Dillon 550 9mm oal issue

[JJE]

Recently got a Dillon 550. Dies are set to load at 1.06 124 gr jhp bullet. I’m getting very consistent depths a little +~ not enough to affect anything. I am getting 4-7 out of a hundred that load way to short like 1.02-1.04. RmR nukes measurements are consistent. Any ideas what could cause a couple to load that short? Fit in the case gauge but obvious there loaded way short. Dies are Dillon.

 

[Hoser]

Recently got a Dillon 550. Dies are set to load at 1.06 124 gr jhp bullet. I’m getting very consistent depths a little +~ not enough to affect anything. I am getting 4-7 out of a hundred that load way to short like 1.02-1.27. RmR nukes measurements are consistent. Any ideas what could cause a couple to load that short? Fit in the case gauge but obvious there loaded way short. Dies are Dillon.

Confirm you are seating 124 JHPs at 1.06 as a goal and are getting 1.02 - 1.270 ?

 

[JJE]

Yes, getting a couple completed rounds out of 100 that are way out of line with the rest. Fixed that 1.02-1.038 on a few per 100.

 

[Hoser]

Pull the bullets from the long and shot ones. Measure them. Most likely it is just the JHP making things seem bad.

 

[JJE]

The bullet itself is seated very low even to the naked eye.

 

[RegionRat]

If the surface used by the seating stem is different than the one you are measuring then the irregularity is due to variations in the difference in those two surfaces.

So for example, if you are measuring to the tip of the bullet with a flat anvil, but the seater uses a circular area below that tip, there will probably be differences between the surface where the seater is referenced versus the tip.

ETA: the only other way is a very severe difference in the seating force to the point where it should be detectable when you check them by bumping them in an arbor style press or one with much more sensitivity than the Dillon.

 

[fkimble@charter.net]

The first couple rounds when all 4 positions are not in use will have some tilt in the shell plate. Measure rounds 5 and up. And make adjustments with all positions in use.

Frank

 

[JJE]

Thanks will give that a try.

 

[kenhwind]

I do not think the Dillon dies have a seating plug for JHP.
A hollow seating plug like Redding uses might be a better option.

 

[RegionRat]

It could still be what Frank was suggesting with shell plate tilt, but the description and amount sound very funny.

Adjusting the slack in the shell plate is important.

When it is left too sloppy, it can tilt. (I would also inspect it to make sure the bottom is flat and each station dimension is matched. There have been QC issues in the past, but not lately.)

Those tilts make it difficult to adjust any individual station since the shell plate loads only the one you are focused on, then can do something different when all the other stations are loaded.
When the shell plate is empty and the first operation tilts the shell plate up, there is usually nothing at the position of the seating die.
By the time the other stations are doing work, the shell plate gets loaded down by those other operations and may tilt differently or not at all.
It would be unusual to get that much difference unless there was something really wonky with the OP's shell plate situation.

The OP will have to run down all the possibilities and make sure there isn't too much slop on that main shell plate shoulder bolt or if that shell plate is rocking, and also make sure the seating stem surface is the same one used for length inspections.

If the ammo is critical, then the last resort is a 100% inspection screen for critical fits.

 

[JJE]

Think I solved the issue today. It was only FC cases and occasionally Blazer. No issues with Starline and Winchester new and once fired. Variations went down to a couple thousandths at worse.

 

[divingin]

Think I solved the issue today. It was only FC cases and occasionally Blazer. No issues with Starline and Winchester new and once fired. Variations went down to a couple thousandths at worse.

I personally don't see how that would make a difference, but as long as you're happy, problem solved.

 

[Rsadams]

It's not uncommon at all to see seating depths different... The thickness of the head on the brass etc.... Longer seating depths are fine as long as they chamber.... Shorter depths can cause pressure problems you don't want... Once the die is set it can't seat any shorter or deeper.... What your seeing is in the brass and bullets...Don't mix your brass if your die is setup with blazer , run blazer... When you change bullets or brass expect depths to change.... I went from Hornady to x-treme bullets in 10mm yesterday both the same weight and it of course changed... I then went from blazer to starline brass and it changed again...

Anytime you change stuff , be ready to check and readjust it again... You will find it hard to get exact depths on pistol and rifle... I proved it to myself by measuring base to ogive on my rifle loads... With calipers the depths aren't exactly consistent but base to ogive shows they were pretty close for sure... Sierra match kings will have you chasing something that isn't actually happening in rifle seating...

 

[JJE]

It's not uncommon at all to see seating depths different... The thickness of the head on the brass etc.... Longer seating depths are fine as long as they chamber.... Shorter depths can cause pressure problems you don't want... Once the die is set it can't seat any shorter or deeper.... What your seeing is in the brass and bullets...Don't mix your brass if your die is setup with blazer , run blazer... When you change bullets or brass expect depths to change.... I went from Hornady to x-treme bullets in 10mm yesterday both the same weight and it of course changed... I then went from blazer to starline brass and it changed again...

Anytime you change stuff , be ready to check and readjust it again... You will find it hard to get exact depths on pistol and rifle... I proved it to myself by measuring base to ogive on my rifle loads... With calipers the depths aren't exactly consistent but base to ogive shows they were pretty close for sure... Sierra match kings will have you chasing something that isn't actually happening in rifle seating...

For 9mm could it vary by a couple hundredths? 124 gr RMR Nukes JHP

 

[TIMO]

The first couple rounds when all 4 positions are not in use will have some tilt in the shell plate. Measure rounds 5 and up. And make adjustments with all positions in use.

Frank

Also, the tool head has some play as well. I have always adjusted the tightness of the shell plate by how it feels when it is indexed through the stations. Not too loose and not too tight.
Just my .02
Tim