New to 9MM reloading COL problem

[Koikeeper67]

I am trying my first 9MM reloads I have been away from reloading for some years now but back at it again. I am reloading on a Dillon RL550B using Lee dies. The problem I am having is my COL keeps changing on me, I am after a COL of 1.1500 and I am getting a range of 1.1500 up to 1.1630 and every thing in between. Could this be caused by running mixed head stamp brass? or any other ideas of what could be causing this? 

 

Thanks 

Doug 

[Sarge]

Sort by headstamp

lube cases

tighten shellplate

only measure from full shellplate

[tdp88]

I load blue bullets to 1.15 and see a variance from 1.14 to 1.16 with most within .02 or so of my target. I assume it’s either from mixed head stamps or the bullet coating and was told that that’s a pretty normal range. It doesn’t make a huge difference at the chrono and my single stack isn’t picky so I just go with it.


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[MemphisMechanic]

1 hour ago, Koikeeper67 said:

I am after a COL of 1.1500 and I am getting a range of 1.1500 up to 1.1630 and every thing in between. Could this be caused by running mixed head stamp brass? or any other ideas of what could be causing this? 

1) The bullet isn’t seated by the tip of its nose where you’re measuring it. It’s seated by the die using the ogive of the bullet, so tiny variations in coating thickness or bullet contour will show up as length variations.

 

2) Yes, mixed brass. Big factor.

 

This is how I’d proceed: Assuming 1.150 is the longest your ammo can be to plunk & spin, run your seating die in to achieve that. In other words, bring it down until your various OALs are now 1.370” to 1.150”. 

 

Take that ammo to the range. Does it make the PF you want to make? Shoot groups with it. Is it accurate enough for your needs?

 

If so, proceed with a life of wandering OALs and cheap mixed brass... and just go shoot. My experience has been that more precise OALs and sorted headstamps result in consistent lengths, but that extra time doesn’t show up in more accuracy from a handgun fired at 20-25 yds. It isn’t worth the effort since you can almost certainly work up ammo good for 2” groups at 25yd with those wandering OALs.

 

Edited October 21, 2018 by MemphisMechanic

[mmlook]

1 hour ago, MemphisMechanic said:

1) The bullet isn’t seated by the tip of its nose where you’re measuring it. It’s seated by the die using the ogive of the bullet, so tiny variations in coating thickness or bullet contour will show up as length variations.

 

 

/\/\/\

What kind of bullet profile are you using? RN?

if you need to hit a target OAL due to mag or feeding requirements, you'll need to modify the seating die, to seat by the tip rather than the ogive 

 

[Hi-Power Jack]

4 hours ago, MemphisMechanic said:

  until your various OALs are now 1.370” to 1.150”. 

 

 

For the newbies out there - Memphis means 1.137".     

 

Don't want anyone getting confused, or hurt.

[IDescribe]

12 hours ago, Koikeeper67 said:

The problem I am having is my COL keeps changing on me, I am after a COL of 1.1500 and I am getting a range of 1.1500 up to 1.1630 and every thing in between.

 

Could this be caused by running mixed head stamp brass? or any other ideas of what could be causing this? 

 

First -- always always tell us specifically what bullet you are loading and for what pistol.  We may see factors in play that you would never think to consider.

Going to add my two cents and bring in all the other pennies into one spot:

 

• Mixed headstamp will increase OAL variation, but not by as much as you are seeing.  If you want to sort by headstamp to negate that variable and allow you to observe the other contributing factors more clearly, go ahead, but once you're in production, this source of variation  is not something to worry about.
• Your shellplate flexes when the ram drive the cartridges up into the dies.  It will flex differently when the shellplate is not full vs when it is full, so for a four-station progressive press, pull aside the first three cartridges off the press.  Feel free to shoot them, but don't use them for testing anything from OAL consistency to velocity to precision.  Shoot them, don't test them,
• Is the table/platform your press is mounted to bolted to a wall?  How stable is it?  If the platform your press is mounted to rocks while you are using the press, OAL consistency will suffer.
• Consistency of YOUR arm is a big contributing factor.  You could do NOTHING to address OAL issues, and your OAL consistency would improve over time as your pull of the lever got more consistent.
• With the exception of FMJ, most bullet variation from one bullet to the next will occur in the nose.  If the seating anvil seats off the ogive, it is bypassing that bullet variation.  This is a GOOD thing, as it leads to more consistent seating depth and more consistent distance between bullet ogive and rifling lands when the cartridge is in battery, BUT when you go to measure it with your calipers, that meaningless bullet variation in the nose that you bypassed with the hollow seating anvil gets measured, and it makes it look like your seating consistency is worse than it is by including variation in the nose that is ballistically irrelevant.
• Lubing cases smooths out passage into the dies, leading to more consistency from one pull to the next.

