Crimping My Style

| January 5, 2015 | 3 Comments

For me, 2014 was the Year of the Blackout. In an effort to reduce weight I gave the AR15 platform a chance. My experiment succeeded, and my AR15 pistol is my EDC. However, short barrels aren’t great for 5.56 and so that led me to .300 Blackout. In summary, I learned a lot this year — and I typically learn by failing.

I struggled the most with handloading my .300 ammunition. I started with 5.56 Lake City blanks, cut and reshaped them, trimmed them, and then loaded them.

Every iteration of my case conversion and reloading process yielded more reliable results.

Most of my rounds would fire. Some would not, despite a very heavy primer strike. This was the most obvious (and embarrassing) during a carbine course wherein I had over 40 failures to fire this way. When loaded a second time they fired fine.


I initially thought my case length was the problem, so pulled all of the really short cases and tried again. That helped some, but not completely.

I revisited how I formed the shoulder on my cases, and that helped a lot.

However, there was one last thing that I couldn’t figure out until almost then end of the outdoor training season.

It turns out that Lake City blanks have varying degrees of primer crimp.


All three of these cases started their lives out as once-fired Lake City 5.56 blanks. They were all cut and reformed by me.

The left and middle cases have the factory crimp in them.

The far right case has been swaged by a Dillon Super Swage 600.

It might be hard to tell from the photos, but the left and middle cases have very different crimps. I loaded the first few hundred blanks myself, and used light but consistent pressure when seating the primers. I had some help halfway through the season, and depending on who was running the press the primer was seated differently.

The biggest problem with the crimp is that the primers wouldn’t always seat completely level. Apparently this results in much more force being needed to detonate the primer. This may also explain why batches that wouldn’t fire in some bolts would fire in others.

Regardless, it was worth the money and the brief extra effort to consistently swage all of the primers. In my first 1800 rounds loaded, I had about a 5 – 6% failure rate due to the poorly seated primers. The failures is that they seemed to run in streaks, which was particularly frustrating during class.



Swaging the primer is easy (usually I have the 600 secured to my reloading bench), and only takes a few seconds. Compared to all of the other prep work I do for the .300 cases, this additional step is well worth it.

If I had encountered the more robust crimps first I would have saved myself a ton of trial and error. Unfortunately (?) the first 300 rounds I loaded only had 2 misfires, and my lucky streak led to a poor technique.


About the Author:

Short Barrel Shepherd Short Barrel Shepherd is a regular guy and works to make Web sites and mobile apps easier for people to use. He spends his free time attending fight-focused firearm, knife, and combatives training, motorcycling, writing, and playing games. His daily carry is a Glock 19 pistol and an AR15 .300 Blackout pistol in a backpack.
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3 Comments on "Crimping My Style"

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  1. David says:

    I finally bought a single stage reloading press last week, so these reloading articles are finally starting to make more sense to me. Thanks!

  2. Andrew says:

    Sorry to hear about your crimping issues. I have a different method of removing crimps. My crimp removal tool is the camfer tool. It cleans the brass off the lip of the primer area with one or two twists. I have never had a miss fire or primer fall out with this method. I am sure other disapprove it works and I already had the tool.

    If you aren’t using a case gauge to verify your resizing I highly recommend it. The only problems I ever experienced with BO was inpromperly sized case necks when my die became loose. Had I been dropping the formed cases in the case guage to check them I would have saved alot of hearth ache getting that case out of my chamber.

    Good luck with the BO I love my supersonic barnes loads for deer and hog hunting.

  3. Phillip says:

    Glad you’re getting it all figured out. I’ve been using a spinning cutter that cuts out the crimp, but the Dillon unit looks a lot faster, so I’m tempted to switch to that. Thanks for the update.

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