Inconsistent .223 sizing on my RT1200 size die

[StealthyBlagga]

I am sizing .223 brass and seem to be getting more length-to-shoulder sizing variation than I think I should. Using an RCBS micrometer case gage, I am seeing an extreme spread of 0.005", which seems excessive to me. Here is my setup:

XL-650 press

Station 1: Lee Universal Decap die

Station 2: EMPTY

Station 3: Dillon FL size die with RT-1200 trimmer

Station 4: EMPTY

Station 5: RCBS Neck Size die

The shell plate is set as tight as possible while still turning smoothly. I am lubing the brass (once fired LC) with Dillon case lube, and making sure the lube gets inside the neck. The Dillon size die is set low enough that the handle is camming over, so I presume there is little slack in the system. Lastly, I am doing my best to hold the handle in the down position consistently.

I am shooting for 0.003" under chamber length, and am seeing a range of 0.001" to 0.006" under chamber length. Am I being too picky, or should I expect better? Should I consider doing full-length sizing in Station 1 and back off the trimmer sizing die? I am also considering the needle bearing modification - might this help?

Whatever suggestions you guys have would be gratefully received - I am hoping to get my reloads dialed in before SMM3G

Edited January 3, 2012 by StealthyBlagga

[Outsydlooknin75]

If you are pulling an expander ball out thru the neck after you have trimmed that could be the problem. Brass could be stretching after you have trimmed it.

I'm not sure exactly what order things happen but I would think size in one station then trim in the next.

Sent from my PG06100 using Tapatalk

[Simon]

I size first and then trim

[DEP44]

I'd put an FL die with neck bushing in 1 and the RT1200 in 3 or 4.

Getting rid of the expander ball makes my press run way smoother and headspace is more consistent since the change.

[StealthyBlagga]

If you are pulling an expander ball out thru the neck after you have trimmed that could be the problem. Brass could be stretching after you have trimmed it.

I'm not sure exactly what order things happen but I would think size in one station then trim in the next.

Thanks for the quick answer. This may be it - I sized 10 cases and pulled them before they got to the neck sizer - they came in at the shorter end of the range and with less variability (extreme spread of 0.002"; 0.007" to 0.005" under chamber length). What I am trying to do is ensure any dings in the neck are removed, neck tension is set correctly, and the square cut edge from the RT1200 is broken (for easier bullet seating). I also have a Lee Universal Flaring die; what do you think about the following alternative arrangement?:

Station 1: RCBS Neck Sizer die

Station 2: EMPTY

Station 3: Dillon FL Sizer die/RT1200 trimmer

Station 4: EMPTY

Station 5: Lee Universal Flaring die

Edited January 3, 2012 by StealthyBlagga

[StealthyBlagga]

...

Station 1: RCBS Neck Sizer die

Station 2: EMPTY

Station 3: Dillon FL Sizer die/RT1200 trimmer

Station 4: EMPTY

Station 5: Lee Universal Flaring die

I just made a batch using the above arrangement. Extreme spread on shoulder length looks to be around 3 thousandths of an inch, which seems more reasonable. I'll try to get out and shoot some groups to see if it makes a difference on paper. Hopefully this is an easy fix.

[D.Hayden]

Have you tried just doing normal fl sizing in Station one, just use the trimmer to trim? It's much easier to adjust the normal die, than the trim die

[RiggerJJ]

Dillon full length with expander ball/decapper in 1

RT1200 in 3 or 4.

Shouldn't need the neck die...

jj

[StealthyBlagga]

Dillon full length with expander ball/decapper in 1

RT1200 in 3 or 4.

Shouldn't need the neck die...

jj

I happen to already have the neck sizer die. I tried in in Station 1, just to true up the neck, still FL sizing and trimming in Station 3, and seem to be getting much better consistency.

In your experience, will a FL sizer before the trimmer give significantly better consistency than sizing/trimming in one operation? How much variability do you see with your configuration?

[snow patrol]

How do you go about adjusting the Dillon size/trim die for the RT1200 so that it only trims, but does not size?

[DougCarden]

Normally you set the size die up first.

You put the die in the toolhead without the trimmer on it.

Turn the die down until with a lubed case you are sizing it how you want it, using a case gauge.

Once it is set where you want it, lock the ring down.

Then you put the toolhead down on the case.

Put the trimmer on and rotate it down until it almost touches the case mouth.

Then slowly adjust it down running until you cut the case mouth.

You then start mic'ing the brass until you set the cutter down enough to get your desired cut. (you have to turn it on and off, kinda tedious setting up)

Once you get your desired cut then lock it down.

Run some brass and mic' it in the gauge with your dial caliper as well.

Doing this you can just set the die so it doesn't resize all the way and then adjust the cutter.

Whatever floats your boat...

Good luck,

DougC

[RiggerJJ]

Dillon full length with expander ball/decapper in 1

RT1200 in 3 or 4.

Shouldn't need the neck die...

jj

I happen to already have the neck sizer die. I tried in in Station 1, just to true up the neck, still FL sizing and trimming in Station 3, and seem to be getting much better consistency.

In your experience, will a FL sizer before the trimmer give significantly better consistency than sizing/trimming in one operation? How much variability do you see with your configuration?

I get +- .002 variance. My Dillon FL is set to do most of the sizing, but not quite all, then the trim die finshes the sizing and trims. That way if the brass I am running doesn't need trimming it can still be run without the trimmer, and it keeps the head evenly loaded, which in my feeble mind is helping with the consistiency.

different strokes, K.I.S.S., etc!

jj

[Mbauer67]

I have also been down this road and found the best results by using a full length sizing die to do almost all of the sizing, then use the trimmer die to final size and trim to length.

[Number99]

I do not size in the trim die. Size first then trim. I run the trimmer down to about .015 off the deck of the trim die and lock it there. Then just use the die to get case length.

[benos]

I have also been down this road and found the best results by using a full length sizing die to do almost all of the sizing, then use the trimmer die to final size and trim to length.

That also seems to be the favorite method of Dillon's employees.

be

[Shadowrider]

I have also been down this road and found the best results by using a full length sizing die to do almost all of the sizing, then use the trimmer die to final size and trim to length.

That also seems to be the favorite method of Dillon's employees.

be

^^^This should work well enough. I do this, only in reverse. I set my trim die to do almost all the sizing when trimming. I try to bump the shoulder back to about zero. The OAL seems to grow about +.005/.007 when sizing without trimming, so I'm assuming that the shoulder is similar. Now that I think about it I ought to check, I may be making more work for myself. Then I run them through the tumbler with walnut and lube the inside necks with mica or moly. Then I load with a normal die setup (w/expander ball) set to about -.003 shoulder setback. The trimmer doesn't leave much of a burr but there is some. I think in regards to the O/P, the small bit of burr in combination with the neck die in station 5 was causing the issue. My method might not be for everyone, as it's a pain. So I do it on large batches of brass. I've got to where I just do at least 2000 to 3000 at a time. That keeps me in ammo for awhile, lately a long while.

Edited January 18, 2012 by Shadowrider