I once compared a Redding Pro seating die to a Hornady New Dimension seating die to see which was more consistent (spoiler alert: they were dead equal).  With both dies, I was using the hollow/concave seating anvil that seats off the ogive.  

I used sorted brass and Berry's 147gr RN. I am pretty sure I did it on a Redding Big Boss II, which is an outstanding single stage press.  The tabletop it was mounted to was rock solid.   I seated 10 bullets with the Redding die.  I numbered the cases, measured OAL, and recorded the measurement by case number.  I do NOT remember the variation and would not want to guess, but there was some varation to be measured from one cartridge to the next.   I then pulled all ten bullets but kept them separated and with the cases they were loaded in with the Redding die.  I then used the Hornady die to seat the first bullet back into the case it went into originally, adjusting the die until until the OAL matched the OAL from the seating with the Redding.  I THEN loaded the remaining nine bullets into their same cases without touching the Hornady seating die again.  They all came out at the same OAL (to the thousandth) as they had with the Redding die.  THE SAME.  Seating dies from two different companies produced the same OAL for nine bullets when I kept the same bullets with the same cases.
 

The lesson there: if your tabletop is solid, and your arm is consistent, most of your OAL variation will come from your components, and it doesn't matter.

Secure your tabletop to a wall, tIghten up your gear, and load away.  You're fine.   

 

Edited October 21, 2018 by IDescribe

[Hi-Power Jack]

3 hours ago, IDescribe said:

 

  most of your OAL variation will come from your components, and it doesn't matter.

 

^^^^^^    True Dat      ^^^^^^^^^^^^^     

[Koikeeper67]

Thanks guys that is a lot of good advice.

 

First off a little history on my reloading I started about 20 years ago reloading for .38/.357 mag and then added a bit of rifle stuff for my .270  Well then life took over and I was working 80 plus hour work weeks so I stopped shooting and reloading. Jumping forward 20 years I got invited to the range by my neighbor and I realized how much I missed it. So I am now back at the range at least once per week and I have dusted off and rebuilt my Dillon and set up a reloading room. I am finding it a great way to relax after a long week at work. But after 20 years away from it a lot has changed so it is like starting over again. Heck the last time I loaded there were no forums to get help from. 

 

Ok back to the reloading

I am using a load from the Hodgdons manual it is a 124gr Berry's HBRN over top of 3.6gr (starting load) of tight group, it lists a COL of 1.150 so I was trying to stick with that to eliminate any unknown factors. I am loading the rounds to be fired in a Smith & Wesson  M&P Pro. I did a plunk test with a dummy round I put together at this length and it tested fine it also fit the mag fine. My plan was to load 10 rounds at each charge weight ( increasing 0.1gr ) with each 10 until I reach the max listed charge of 4.1gr .  

 

So what I am getting from all the info you guys are sharing is a little fluctuation in the COL is not an unusual thing and nothing to worry about as long as they fit the gun.

 

Later

Doug

 

 

[pskys2]

With a Dillon 550 at least I notice a .005" difference between a full shell plate and the 1st and last rounds.  But that doesn't make any difference.  If the variations are less than .01" you're ok. Over that is not a huge deal unless you are running the edge of the pressure curve.  Anything over .02" difference you may see feeding issues, depending on gun.

Note you will also see a variation between the seating stage measurement and the final crimp measurement.  Also if the crimp is varied by say different brass thickness or bullet diameter it will also effect the oal.

At one time there was a kit made that used set screws to secure the tool head and eliminate the above variations, I picked up one at a match but never used it as it's just not a huge issue.

[Hi-Power Jack]

3 hours ago, Koikeeper67 said:

 My plan was to load 10 rounds at each charge weight ( increasing 0.1gr ) with each 10 until I reach the max listed charge of 4.1gr .  

 

 

No need for that fine a difference - I'd go every 0.2 grains instead of every 0.1.     

 

One tenth of one grain of powder is almost insignificant.

[ltdmstr]

Well, I load thousands of rounds of 9mm with Zero124g jacketed bullets and SNS 124g and 147g coated bullets and mixed brass.  Variation in OAL is .001 to .002 max.  So I'm not buying the argument that mixed brass, etc. is the cause.  I would say it's either an operator issue or something with the seating die (insert).  I'm currently using a 1050 with Redding dies, but I get the same results on a 550.  

