any idea t what is causing my COL to vary +/- 10 thousands" ?

[cecil]

my press is a sparing used Dillon 650.. I checked the tightness of the shell plate (9mm)... checked the shell plate for any broken part or debris jammed in the shell plate checked the locator pins for damage and everything looks good ..… when loading with mixed brass my loaded cartridges vary in length +  / -   10 thousands... if I load 200 cartridges 18 to 22 are always too long... I take out the locator pin on the bullet seating position and re-seat & crimp all the cartridges that are too long .. when I check those re-run cartridges again... 5 to 7 are still too long.. I re-run the cartridges again and I get at least 2 that are still too long.. I think the problem is the shell plate .. …  any advise would be greatly appreciated … checking the cartridges several times for length is a PIA... 

 

tia

[Sarge]

Just now, cecil said:

my press is a sparing used Dillon 650.. I checked the tightness of the shell plate (9mm)... checked the shell plate for any broken part or debris jammed in the shell plate checked the locator pins for damage and everything looks good ..… when loading with mixed brass my loaded cartridges vary in length +  / -   10 thousands... if I load 200 cartridges 18 to 22 are always too long... I take out the locator pin on the bullet seating position and re-seat & crimp all the cartridges that are too long .. when I check those re-run cartridges again... 5 to 7 are still too long.. I re-run the cartridges again and I get at least 2 that are still too long.. I think the problem is the shell plate .. …  any advise would be greatly appreciated … checking the cartridges several times for length is a PIA... 

 

tia

If you do a search you will see we all talked about this exact same thing just last week.

[Hi-Power Jack]

2 hours ago, cecil said:

 ... if I load 200 cartridges 18 to 22 are always too long... 

 

Could you define "too long" ?

 

Do you mean they are .001" longer than you are looking for ?

 

Or, they don't pass The Plunk Test ?

 

If they're .001" too long, that's really no problem.

 

If they don't pass The Plunk Test, shorten your OAL by .001"

and try again - they should all pass next time     

[dillon]

an overall length variation of .010" is typical, due to individual variations between projectiles. RN projectiles can exhibit even higher variations. Mixed brass does nothing to reduce this dimension. It helps if you keep a fired case in station 1 when adjusting the seating die. This ensures that you have the same upward toolhead pressure during setup as you will when actually loading. The shellplate is going to be pushed down to stop against the top of the platform when seating bullets, so that has no effect on OAL.

[CTJer]

Are all the “too long” ones the same headstamps?

[MikieM]

You'll drive yourself crazy trying to get OAL to plus or minus nothing. My worry is a loaded round that's too long.

Since we all load for handguns around here (even the PCCers) the old plunk and spin test is the best, and easiest way to find the over-all cartridge length. Through experimentation find the maximum OAL for the particular chamber you are loading for and then adjust your seating die so that no matter what the variances are the OAL will never be any longer than your established maximum.

It is my opinion that variances in loaded length is due to shell plate movement caused by different head stamps.

Edited August 31, 2018 by MikieM

[ddc]

I've found that there can be some surprising OAL length differences when comparing runs made with different headstamps.

 

Select out 5 to 10 CBC (very "stiff" feeling when sizing) cases and similar number of Blazer (much easier to size) brass cases.

 

Load them up and check the OAL's. The CBC loads will be longer than the Blazers.

 

 

[Sarge]

On 8/29/2018 at 11:09 AM, dillon said:

an overall length variation of .010" is typical, due to individual variations between projectiles. RN projectiles can exhibit even higher variations. Mixed brass does nothing to reduce this dimension. It helps if you keep a fired case in station 1 when adjusting the seating die. This ensures that you have the same upward toolhead pressure during setup as you will when actually loading. The shellplate is going to be pushed down to stop against the top of the platform when seating bullets, so that has no effect on OAL.

Sorry, but it’s a proven fact oal varies more when using mixed brass. 

[lgh]

On 8/29/2018 at 10:09 AM, dillon said:

an overall length variation of .010" is typical, due to individual variations between projectiles. RN projectiles can exhibit even higher variations. Mixed brass does nothing to reduce this dimension. It helps if you keep a fired case in station 1 when adjusting the seating die. This ensures that you have the same upward toolhead pressure during setup as you will when actually loading. The shellplate is going to be pushed down to stop against the top of the platform when seating bullets, so that has no effect on OAL.

