Business Meeting–January 31, Saturday 5:30pm—Heritage Cafeteria—Battlefield and Fremont
2009 Schedule – All Saturday Events
|
Date |
Time |
Activity |
|
Jan 31 |
5:30 |
Eat/Meet –Heritage Cafeteria |
|
Feb 7 |
8:00 |
Fun Shoot |
|
Mar 7 |
8:00 |
Beginners Clinic |
|
Mar 21 |
8:00 |
Beginners Match |
|
Apr 18 |
8:00 |
Any Rifle Match |
|
May 9 |
8:00 |
JCG Match $$ |
|
May 23 |
8:00 |
|
|
June 27 |
8:00 |
Vintage/Springfield Match $$ |
|
July 18 |
8:00 |
Carbine Match $$ |
|
Aug 15 |
8:00 |
Rimfire Sporter Match |
|
Sep 12 |
8:00 |
Any Rifle Match |
|
Oct 10 |
8:00 |
JCG Match $$ |
January Business Meeting and Door Prize
Our January Meeting is scheduled for 5:30 at the Heritage Cafeteria, Battlefield and Fremont in Springfield. This is the same place we have had it for years, in fact the only place we’ve ever held it. Try to get there a bit early, find the room over to the side and leave your coat, go through the serving line, back to the room, and eat. Introduce yourself to someone you don’t know or even to someone you do know. What I mean is, we sometimes don’t recognize each other without all our shooting paraphernalia, hats, glasses, etc on. So don’t be shy, say hi to someone while you eat.
By 6pm or so we should all be ready to have the business meeting. I’ll bring a printed agenda, but it will be traditional: Treasurer’s report, Membership report, Match Director’s report, Web-master’s report, President’s report, old-business, new-business, and anything you wish to say. If you’ve got some ideas, even if you haven’t thought all the way through how things might work, bring them and broach them. Time for discussion is always very short at our Saturday shooting meetings, so the business meeting is a good time just to toss stuff around. Your input on all things associated with the club is solicited—make yourself known.
For the first time, we will be giving away a door prize. I toyed with a number of ideas on this, things folks could use, things guys might want, you know, the usual shooting stuff. And then I got what I think is a good idea (you may disagree). The club owns 3 Mossberg .22 rifles, ostensibly for use by juniors. For whatever reasons, our junior participation is limited, and it seems to me that our membership has become quite good at loaning your fellow shooters a rifle, should they need one. So I see the Mossbergs as pretty much surplus equipment, and we will be giving away a Mossberg M44 .22 rifle to a lucky winner. You must have a valid 2009 membership in order to participate, and Mike Thorn usually has a pile of new membership cards with him at the meeting along with his Notary kit so that you can join the club and sign the CMP Affidavit.
One door-prize ticket will be issued per adult member in attendance. (As you know, we offer family rates, and we don’t charge extra for children in our membership. We do have a few juniors who join without the family joining, and we would consider them the same as adults. The intent here, and I hope you agree, is simply to lay out the ground rules for a drawing such that each person who pays for a membership has an equal chance of winning the door prize.) Some examples: a husband and wife, family membership, one ticket; husband and wife both join separately, two tickets; family with seven kids and one adult, one ticket; junior member with no other family members joining, one ticket. Pardon me for being the guy that reads the fine print at the speed of light on the radio, but I just want to make sure there are no hard feelings. A raffle is self-limiting—you buy the ticket you get a chance (and even here I screwed up once), but a door prize for members, given the complexity of the way we do our family and junior memberships could cause misunderstanding. Whew! I’m glad that’s done, and I hope someone gets a rifle they will treasure.
Some Thoughts on Accuracy
I have been re-reading Harold Vaughn’s Rifle Accuracy Facts, the best, most scientific treatise ever created on shooting. Harold, in real life, was a WW II fighter pilot and rocket scientist with NASA, so he has some pretty good credentials for examining the flight characteristics of things. He set out to find out what influences the accuracy of a rifle, and he left very few stones unturned in experimentation and hypothesis testing. He went so far as to attach strain gauges to the receiver and accelerometers to the muzzle in order to measure the response and movement of the rifle once the cartridge was fired. One thing he didn’t do was provide easy explanations of the type that begin “everybody knows that….” He went out and tested each factor and then created a very sophisticated mathematical model of what happens inside a rifle once the trigger is pulled. If you are interested in the details of the influences on accuracy, this book is a must-read.