[IDescribe]

1 hour ago, ltdmstr said:

Well, I load thousands of rounds of 9mm with Zero124g jacketed bullets and SNS 124g and 147g coated bullets and mixed brass.  Variation in OAL is .001 to .002 max.  So I'm not buying the argument that mixed brass, etc. is the cause.  I would say it's either an operator issue or something with the seating die (insert).  I'm currently using a 1050 with Redding dies, but I get the same results on a 550.  

 

 

Redding dies have a reversable anvil, ltdmstr.  Are you using the flat side?

 

 

Edited October 21, 2018 by IDescribe

[ltdmstr]

No, the cupped side on the Redding Pro Seat die.  And I'm loading both round nose and flat points.

[SlvrDragon50]

14 hours ago, IDescribe said:

 

First -- always always tell us specifically what bullet you are loading and for what pistol.  We may see factors in play that you would never think to consider.

Going to add my two cents and bring in all the other pennies into one spot:

 

• Mixed headstamp will increase OAL variation, but not by as much as you are seeing.  If you want to sort by headstamp to negate that variable and allow you to observe the other contributing factors more clearly, go ahead, but once you're in production, this source of variation  is not something to worry about.
• Your shellplate flexes when the ram drive the cartridges up into the dies.  It will flex differently when the shellplate is not full vs when it is full, so for a four-station progressive press, pull aside the first three cartridges off the press.  Feel free to shoot them, but don't use them for testing anything from OAL consistency to velocity to precision.  Shoot them, don't test them,
• Is the table/platform your press is mounted to bolted to a wall?  How stable is it?  If the platform your press is mounted to rocks while you are using the press, OAL consistency will suffer.
• Consistency of YOUR arm is a big contributing factor.  You could do NOTHING to address OAL issues, and your OAL consistency would improve over time as your pull of the lever got more consistent.
• With the exception of FMJ, most bullet variation from one bullet to the next will occur in the nose.  If the seating anvil seats off the ogive, it is bypassing that bullet variation.  This is a GOOD thing, as it leads to more consistent seating depth and more consistent distance between bullet ogive and rifling lands when the cartridge is in battery, BUT when you go to measure it with your calipers, that meaningless bullet variation in the nose that you bypassed with the hollow seating anvil gets measured, and it makes it look like your seating consistency is worse than it is by including variation in the nose that is ballistically irrelevant.
• Lubing cases smooths out passage into the dies, leading to more consistency from one pull to the next.

I once compared a Redding Pro seating die to a Hornady New Dimension seating die to see which was more consistent (spoiler alert: they were dead equal).  With both dies, I was using the hollow/concave seating anvil that seats off the ogive.  

I used sorted brass and Berry's 147gr RN. I am pretty sure I did it on a Redding Big Boss II, which is an outstanding single stage press.  The tabletop it was mounted to was rock solid.   I seated 10 bullets with the Redding die.  I numbered the cases, measured OAL, and recorded the measurement by case number.  I do NOT remember the variation and would not want to guess, but there was some varation to be measured from one cartridge to the next.   I then pulled all ten bullets but kept them separated and with the cases they were loaded in with the Redding die.  I then used the Hornady die to seat the first bullet back into the case it went into originally, adjusting the die until until the OAL matched the OAL from the seating with the Redding.  I THEN loaded the remaining nine bullets into their same cases without touching the Hornady seating die again.  They all came out at the same OAL (to the thousandth) as they had with the Redding die.  THE SAME.  Seating dies from two different companies produced the same OAL for nine bullets when I kept the same bullets with the same cases.
 

The lesson there: if your tabletop is solid, and your arm is consistent, most of your OAL variation will come from your components, and it doesn't matter.

Secure your tabletop to a wall, tIghten up your gear, and load away.  You're fine.   

 

Any clue if a Hornady seating die is different from the seater + crimp die? I'm not using the crimp function in my combo die anymore, but honestly my OAL is pretty consistent considering mixed headstamp.

[Koikeeper67]

So I went over my procedure again and triple checked everything. 

 

1 removed the anvil from the seating die and cleaned it ( it was not bad ) 

2 re set the shell plate got it a bit tighter then it was before, if I go any tighter now it binds up.

