Gun Thread: Mail Call! [Weasel]

And who better to deliver our mail than Son of Mailman!!

Last week our pal RI Red posted a good question in the comments. I thought it would be nice to write a little more thorough response than could quickly be done in the comments, so I asked to defer the answer to this week. Here 'tis:

RI Red asked:

Can you describe the sequence of events you use for setting up a shot, and what of the equations are you doing in your head at the last second?

By the time you're behind the rifle looking through the scope with your finger on the trigger, a lot of things need to have already happened to give you a reasonable chance of consistently hitting the target. The "sequence of events" really begins way before you find yourself on a rifle range, and on game day is as much about the things you don't have to think about, as it is about the things you do.

1000 yd Setup, Phoenix, AZ

First off, let's think about the target. It's 1,000 yards away and the 'X' and 10 rings are 5 and 10 inches in diameter, respectively. If you find yourself placing more than a few shots outside the 10 ring during a 20 round match, you get the participation trophy. So the question becomes what is necessary to place say, 17 out of 20 bullets into a 10 inch circle, and perhaps 10 of those 17 inside the 5 inch X ring? The short answer is to do everything in the process as consistently as possible, and eliminate as many of the myriad factors as possible that can lead to an errant shot. Seems obvious, but if the bullet doesn't go where I expect it to, then I really don't want to start working on a list of 20 different factors which could be causing the problem.

So allow me to take a few steps back, and for the sake of the argument lets assume for whatever reason the shots you're taking are really important and you want to make them count.

Ammunition
A significant amount of time is spent reloading match ammo. By the time I get to the firing line with 20 rounds for a match, I've probably already invested an hour or two in preparing just those 20 rounds. That includes case preparation (trimming, cleaning, annealing and sizing), sorting match grade bullets by ogive measurement, trickling powder to a precise weight by the fraction of a grain, or literally by the speck, and then finally seating the bullet. Absolute consistency in match ammunition, both in sourcing and preparing components, and assembly of the finished product, is essential. All that consistency pays off, though. The extreme spread in muzzle velocity for three rounds of my match ammo is not more than 6 fps indicating a standard deviation of around 3 fps, or less. This consistency eliminates the unforced error of elevation on target due to velocity excursions. I am absolutely confident in my ammunition when I get to the line.

Mental Preparation
This is something you don't hear much about, so I will include it here. A day of competitive shooting is stressful and I'm usually exhausted when it's over. By the time I get back to the hotel in the late afternoon, I have enough time to clean the rifle, check my gear, grab a sammich and relax for a while before it's time for bed. The next day I get up around 5am, get something to eat, check the weather, load the car and it's off to the range. Do this every day for a week and you're pretty pooped! If you're out late frolicking with strippers, then chances are you will not perform at your highest potential early the next morning. Be prepared and have confidence in your equipment and your abilities. I've seen timid or otherwise non-confident shooters lose matches based on this aspect alone.

Equipment and Setting up Your Gear
Keep it Simple. I take exactly everything I need to the firing line, and little else. I pack my range bag exactly the same way every time, and set up my gear on the firing point in exactly the same way, every single time. I don't know how many matches I've shot but it's a lot, and I know where everything is by touch without getting up from the rifle or spotting scope to look for it. I don't want anything to disturb my position behind the rifle once I get settled in, if at all possible. You should be relaxed and comfortable, not scrunching yourself up or straining your neck to get the proper eye relief behind the scope.

FREE TIP: For those of you shooting longer distances, please pay attention to the rear bag in your setup. After goofy ammo, it's generally the biggest culprit in errant shots, particularly elevation, and the thing most new shooters overlook. You need a very solid platform and after the recoil of a shot you want the rifle to return to exactly same position as it was before the shot. If your shit is all wobbly and unstable, then chances are you're wasting ammo.

Performance and a Cold Bore
The first few shots of a clean, cold barrel do not behave the same once they leave the rifle as the next 80 or so will. I know that my long range match gun shoots a cold bore shot high/right about 1 MOA, and I expect it. It pays to know this if you cannot take fouling shots and a first round hit is important. Most matches allow a blow-off period at the start of the day to allow shooters to foul barrels. Some law enforcement and military shooters will foul their rifles after cleaning them and before putting them away.

So these were some of the things I have taken care of and checked off my mental list so I do not have to worry about them once the shots begin to count.

