Essential Accessories
The Hawkeye Precision Borescope.
About two years ago, I bought a bore-scope. It’s something I had always wanted – but didn’t really need - or so I thought! The hefty price-tag had always stopped me taking the plunge but then the value of the dollar started to slump and with the exchange rate hovering around 1.9, I jumped-in with both feet and bought the basic kit. With postage, import-duty and VAT it cost me well over £300 but I’ve never regretted the purchase and like so many things, you soon begin to wonder how you managed without it!
Ken Harrington, the marketing manager at The Gradient Lens Corporation – makers of the Hawkeye Precision Borescope - was over in
“Would you like to do a write-up on our borescopes?”
“You bet!”
“In that case we had better send you (on loan!) our top of the range model.”
The deluxe version came in a steel case with focussing eye-piece. Mine's in a cardboard box!
The Hawkeye Precision Borescope duly arrived and in addition, Ken was able to supply some of the photographs that accompany this article, as my digital dabblings don’t quite run to photographing the inside of a barrel! But, let’s get on with it and see what all the fuss is about.
The Gradient Lens Corporation has designed, engineered and manufactured precision optics and optical instruments for over twenty years. They are located in
The right-angle eyepiece saves having to kneel on the floor - handy for a gunsmith who will use it regularly.
My own personal borescope is the most basic kit and comes in a cardboard box. It’s non-focussable (no problem for bores between .223 and .45) and the eyepiece is straight (rather than the angled version available at extra cost) however, I am well pleased with my purchase.
But what use is it? Why do you need one? The best use is undoubtedly inspecting the condition of your rifle’s bore. You can tell immediately if your cleaning regime is effective, or inspect for throat-erosion and the general condition of the rifling. In addition, I have found that it is very useful for inspecting newly-cut chambers – making sure they are free from scoring and other machining defects and you can even have a good look at the muzzle-crown - from the inside – one of the most important parts of any barrel. Tiny burrs can often be present on newly-cut crowns and even the minutest of damage to a crown (often caused by careless cleaning) can play havoc with accuracy. For the professional gunsmith, you could say that a borescope is the equivalent of a doctor’s stethoscope.
This is the tiny 45 degree mirror. This tube also contains a series of lenses.
In addition, you can look into all-sorts of small orifices – like cartridge-cases. Head separation for example can be dangerous as well as ruining your shoot. If you experience head-separation from one case, does it mean that others are on the verge of splitting? Do you chuck ‘em all away or take a chance? The borescope will quickly reveal the first signs of stress within the case. You can also have a look inside your dies – if they are perhaps marking the cases, or even inside your bolt – an often overlooked area which can be responsible for delayed lock-time and light-strikes. Of course, the borescope wasn’t invented for the convenience of shooters – they are used throughout industry and I’m sure you are already envisaging inspection of your own particular inaccessible orifices!
The lens-tube fits inside another tube
The basic borescope kit will do for most of us, although the ability to focus and the ease of use via the right-angle eye-piece are ‘nice to have’ additions. Fortunately, the lens-system has excellent depth of field and a magnification of around 10 power and I can’t think of any application that the average shooter will encounter which could not be inspected by the basic model. The outer stainless-steel tube is 0.188 inches in diameter so .17 barrels are out but .223 is no problem. I perhaps use my borescope on average a couple of times a month but a busy gunsmith might use one on a daily basis and this is where the angled-eyepiece proves useful. Similarly, a means of focussing will also be occasionally handy so it’s worth forking out the extra if the ‘scope is in regular use. My cardboard-box is fine for careful home use but the proper metal case is better for protecting a delicate instrument which may be subject to accidental damage.
Shooting colleagues occasionally ask to borrow the borescope and they are sometimes horrified by what they see and on occasion it has prompted a rapid ‘get-shut of it’ policy! A borescope would be a great money-generator for any gunsmith! If you are going to buy a secondhand rifle and can’t test it on-range, a quick look with the borescope will tell you if there are any horror stories lurking in there and it could be a good way to get a price reduction!
If shooting classic military rifles is your bag, then again the borescope can save you from buying a piece of junk. What looks like a bright, shiney bore when you hold it up to the light and peer down the barrel, is often completely worn-out.
