Steve Hurt
As a bullet manufacturer we do a lot of product testing ‑ at the range, over a bench and in the field and as with any form of testing, it’s essential to isolate as many variables as possible and identify and quantify relationships with other factors wherever practical. While this may seem obvious it can be incredibly challenging to achieve, as there are often multiple related variables involved. The first issue to resolve is always the matter of ‘dependent’ and ‘independent’ variables . . . the old ‘cause and effect’ dilemma.
For example, did the chalk break because I dropped it or because it hit the concrete? It may seem a silly question but when you think about it, it becomes a long rabbit hole indeed. Apply this principle to ballistics and a lot of scientific thought, time and money are required. The biggest issue is removing as much ‘human error’ from test results as possible, and the number one challenge most shooters face in testing their gear is that a human being is required to shoot the total package – and we all have our good and not so good days on the trigger.
Since a human being cannot be removed from the shooting equation (at least in the civilian context), we’ve noted that many shooters struggle in acquiring, borrowing or accessing a suitably solid rest to gain the best, most reliable results from their testing. Now this article is not centred on testing protocols, as there are better qualified people than me to discuss such matters, it’s simply an exploration of the tools we find have produced the most reliable results for analysis and hopefully give the reader something to ponder.
When testing a load there’s clearly nothing more stable and consistent than a railgun, but these are specialised pieces of equipment with little practical application elsewhere. And whatever the results might be, they can’t be directly transferred to performance in another firearm. This germinated in us an idea to apply the principles of a railgun to a more universal platform for testing common use firearms such as target and hunting rifles.
The idea was to remove human error as much as possible while providing the opportunity to systematically review results with rifles as they are or components in isolation, such as barrelled actions, optics, stock and bedding issues. Load development and less obvious subjects like muzzle brake performance, among other issues, only become possible to assess when working from a known base line. The resultant contraption is what Outer Edge Projectiles refer to as their ‘machine rest’.
These ‘machine rests’ are not made for sale but are provided for no other reason than to stimulate thinking shooters with ideas for their own consideration and application. Clearly this project was a major exercise – the steel base weighs 30kg alone, has a radial footprint of 1200mm or 2400mm in diameter and can be pegged to the ground if necessary. It isn’t. This beast doesn’t move at all, even when testing the heaviest recoiling rifles. It has a full 360-degree pan which can be locked into position, the braced legs provide coarse levelling (cant) adjustment as well as rock-solid stability, it’s modifiable in height from 1200mm to 1300mm (frame included) and is all we need for our purposes.
The aluminium frame has fine (damped) pan and elevation alterable and is adaptable in the clamping mechanism fore and aft to handle a wide variety of firearm types, styles and sizes and is flexible for use on concrete range benches. It can accommodate bolt, falling block and lever-action firearms and is also able to receive barrelled actions without the stock, converting it into a true railgun. The frame supports a triple rail lineal bearing mechanism that’s spring tensioned and damped for consistency – once a firearm is locked in, it can only move rearwards. Preload tension and recoil damping are adjustable. It also weighs 30kg for a total unit weight of 60kg plus the weight of the firearm. The frame is 1200mm long and 700mm wide including shelves.
Results from this ‘machine rest’ can tell us a great deal but how will the same firearm perform when used from other types of rests? Let’s consider other options.
Joystick front rests and sandbags
All benchrest competitors and most shooters doing even basic sighting-in at the range have used a benchrest/sandbag arrangement at one time or other. Now like all things, there are benchrests and there are benchrests. The Seb Mini is a popular, high-quality example of innovative engineering.
Of the joystick style it’s also fairly expensive (well north of $1000) so may be beyond what most recreational shooters would want to pay, but a polite request to an experienced competition shooter at the range may open your eyes as to what’s available and whether or not it suits your particular need. An appropriate rear bag is an essential partner to this equation.
Bipods
These are the least expensive rifle support most commonly used by the majority of shooters. Not so long ago the Harris bipod was both the best and best-known on the market, now there are almost as many bipods on offer as there are opinions on them. Anything said about one brand or another, good or bad, is going to stir someone up and it’s not my purpose to anoint or discredit any particular brand or type, as most seem to have a niche market or application of some description.
When the objective is to achieve the ultimate in accuracy for testing purposes, as opposed to field expedience, there are a few abiding principles to consider which have universal value. Firstly, regardless of type or style, the bipod should not engage a hard surface (like a concrete bench) without some form of shock dampener (a piece of carpet or soft rubber feet). Hard feet sitting on concrete, steel or hardwood will bounce, it’s that simple. Damping shock transfer has the capacity to reduce dispersion (improve accuracy) significantly. Every bipod I’ve owned, regardless of type, has had any hard feet replaced with soft rubber ones from a walking stick manufacturer – Leki feet are my favourite and available in Australia.
The other majorly important point for ultimate bipod accuracy, as opposed to field deployment efficiency, is torsional transfer. I’ve watched many slow-motion videos of our testing procedures – observing muzzle brake and bipod behaviour – and it’s worth noting most commercial bipods do two things consistently inconsistently. They’ll bounce up and to the left or right depending on barrel twist, and require resetting of the fine cant adjustment if this is a feature option on the unit. This occurs because the bipod has hard feet and because the apex of the bipod’s leg apex and fulcrum is below the barrel bore, allowing torsional leverage from the barrel’s rifling to be applied to the pivot point.
A bipod with the leg apex on or above the bore will produce the most stable platform possible, as the leverage applied by barrel torque is greatly reduced. While this style of bipod is less common, more and more shooters and manufacturers are realising the benefits of these principles, with an increasing selection to choose from and an ever-widening number of manufacturers.
Tripods
Although the popular use of tripods, as opposed to shooting sticks, is relatively new to the hunting scene (largely made popular by the rapidly-growing Precision Rifle Shooting fraternity) they’ve actually been used by shooters for quite a while. Again, the same scientific principles apply to tripod use as they do bipods. Central spigot-style camera bipods have major ‘centre of gravity’ stability issues ‑ especially at full extension – and should be avoided.
A cone head tripod without a central spigot is the most stable option and the range of height options is amazing. From bipod equivalent prone elevation to free-standing for the tallest shooter, tripods have it covered. As far as shock absorption and general use are concerned, the carbon fibre varieties are lighter and more robust. Tripods also provide a scale of 3D adjustment which simply can’t be matched by other systems.
In conclusion, a solid rest will substantially improve your results and I hope this has given you some ideas to consider. There are other worthwhile choices to ponder centred around shooting from a vehicle of course, but these are not generally used in the context of competition or testing. Vehicle rests are another subject altogether.