The Shot
So now I have all my gear and rifle set up and there are only a couple of things left to do, namely dial in the elevation and windage and wait for the match to begin. First, we'll look at elevation adjustments. If you have been shooting for a while you'll probably have an approximate idea how much elevation is required to place a shot on a 6' x 6' target frame at this distance. You may know this from your general experience shooting at 1000 yards, or from actual experience on that specific range, or by use of any one of a number of ballistic computers. However, to make the shot with less than 5 inches of vertical dispersion (10 ring) above or below the intended point of impact requires a little more precision.

Let's say you took notes the last time you were on the same range and recorded an elevation of 37.5 MOA. You take your first shot and it is one full MOA, or about 10.5", low. Welcome to the 8 ring, and congratulations on losing the match. So what happened? Well 37.5 MOA may have been the correct elevation a month earlier, but clearly it's not correct today. Is it your ammo? Or is something loose on the rifle? Is it the rear bag thing that Weasel told you about? Did you record the wrong value last month? Maybe you just suck. Are you going to shoot again and risk another low shot? All those factors can contribute, and are all entirely avoidable.

How about the weather?

If you know the weight of the projectile and it's velocity leaving the barrel, and certain atmospheric conditions affecting air density then you can compute a firing solution. Most generic range cards use a "standard" atmosphere, from which there are several to choose. I use the ICAO atmospheric model, which is; air temp 59 F, air pressure 29.92 Hg, 78% RH and an elevation of 0' or sea level. But what if you're not shooting in precisely these conditions? What if you take a trip from your home range near the beach and go hunting in the Colorado mountains? Since it's cumbersome to record and use all of that data, it can be combined into the single reference value Density Altitude (or DA) which is simply expressed as a variation in altitude to the standard column of air at sea level. If you have been faithfully recording data in a little notebook in your range bag, you should have been including the DA, range to target, and the necessary elevation in MOA or mils for future reference.

Density Altitude is published for local airports, and many online calculation tools exist, but you need data in real time as the DA changes throughout the day. If you're interested in this level of precision, I strongly recommend investing in a Kestrel Meter a compact weather instrument with an anemometer and which calculates DA based on your current conditions at the range. CAUTION: DO NOT take your Kestrel to the firing point in a match!

So all you need to do is look in your data and find the last time you shot at the same disance with the same rifle and ammo, and dial the same elevation based on DA. It doesn't matter where on the planet you observed the data, if accurately measured, it will still be valid. See why recording your data is important? In this case you check your Kestrel and see that your current DA is 1047 feet above sea level (do this before the match, not after it begins!) and your data shows an entry from the previous year with DA of 1000 feet ASL and elevation of 38.5 MOA. In this example, you dial the 38.5 MOA, take a shot, and are in the 5" X ring. You are one bad ass mo-fo, and the ladies are all swooning at your bad-assery!

Wind
OK. So we're finally getting to the answer to RI Red's question. What am I thinking of during a match and right before I take a shot? What calculations am I making in my withered and atrophied little brain? The answer is wind. I am almost entirely focused on changes in wind conditions across the range. Literally from the time I step onto the range to the time I'm packing the car to head home, I am looking down range and observing the wind conditions. This has become such an ingrained habit, that I find myself estimating wind when I am not on the rifle range.

An entire book could be written on wind estimation for shooters, and many have. Here's a great one: Prone and Long Range Rifle Shooting covering a variety of topics written by my friend Nancy Tompkins. Nancy is a delightful person and a great competitor, and while I bigly recommend her book, there are many others available, as well. I was extremely fortunate to have had one of the best rifle instructors in the country teach me how to shoot and read wind, and I have spent countless days and weeks over a period of years on a 600 acre hay farm estimating wind and shooting at long range. It's a little bit science and a LOT of art, and while unfortunately not something I can cover here in exhaustive detail, I can however give you an overview of my process.

Point 1: A bullet in flight is stabilized by spinning, and for very complicated reasons, this spinning causes the bullet to drift in the direction of rotation. This is 'spin drift' and with a .308 will add between 3/4 and 1 MOA of (usually right) drift at 1000 yards.

Point 2: All wind is not equal. A 3 mph wind blowing from 9 o'clock directly perpendicular to the bullet's line of flight has a greater effect, or a "full value", than a 3 mph wind blowing from an angle, which is between 50% and 70% of full value. Buy an anemometer and practice, practice, practice estimating wind values and detecting changes in wind direction.

Point 3: Headwind and tailwind: These are the worst kind of wind, and very difficult to read accurately. It can also affect elevation; headwind slightly low, tailwind slightly high. Be vigilant for changes that introduce a lateral wind value.