On the other hand, our control of these factors in highpower rifle competition is somewhat limited. And if all you want to do is improve your scores, your time would probably be better spent on practicing your offhand shooting with an air rifle. Still, there are a few nuggets here and there that might be useful for the beginning shooter or reloader. Most of it is common knowledge for successful match shooters, even if the theory and detail behind the practice is somewhat vaguely understood. But there is so much voodoo printed about ammunition reloading that I am unsure how anyone starts out in that field. So let’s consider two or three things Vaughn found important that we might want to consider (or ignore).
A large part of his experimental research went into demonstrating that non-axial recoil of the rifle before the bullet left the barrel impacted accuracy. In other words, the receiver flexed, the bolt flexed, and the barrel flexed, all in unpredictable manners, thus disturbing the flight of the bullet away from the point at which it was aimed. It’s pretty easy to see why one rifle might be more accurate than another (the Savage 110 comes to mind as an extremely symmetrical action with a predictable bolt lockup, and it is known for its off-the-shelf accuracy), and the measures Vaughn took to reduce, eliminate, or damp these vibration were quite interesting.
One interesting section on muzzle vibration found Vaughn experimenting with fast-burning and slow-burning powders in the .270 Winchester cartridge in order to vary the chamber pressure and muzzle vibration He varied the powder charge between 45 and 65 grains with different powders, and the results are too complex to summarize here. Imagine being able to experiment with that amount of powder! It seemed that the right choice of powder and load could have a half-minute of angle influence on group size, and I think that this is where a lot of the aforementioned voodoo in reloading enters the discussion. With a large cartridge, multiple bullet weights, and the ability to vary the powder charge by 15-20 grains, there is almost an infinite number of permutations and combinations of loadings to experiment with. It would be easy to burn out a barrel just finding the best load.
Indeed, half way through his research Vaughn was disappointed in one of his experiments—he had expected better improvement in accuracy than he got from a particular modification, so he borescoped his rifle and found out the barrel was worn out. A new barrel put him back on track, and I think there is a moral there: make sure you have a good barrel before you try to fine-tune all the other stuff.
But we in the service rifle discipline have exactly zero ability to modify our rifles in the manner that Vaughn did. We can re-barrel, but other than that, we basically have to shoot what we buy off the shelf.
Luckily, the AR-15 platform seems to solve many of Vaughn’s problems: bolt lockup is excellent because of the multiple lugs, the barrel is short and fat, thus decreasing the amplitude of vibrations, and the amount of powder we can put in a .223 cartridge is not particularly variable, so our choices are limited to good, better, best in the choice of loads. And shooting with a tight sling damps all the vibrations in a predictable manner (you do shoot with a TIGHT sling, don’t you?). So the rifle issues are non-issues with the AR-15.
In examining the travel of the bullet from cartridge to barrel exit Vaughn found multiple sources of error in bullets and brass. But when you sort the whole thing out, it basically comes down to: shoot the best bullet you can buy, and then you don’t have to worry; besides, you can’t do anything to discover or remedy ‘bad’ bullets yourself—you are at the mercy of the bullet manufacturer. This is pretty much what we’ve known all along. Good bullets (such as JLK or Sierra Match Kings) shoot good, bad bullets (such as military surplus pull downs) don’t. Well, duh!
One interesting finding was that the interplay between barrel vibration, bullet exit from the muzzle, and gravity was such that it was worth the time to find a load that hit the ‘sweet spot’ in barrel vibration where barrel vibration up and down compensated for variations in powder (muzzle velocity). Match shooters have known this for a long time, and the process of evaluation is called the Audette method. In a nutshell, in testing a bullet and load combination, load a number of cartridges with 0.2 grain powder differences (say, 23.2, 23.4, 23.6, 23.8, 24.0) and shoot them very carefully at 300 yards (off a bench, with a scope). You should be able to see where each bullet impacts, and you will find subtle change in impact point caused by the change in powder weight. Usually, but not always, the faster muzzle velocity will cause the bullet to impact higher on the target because the flight time is decreased and gravity has less time to pull the bullet to earth. At some point (the sweet spot) you will find that minor powder variation (plus or minus 0.2 grains) doesn’t change the impact point. Here the muzzle is near the top of its vertical oscillation. If the bullet exits the muzzle a little before or after the top is reached, the deviation is very small. This is the load you want, because then small variations in your powder load won’t affect accuracy—so you can load your cartridges fast, from a powder drop, without weighing each charge.
