New to 9MM reloading COL problem

[ironpony]

Maybe this is worth mentioning here, I did this an hour ago.
124gr. MG jhp over 4.1 gr. HP-38 @ 1.080
G19 g5 ran well, soft.
G34 g4 every other round FTE.

Im guessing if I extended oal out to the lands 1.140, I might be close to a squib G34?

[MemphisMechanic]

Without chronograph data we couldn’t say.

 

I’m genuinely curious how much velocity you’d lose. But it will vary on powder and bullet choice.

Edited October 22, 2018 by MemphisMechanic

[ddc]

4 hours ago, jripper said:

Yes.  In this case I meant OAL. 

I was 99.999% sure you did. 

[Koikeeper67]

Just thought I would give you guys a bit of an update, I made a quick trip to the range after work today ( I just could not wait until Friday) the reloads work great 

 

3.6Gr of tight group is not enough to reliablely cycle the weapon (no big surprise here) 3.8 seamed to do alright and 4.0 was a good stout load. I am going to load some right in the middle at 3.9 and see how they do. 

 

Again thanks for all the help and ideas. 

[rustybayonet]

With a 550 you shouldn't get that big of variation. What bullets are you using?

 

[jripper]

The bullet shape and the shape of the bullet seating punch may be the problem.  For instance, if you run a semi wad cutter bullet in a round nose punch, it may not fit perfect, and could cause variances in the OAL.   Are you bullets looking deformed on the end?  Jacketed or lead bullets?

 

[IDescribe]

On 10/22/2018 at 10:47 AM, jripper said:

How can mixed headstamp brass cause a noticeable COL?

 

 

On 10/22/2018 at 12:30 PM, ironpony said:

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).

 

Remember how we previously discussed how you should not count the first four or final four rounds off a progressive press when measuring OAL consistency?  It's because the shell plate rocks and flexes under force, as does a the toolhead, so the things that flex do so differently with a different number of cartridges loaded onto the shellplate because force is being applied in different locations than when the shellplate is full. 

 

Well, guess what...     Even when the plate is full, the force distributed around the shellplate is not evenly distributed.  It takes far more force to resize a case than it takes to perform the functions at any of the other stations.  The most force applied to the shellplate is applied at the sizing station.  And because cases of different headstamps are made of different alloys and have different casewall thickness, and lengths, etc., etc., you can have significant amounts of difference in the force needed to size a case from one case to the next, and different amounts of force result in different amounts of rocking and flex, and different amounts of rocking and flex result in greater OAL inconsistency.  

 

[jripper]

13 hours ago, IDescribe said:

 

 

Remember how we previously discussed how you should not count the first four or final four rounds off a progressive press when measuring OAL consistency?  It's because the shell plate rocks and flexes under force, as does a the toolhead, so the things that flex do so differently with a different number of cartridges loaded onto the shellplate because force is being applied in different locations than when the shellplate is full. 

 

Well, guess what...     Even when the plate is full, the force distributed around the shellplate is not evenly distributed.  It takes far more force to resize a case than it takes to perform the functions at any of the other stations.  The most force applied to the shellplate is applied at the sizing station.  And because cases of different headstamps are made of different alloys and have different casewall thickness, and lengths, etc., etc., you can have significant amounts of difference in the force needed to size a case from one case to the next, and different amounts of force result in different amounts of rocking and flex, and different amounts of rocking and flex result in greater OAL inconsistency.  

 

OK.  But is it significant?  How much of a variance?  I doubt it makes any significant difference for 95 % of handgun applications.

[David.Hylton]

Stop for a moment and think about how small your variance actually is. With your COAL range, your are running 1.1565" +/- 0.0065".

6.5/1000 of an inch variation is very small.

 

Coated bullets can vary that much (mine sometimes have small lumps/bumps), grime build up can interfere with the press operation, your technique and all of the other matters discussed earlier can add up to that.

 

I think it is a testament to Dillon quality and tolerances that you can keep ammo within .013 inches running a volume-oriented loading press.

 

 

[ltdmstr]

.013 is actually pretty darn bad.  .001 or .002 is acceptable and that's what I get with numerous presses for 9 (1050), 40 (1050) and 45 (550).  So it's not rocket science.  It's just a matter of getting things set up properly and performing routine maintenance when needed.

Edited October 25, 2018 by ltdmstr

[MemphisMechanic]

3 minutes ago, ltdmstr said:

.013 is actually pretty darn bad.  It should be .001 or .002 is acceptable and that's what I get with numerous presses for 9 (1050), 40 (1050) and 45 (550).  So it's not rocket science.  It's just a matter of getting things set up properly and performing routine maintenance when needed.

 

Disagree. On my 650 with everything tightened up (shellplate bearing kit to reduce it’s flex) I routinely see .010” with a coated bullet and mixed brass.

 

If I sort out the winchester cases and use Precision Delta bullets it drops to .001” to .002” so I know it isn’t operator error, or how the press is set up.

 

But the .010” variance ammo still chronos with an SD under 10, and groups around 2.25” at 25yds - so it’s more than good enough for USPSA service.

