Month: April 2008

Scope Selection&Fitting

Posted by on April 27, 2008

I have soap boxed before about poor choice of scopes, in particular making sure they can be fitted to the rifle. Thirty years ago most scopes had 32mm objectives and there was no problem fitting them to pretty much any rifle. Soon after that 40mm objectives appeared and soon became dominant. Now 44mm is common and we see even 55mm occasionally. But the nominal diameter of the objective is not the whole story. My old Nikko Stirling 3-9×40 is 48mm dia at the objective but a newer Nikko 3-9×42 is 58mm despite the objective being only 2mm bigger.So what, you might ask ? There are two common effects. First, the scope can’t be fitted because the objective fouls the barrel or the back sight. That would be taken care of by higher rings, and I choose rings high enough for the job where I am fitting a scope from scratch. But many of the scopes I fit are upgrades from cheaper scopes so the rings are already on the rifle. As it is traditional to use the lowest possible rings they are often too low for the new scope.The second problem can’t be solved by higher rings. Most scopes are variable. All else being equal variable scopes have shorter tubes than fixed scopes because part of the tube is occupied by the adjustment ring. The result is that many scopes barely fit between the rings. It is worse with the big objectives because the objective bell is longer and the tube shorter. It is a common problem.Yesterday I fitted a Swarovski Habicht 3-10x42A scope to a rifle on an FN 98 action. The old scope was a Tasco 4×40 in Millet bases and rings. These are the same as Redfield, Burris and Leupold rotary locking bases and rings. The objective clears the barrel by just enough to pass a business card, but the ocular lens is so big that the bolt can’t be inserted into the action. They are low rings so the problem will be solved by higher rings at the owner’s expense. Tube length is only 138mm and the scope fits between the rings with no fore and aft movement to set proper eye relief. Extension rings will be needed to fix that.You might say that those are easy problems to fix. Indeed, but why are owners so ignorant that they can’t figure it out when they buy the scope ? More to the point, why don’t the camera shops that sell the scopes tell the customer ? Because they don’t know, that’s why. They sell expesive scopes about which they know nothing and which they don’t know how to fit to the rifle even if they could legally have the rifle in their possession. I’m not desperate for the peanuts I earn from fitting scopes and I wouldn’t fit scopes I haven’t sold on principle. I do it because my boss says so.That doesn’t mean I object to camera shops selling scopes. As a free marketeer I accept the right of anyone to sell what he or she likes, and the right of customers to buy from whomever they like. My point is that it makes no sense to buy expensive scopes from people who know nothing about them, then expect those with the expertise to fit them, and in many cases complain about the modest fitting charge after having given the real profit to the camera shop. It takes me at least two hours to fit a scope properly, sometimes as much as four hours if I hit glitches. We charge R300. I’m thinking we should charge R500. After all, we are doing the real work.As a side issue I’ve said before that rings are never properly aligned unless they are worked on to make them so. In fact I’ve never found a pair that was straight before I made them so. This pair wasn’t straight either. But more interesting was that they were lined with a layer of some sort of plastic adhesive tape. Can’t imagine why unless the guy who fitted the first scope figured he needed to do that for some obscure reason. Whatever the reason, there’s no substitute for precise ring alignment and concentricity, which is itself a good reason to buy scopes from those who know what they are doing.[Originally posted to SATalkGuns -- Admin]

Range Safety

Posted by on April 27, 2008

We all think of range safety in terms of safe gun handling, and indeed that is where the main risk lies. But there are other risks. I don’t know whether a range has ever been attacked by crooks to get some free guns, but in the present scenario the risk can’t be dismissed. All it needs is half a dozen gremlins with serious weapons to attack when shooters are at the targets and guns all empty, especially if they are prepared to shoot the RO and SO out of hand which is also not unlikely.Anyhow, it was discussed at a recent meeting of Somerset West Pistol Club, as part of regular discussion of safety in general. It was agreed that, while we shouldn’t get paranoid about it, the risk exists and we should take reasonable measures to minimise it. When I am on SO duty, I periodically take a look around the outside of the range to see what and who is there, also so that anyone who might be casing the range will see that we are not unaware of it and might not easily be taken by surprise. That is of course a small thing, and is my personal first effort at improving my own performance in that regard. Access control is another thing that is being looked at. We are also considering that shooters should carry their guns to the targets not leave them on the bench for easy taking, but that has not yet been decided. I am considering keeping my loaded SMLE slung over my shoulder while on SO duty, as a more effective weapon against armed attackers.Our range is enclosed on all four sides. At the back is a high brick wall right up to the roof over the firing line. It is about 4m high. It is parallel to the firing line and about 6m behind. It is about 4m behind my back as I patrol the length of the line watching for problems the RO might not see. It has a couple of openings for ventilation just below roof level. I’d like to close those but I have not considered them a serious enough problem to push it. Imagine my surprise when I arrived for duty yesterday to find a big hole in that wall with a double steel gate through which anyone can backshoot the SO at a range no more than 6m at any point. The reason is to provide direct access from the range to the braai area, and it was apparently agreed upon by all the committee except my buddy Richard Bowman. Lemme tell you it feels real exposed concentrating on the activities on the firing line with my back exposed to that hole, and I have kicked up a big fuss about it. The worst of it is the rank stupidity of people I thought knew better, and whom I will not be able to take seriously in future.[Originally posted to SATalkGuns -- Admin]