3 I set the first 3 rounds aside then I re adjusted the seating die with a full turret on the press. 

 

Now I am getting real close to my 1.150 COL in the area of 1.150 - 1.155 I am happy with that. 

 

once I got it to where I was happy I ran a single case through the press and it was short ( about 1.1485) 

 

thanks again for all the help and suggestions  

 

I am sure I will have more in the near future, and I hope to be able to add my input to the community  

 

Doug

[jripper]

How can mixed headstamp brass cause a noticeable COL?

 

[MemphisMechanic]

12 hours ago, Koikeeper67 said:

once I got it to where I was happy I ran a single case through the press and it was short ( about 1.1485) 

 

Doug

 

That’s an important thing to learn; if I’m targeting a window of 1.120” to 1.130” OAL (which is about the precision my XL650 gives with bulk coated bullets) I know exactly what OAL to set a single round to, so that I can fill the shellplate and begin cranking out ammo that is within my tolerance range.

 

I’d also be willing to bet you’ll learn OAL isn’t terribly sensitive with minor 9mm loads until it gets really short  (1.080” vs 1.195” might show a velocity difference.)

 

However. Multiple times, multiple powders, I have shortened a load from 1.150” all the way to 1.115” for a gun with a short chamber, and found an increase in velocity that ranges from slight, to none.

 

I’d be more worried about the accuracy issues you might find with ammo OALS wandering around by huge amounts than I would worry someone might blow up their gun with it.  

 

(9MM Major, hot defensive loads, and really short loads need not apply to this discussion.)

 

Edited October 22, 2018 by MemphisMechanic

[ironpony]

How can mixed headstamp brass cause a noticeable COL?
 

Same question here.

Shouldn’t a shell plate properly tightened be exactly the same distance from the seating die every time? Or is it reading the head stamps (sarcasm, sorry).

Currently finding my Glock loads 1.140 do not plunk in my Gen 5 G19 barrel until I get them to 1.080. I’m guessing the answer is a different setting for the 19 (Montana JHPs).

[Sarge]

4 hours ago, jripper said:

How can mixed headstamp brass cause a noticeable COL?

 

I won’t pretend to know why, but it is a fact different head stamps create different length loads

[ltdmstr]

4 hours ago, jripper said:

How can mixed headstamp brass cause a noticeable COL?

 

 

Production processes vary by manufacturer, so there are differences in material content, case wall thickness, internal dimensions, hardness, etc.  Also, brass tends to work harden and become brittle with multiple firings and reloadings.  So brass that's seen more reloading cycles will be harder than the "newer" stuff.  In addition to variations in dimensions and hardness, the amount of resizing can also cause variations in seating depth if the i.d. of the case is significantly smaller than the bullet o.d. (call it excessive sizing for lack of a better term) both from resistance to the initial seating pressure and from spring back when the pressure from the die is released.  Having said all that, the variations in OAL should be relatively small.  Like a couple thousandths of an inch.  If there's more, chances are something else is causing it.

[jripper]

47 minutes ago, ltdmstr said:

 

Production processes vary by manufacturer, so there are differences in material content, case wall thickness, internal dimensions, hardness, etc.  Also, brass tends to work harden and become brittle with multiple firings and reloadings.  So brass that's seen more reloading cycles will be harder than the "newer" stuff.  In addition to variations in dimensions and hardness, the amount of resizing can also cause variations in seating depth if the i.d. of the case is significantly smaller than the bullet o.d. (call it excessive sizing for lack of a better term) both from resistance to the initial seating pressure and from spring back when the pressure from the die is released.  Having said all that, the variations in OAL should be relatively small.  Like a couple thousandths of an inch.  If there's more, chances are something else is causing it.

Got ya.  So the answer is it does not make a noticeable difference.  A couple thousandths in pistol reloading is not a noticeable difference.

 

[ironpony]

Good to know these small details, thanks for the answers and thanks OP for asking this.

[ddc]

4 minutes ago, jripper said:

Got ya.  So the answer is it does not make a noticeable difference.  A couple thousandths in pistol reloading is not a noticeable difference.

 

We need to be careful with a statement like that. As long as you are just talking about OAL then a couple thousandths is not a problem.

Just be aware that a couple thousandths elsewhere, such as diameter, can be a huge problem.

[jripper]

1 minute ago, ddc said:

We need to be careful with a statement like that. As long as you are just talking about OAL then a couple thousandths is not a problem.

Just be aware that a couple thousandths elsewhere, such as diameter, can be a huge problem.

Yes.  In this case I meant OAL.