caused chambering problems and light strikes and I had to trouble shoot the issue. PITA.  Then I had to pull the bullets. PITA. If you run them on the short end (for your chamber), it won't matter, at least for chambering.

 

My first experience with running bullets that were “too long” was at a club match. Gun kept not going fully into battery so I would tap rack which took out the round, and it would fire a few times then not go into battery again. Second time I tried just tapping the rear of the slide thinking it was maybe a weak recoil spring. This particular time it was not a good idea as the bullet seated itself on the lands of the rifling. After some work, I got it out and inspected it. I should’ve mentioned that the COAL was right at 1.120 on those bullets, BUT it was a different profile! Turns out that particular bullet needed to be at 1.110 maybe 1.115 (I forget the brand/type but I think it was a RNFP). 

 

Yes, before you jump to conclusions, I did do the plunk test. However i did it on my other SP-01 (prod) not on my newly converted to CO SP-01. So, lesson was plunk test for EACH gun. But really, I just do my plunk test on the ‘shallower’ barrel of my CO gun. 

 

I’ve finally settled on a good practice, and a good match bullet that both work in the CO gun at 1.120, loaded to right at 129-131 PF. The quest for that balance of PF/affordability/Accuracy has been a little bit of a journey, albeit enjoyable. Next step, as evidenced by this thread, is to go with same headstamp brass. I’ll see if that’ll shrink my groups ever so slightly...