Are indoor range shots more accurate that outdoor airgun shooting?

Readers will be aware that most of my competition attendance occurs within an indoor range environment these days. Up until the past year or so, I could be counted upon to attend most if not all the outdoor HFT events within my own area of the Northwest of England, in particular to compete for the local Gauntlet trophy, which I managed to win the veterans category a couple of times.

My son James continues to compete all over the north and midlands of the UK and is still able to deliver the goods regarding wins and overall performance.

Unlike me, he has not succumbed to the relative ease of total indoor shooting and the series of challenges that we must face as competitive shooters indoors.

When I put this to him recently, I was as usual given short shrift due to his view that any shooting not involving the assessment of what the wind is doing is far less difficult, due to the obvious windage allowances we must make to successfully hit the target when shooting outdoors. (Click here if you’re looking for some new airgun targets to set up at home, or here for a list of the top indoor airgun ranges). 

Indoor vs outdoor

Those of us who have experienced outdoor conditions and what we must do to hit the target via the use of windage and distance assessments will be well aware
of just how wrong we can be on occasion as we completely miss the intended target, be that a knockdown field target or a browsing bunny.

Unlike outdoor benchrest shooters, we are not allowed visible assistance from equipment such as wind flags to help us make our shooting solutions, but must
rely upon long-developed personal skills such as windage assessment that my son has managed to develop into an art form over decades of shooting. There are very few shooters able to match him on the HFT course when there is a serious wind blowing, as I have myself witnessed many times over the years.

As an outdoor shooter, you can obviously feel and see the effects of air movement most of the time, although as James always reminds me, even on a calm day there usually remains some slight breeze which can affect the fall of a shot.

I can remember watching James take a shot at a national UKAHFT shoot years ago when most of us did not even get to hit the target faceplate. Following about 10 seconds of assessment, James took the shot and dropped it much to my and the other shooters’ amazement.

When he advised me how much he had allowed for wind deflection I was genuinely shocked, as due to the roaring crosswind he had aimed at least a foot off the target at about 40 yards distance.

Andy’s son James is a master at assessing the wind, as he’s doing here before taking a shot from the kneeling position

The reason I am regaling you all with these tales is that I have continued to think about myself and other long-range indoor shooters using sub-12 foot pound airguns when taking on targets with 6mm bulls at distances up to, in our case, 56 yards.

Now being indoors (unless of course your indoor range is draughty) should mean that the air remains relatively still and will not affect the fall of shot downrange. If this were the case, it would make things so much easier to produce amazingly accurate groupings via our shooting combinations than it actually is.

It is sometimes possible to produce some excellent groupings outdoors that match and can even exceed what is possible indoors, and despite the support provided by equipment such as high quality bipods and the relative comfort of an indoor seated position, strangely an outdoor grouping, admittedly usually taken from the prone position and supposing that the shooter is not faced with tricky wind conditions that can take those pellets off into different directions at will, can sometimes actually exceed that which is possible indoors.

Now you might think that the previous paragraph is a ridiculous statement, but on occasion it has proven true for myself and many other shooters who shoot both indoors and out. I was recently, as many of us do I think, perusing the US-based Airgun Nation website and noticed a fascinating article regarding this very issue. The article concerned the findings of the Accuracy Research Team set up by Daystate to evaluate performance-enhancing items such as super grade barrels for their production guns. I think this makes for some interesting reading.

These ART guys brought to my attention that my home range situation of shooting from the indoors to the outdoors is a very destabilising scenario for a projectile. In their testing, they paid for a couple of months of membership at an indoor 100-yard range with the idea of gathering data on wind effect, the theory being that no wind indoors should make tiny little bug-hole groups. Wrong!

Calculations required

Instead, they found it was harder to achieve sub-MOA groups on an indoor range than an outdoor one. They hypothesised that there were possibly layers of settled air that the pellets were traversing on their way downrange.

As the trajectory curve goes up and then comes back down, it was thought that it was having to cross barriers between temperature and density. Since air is calmer inside than outside, there is never enough air movement to disrupt the layers and create a more consistent medium for the projectiles to pass through.

One of them later received validation from the Berger company at some sort of big industry event (think SHOT Show). The Berger employee said that they had seen the same thing when testing firearm projectiles indoors. The ART guys thought down and updrafts from HVAC systems running and/or switching them on and off could be wreaking havoc on their data.

Here’s the 56-yard indoor range at Rochdale – it’s a long way to the back wall for a lowly pellet shot from a sub-12 ft-lb air rifle

Back to my humble little home range. On top of the still and possibly horizontally settled layers in the indoor section of the pellet’s path, I’m also basically shooting into a vertical wall of warmer, thermally influenced air and wind about 12 yards downrange from the end of the gun, when it hits the outside environment. I also cannot feel the individual upticks and downswings in shifting wind currents because I’m inside.

So when I’m shooting from indoors to out, especially when it is windy, there are a lot of details about the situation that make it less than ideal for supreme accuracy measurements. This is a lot of next-level stuff for me, as my usual shooting (Field Target, target practice in the backyard, and pesting) simply doesn’t require the precision these guys are striving for.

I remember in a recent article I wrote commenting that one of the reasons that when my clubmates and I shoot our long-range indoor competitions and we are plagued by the odd “dropper” this can be due to variations in air density as the pellet spirals its way downrange.

As I tried to describe in that article, I consider the air in between us and the target as similar to a body of water and the very real set of thermoclines that exist at varying depths.

This means that colder and warmer levels of water feature at different depths, so affecting density. I wonder if this is the case with the air at our indoor shooting ranges? Hopefully, that gives us all something to think about!

Click here for more advice from Mike Morton on how to improve your airgun marksmanship.