With all due respect to the great people at Dillon, many people have found that mixed brass changes OAL. Maybe theoretically it shouldn't matter but when applying the infallible method of trial and error, it matters. I haven't measured  the oal variation on my 650 in a while but, IIRC, it is way less than 0.010 when I use single headstamp 9mm brass.

[858]

My overall length variation with mixed brass for 40SW is closer to .002. I would consider .010 to be a problem and would start looking at die body interference with the shell plate or crimp settings. I don't see an overall length difference with mixed brass in 40SW, sometimes in 9mm but it is still under .005.

Edited September 3, 2018 by 858

[Smitty79]

It is very bullet dependent too.  In 9mm, with Blue Bullets 147 FP, I saw +- .01 on 100 round run.  I measured everyone of them.  With Acme 147s, +- .006.   After I removed and reinstalled the pedestal, to replace the indexer, the Blue Bullets dropped to .006.  The realignment helped reduce stoppages in station 1 also.

[ddc]

On 8/29/2018 at 8:09 AM, dillon said:

an overall length variation of .010" is typical, due to individual variations between projectiles. RN projectiles can exhibit even higher variations. Mixed brass does nothing to reduce this dimension. It helps if you keep a fired case in station 1 when adjusting the seating die. This ensures that you have the same upward toolhead pressure during setup as you will when actually loading. The shellplate is going to be pushed down to stop against the top of the platform when seating bullets, so that has no effect on OAL.

dillon,

I want to make sure I understand that statement.

So just to be clear... are you saying that you believe that OAL variations have nothing to do with the headstamp? i.e. nothing to do with the brass itself whether it be the dimensions of the brass or its material properties? That OAL is all due to differences in projectiles?

[Smitty79]

7 hours ago, ddc said:

dillon,

I want to make sure I understand that statement.

So just to be clear... are you saying that you believe that OAL variations have nothing to do with the headstamp? i.e. nothing to do with the brass itself whether it be the dimensions of the brass or its material properties? That OAL is all due to differences in projectiles?

  I measured and "binned" the OAL for 100 rounds made with pick up brass.   All Blazer, 15 of them, were in the lower half.   All CBC, 4 of them, were in the upper.   That's not random.

[ddc]

6 hours ago, Smitty79 said:

  I measured and "binned" the OAL for 100 rounds made with pick up brass.   All Blazer, 15 of them, were in the lower half.   All CBC, 4 of them, were in the upper.   That's not random.

 

I agree. That is what I would expect to see if I did the same test.

 

[Youngeyes]

All the answers and speculations on the different reasons for AOL differences seem valid. .01 or .02 mean little. What matters is the SD of my loads. Consistency of PF and accuracy are what is the true measure of whether you are out of specs or not. I do know that when I use mixed head stamps, my SD goes up. YMMV

[Skelt11]

I’ve been chasing my tail on this the past few days myself. I’ve read all the posts regarding the issue. My desired oal is 1.140. I can’t seem to get right on that but I’m getting anywhere from 1.1415 to 1.1430. Every once in a while I’ll get one out to 1.1450. I tried adjusting the seating die several times but no matter how small the tweak I ended up further off. I spoke to a rep at Dillion today and he said +/- .005” is normal and is due to the differences in brass used that are in the stations before the seating die. Just thought I’d share what he told me. 

[Joedirt199]

I run the longer ones back through the seating die and crimp after getting them all done. Seems to catch the longer ones and seat them closer to the number you are trying to hit.

[jdk129]

Two thoughts on this subject:

1. Ensure that all the stations have cases in them when checking/adjusting your OAL

2. Ensure that the bolt on which the shell plate rotates is seated tightly and still allows rotation.

 

My $.07 worth.

[ddc]

22 hours ago, Skelt11 said:

I’ve been chasing my tail on this the past few days myself. I’ve read all the posts regarding the issue. My desired oal is 1.140. I can’t seem to get right on that but I’m getting anywhere from 1.1415 to 1.1430. Every once in a while I’ll get one out to 1.1450. I tried adjusting the seating die several times but no matter how small the tweak I ended up further off. I spoke to a rep at Dillion today and he said +/- .005” is normal and is due to the differences in brass used that are in the stations before the seating die. Just thought I’d share what he told me. 