Point 4: Different bullets at different velocities respond to wind, well, differently. You should know the ballistic coefficient for the bullet you're using, and plug it into a ballistic calculator to determine the 1 mph full value wind effect for your particular setup. Ballistic AE is the iOS app I use.

Point 5: Learn to read and use different wind indicators; mirage, flags, dust from bullet impact in the berm, leaves, grass, etc. Continually try and determine which of these indicators is reflecting the conditions your bullet is encountering. When you are not looking through the riflescope you should be looking through your spotting scope if one is available.

Point 6: Look at the entire range for indicators of changes with wind. Preference should be given to indicators on the UPWIND side of the range whenever possible. Do not become fixated on only one indicator. Do not become so focused on wind speed that you fail to pickup changes in wind direction.

Point 7: There is often more than one wind vector on a rifle range. Look at the entire range and be prepared to net the effects together. Be aware of gaps in a treeline or other natural terrain features which might affect the wind along the course.

Point 8: When you are confident of the windspeed and direction, and the deflection it will have on your bullet, then take the shot.

So, An Example
You are setup at 1000 yds, and have your elevation dialed in based on you rifle data and current DA. You have been watching the wind all morning which is light and slightly variable. You estimate wind speed at about 4 mph and wind direction from around the 10 o'clock position. You multiply 4 mph times 70% and get an effective wind value of 2.8 mph. You know at this distance the influence on a bullet for each 1 mph wind effect is .52 MOA. In your head you multiply 2.8 x .52 and get 1.46 MOA, or 3 x .5 and just use 1.5 MOA rounded. Either dial the 1.5 MOA left wind or hold off from the target center and take the shot. Shit! The elevation is good but you're out to the right in the 9 ring. WTF? Well Dumbo, you forgot the effect of one full minute of spin drift to the right. You have to add the effect of 1.5 MOA of wind blowing the bullet right with the 1.0 MOA of spin to the right. The correct firing solution for that condition is 2.5 MOA left hold. Or you can begin the string at 1.0 MOA left wind on the windage knob, and adjust from there.

FREE TIP: You can either add 1 MOA (or whatever) of left spin correction to your rifle zero, for a 1000 yd zero, or just include it in your corrections. Either way, you have to remember it's there.

ANOTHER FREE TIP: Learn to hold off (aiming right or left of center) for wind. You can easily get lost in making scope adjustments and really screw things up. Badly.

AND ANOTHER FREE TIP: It's OK to use a little "Kentucky Windage" as long as the conditions are generally consistent. If there are large directional or velocity changes you may need to stop shooting and start doing the math again. If you get lost in wind changes, just relax, reset everything to zero, and recompute the solution.

STILL ANOTHER FREE TIP: If things really start going to shit, stop shooting and figure out what is going on. If there is a significant change, don't be afraid to wait it out until a preferred condition returns.

ONE MORE TIME: I am reading wind and making adjustments to my point of aim until the very last second when I take the shot. Never stop reading wind.

Hopefully this will give you some things to think about. Each one of the topics above could be a long article by itself, but this should give you a high-level overview of the general process I use. I hope you can take away one or two things to help in your particular situation, especially if you're interested in long range shooting. For those not particularly interested in long range shooting, thanks for indulging those of us who are!

Merry Christmas everyone.

Link-O-Rama
Article: Spindrift
Website: Kestrel Meters
CIHPRS Website: Wind Excerpt from B. Litz' Book Applied Ballistics
Accurate Shooter: Tutorial on Scope Parallax

The This Old Gun feature is reinventing itself, will return next week as the Mail Bag. I sometimes get questions by email which might be of interest to everyone, so in addition to featuring items from Moron's private collections, I think it would be nice to also periodically include a Q & A feature.

OK you clowns - buy a copy of the cookbook. If you already have one for your own bad self, then give one as a gift this season. Remember; it's only pennies per day, all proceeds go to charity, and if you don't buy a copy then bluebell will be sad.

And you wouldn't like bluebell when she's sad.

Finally Don't forget to mark your calendars for the NoVaMoMe on February 9, 2019. If you are interested, please email the organizers! There is also a link in the main page left sidebar.

Please note the new and improved gmail account MoronGunThread for sending in stories and pictures. Again, that's morongunthread at gmail dot com. If you have a question you would like to ask Gun Thread Staff offline, just send us a note and we'll do our best to answer. If you care to share the story of your favorite firearm, send a picture with your nic and tell us what you sadly lost in the tragic canoe accident. If you would like to remain completely anonymous, just say so. Lurkers are welcome!

That's it for this week - have you been to the range?

posted by Open Blogger at 07:05 PM

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