"Plunk-Test" .45acp Question...

[Blazerbowe]

Still fairly new to reloading, but getting better and better each time out. One of the best bits of advice I got from this forum was using the "plunk test" to help with determining proper OAL. This has helped immensely. My question, however is this:

Loaded a new batch of 185 gr Hornady XTP .45 acp rounds last night. My brass is a mix of my own once-fired brass (a mix of Remmington and Winchester mostly). I seated the rounds to a consistent 1.200" OAL. After finishing 100 rnds, I used the barrel of my Kahr to perform the "Plunk-Test".... just to see. 95% of the rounds I made performed perfect. A handful, however, would not slide in more than half way. With pressure, they would seat. But definitely not a plunk.

Just curious at to what usually is the cause of this? Is it just a bad piece of brass? Or is there something else that can cause this that I'm not seeing. Micrometer measures are all pretty much identical.... but a few rounds just don't plunk. Not terribly worried.... just looking for knowledge. Thx!

 

[rcmodel]

Best guess is a slightly bulged case from seating short bullets crooked, or over crimping.

Take one that won't "plunk", and color it all over with a black magic marker.

Then put it in and take it out.

Where the black rubs off is the problem.

rc

 

[Walkalong]

Try the magic marker. It works.

Plunk Test, with Pics
.

 

[56hawk]

How much are you crimping? Differences in case length might be just enough to cause 5% to have problems.

 

[Lost Sheep]

Related thread

Please see this thread for a comment.

http://www.thehighroad.org/showthread.php?t=691050

Did not feel it appropriate to clutter this thread, as it is just a bit off-topic.

Thanks for reading.

Thanks, Blazerbowe, for posting your question.

I cannot add any more advice than rcmodel, but to ask two questions. Does it happen with the Winchester brass more than with the Remington? If you measure the diameter of the cartridges (or the bullets themselves before seating) is the diameter consistem, that is, could they be out-of-round?

Lost Sheep

 

[Blazerbowe]

Thx everyone for the responses.

As for crimping, I haven't been putting hardly any crimp into the round. Just a smidge to remove what little flare I have added. I'm using a Hornady LNL press with Hornady dies and I'm seating with their single seating/crimp die at the last stage. Again, very little crimp if any.

I did the test with the magic marker and sure enough, it seems just a small portion of the brass has a bit of a bulge. Not sure if I caused it by seating a bullet crooked, as rcmodel suggested, but nonethless I've got a hair-bit of a bulge. I didn't check to see if was a Win or Rem issue.... but I will.

I racked these through my 1911 and they seem to chamber fine inside the gun. Just don't pass my "Plunk Test" with the barrel out. Think these are safe to shoot? Or should I find the culprits and remove them? Thx again for all the expertise. Really enjoying my new found hobby!

 

[Blazerbowe]

Thx for the link Walkalong.

http://www.thehighroad.org/showthread.php?t=506678

There's some good info in there!

 

[Otto]

Loaded a new batch of 185 gr Hornady XTP .45 acp rounds last night. My brass is a mix of my own once-fired brass (a mix of Remmington and Winchester mostly). I seated the rounds to a consistent 1.200" OAL.

Hornady specifies 1.225 COL (minimum) for the XTP 185. I don't recommend seating below their published load data.
Suggest you find a bullet that doesn't jam into the Karh's short throat.

Here's a Hornady factory round in a Karh chamber...the problem is obvious.

 

[rcmodel]

Just don't pass my "Plunk Test" with the barrel out. Think these are safe to shoot?

They are perfectly safe if you, or the slide, can always push them in all the way.

It starts getting unsafe when you get one stuck in the chamber and need to unload it without shooting it.
And you can't pull the slide back to do it.

Then you got a safety problem.

rc

 

[918v]

I vote crooked bullet seating. The bullet shank is rubbing the freebore cuz the round is not concentric.

 

[Scuba_Steve]

Thanks so much for posting the magic marker trick. I've only been reloading since mid-summer and had no issues with 45acp, 10mm, .357, and .44.

However, my 9mm had 1 or 2 per hundred that would not pass the clunk test. The marker clearly shows the problem about 1/8" from the base of the casing. My theory is the shell plate was causing it, in my early reloading I don't think I was tightening it dowwn enough.

 

[Walkalong]

The marker clearly shows the problem about 1/8" from the base of the casing.

I have a tight chambered (SAMMI minimum) EMP. It runs like a Swiss watch with factory ammo or reloads that pass my Wilson case gauge. .391 and smaller where you are talking about chambers fine. Anything over about .3915 is problematic. .393+ will chamber in my other 9MM chambers, but even so, I now gauge all my sized 9MM brass. I have to toss about 10 to 15% of range brass and 5% or less of my fired brass. Try measuring one of those spots on a round that will not chamber easily and see what it is. I do not gauge the finished round. No problems.

I have switched back to my Lee sizer since the pic with the cases. It sizes them a hair tighter at the case mouth. It does not size them any smaller near the base, but it doesn't leave any little uneven spots where the sizer stops.

 

[Ritchie]

It sounds like a taper crimp die might be a big help. Seat and crimp in separate operations. Until yours arrives, it is theoretically possible to remove the decapping stem from the sizing die and barely start the case into it. The safety of this process is dubious and debatable. I do not recommend it and leave you the council of others wiser than myself. Especially with a progressive press.

 

[Walkalong]

A taper crimp will not help his problem near the case head as described, whether form a taper crimp die or the sizer.

 

[erikk8829]

Lee bulge buster in a SS press will solve the problem 99.9% of the time

 

[Walkalong]

If my regular sizer will not size a 9MM case to fit my Wilson case gauge, I toss it. I figure it has been over stressed and I have so much 9MM range brass that recycling a few here and there is no big deal.

Can they be "saved" with the new bulge buster or G-RX dies? I guess so, but I am happy with my way.

Lee says it doesn't work with 9MM.

As far as .45 ACP goes, what kind of pressure does it take to bulge one at the base where it doesn't chamber well? I don't know, but the .45 ACP operates at low pressure, if loaded properly.