Monthly Archives: March 2015

Cyber-shooting… :o

An edited reprise of an article I did some time back, called Over-thinking Barometric Pressure.


In this age of gadgetry we’re seeing more and more emphasis on barometric pressure calculations when figuring your bullet’s trajectory. Do these numbers really affect your bullet’s flight? Yes–of course they do. But the question is, how much?

Our long range shooting training curriculum places a strong emphasis on freeing ourselves as much as possible from dependence on anything that requires a battery. It is our belief that if you become too dependent on your smart phone or your Kestral–or even your range finder, you’re going to be rendered largely ineffective in a situation where you don’t have these amenities. (And we must now wonder how anyone ever worked without these things, right?)  To hear the modern day cyber-shooter tell it, Carlos Hathcock couldn’t have shot himself in the foot in Viet Nam, as he had no cool toys.

I have long ago lost count of the times a shooter has come to a match, or range rental session, complaining that his data was totally off in his ballistic program.  That has nearly become the rule in fact–rather than the exception.  The question then becomes:  If you end up needing to tweak your ballistic program every time you come to shoot, or else you’re missing 18″ targets as close as 800 yards–then you may want to consider an altered game plan.  Computers are simply too prone to operator error.  “I’ve got my Kestral programming down to a science” one says.  I hope you’re right.  I hope that if the day ever comes that you really need that data, the instrument doesn’t let you down.

We highly recommend written or typed data cards with 25 yard drop and windage increments.  Once that chart has proven true for your rifle and load, you can get good hits in various atmospheric conditions simply by knowing how to compensate for condition changes in the weather.  Having 2 or 3 cards for various conditions is a very good idea.  This set of cards will also help you understand how precious little temperature and altitude changes will affect your data until the range exceeds 600 yards or so for a good long range load.

And If you use the cards regularly, something else happens:  You will begin to memorize the tables.  This seems never to happen with cyber-shooters who are always relying on their smart phones or Kestrals to tell them what to do.  I can name as many as three seasoned shooters (though I won’t name them, of course 🙂 )… who I’ve witnessed dial egregiously incorrect elevation solutions because they made a mistake in interpreting their electronic ballistics program.  The most common blunder:  “I picked data for rifle 1, and I meant to be using rifle 3 in the program.”  But when you dial 33 MOA of elevation to hit a 900 yard plate while shooting your 6.5/284 you’re going to miss really, really high… and you should have known that, no?  But alas, the Kestral wasn’t questioned, because the pattern had become to range the plate, then punch up the number, and dial up the scope setting with the autonomy of a robot.  The method seriously takes too much of the thinking out of the equation, and when blunders occur, they’re often embarrassing ones to say the least.  Compare this situation to the shooter who knows his/her trajectory almost (if not) by heart.  A mistake such as reading the wrong line on the card would be caught immediately, because of the ingrained knowledge of the trajectory table.

“But my Kestral tells me the barometric pressure, and that’s important.”
Yes, barometric pressure can only be known through the use of electronic devices (but you’d be surprised how these things can give different readings from the SAME place sometimes; watch next time they all come out of the shooting packs at the same time and see what I mean). You can go to Weather Bug on your phone, and it’ll tell you… if you have a Kestral, it’ll tell you… but if electrons cease to flow through your wires, you’re out of luck. How bad might that end up being?

Actually, not as bad as many would lead you to think. If you’re using a decent long range bullet (and if you’re not, you’ve got no business shooting it past 500 yards), then the average barometric pressure swings in a given area are not going to be enough to move you more than a half minute off vertical at 1000 yards. Ogilvie will contrive situations where he swears he would have to know BP to get a hit on an 18″ plate at 1000 yards… but he’s contriving, remember. 😉  I shoot mostly the 178 Hornady AMAX these days, at 2550 to 2600 fps. By looking at the yearly highs and lows for barometric pressure in my area, I can see that the most I’d be high or low (if I base my drop chart on the average) would be about 5 inches at 1000 yards.

Here is a local weather station chart for my area. Note the barometric pressure high and low for the year…

Weather History for Weather Station KVAWYTHE1 | Weather Underground

If you’re using a bullet that has a higher BC than my .308 bullet does, and especially if you’re driving it faster, you’ll see even less of an issue.  It is advisable to check the BP swings in your area to see what the average is, and how far above and below that point the pressure might likely go.

NOTE: I’m not saying that you should disregard your barometric pressure input if you have access to that information. I’m simply saying that you ought to make yourself aware of what to expect in your given area as far as pressure swings throughout the year.