 

Edited October 25, 2018 by MemphisMechanic

[jripper]

28 minutes ago, MemphisMechanic said:

 

Disagree. On my 650 with everything tightened up (shellplate bearing kit to reduce it’s flex) I routinely see .010” with a coated bullet and mixed brass.

 

If I sort out the winchester cases and use Precision Delta bullets it drops to .001” to .002” so I know it isn’t operator error, or how the press is set up.

 

But the .010” variance ammo still chronos with an SD under 10, and groups around 2.25” at 25yds - so it’s more than good enough for USPSA service.

 

I think that's probably more of a function of jacket bullets vs. cast than the actual brass.  Leads bullets are more likely to deform slightly.  But, I totally agree that for USPSA and most pistol applications, it's more than good enough. 

[MemphisMechanic]

23 minutes ago, jripper said:

I think that's probably more of a function of jacket bullets vs. cast than the actual brass.  Leads bullets are more likely to deform slightly.  But, I totally agree that for USPSA and most pistol applications, it's more than good enough. 

 

That’s my point. Mixed brass matters some. Bullet contour matters some. But it only matters when you’re on an internet forum discussing thousandths of an inch.

 

 It doesn’t appreciably show up in how the ammo shoots, however. So we can let this topic go.  

 

Edited October 25, 2018 by MemphisMechanic

[Sarge]

1 hour ago, MemphisMechanic said:

 

That’s my point. Mixed brass matters some. Bullet contour matters some. But it only matters when you’re on an internet forum discussing thousandths of an inch.

 

 It doesn’t appreciably show up in how the ammo shoots, however. So we can let this topic go.  

 

In performance I generally agree. But one or two thousandths can often be the difference between fitting and not fitting in a particular gun. If you are loading a bullet shape that needs to be at 1.10 MAX to chamber you don’t want to have to load to 1.00 to make sure it fits. The tighter you can keep the variations the longer you can load.

[SlappyMcTrigger]

2 hours ago, MemphisMechanic said:

On my 650 with everything tightened up (shellplate bearing kit to reduce it’s flex) I routinely see .010” with a coated bullet and mixed brass.

This is consistent with what I’m getting on my 650 using mixed headstamps and blues. I also have a bearing kit which allows for a tighter shell plate. 

[IDescribe]

14 hours ago, jripper said:

OK.  But is it significant?  How much of a variance?  I doubt it makes any significant difference for 95 % of handgun applications.

 

I was responding to a question (yours being one of them) about how mixed brass contributes to OAL variation.  I described how.  

 

Whether or not it's significant is application dependent.  I don't find .007  significant for coated RN out to 35 yards for 9mm minor, but I wouldn't want it for a Berger VLD out to 10000.   

[IDescribe]

Guys, if you are using a seating stem that seats off the ogive, any variation in the tip of the bullet (where most variation occurs with most bullets) will be reflected in OAL consistency because an ogive stem bypasses it.  It pushes from below the tip. 

 

The good news is that it doesn' matter.  The  actual tip doesn't touch the gun.  Feed ramps are not perpendicular to the cartridge when it is stripped from the magazine.  It's slanted.  The contact point between the bullet and ramp, between bullet and chamber roof, wherever contact points are throughout chambering, the actual tip NEVER touches the pistol.  We talk about OAL constantly (the distance between the tip of the bullet and the headstamp) because that's all we can measure.  But we don't really care about the number.  We use that number to control other things indirectly.  

When we determine max OAL without rifling engagement so that we know what OAL to load to without jamming the bullet into the rifling upon chambering, we're not really looking to control OAL.  We're using OAL to indirectly control the distance between the bullet shoulder and the rifling.

When we determine OAL in load development to adjust charge weight when we have to load significantly shorter than published load data, we're not really looking to control OAL.  We're using OAL to indirectly control how deeply the bullet base is seated into the case -- because THAT affects pressure.

If you use a flat anvil, you will have more consistent OAL, but seating depth and the distance from bullet shoulder to rifling lands will suffer for it.  If you seat with a hollow anvil that seats off the ogive, your OAL will suffer (a little), but those other two variables that DO matter will be more consistent.

Wire your gear tight.  Use the hollow side of the seating stem.  Pull steady.  And don't sweat the OAL variation.  

[MikieM]

Remember to measure your loaded round from a shell plate that was full at the time the bullet was seated. If you load only one test round to set your OAL and then lock down your seating die, subsequent bullet lengths will be longer due to the pressure placed upon the shell plate as the ram goes up. A Redding micrometer die comes in handy here.

Mixed brass has nothing to do with COAL. The only thing about mixed brass that might come into play is in the crimp due to case wall thickness.

In our line of work the differences in OAL, from round to round, will not effect performance unless, of course, the bullet is seated too long and the gun won't go into battery. A too light, or too heavy a crimp certainly could, however.

Seat a bullet into an empty case and plunk it into your gun's chamber, then rotate it. Keep seating the bullet out further until the round will no longer rotate. Now, increase the seating depth about a thousandths of an inch at a time until the round will freely rotate again. This measurement is your max, or don't exceed number. Load your ammo at, or under this number.

 

[tires2burn]

On 10/20/2018 at 9:34 PM, mmlook said:

/\/\/\

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 

 

I use lee dies and filed the bullet seater insert flat. No more problems.