Another point in reloading I found interesting was his equation for calculating the expected change in impact caused by variation in muzzle velocity. Again, to summarize in just a few words, when you chronograph a bunch of cartridges (all the same loading), you will find variations in muzzle velocity, and the range of values defines what reloaders call the extreme spread (ES). An ES of 30 fps is not unusual for a sample of 10 cartridges, and at 100-200 yards has only a 0.1” or so effect on your bullet impact, which is insignificant. At 600 yards, though, things can get interesting, at least to me, because I know my loads have fairly large ES, and 50 fps ES can cause a variation of a full minute of angle (6”). That’s too much and convinces me to work just a bit more on load development. The summary statement here would be that a large ES has no practical impact on our scores at short ranges (out to 200 or even 300 yards) because the scoring rings are relatively big—a tenth or even a half-inch variation won’t make much difference. But the variation increases with distance, and at 600 yards it can become significant.
So, most of the information in Rifle Accuracy Facts confirms the procedures that good shooters have used for a long time, even if they didn’t know the reasons behind them.
On one other issue, though, Vaughn contradicts traditional wisdom. Coating bullets with molybdenum disulfide (or other dry lubricants) is a trick shooters have tried with increasing frequency it seems. For the past 2 years I have been coating my 600 yard load (JLK 90 grain bullets) with moly. The usual claim is that it decreases bullet friction either at the throat or in travel down the barrel. Vaughn destroys this myth. His mathematical model, which almost perfectly predicts the flight of a ‘normal’ bullet, shows virtually no effect on bullet flight from changes in friction inside the bore. And his experimental tests seem to confirm that what moly does is lower the chamber pressure by utilizing some of the powder energy to vaporize the moly and its wax coating. He got lower velocities with moly on the bullets (which is typical), and when he increased the powder charge to increase velocity back to where it had been with uncoated bullets, the accuracy decreased.
By the way, Kevin Thomas, the Sierra Bullets technician published an article some years back in which he fired many thousand of rounds through two different barrels, one using moly-coated bullets and one using normal bullets. Thomas found absolutely no difference in how much wear and tear the barrels experienced. So let’s review: no gain in velocity, no gain in accuracy (in fact a loss of accuracy), and no gain in barrel life. All in all, I think I’ll throw the moly out.
What I learned from the book is the obvious: buy good rifles, buy good barrels, buy good bullets. Don’t worry too much about load development as long as your bullets are good ones and the range at which you shoot them is 300 yards or less, but it might pay to spend a day chronographing your 600 yard load. At least now I know why.
Finally, since we’re looking at things that affect accuracy here, I’d like to make a couple of my own comments about the AR-15 rifle. As we use it (nicely modified sights, float tube, etc), it is the most accurate service rifle ever created. If you purchase one of the custom uppers from White Oak, Compass Lake, or a few of the other noted gunsmiths, you will find it is no trick to make match bullets shoot under an inch at 100 yards (1 minute of angle). In fact, I would say that you should expect to get ¾ minute of angle accuracy from a custom upper with a typical load and match bullets. If you don’t there is likely something wrong with the barrel. And just about any match bullet you put down the tube will shoot well.
One of the better shooters and writers in highpower is Konrad Powers:
http://www.illinoishighpower.org/konrad/
He has posted some very interesting articles about using an electronic trainer to simulate firing using a computer at home along with his thoughts on load development for the AR-15. He says he doesn’t do load development—he just uses commonly available recipes from good shooters. Actually, the most frequent recipe I know of from his group of associates is (for .223 Remington) 24.0 grains of Reloader 15 powder with a Remington 7 ½ primer. This will work for any bullet between 77 and 90 grains. It’s basically what I use.
So there you have it. We started this peroration trying to understand what affects rifle accuracy, and we end it with the very practical advice: buy a good rifle, buy good bullets, use known-good loading data and go shoot. What could be easier?
Bill Corcoran (417) 862-861 williamcorcoran@missouristate.edu