Glen Zediker recollects and reflects on the first advice he ever got on choosing a load: all things in moderation, pressure and velocity included! READ IT ALL
I spend a great amount of space in this department warning, and I hope educating, on the signs, signals, dangers of excessive cartridge pressure. That’s all been and being done because, for the majority, maximizing velocity is an ammo-goal. Hunters, varmint and game, competitive longer-range shooters, usually want the most they can get from bullet flight performance, and also impact strength.
For me, there’s zero doubt that more speed is a better score on a full-length NRA High Power Rifle course. (Side note: it is a fallacy that lighter loads are more accurate. They’re not, or not because they’re lighter. Some of the best perforations I’ve seen are with maxed loads.)
But! I shoot a toned-down load for reduced-distance courses (as well as for the 200-yard events on full-length), and my general-purpose clods-and-cans load is a lower-stress recipe.
I mentioned last time that I had recently fired a good deal of current NATO-spec ammo and was, I guess “impressed” is the right word, with its power level. The stuff I make up for afternoon fun-runs is a good deal less stressed.
I’m not at all recommending a “light” load. Just let’s call it a solid “medium.” Looking over my notes for the past umpteen years, going through my last most current load-data notebook, I saw what was to me an interesting happenstance. I tended to be pretty much right at one-and-one-half grain less than maximum (and about two grains with .308-class rounds).
Thats not a light load! It’s “three halves,” three one-half grain drops. That half-grain, and some might recollect my mentioning this a few times in the past, is my always-recommended “come-off” step for any pressure sign (not a tenth or two, but a “full” half grain). Any other over-pressure indicator from that point then signals need to come off another “full” half-grain. So I pretty much come off those two halves from the get go, add another, and, guess what? Never nary a pressure concern.
Slightly faster-burning propellants, in my experience, lend themselves better to the “medium” power level reduction in terms of maintaining accuracy. As always, “faster” and “slower” are values within a small range of propellant rates suitable for a particular cartridge and bullet. And, in following this plan, when needed bump it up to full speed with predicatable results.
For .223 Rem.-class cartridges, a half-grain is worth ballpark 40-50 feet per second, again depending on propellant.
The advantages of a “medium” load are predictable, but here’s my list: plain old easier on the gun, and on the barrel, and on the self. Again (and again) I’m not talking abut a “light” load, just one that’s maybe 95-percent, a solid 150-200 feet per second less than published maximum. Case stress will be reduced, and that’s associated with length trimming frequency and overall “life” before primer pocket enlargement and general stretch-thinning, cracking symptoms retire the brass.
Back to my “story,” which was the interesting happenstance (all this was all brought back to me by the initial outing with my new old AR15 I talked about last edition, and my 16-year-old son asking me if I could teach him how to reload because we ran out of ammo so quickly…): So. When I first learned to reload I was 15. This event coincided with my first AR15 rifle, which was purchased new at a Skaggs drugstore. Right. My mother did not eagerly agree to sponsor a reloading setup, but, being a wise-enough woman, did interpret the math the same way I did: I could shoot a lot more for a lot less if I was doing my own. So, I had a friend, Gary. Most fortunate man to know. Gary, and I see this more clearly each year that passes, knew more about guns and shooting than any 10 people I have since encountered.
We went to Bald Bob’s Sporting Goods in Rifle, Colorado. He chose an RCBS kit for me, a piece at a time. Bob sold RCBS only. Press, dies, scale, meter, case lube, doo-dads, and, of course some propellant and brass and bullets and primers. And a Sierra Bullets loading book. So, back home, and a short time later, there I sat before my new array of green pride-and-joys. After stern lectures about things I was never supposed to do, and at least an equal number of things I was always supposed to do, we got this show flowing downriver.
Gary had chosen IMR 4198 for me for a propellant. He said it was clean-burning and economical. Didn’t take much of it. I had some Speer 55-grain full-metal-jacket bullets, some Remington cases to go along with the empties I had saved in a paper bag, and some CCI primers. Now. We looked at the loading tables in the Sierra Manual, and he had me find my cartridge and bullet. (He already knew exactly where we were going, so this was for my benefit.) He pointed out the “maximum” load and the “starting” load, one on the far right and the other on the origin point of the table on the left. He then counted back two places from the far right: 20.5gr. He said, “There. That’s the one. It’s not going to give you any troubles, and it’s adequate for function.”
“That was easy,” I thought.
I have since learned that advice was too good not to share.
If you’re looking for a good load, and you know the propellant is wisely-chosen, going two steps down from the manual-listed maximum should, indeed, be a great place to start, or to stay if you are sans chronograph. Time after time, I have noticed over the many, many years I have now been doing all this, that the “two steps back from max” procedure is safe, sane, and satisfying.
I shot about a gozillion rounds of 20.5 grains of 4198 through that SP1. Since it was not a max load, I could also change the bullets without worry, going from one brand to the next at the same weight, of course. I could change cases and even primers. It was a tenth shy of one-and-one-half grains under maximum. I don’t recollect ever grouping that rifle on a paper target. I zeroed it based on preference and I also don’t recollect ever missing anything I aimed at by more than a little bit, and never twice.