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.45acp not passing the plunk test.

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October 22, 2026, 01:36 PM
the Hudge
.45acp not passing the plunk test.
Hello, I have a Dillon RL 550 and am having the darndest time reloading .45acp. I believe my problem is the crimping die as my COL is textbook. I have and used both types of crimping dies and the loaded rounds will not chamber.
Any help would be appreciated.
October 22, 2026, 04:49 PM
colt_saa
Need more info here.

What projectile are you using?

What brass are you using?

Is this a NEW problem? Or one that has just popped up?

An easy fix would be to chuck up the expander plug in your drill and reduce the diameter a bit so that you increase the neck tension in the brass presuming this is just practice ammunition

If you are building defensive ammunition I would try a different projectile. Either a different batch from the same manufacture or something totally different


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October 22, 2026, 06:18 PM
sigarmsp226
Another thing to try is taking a case off of your press right after you have completed the resizing of the brass and drop it into your case gauge and/or pistol barrel. If it will not pluck or fit then you need to screw your resizing die down so that it kisses the shell plate holder. If it does pluck then you know it is related to your powder drop/case belling die or your crimping die.

Also some barrels have a very tight chamber and because 45 projectiles come in various diameters you may find that you need to try a smaller diameter projectile.
October 23, 2026, 01:03 PM
the Hudge
.452 lead round nose.
Mixed brass.
New problem as I just got this RL550 and this is my first run with it.
I’ve been reloading for decades but this my first 550.
October 23, 2026, 01:04 PM
the Hudge
Thanks for the info S226
October 24, 2026, 02:15 AM
sigarmsp226
Budge - Forgot to mention this - because you are belling your case mouth while dropping your powder charge, try and minimize the amount of bell on your cases. As I know you are aware, everything you bell must be then removed in your crimping process.

It is a little bit of a pain to fine tune this step because of how Dillon builds their powder drop/case flare station.

Ask me how I know…. Good Luck.

This message has been edited. Last edited by: sigarmsp226,
October 25, 2026, 03:43 PM
cyberiad
I agree with sigarms, I use a Shockbottle 'hundo' case gauge and every time the rounds won't fit it's due to not enough crimp. The bell has to be 'just right.' I probably bell less than I need to but I'd rather a bit too little than too much.
October 26, 2026, 12:36 PM
Jim Watson
quote:
Originally posted by the Hudge:
I believe my problem is the crimping die as my COL is textbook. I have and used both types of crimping dies and the loaded rounds will not chamber.


COL for that exact bullet? Try seating deeper, with a dummy if you worry about powder space.

Both of WHAT types of crimping dies?
October 28, 2026, 09:44 AM
the Hudge
Jim, A roll crimp and a taper crimp. Two different dies. I am currently using the taper crimp as the roll crimp was not working ether.
October 28, 2026, 12:18 PM
Chris Orndorff
Um….45 headspaces on the case mouth, so roll crimping is a no go.


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October 28, 2026, 04:32 PM
ugeesta
The 550 is easy to set up. just follow the directions

Do you have any factory ammo that you can compare dimensions with? Might show where your cartridge is out of spec.

Also, have you used .452 diameter projectiles before or is this the first time. I use .451 diameter Precision Delta 230gr FMJ bullets without issue.

Yes, stay with the taper crimp.




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