The big things affecting your trajectory are altitude and temperature. If you’re keen on these two numbers, you should be able to hit within 1 MOA high or low at 1000 yards with any decent long range load recipe. And temperature and altitude are two things that are not hard to know without electronics.  The FDAC card (Field Density Altitude Compensator)  by Adaptive is based on this basic truth:  If you know the approximate temperature, and the approximate altitude, you can modify your long range trajectory numbers to ensure a hit.   Barometric pressure does not come into the basic equation.  FDAC

I do like to use one of these FDAC cards while teaching, as it is a useful tool for demonstrating to students how little the trajectory (of a good long range load) changes in different density altitudes out to 600 yards or so.  The card set is bullet specific (my cards are for the Sierra 175 grain Matchking bullet), and there are 5 different inserts for varied velocities from 2500 fps to 2700 fps.  Many bullet options and velocities are available, check with vendor at link above.

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7 shooting match hacks…

range 4

Many long range shooters enjoy competing in matches, and we host matches every 4 to 6 weeks here at the BangSteel range in southwest Virginia.  It’s a real pleasure to meet the shooters who come from all over, and I must admit that I love watching bullets though the spotting scopes as they go downrange.  And I do learn a lot by doing so.

In our matches, we generally use the “lone shooter” format, where the rifleman must spot his or her own shots at the target.  Shooting steel at ranges from 400 to 1000 yards, with proper technique on the rifle, you will be able to see where your shots land in the target’s vicinity–and you’ll therefore know how to adjust for a follow up hit, if you should miss on your first shot.

These tips will help you turn in a better score at our matches (and also at most other such matches):

1.  Spot your own impacts.  If you cannot see where your bullets land, you won’t be able to correct for a follow up hit.  It’s amazing how many folks who are otherwise excellent shots end up being unable to see their impacts in their scope’s field of view, and consequently have no idea where to hold for a follow up hit.   If you’ll dial down your magnification to 12 to 14 power max, your field of view will be increased and you will be much more likely to see your bullet strike in the distance.  Proper recoil control (stay as straight behind the rifle when shooting prone as you comfortably can) will help very much with spotting impacts.  And don’t forget to stay on the scope.  I once had a client who said he wasn’t able to see his impacts at 1000 yards.  He got behind the rifle, took a shot… and turned around and looked at me before his shot ever even arrived at the target! 😮

2.  If you know that ordinarily you can spot your long range bullet impacts in your riflescope, but find that on occasion you don’t see the shot land (and you miss the target), it’s highly likely that your shot went over the target, and impacted the ground behind the target.  Follow up by holding at the bottom of the target (with same windage) and there’s a good chance you’ll get a hit.  At the very least, the new aiming point might result in a ground strike that you see–and you can get a 3rd round hit with proper hold.  Whatever you do, if you’re unable to see your bullet strike, and you know you missed the target–don’t do the same thing for a second shot and expect a hit.  Hold more or less wind, or drop the elevation a bit for the follow up shot.  Doing the same thing twice and expecting a different result is, as they say, the definition of insanity. 😮

3.  Watch the plates.  As the various shooters in the match shoot at the targets, their shots will tend to congregate (as odd as it may sound) in the same areas on the steel targets.  I believe this is because on any given day, the weather conditions (wind in particular), and even target lighting due to cloud cover or lack thereof, will cause the collective group to favor sight settings that over-compensate (or under-compensate)  in the same direction.  If you’re called to shoot later in the match, take note of where all of the shots seem to be gathering on the steel plates.  For instance, if they’re favoring far to the right, and wind is coming from the left, most folks are underestimating the wind.  If there are some good shooters ahead of you, and it’s happening to them too, it might be a good idea to hedge your wind call up an MOA, or a quarter mil.


4.  Bring a spotting scope to the match, if you have one.  Spot the other shooters as they’re shooting, and see if you can see the bullet’s path as it moves through the air (heat trace).  This will show you what the wind is really doing, and you will often be able to see that there is little to no wind initially in the trajectory, but a pick up in the wind as the bullet nears the target begins to move it to the side.  Remember that when your turn comes to shoot, and scope the vegetation in that area to see if you can note any movement that would indicate that conditions are still the same when your turn to shoot comes up.

5.  Spot your first impacts on the plates (early in the match), and note whether your data is on–or if it’s running high or low.  If you see if you’re off one way or the other, remember this when you dial your scope to hit other plates at other distances.  If you’re shooting high at 500 yards, odds are you’re going to over-shoot the 800 yard plate as well.  Adjust as necessary.

6.  Relax.  Don’t get excited.  Getting excited results in poor performance, and ham-fisting bolts (and needlessly breaking them in some cases).  Just shoot steady, and as calmly as you can, and you’ll shoot much better.

