Help with Bullet seating on Hornady LNL AP

[Parks2055]

Hey Folks,
I have been loading for a few weeks now and having some trouble with consistant COL.
Loading 40S&W on Hornady LNL AP with Lee 4 die carbide set.
I have been loading one at a time until I become confident adding more shells and keeping an eye on everything.
Loading one case through all the stations I get a consistant COL 1.123 to 1.127 which seems to be acceptable, but when I add more shells to the plate the COL is jumping up to 1.130+.
I don't feel that I am getting too much resistance with all 5 stations filled to affect seating.
Should I back off the sizing die a touch and see if that helps?
Any other suggestions?
Thanks!

 

[kingmt]

My guess is it is your powder measure but it isn't enough to worry about.

 

[BYJO4]

There will always be minimal flex with the shellplate when all 5 stations are in use. Make your final length adjustment with brass in all the stations. OAL should be very consistent (plus/minus .002).

 

[dbarnhart]

You may want to grab a dozen factory rounds and measure them. Last time I did that I found more variation than in my LnL-produced loads.

 

[Walkalong]

It doesn't matter what OAL you get running one round through by its self. When you are running with all five stations in use the OAL will be different due to flex in the press. As long as the OAL spread is .005 or less when doing running with all stations in play, I would not worry about it.

I don't feel that I am getting too much resistance with all 5 stations filled to affect seating

I do not even have the sizer in and it matters. When crimping in a second step (fifth station), the first round that gets seated (No crimping going on yet) will be up to .005 shorter than the next rounds being seated with crimping going on.

You can't feel .005 flex.

 

[gregj]

Ditto on flexing of the sheel plate. I see this as well on my LNL. I dont fine tune my OAL until all 5 stations are in use. The first and last rounds may be off a little, but it'll never be enough to matter.

 

[john16443]

Like stated, base the final COL on what comes out of the press when all the stations are full. There should be good consistency then. At the start of the session that isn't a problem, but at the end of the session when you're down to your last 3 bullets to seat, you have to do something to keep the first 3 stations full. I just keep a handful of fired primed cases handy, and after I feed the last case that will receive a bullet, I keep feeding these used cases to keep the shell plate full. Once my last completed round is ejected all I have to do is dump a couple cases of powder back in the hopper, and remove the empty cases for future sessions..

 

[sugarmaker]

I made a post about this several months ago with pictures, but:

If you want consistant OAL with various shell plate loads, the following work for me:

1.) I cut an old washing machine rubber foot in half and made a squash washer that I leave on the plate full time. I'm guessing it takes 2-300 lbs to compress at top stroke. This will cut your variation in half all by itself. It basicly removes the slop in the linkage and ram by seating them each time.

2.) Use a non-crimp seater and adjust it to bump the shell plate .002 or so with a fully loaded press (including crimp) and the above washer in place. Then adjust the seater stem for OAL. Crimp in another station. Your OAL variation will shrink to that caused by bullet ogive variations and will be hard to measure with calipers (Like .001). You will not damage the die as the press is a big aluminum rubber band and has enough give so it doesn't develop that much force on the die base.

 

[kingmt]

For a 40 S&W? Why even worry about it?

 

[Bovice]

You will not damage the die as the press is a big aluminum rubber band and has enough give so it doesn't develop that much force on the die base.

This is not true. Your applied force is what it is. That force creates a stress over the face of the die that is hitting the shell plate, where

Stress = Force/Area of contact

Repeatedly causing this stress will, over time, wreak havoc on your die threads. the threads are experiencing the same force over a smaller area, and if the stress exceeds the yield stress of the die material, your threads will be damaged. The "rubber band" analogy of the aluminum is true only to the extent that you are straining the aluminum. As long as this strain remains in the elastic region, the aluminum will return to it's original size.

I do not suggest that you set your dies so low as to be compressed directly by the ram. Even if you don't reach critical stress levels, over time you will have material fatigue. Given the high cyclic rate of a progressive press and the expected service life, this is a concern.

0.005" of high-to-low spread is perfectly fine. You might get it down to 0.003" with some practice, but it won't make any difference in your ammo. On my LNL with .40, I am between 1.130 and 1.125.

 

[BWB]

Don't forget to check that the plate retaining socket screw is tight. It seems to be a trait of these presses that it is very likely to work loose, either gradually or not so gradually, which will cause uneven shifting of the shell plate on the column. I have a fix for this, and I'll try to get some pictures and figure out how to post them.

 

[Parks2055]

Great advice - Thanks to all!

 

[Master Blaster]

Screw your seting stem down so you are getting the correct OAL with All five stations in use.