Usually you can’t...if you CANT: Get a scope level

Two dollars and five cents doesn’t sound like a huge amount of money however times it by 150 and it starts to mount up. $307 sounds a little more significant as a dollar figure I guess right? So what do these numbers mean? Well, 150 is about the number of bullets I would shoot in a session of practice for my competition shooting and $2.05 is the cost of each round. I make my own so they are a little cheaper and much more accurate than factory rounds are. I practice behind my competition gun about 9 times a year and compete about 5 times and use about 150 rounds per competition. That works out to 2,100 rounds at a $4,305 total investment in ammunition. Long range tactical shooting is an expensive sport.

Due to the cost I strive to get the best out of each and every round I send down range. I work to become an expert at reading the environmental conditions, perfect my breathing and trigger-pull protocol and have my equipment set up as perfectly as possible. One piece of essential equipment for a long range shooter is a scope level.

What is a scope level

It’s a small bubble level that gets mounted to the gun or scope permitting the shooter to check whether the rifle is level prior to firing. I use an Accuracy 1st scope level which uses a ceramic ball floating in fluid inside the level rather than an actual bubble. At different altitudes and temperature a typical fluid level bubble can change in size giving inaccurate readings. The ceramic ball stays constant in size. It is more accurate. I also have a small tritium vial inserted into the back of my level. Tritium is a radioactive isotope that glows for about 15 years or so. I use this to light the level up for low-light situations. It glows through the level and provides enough illumination to read it by. The scope level I use is designed specifically for military use where this feature could be a life and death thing.

Why use a bubble /scope level

When adjusting point of impact on a scope the shooter moves (dials) the relevant elevation required into the scope. It moves the cross hairs upwards the further out the target is. A 1000m shot needs more elevation dialled in than a 500m shot for instance. More elevation arcs the bullet in at a greater angle defeating gravity and increasing the point of impact distance accordingly. Bullets don’t fly flat and straight, they fly in an arc heading upwards from the rifle muzzle, reaching a zenith, and then they arc downwards to the point of impact. Gravity pulls downwards and so the bullet needs to compensate.

So, if the rifle is canted (leaned) one way or the other something different happens. Let’s say your rifle is canted to the right by 3 degrees. (An almost imperceptible amount). Let’s also assume you need to input some elevation to reach the target and so you dial in the relevant elevation to the scope. Because the scope will dial the crosshairs directly vertical to itself your cross hairs will simply move upwards and to the right, the direction of your 3 degree cant. Make sense?

From here you are in big trouble. What will happen is that the crosshair will not have travelled up in elevation as far as the input desired, and that you actually dialled in, as it is also travelling to the right, at an angle, at the same time as upwards. You have also added additional windage as the crosshairs have moved right.

Quite simply the bullet will miss the point of aim low and right. Make sense still?

There is no point in trying to level the crosshairs on something down range because you’ll never know what is level and what is not. That’s where the scope level comes in.

What difference could it make

Out of a possible 360 degrees 3 degrees is a small amount. As I said most people would never even realise the rifle was canted by that small amount. I have done some tests though and what effect that small amount of cant may have on my shot and it’s quite interesting to see the result.

Applying a 3 degree right side cant to my rifle for a shot taken at 914m (1000 yards), after dialling the correct elevation setting to the scope it took the bullet almost 61cm (24 inches) to the right of my intended point of impact. That’s a huge amount and is a miss every day of the week. (This test was using a 175gr Sierra HPBT projectile from a .308 calibre rifle).

This afternoon I changed the scope mounting rings on my competition rifle and so had to re-level the scope all over again. I actually hate doing it to be honest. It’s an involved process using little bubble levels to make sure the rifle is dead level, a plumb line and various little bits and pieces as per the image. It took me about an hour to get right and to be honest I am not really happy with the accuracy of my efforts. I will have another go on the weekend. It’s such an important part of my sport, in fact any long range shooting, though and so is something I persist at until I am happy it’s perfect.

I have tried not to get too technical in the post and hopefully I have explained the concept of rifle cant and the importance of a scope level to the accuracy of a shot. When you watch some Hollywood movie now and see someone shooting a rifle at a 90 degree cant hopefully you’ll scoff and say, “he wouldn’t hit a thing!” Well, of course the actual range and calibre makes a difference I guess, but shooting rifles at a cant is not the easiest thing to do when working hard at it, let alone in the middle of a firefight. The guy on the left is probably not that much of a threat for the reasons above. Oh, and not looking where the gun is shooting won't improve your accuracy either. IMAGE SOURCE

Design and create your ideal life, don't live it by default.
@galenkp