XL650 OAL Variation

[hermes_actual]

I have an XL650, Lee U die, SSI Alpha Dropper powder funnel, MBF bullet dropper, RCBS competition seating die and Lee Factory Crimp die. My OAL goal is 1.100. I'm able to achieve this consistently with roll-sized Blazer brass. With non-rollsized mixed brass, I will sometime see longer OALs (up to 1.125) which don't feed reliably in my pistols. I don't want to have to rely on rollsized brass if I can avoid it. Any thoughts appreciated.

[HesedTech]

2 hours ago, hermes_actual said:

up to 1.125

The reason you get a constant OAL with a single stamp of brass is because the cases are the same. 9MM has a tapered thickness from base to opening and the thickness varies between brands. Additionally not all brass alloys have the same softness/elastic deformation. Throw in the movement of the press and your hand's inability to actually measure precision force and there you go, a variation in OAL.

 

Roll sizing only sizes the bottom third of the case so the sizing die does the most work. 

 

However, .025 variance is a bit large for me. Suggestion is to make sure you are setting up your press with all the stations filled and your pull is all the way to the stop.

 

Lots of threads here on this very thing.

 

The quest for perfection!

[Dr. Phil]

Agree that the variation is a bit large. Mine was a bit less so I dropped my O.A.L. to 1.080 which fits in all of my chambers and I use that for everything.

[hermes_actual]

13 hours ago, HesedTech said:

The reason you get a constant OAL with a single stamp of brass is because the cases are the same. 9MM has a tapered thickness from base to opening and the thickness varies between brands. Additionally not all brass alloys have the same softness/elastic deformation. Throw in the movement of the press and your hand's inability to actually measure precision force and there you go, a variation in OAL.

 

Roll sizing only sizes the bottom third of the case so the sizing die does the most work. 

 

However, .025 variance is a bit large for me. Suggestion is to make sure you are setting up your press with all the stations filled and your pull is all the way to the stop.

 

Lots of threads here on this very thing.

 

The quest for perfection!

Thanks Doc! Makes sense.

[hermes_actual]

13 hours ago, Dr. Phil said:

Agree that the variation is a bit large. Mine was a bit less so I dropped my O.A.L. to 1.080 which fits in all of my chambers and I use that for everything.

Thanks. Might do the same...

[Miranda]

there is an amount of tolerance in the moving parts

and If your cases are mixed you have to keep any slop to a minimum.

my best guess is that a tough to size case will force the other side of the shell plate up

and... create a slightly shorter OAL in the round in the seating die.

 

the shell plate a snug as possible will help.

 

miranda

[lgh]

"Suggestion is to make sure you are setting up your press with all the stations filled"

 

Start with this. I've found it critical.

 

Lots of threads on using mixed brass.  Some have no issues and some do.

[Runswithwood1]

If you're not roll sizing all of your brass I would suggest dropping the average oal, I had to in my 2011s and have stuff ranging from 1.12-1.14 range and works fine

[Gunner66]

I started with a U Die and switched to a Dillon Sizing die.  There was no difference in OAL variance with mixed brass.  I would suspect that the seating die.

[Sarge]

On 8/20/2024 at 11:55 AM, HesedTech said:

The reason you get a constant OAL with a single stamp of brass is because the cases are the same. 9MM has a tapered thickness from base to opening and the thickness varies between brands. Additionally not all brass alloys have the same softness/elastic deformation. Throw in the movement of the press and your hand's inability to actually measure precision force and there you go, a variation in OAL.

 

Roll sizing only sizes the bottom third of the case so the sizing die does the most work. 

 

However, .025 variance is a bit large for me. Suggestion is to make sure you are setting up your press with all the stations filled and your pull is all the way to the stop.

 

Lots of threads here on this very thing.

 

The quest for perfection!

For me all of the above plus lube cases is a must for consistant oal.

[Sarge]

23 minutes ago, Gunner66 said:

I started with a U Die and switched to a Dillon Sizing die.  There was no difference in OAL variance with mixed brass.  I would suspect that the seating die.

No such thing as no oal variance with any brass. You can get pretty close using the guidance provided in this and several other threads on the topic. U Die is what I use because I got a little set back with a Dillon.

[Gunner66]

53 minutes ago, Sarge said:

No such thing as no oal variance with any brass. You can get pretty close using the guidance provided in this and several other threads on the topic. U Die is what I use because I got a little set back with a Dillon.

You are correct,  should have said minimal variations.  1.123, 1.127, 1.120  etc.