45ACP Problems

[noylj]

Who cares?
Unless you are shooting well beyond 50 yards, COL doesn't matter--other than if it is a lot shorter (say more than 0.100" shorter), it can cause pressure problems.
First, get a custom seating plug that only contacts the bullet as low on the ogive as possible and doesn't come close to touching the meplat.
Two, keep the shell plate full of cases so there are no variations at the beginning and end of the loading cycle.
Three, if the round passes the "plunk" test, go and shoot them and determine if they are causing you any problems.
Four, measure every bullet before you seat it to be sure that the COL variation is not just the bullet. While doing this, check the bullet diameter.
Five, get a comparator so you can measure COL at the ogive datum.

 

[Steve912]

On my LNL I set oal with a shell in all stations. The last 3 rounds of a run will always be between .005" to .008" shorter. I have been thinking of doing the shim mod to the subplate but haven't gotten around to it yet.
Has anyone done that to see if it makes a difference?

How about three deprimed cases, cut down 1/2" from mouth? Feed them into shell plate behind your 'last loaded' round?

 

[jonnnyboy]

I ran into a similar problem like this that had me stumped until I noticed that on some of my loads, I had left the primer just slightly proud. The differences in the case manufacturer had given me some cases that were tighter in the primer pocket and that made just a little difference in the force it took to seat the primer. It's an easy fix if that might be the problem. Hope you get it figured out.

 

[Ballistic147]

I ran into a similar problem like this that had me stumped until I noticed that on some of my loads, I had left the primer just slightly proud. The differences in the case manufacturer had given me some cases that were tighter in the primer pocket and that made just a little difference in the force it took to seat the primer. It's an easy fix if that might be the problem. Hope you get it figured out.

Yep, checked the primers right after checking for a loose shell plate and die. That's one thing I like about the LNL is you really get a good feel on primer seating. I can generally tell if there's a problem by the feel of the lever.

Guess my years of building race engines for motocross gets the best of me sometimes. With those, .0005" could be the difference in finishing the race or seizing up on the first lap. I know what my press is capable of so now I just need to find out what's standing in the way of getting there. Thanks again to all for the input. It's greatly appreciated!

 

[Carrier]

How about three deprimed cases, cut down 1/2" from mouth? Feed them into shell plate behind your 'last loaded' round?

I just back seat die out a smidge when I get to those last rounds and get pretty close.

 

[flyrobb]

Thicker brass will resist bullet seating & deform the bullet nose. There can also be a slight springback. You will always have greater oal variation woth mixed brass.

I have certainly deformed a few HP bullet nose and that makes sense when seeing a shorter COL. The spring back would account for a longer COL and I hadn't thought of that.

I usually never see more that a couple thousands difference, +/- in COL (seating and crimping in separate steps) but the .015 variance the OP is experiencing seems excessive and would seem to point to a press problem, not case variances.

Another learning moment in the Reloading Forum.

 

[Ballistic147]

I have certainly deformed a few HP bullet nose and that makes sense when seeing a shorter COL. The spring back would account for a longer COL and I hadn't thought of that.

I usually never see more that a couple thousands difference, +/- in COL (seating and crimping in separate steps) but the .015 variance the OP is experiencing seems excessive and would seem to point to a press problem, not case variances.

Another learning moment in the Reloading Forum.

You and I seem to think alike. A few weeks ago I loaded 1k 9mm's and last week I loaded up 500 rounds of 40S&W. All were loaded using mixed brass with the Hornady seat/crimp die and all came out +/- .003" within my established COL. This 45 thing still has me baffled. Probably do a run of 380's this weekend and see what happens.

 

[forestswin]

 Ballistic

I think your issue comes from differences in case wall thicknesses of the mixed brass.

Not sure, but I don’t think you said it so far, but are you combining seating and crimping in one step?

If so, with cases that have thicker walls – you may becrimping a little too much and the crimp may be stopping that last little amount of seating.

Another question is ----- have you measured the COL on the different cases before you crimp them?

Is the crimp changing the COL?

I mostly crimp at .470 so your crimp seems tight

a thought is adjusting the crimps according to the different case wall thicknesses – back off for the thicker case and tighten up for the thinner ones

Or back off on the crimp to .470 or so for all cases and see if they still have good bullet pull