As I mentioned before, if a rimfire round fails to fire when you are out plinking, it’s annoying. If it fails to fire in a match where speed is a major factor, it can be a disaster.
There are a number of things that can contribute to rimfire ammunition not wanting to go bang when encouraged to do so by the firing pin. Not all manufacturers use exactly the same formula for their primer compound, I’m sure. The primer compound may not be equally distributed around inside the rim. The thickness and hardness of the brass at the rim can make a difference. Brass hardens with age, so older brass, or ammunition that’s been sitting around for years may or may not work the same as when it was new.
Moisture can have a huge effect on reliability. I had half a brick of Federal bulk get rained on and it got pretty wet. Not enough to make the box fall apart, but wet, nonetheless. There was no water actually in the box to pour out, so I put the box inside the house to dry. A few days later I checked it, and everything was completely dry. I tried shooting the ammo, and every fifth or sixth round would not fire, even with multiple firing pin strikes. Would a high humidity environment affect reliability? I can’t say for sure, but if I lived in a high humidity area I might consider keeping my ammo in zip lock bags!
Some brands of ammunition seem to have a much higher rate of failure to fire (FTF) than others. Some brands also seem to work OK in one gun, but not in another. As I also mentioned earlier, what may be excellent ammunition today may change for the worse, and the folks making today’s less reliable ammunition may clean up their act and become the best. With any ammunition recommendations, you should bear that in mind.
From my experience, and from watching other shooters in matches, Remington bulk pack seems to be the most unreliable of those brands readily available. From my limited experience with Remington bulk, I would see perhaps ten or twelve FTF’s per brick. Remington’s higher priced ammo, built by Eley, is probably quite good, but I’ve not shot enough of it to say either way.
Federal bulk pack, my favorite practice ammunition, seems to FTF three to five times per brick. I’ve also tried Winchester Dynapoints and found them to be similar to Federal reliability-wise. Dynapoints also seem to be quite accurate, particularly if you weigh them and match them into lots by weight. When Dynapoints were available in Walmart for around fifteen dollars a brick they were a good choice as practice ammunition, but when Walmart dropped Dynapoints and K-Mart started carrying them, but at over thirty dollars a brick, I stopped shooting them completely. I still have a brick or so, and I am gradually using them up in e-Postal matches.
There are also a number of other brands of rimfire ammunition I’ve tried over the last few years. For several years I used Sellier & Belliot Club. It was extremely reliable, moderately priced, and quite accurate. It also had a heavy wax/grease lubricant on the bullets that could interfere with feeding, particularly if the weather was below seventy degrees, which is pretty normal for Western Washington. After some experimenting I discovered that if I dumped the rounds out of their box onto a paper towel, sprayed them with Brake-Kleen, let it soak for a couple of minutes, them rolled them between several layers of clean paper towels most if not all of the lubricant would be removed. After letting them air dry for a few minutes I’d give them a light spray of CRC Heavy Duty Silicone spray, roll them around a bit more to distribute it, then put them back into their individual holes in the ammo box. Unfortunately S & B Club is no longer available, at least if it is, I can’t find it.
I have only limited experience with American Eagle, a Federal manufactured product, and it seemed to be similar to Federal Bulk, no worse, and possibly a little better. CCI Blazer seems to be quite good for reliability, but not quite as accurate as some other choices. If I could find it in bulk at a reasonable price I’d probably switch to it for practice. I bought a case of Eley Sport, which appears to be the same as Aguila Super Extra Standard Velocity, or at least very similar. The Eley Sport is built in Mexico by Aguila. I’ve only shot the better part of one brick of it so far, and not a FTF at all. I need to shoot a lot more of it, though, as this is a rather small sample to go by.
Match ammo? For the last few years I’ve been using CCI Standard Velocity, and it’s been very good. It almost always fires, and it’s also very good for accuracy. There’s a rumor that CCI Green Tag is nothing more than CCI Standard Velocity that’s been sorted by weight. I have no idea if that’s true or not, but it shoots well enough that it could be possible.
So far everything I’ve mentioned has been relatively low velocity ammunition. For some guns there just isn’t enough energy to reliably cycle the action. Personally, I think just about any rimfire semi-auto pistol, properly tuned, will run on standard velocity ammunition without problems. In Steel Challenge, where I regularly compete, delivering a lot of energy to the steel plate has no advantage, and the hotter the ammunition the more muzzle rise you have to contend with. No point making it any harder that it already is! If your gun will only run on CCI Mini-Mags, I suspect either the gun’s action is still a bit rough, the slide spring is too heavy, or the slide itself is too heavy, or possibly a combination of all three.
If you are having higher FTF rates than these, you very well may have something, or multiple things, not quite right in your pistol, not far enough wrong that it doesn’t run at all, but just enough wrong that the gun is adding some FTF’s of it’s own.