45 ACP Primers: Large Vs. Small

Two .45 ACP cartridges that look pretty much alike… but are they?

CCI’s Blazer line of economy ammunition has been around for a while. Originally they were Berdan-primed aluminum cases, but then they introduced Blazer Brass. Still inexpensive, but with boxer-primed brass cases. This brings me to my shameful confession…

“Hi, my name is Mike, and I pick up brass at the range.”

I reload, and some of them are pretty odd calibers so grabbing the brass just makes sense. I usually only grab my brass but random stuff gets mixed in. Years ago as I was sorting my brass I noticed something odd; some of the .45 ACP brass had small-pistol primers. All of it was Blazer, so apparently at some point they switched to small-pistol primers. OK, whatever. I tossed them in a different bin from the regular ones and went about my life.

Yep- CCI Blazer Brass .45 ACP uses small-pistol primers.

Over the last several years I’ve wound up with quite a few of these cases, and today I decided to load some. As I was doing so it occurred to me to wonder- does it make a difference? I mean, if it does I would assume CCI loaded their ammo to compensate. But what about us re-loaders?

I had some target loads on-hand, using a 200gr. LRNFP bullet over 6.2gr. of Universal with Winchester WLP primers. This is a pretty light load, so I figured I wasn’t likely to get in trouble with it. I duplicated these, but used the CCI Blazer brass with Federal Small-pistol primers. I set up my backstop and the Caldwell Chronograph and fired some shots.

My test-gun was the 1911 ‘Street Racer’ fukll-sized gun with a bar Sto bull-barrel.

Testing yielded a couple of surprises, the first being that this a far weaker load than I thought. Lee Precision load data says that this bullet with 6.0gr. of Universal makes 891 fps. but I got a very different result from 6.2gr-

Small Pistol Primer: 742fps. average with an extreme Spread of 44 fps.

Large Pistol Primer: 737 fps. average with an extreme spread of 23 fps.

This is way, way slower than the listed velocity led me to expect! OK, I know chronographs and conditions vary, but a minimum difference of 150 fps.?! This is one of many reasons reloading data should be approached with caution.

The second surprise was that the CCI cases all failed to extract. I a can’t account for this. I measured the two types of cases and for all practical purposes they’re identical, differing by only .002″ here and there. That’s about as much variation as I find between any two random cases of the same brand. Removing the cases was no problem; I inserted a rod down the barrel and they popped right out. The standard cases did eject, but with less enthusiasm than usual.

One thing I did change on the gun; I installed a new hammer-spring that is significantly stouter than the one that was in it before. It’s noticeably more difficult to rack the slide. It still isn’t hard, but overcoming the tension on the hammer does take more effort. I suspect this load was only just powerful enough to cycle the gun, and the new spring was enough to interfere. This does not explain why the CCI cases failed to extract. Perhaps they use a cheaper, ‘stickier’ alloy of brass that was just enough with a load of marginal power to make a difference.

Summing it Up

Looking at the results I cannot say that using small-pistol primers made any real difference. Yes, the extreme spread was almost twice as large, but it wasn’t a huge difference even so, and could just be a difference between the brands of primers. If you want to use CCI Blazer Brass .45 ACP cases with small-pistol primers go for it; it really doesn’t seem to make a notable difference in velocity.

Stay safe and take care.

Michael Tinker Pearce, 24 October 2021

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