The Importance of Dope
by Glen Stilson
When I head to the shooting range for some practice or out into the field for a hunt, I always make sure I bring my dope. No, I’m not talking about the much debated green leafy plant; I’m talking about D.O.P.E., or ‘Data on Previous Engagements’. There are a few other versions of the acronym that I’ve heard, such as ‘Data Obtained Previous Engagements’ and ‘Data on Personal Equipment’, and really any of them work, but I prefer to use the first one. Now, before we get started it’s important to note that if you zero your rifle at 100 yards and never really shoot it beyond 200 or even 300 yards, and you never really take it beyond that, then this information is still for you – dope, or data, is not just for long range shooters.
So what exactly does this dope consist of, and why do we want to carry it around with us? To start with, dope can be as simple as a single sheet of paper attached to the rifle, often laminated and taped to a stock or a scope cap. It can move up from there to a basic notebook, kept in a stock pouch or a pocket. Personally, I prefer the Rite-in-the-Rain notebooks, with the accompanying pen, so that my hard earned dope doesn’t run off of the paper if it gets a little wet. From there you can get into a full dope book, or data book, which can be pocket-sized or be as big as a full-sized 3 ring binder. Which one you choose depends on your situation and your style of hunting – lightweight and mobile is more important to some than it is to others.
Once you’ve figured out where you are going to keep your dope, you have to figure out just exactly what you are going to record. Everyone will be different here, depending on the kind of optic you use and the type of shooting you do, but at the very least you should be recording 1) zero information, 2) cold bore variations, 3) round counts, and 4) optics adjustments. Depending on your type of reticle, you should also consider recording holdovers, wind adjustments, movement leads, and similar information.
For the time being, let’s go back to those first four items I mentioned, and why I think they are important, based on my own personal experience. First, you should record information about your zero such as bullet type and weight, altitude, outside temperature, and how on your scope turrets the zero is marked, whether with numbers, colors, or hash marks. This can be as simple as ‘Zero 100yd 168gr Nosler 4850MSL 68F Red’, which would indicate a zero at 100 yards with a 168gr Nosler bullet, at an altitude of 4850 feet above mean sea level, with an outside temperature of 68 degrees Fahrenheit, and that red marks on the scope turrets mark the location they were at when zeroed. The reason all of this information is important is because a zero can shift, not just mechanically (hence the red marks), but also as altitude and temperature change. Recording how your rifle’s point of impact shifts at various ranges under different conditions can also be important, depending on how drastic of a change you expect. If you sight your rifle in at a shooting bench located at 1200ft MSL and 80F, and you head up to the mountains to hunt at 7000ft MSL and 45F, your point of impact can absolutely be affected, especially at extended ranges. Additional marks can be added for quick field adjustments depending on conditions.
The second set of dope that should be recorded is the cold bore variations. A bullet will not leave a cold barrel the same way that it will leave a barrel that has recently been fired through, and knowing what your cold bore, or CB, shift may be is incredibly important. Let me give you an example: my personal hunting .308 WIN rifle has a CB shift of .5” left at the 7 o’clock position if the outside temperature is between 40 and 80 degrees. If it drops below 40 degrees then the position shifts to 6 o’clock but remains .5” from zero. If the temperature rises above 80 degrees then the CB shift is at the 8 o’clock, but again remains .5” from zero. This doesn’t matter much at 100 yards, but go to 300 and that 1.5” shift may result in a wounding hit, especially if I even just slightly jerked the trigger and sent it even further from zero, or perhaps misjudged the range to begin with. Reach out to 500 yards and the shift could be 2.5”, which could mean a miss altogether, depending on the size of the animal or the location I am trying to hit. Sure, a broadside shot won’t be affected much assuming I do my part behind the trigger, but does a shot like that always present itself? Not to mention that I have seen rifles with much greater cold bore shifts than .5”. You’ll only get one chance at each practice outing to record your cold bore, so make it count. And if you clean your bore before you shoot, or CCB, then you’ll need to record that dope, as well. Never clean your barrel before a hunt!
The third and fourth points that I always record for every rifle are round counts and optics adjustments. Round counts are good to track because I need to know when it’s time to fully clean the rifle instead of just cleaning a few key parts, and I also need to keep track of what kind of ammo I am shooting through the gun, as well as maintenance procedures. Optics adjustments are critical because – wait – did I just click it 6 times or 7? Am I sure I went right, or did I go left? What adjustments did I make last time I was at the range and I was shooting so well? I need all of this information to keep track of what I am doing whether I am adjusting for zero or adjusting to make quick changes in the field.
There are all kinds of dope that you can record for your rifle, and if you purchase a normal dope book (I recommend Impact Data Books) then there will be all kinds of things that can be recorded, some of which you may not understand. Remember: your dope is for you, so only record what matters to your situation, your hunting style, and your needs. Regardless of what you decide to do, just make sure you keep your dope handy when it’s time to make the shot.