7.  Bring good ammo.  Many folks will put together handloads for maximum velocity (feeling that this will give them and edge in competition).  If they load this ammo to max pressure, the rounds may not give pressure problems on the first or second firing of the brass, or in certain weather conditions.  But given the right circumstances, these loads will reach a tipping point.  Murphy says it’ll be during a shooting match.  Good ammo is reliable ammo.  Don’t load “pedal to the metal” with the notion that you’re going to get some wind drift or trajectory advantage over the competition.  The guy shooting the slower load may edge you out because his rifle is working–and yours isn’t.  😮

8.  (a bonus)…. HAVE FUN! 🙂

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A dozen reasons my rifle quit shooting… :o

70 gr SMK, 3031IMG_0028

We get a lot of feedback and queries from folks who are asking what has happened to the accuracy of their rifle.  Often, these questions are accompanied by an attached file of the target, showing horrible accuracy.  There are several things that can happen when a previously known good combination of ammo (either factory, or load recipe) and rifle all of a sudden “goes south” on you.  In the order of most likely to less likely, here are some ideas.

1.  Loose nut on the trigger.  The number one issue harming accuracy in a system previously known to be shooting well is a loose nut on the trigger.  That means you.  Sorry… I’ve been there and done that too, but many times we don’t realize that we are not shooting our best.  Yes, some days we can actually discern that we’re not on our game, but these days make it all the harder on us when the “gray days” come around… we don’t think we’ve done anything wrong… all seems well, but in truth, we’ve not done our best.  Lay off the coffee, and make nice with the wife before you leave home, and all will be better next time.

2.  Loose screws.  In order of most often, to least often, the screws which work loose on your scoped rifle are:  Action screws (which hold the barreled action into the stock), scope base screws (bummer, but you have to remove the scope from the base to check these), then scope ring screws.  Also, make sure your bipod screw attaching it to the forearm is tight.

3.  Heavy mirage in the scope, or failure to adjust the focus (parallax) before shooting.  Always be sure to set parallax (if your scope has that adjustment) before shooting for group.  And make sure you’re looking through the scope with the correct eye position behind it, eliminating all crescent shadow from the scope edges.  Read the set-up instructions which came with your scope for more info.

4.  Altered shooting position.  You had the rifle grouping well when you were shooting off the bench, but in the prone position it’s just not working right.  See number 1 above.  It’s you.  You’ll need to perfect recoil control in the prone position in order to get the accuracy back.

5.  Changed bullet lot, or powder lot.  While powder lots are normally pretty close, some bullet types are very sensitive to lot-to-lot variations.  Berger VLD’s seem to be the biggest offender in this category (that I’m aware of).  If you like shooting VLD’s, it’s a good idea to get a large batch of the same lot number–otherwise you’ll be re-developing the load when you go to a new lot of bullets.  Traditional style bullets are not nearly as picky in this regard, and this is the main reason I have always stuck with those types of bullets (i.e. Sierra Matchkings, Hornady AMAX’s, Nosler Ballistic Tips, and such)…  an aside:  We’re giving you the benefit of the doubt that you already know not to go to another make of brass case without re-developing the load. 😉

6.  Scope has crashed.  It’s not likely to happen, but it does happen.  A slightly loose lens can wreak havoc on your groups.  If you’ve ruled out the other possibilities, it might be a good idea to replace your scope with a known good one, and re-test your rifle.

7.  Bedding has come loose, or floating barrel is impeded by debris of some sort.  Remove the barreled action from the stock and inspect.

8.  Muzzle brake or threaded barrel thread protector has loosened.  Tighten it up.

9.  It’s freezing outside.  When temperatures plunge, it’s much more difficult to shoot accurately.  Your body’s response to freezing temperatures, compounded with lowered sensitivity in your trigger finger can make a 2 MOA rifle out of your tack driver.  Practice in very cold weather to improve accuracy.

10.  Temperature change has moved your load off of the accuracy node you had been on.  If you are not using an OCW load you will find that temperature swings will alter the accuracy of your load considerably.  And even when you are using a proven OCW load recipe, you might find that higher outside temperatures speed your bullet up to the point that it is exiting the muzzle well outside of the OCW zone.  This can also happen when it gets very cold outside (bullet slows, moving the muzzle exit off of the node).  Using temperature stable powders can help this situation.   If your bullet is only marginally stabilized (twist rate and velocity *barely* keeping the bullet stable), then a drop in temperature can cause the bullet to go unstable, due to the lower velocity.

11.  It’s time to anneal, or replace the brass.  When you reload the brass cases a few times, the necks will “work harden”… this means that consistent neck tension from one case to the next is no longer being achieved.  Anneal after 3 firings for most brass brands, and you’ll find that accuracy is much improved.  We have a short video and article here on this blog about annealing.

12.  Barrel is worn out, or crown of muzzle has been damaged.  It happens.  Barrels don’t last forever (except for our .308 barrels that is… ; )  )… I’m digressing… but barrels do wear out, and if you’re shooting a fast 6mm or 6.5mm, you can expect to be replacing the barrel somewhere between 2000 and 3000 rounds for many of these guns.  But do check the crown, or have a trained gunsmith check it.  Sometimes a slight nick in the crown can occur, and this ruins accuracy.

These 12 issues are by no means the total list of things that can cause accuracy problems in a previously known accurate system (rifle, load, shooter).  But they’re the most common, and should be considered when groups start to open up on you.

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