 

I think what you are seeing is typically about as good as it gets. There may be some machines that due to tolerances that stacked up in the right direction can do better but on average I think your numbers are where they should be.

 

[Skelt11]

18 minutes ago, ddc said:

 

I think what you are seeing is typically about as good as it gets. There may be some machines that due to tolerances that stacked up in the right direction can do better but on average I think your numbers are where they should be.

 

 

Thats good to hear. I reset my dies probably three or four times trying to get them spot on. I’ve read several places that as long as the oal functions in your guns then you’re good. So is the recommended oal in receipts that big of a deal? I’ve read several threads on some other forums that some are running a 1.10 with the same bullet weight and powder. I’m still learning the impact of oal and performance of the round I guess. 

[ddc]

2 hours ago, Skelt11 said:

 

Thats good to hear. I reset my dies probably three or four times trying to get them spot on. I’ve read several places that as long as the oal functions in your guns then you’re good. So is the recommended oal in receipts that big of a deal? I’ve read several threads on some other forums that some are running a 1.10 with the same bullet weight and powder. I’m still learning the impact of oal and performance of the round I guess. 

 

The stated OAL in a load recipe is not meant to imply that it is the only OAL you should consider.

 

If the recipe comes from a commercial source such as a powder company then it is the OAL that they used that created a cartridge that they considered to be appropriate for that powder and also was safe as far as pressure considerations are concerned.

 

It should be considered a reasonable starting point for your own load development. If the charge weight you think you will use is at the upper end of the load range I would suggest starting a little lower and checking for any adverse pressure indications as you work it up.

 

There are so many variables to consider as far as varying OAL, choosing bullets, selecting a powder, stc... there is no way to put it all in a single chapter in a book let alone into a single email.

 

I would suggest you start with a known recipe from a commercial source and stick to it as closely as possible. As your experience grows you can start to consider variations on that.

 

Alternatively if you are working with a mentor then I would follow their suggestions.

 

Edited September 6, 2018 by ddc

[lgh]

On 9/5/2018 at 1:00 PM, Skelt11 said:

I can’t seem to get right on that but I’m getting anywhere from 1.1415 to 1.1430.

Skelt -  Unless you have really, really precise and accurate calipers, it is probably not possible to measure accurately to 1/10,000. The calipers might read to that level but that does not mean it is accurate to that level. So in your example, the comparison is more appropriately 1.142 to 1.143.

[kneelingatlas]

While I can conceed some small degree of OAL variation is due to inconsistency in brass geometry at the rim, I think the bulk of it is due to inconsistency in bullet shape.  Think about it, you're measuring OAL from the base of the case to the tip of the bullet, but that's not necessarily the spot on the bullet which contacts the seating die, depending on the office of the bullet, the seating die contacts the bullet somewhere further down so as the diameter at that particular cross section of the bullet varies, so will the OAL.

 

I'll bet is you were using wadcutters and a flat seating die, the OAL tolerance would be much smaller.

[scubajosh77]

37 minutes ago, kneelingatlas said:

While I can conceed some small degree of OAL variation is due to inconsistency in brass geometry at the rim, I think the bulk of it is due to inconsistency in bullet shape.  Think about it, you're measuring OAL from the base of the case to the tip of the bullet, but that's not necessarily the spot on the bullet which contacts the seating die, depending on the office of the bullet, the seating die contacts the bullet somewhere further down so as the diameter at that particular cross section of the bullet varies, so will the OAL.

 

I'll bet is you were using wadcutters and a flat seating die, the OAL tolerance would be much smaller.

Agree 100%.  This is why for precision rifle loads I measure OAL with the Hornady Comparator at the ogive.  Not sure if there are inserts large enough to do pistol calibers or it'd be worth the time but it's a fact that even the nicer match grade rifle bullets can vary in length.

[Ssanders224]

Has it been established what projectiles the OP is using?  Small variances in ogive can absolutely affect OAL to this degree. 

 

Also, make sure you are not measuring high primers.  I've seen guys not consistently seating primers below flush, and then drive themselves crazy because they cannot figure out why some rounds are measuring long.