Of course, most of us aren’t used to looking inside rifle bores and yes, you need to get familiar with what a bore in good condition looks like. I did this by looking down a selection of new match barrels – both cut and button-rifled and also by looking at a few new ‘factory’ bores on test rifles. You soon begin to get a feel for it. The mirror is angled at 45o so you get a very clear picture of the rifling in close-up. The mirror is designed to rotate so you can inspect the rifling radially as you advance up the bore. The probe is 17 inches long, so if you go in from both ends you can cover a 28 inch barrel with an action fitted. Having said that, most of the problems tend to occur at the chamber-end in the first six-inches of the barrel.
Most readers will be aware of the fouling which can build up on a bore from burnt powder and the bullet’s copper jacket. The powder-fouling is not too difficult to remove but copper can be another matter. If copper is left in the bore it will tend to attract more copper until the build-up is sufficient to start distorting subsequent bullets. Copper-fouling is often most prevalent when running-in a new barrel and when I was running in the barrel of my ‘project’ rifle, I was ‘scoping the bore after every cleaning. Copper build-up was moderate and I was managing to get most of it out quite easily using Sweets but there was one stubborn streak about three-inches down from the muzzle. It took me a good hour to get rid of it with JB paste but at least I knew where to ‘work’ the bore. Without the use of a borescope, it would still be there.
Picure on the left shows the lands just forward of the chamber - this is a brand-new barrel and the reamer-marks can be clearly seen across the lands. When you run-in a new barrel, you are smoothing-out these marks - which will initially strip copper from the bullet. The right-hand shot shows a typical fire-cracked and copper-impregnated bore just forward of the chamber. This can happen very quickly - in as little as 1000 rounds. Copper will be stripped from the bullets and accuracy will suffer.
A few years ago, before I had a borescope, I shot a 6mm-284 in 1000 yard benchrest. It was a great rifle and a great cartridge – though a noted ‘barrel-burner’. In its fourth year of competition, with over a thousand rounds down the barrel, I began to have a problem. About one in every ten shots didn’t hit the target. This completely ruined several shoots before I finally realised that the ‘missing’ bullets were in fact ‘exploding’ en-route to the target. Reason? When the barrel was eventually ‘scoped’ the first twelve inches or so were completely ‘fire-cracked’ - just like the above photograph. The fire-cracking was so severe that it was tearing-up the bullet-jackets – so badly in some cases that they clearly weren’t holding together under the centrifugal-force generated when spinning at something like 300,000 rpm. Having my own borescope would have revealed this problem and saved me a wasted season.
This is a good bore which isn't getting cleaned properly and you can clearly see the copper and powder-fouling. In this condition, it will never deliver its maximum accuracy - but how would you know what the problem was - without a borescope? The photograph shows only a tiny portion of the bore - about one tenth of one-percent of the barrel. Imagine the amount of copper - it will take hours to remove it using a good copper-solvent. But remove it you must - to restore accuracy. Better not to let it build-up in the first place of course but that's easier said than done.
Another example. A shooting colleague started to have difficulty chambering rounds in her .308 Target Rifle. She has shot the same rifle, with exactly the same bullet, dies etc. for five years. She is a fanatical bore-cleaner – the type who never puts a dirty rifle away. She always uses a bore-guide and has all the proper jags, brushes, fluids and patches. The borescope quickly revealed the problem - a hard ring of copper and carbon had built-up immediately in front of the chamber. When you use a bore-guide (and you always should do) it can sometimes ‘protect’ this bit of the bore from the cleaning-brush. Although the rest of the bore was spotless, this tiny part was not. Once we knew where the problem was, it was simple matter to carefully remove it. The borescope told us exactly when we had done enough.
More horror photographs! Could this be the condition of your rifle's bore? If so, you're wasting ammunition!
Are you sold on borescopes? OK, but exactly what do you get for your hard-earned? In some respects not much! A couple of stainless-steel tubes, a series of lenses, a mirror and a light-source. The light-source is simply a Maglite torch – the other bits are not so simple. The borescope is a tube within a tube. The outer tube will easily pass down a .223 bore but the lenses are in the inner tube, so you can imagine how small they are. Does anyone else make a borescope? Yes – is the simple answer but they are for serious industrial use and they are way more expensive than the Hawkeye.
A borescope is about the same price as a new barrel but by improving your cleaning and bore maintenance regime, it could pay for itself in a few years. If you want one you are going to have to do what I did and buy one. Gradient Lens are happy to deal with individuals but we do have a
Have a look at the website at www.gradientlens.com