COL 'consistently' off on a LNL, progressive in general

[balmo]

I finally moved on form a turret press onto a Hornady LNL. So far, I love how I can load faster on a progressive press.

I had some weird observation though. When I first started loading on the LNL, I only had one case on the shell plate at a time. COL was 1.128 (on a 40sw). When I started loading progressive the COL bumped to 1.138, a 0.010 difference.

What's weird was that all my rounds loaded progressively was 1.138 (with an awesome tolerance of +-0.002) Have you guys experienced having a variation in COL when loading one at a time versus loading progressively on a Hornady LNL, or on a progressive press in general?

[louu]

I have the same problem and don't know why it happens either. I also know that when in finishing the last five cases every one is different too. I think maybe the base plate tips a little,,, I don't know

[dave33]

With only one case in the press at a time all the torque is on only one point, driving the bullet a little deeper in the case. With a case in all the stations the force is spread out more evenly, thus not seating the bullet quite as deep. I bet if you look close you get a little bit more case flair with only one case in that station and the rest empty vs. having a case in all stations at the same time.

Either use a case in every station during setup or toss the first 3-4 rounds and the last 3-4 rounds in the practice bucket, if that amount of difference matters in your loads.

[JRM83]

With only one case in the press at a time all the torque is on only one point, driving the bullet a little deeper in the case. With a case in all the stations the force is spread out more evenly, thus not seating the bullet quite as deep. I bet if you look close you get a little bit more case flair with only one case in that station and the rest empty vs. having a case in all stations at the same time.

Either use a case in every station during setup or toss the first 3-4 rounds and the last 3-4 rounds in the practice bucket, if that amount of difference matters in your loads.

This.

[darkvibe]

Set it up with all stations full and don't worry about the first and last 4 rounds, the .010" shorter won't make any difference.

[Absocold]

LnL has the least COL variation of any progressive press. I've tested a great many various presses over the years and (sorry Dillon) the LnL has been the most consistent. To get any better you have to move to a single station press. And before you ask, the best single is the Forster Co-Ax.

So I wouldn't worry about your variances, it's about as good as it'll ever get. As to single loading versus progressive loading on the LnL, someone else already gave the answer: it involves variance stacking. You'll get the same effect on any hobbyist progressive.

[bodybag0]

Same thing happens to my LNL. No biggie.