Re-thinking the "plunk" test.

[prs]

I have reloaded since the mid 1970's, but I am a relative New Bee to reloading for the 45ACP. I learned the hard way about the "plunk" test. So, last evening I was setting up to load some Lyman 200 grain flat based wad cutters, the older design. Used the plunk and was good to go. Then it dawned on my slow thought process that a sized and internal sized empty should fit the same way, right? It did, the very same, of course. Then it further dawned upon me that it might be nice to use a 90 degree angle probe to see if the head spaced empty case was aligning flush with the inner circumference of the leade when said case was taper crimped the same degree as the finished rounds. My two 45s have fairly abrupt leades and tend to scrape some boolits. I did not have such a 90 degree curette at home, but I will take a carbon fiber one home tonight. What do you Guru's of the 45ACP think? Folly or some potential benefit? If it takes more than just a small amount of taper crimp to match, I will forget about it for sure. Typically, I crimp just enough to restore the bell to the sized dimension.

prs

[fouronesix]

No matter what anyones posts- you'll probably get 3 or 4 different absolute/sure enough answers :) If the end of the throat (leade) part of your chamber is plumb and concentric and the case mouth is square and plumb, the result will be obvious- the round will headspace square and plumb and give the best chance for reliability and accuracy.

A taper crimp is the way to go with the 45 ACP- just a light touch as you are doing and just enough to hold the bullet in place during it's rough ride from magazine into full battery.

Where 45 ACP loaders and other headspace-on-mouth semi-auto loaders have problems is in first over flaring the mouth for bullet seating then trying to use a roll crimp die or over doing it with a Lee pistol FCD with the carbide collar that in effect is a roll crimp type set up. Many times that's where the errors in headspacing and out of alignment full battery chambering problems begin.

As far as trying to gauge it somehow for a taper crimp die? I think by making sure the case mouth is square to begin with then correctly using the taper crimp die- you shouldn't need to do much else.

[mdi]

How are you going to tell if the case is headspacing correctly with a 90 degree gauge? For semi-autos no crimp is necessary, just remove any case mouth flare with a taper crimp die. Mebb I just don't understand the question:???:

[Mk42gunner]

Chances are your chamber is longer than even a SAAMI spec case. I have always looked at the plunk test as a check that rounds will chamber, not one that verifies minimum headspace of a loaded cartridge.

Anymore, I only check the first time I load a new boolit, after that I just set my seating and crimping dies with the original dummy I make with said projectile.

Robert