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GUNS Magazine May 2010 - Page 20
UPONARS • GLEN ZEDIKER • RELoAdING PUzzLES And pieces thereof. lot. They do. These changes are usually minor, sometimes major. I recollect different times over my career in all this when a “bad” lot of propellant, for instance, had us all talking (and scrambling to buy up the rest of what was left of the “good” stuff). All new components should be tested and compared to that previously used. Folks, that’s what all the notebooks are for. Slight differences in cases, primers, propellant, and bullets too, mean, for me, backing off my usual load a half grain and going from there. The closer anyone is to the pressure edge the more this matters. Speaking of the edge, here’s another point I hope you all take to heart. Let’s say a load has been working fine—good groups, flawless function—and then “suddenly” starts exhibiting pressureinduced symptoms. Maybe extraction/ ejection changes, cracked or pierced primers, case damage. Pressure symptoms don’t seem to show as easily in .223 Remington as they may in other cartridges. Spent primer condition clues especially. Here’s the point: If a load starts exhibiting pressurerelated symptoms the load was already over pressure! The question is by how much? If you ever see a problem, back off a half-grain of propellant next go-around. See another? Back off another half-grain. Reasons the symptoms became suddenly clear can, among other things, have to do with range temperature or case condition (brass casings get harder, case necks get thicker, and the head gets thinner with each firing). Hotter or colder (some propellants are affected differently by extremes) temperatures can cause a load to spike. I realize the gentleman’s question didn’t involve him actually experiencing over-pressure problems, but I wanted to jump ahead a little to round out this little reader posed this question A and it is complicated enough to warrant a column, so here are the answers, and yes indeed, there is more than one answer. Dear Sir, In reloading .223 Remington I am using 24.5 grains of H-322 powder with a Remington 7-1/2 primer under a 55-grain FMJ bullet usually in a Federal case but occasionally in GI cases. I have been doing this for about 10 or so years. I am shooting them out of a Colt LE Carbine and a Ruger Mini-14. They have proven to be quite accurate. Now it seems about every loading manual except the Speer No. 12 book rates that load as too hot or doesn’t list it at all. Speer No. 12 was the original source for that load. I realize the components used by ammo manufacturers will obtain specific results and are not available to me. I was trying to get close to the 3,250 fps listed by Federal (ATK). Why is that load suddenly unsafe? Should I change the load? I have about 1,100 or so of them loaded. Respectfully, Fred J. Brightman Sun City, Arizona I’ve checked and asked around (I don’t have much experience with H322 in .223 Remington although I have used it in .222 Remington, with great results) and, rounding a little bit up and down, concluded the load given by our reader is close to a grain over most recommendations. Does that mean it’s truly over-pressure? Not always, but maybe, and, if nothing else, sure warrants some detail in an evaluation. There is zero question whether handloading components change lot to AHornadylNltoolwillletyougaugethefirst pointofbulletcontactwiththelands,andthat tellsalot.Inthiscase,it’sindicatingaNAtO chamber(usingaSierra80-grainMatchKing). It’sveryimportanttoknowthechamberinyourrifle.Manybarrelsaren’tevenstamped.this onefromDPMShas“5.56”punchedin,indicatingaNAtO-specchamber.I’dliketoseeall manufacturersbealittlemoreclear,andifyoudon’tknowyou’dbettercheck. ditty. Since he says he’s using the load in a Colt-brand carbine and a Ruger Mini-14, he’s running his ammo into a NATO chamber. Ruger says its rifle is chambered in .223 Remington, and that’s usually stamped on the barrel, and also 5.56… That means “NATO.” I’ve brought up the differences between .223 Remington and 5.56x45mm NATO in other articles, but the essence is that—and you better believe it—there are differences. Primarily, NATO chambers have more room ahead of the case neck than SAAMIspec .223 Remington chambers. A NATO chamber will take a good deal more pressure. Some tests done in the industry have shown up to 15,000 psi difference in NATO ammunition compared to commercial .223 Rem ammo. Now, that doesn’t mean everyone should up any load given for .223 Rem. just because their rifles have 5.56 chambers! Not hardly. One thing it plainly points out is that it’s important to determine what the chambering was for the test gun the loading data was acquired from. And with that, here’s the finish. If everything was just perfect, then every published load would give the same feedback. Of course that doesn’t happen. I’ve seen maximum loads listed that were way too hot for some of my rifles, and some that were amazingly empty compared to the amount of propellant I ended up using. After time, and especially time spent with the same cartridge and a select few propellants, you’ll get a good idea of where to start. After enough “incidents” 20 WWW.GUNSMAGAZINE.COM • MAY 2010