Bolts for Safes

Posted by on April 27, 2008

Sometimes things slip through the cracks. Too often in my case I guess. I recently mentioned that rawlbolts are not always the best choice and that coach bolts are often better. Somebody, might have been Peter Moss, asked what coach bolts are. Can’t remember whether I explained, so here goes. Put at it’s simplest a coach bolt looks like a big Fischer plug. But it is more than that. Most plastic plugs are just that, plastic, which perishes over time. For long life you need nylon plugs which don’t perish. The bolt is really a big wood screw but has a hex head. An 8mm screw fits a 10mm plug. They come in various lengths. For safes you want them as long as the brick thickness will allow. I use 10mm screws with 12mm plugs for safes. About 120mm long is OK. Remember that the whole 120mm does not penetrate the wall because of the thickness of the safe, washer and often a spacer between safe and wall. I’ll come to that later.The best place to get coach bolts is Ramset who must have a depot or agent in all cities and towns. Ramset is well known in the construction industry and is a supplier of all sorts of fixing screws like chemical anchors and the like. If memory serves they told me that a 10mm coach bolt has a pull out strength of 4 tonnes in concrete.Some will tell you that installing a safe is an easy half hour job. Depends what sort of job you want and I’ve never installed one in less that two hours. The longest took five hours. The ideal position is a flat wall thick enough to accept long bolts but I seldom had that advantage. Mostly a cupboard is the only available place and most people want them concealed anyway. In Cape Town most cupboards have a masonite back which is usually some way of the wall, so the masonite back is pulled out of line when the bolts are tightened. On a plastered wall you can’t see where the brick joints are so it is hit and miss whether you drill into a suitable place in the brick. There are various kinds of brick. Some are hollow extruded. If you don’t drill those in the right place the bolt won’t get adequate grip. In one case I had to drill new holes in the safe because it could be fitted in only one place and the holes I drilled in the brick didn’t allow enough grip. Fortunately there were a few bricks left over from the construction, from which I could gauge where to drill the new holes. Which is why matching holes had to be drilled in the safe. I’ve had other bricks that were so soft that they crumbled when the bolts were tightened. That was solved by chemical anchors.It’s a good idea to enlarge the holes that are usually in the safe. Also to drill more of them. They are sedom more than 8mm, maybe 10mm if you are lucky. It is notoriously difficult to drill a hole in an exact position in brickwork. It takes only a millimetre or so error to make installation impossible. The answer is to enlarge the holes quite a lot to allow some latitude in positioning the safe. I make them at least 15mm. Then you use a big washer. Two or three of those big disc washers called fender washers works quite well, alternatively those 50mm square x 5mm thick washers used for roof construction. Both cover the hole and distribute the load over a wider area.Most safes come with two holes. That might do for those tiny one handgun safes but not for rifle safes, which should have at least four or six for the bigger safes. I provide one at each corner, about 50mm inboard from the corner to allow access for spanners from the inside, and two halway down.Rigidity, or the opposite (flexibility) is a function of material thickness, shape and size. A small safe will be less flexible than a big one. Rifle safes will flex quite a lot. Most walls are not perfectly flat. The result is that tightening the bolts will often pull the safe out of straight enough to prevent the door closing properly. That’s why spacers are often needed between safe and wall. My own safe has been installed in five different flats or houses. In addition I’ve installed quite a few for other people. Every one has needed spacers. They can be thin enough that steel washers will do, but sometimes two pieces of 3mm masonite has been necessary. Believe me, it takes a hell of a lot of cut and try to get it right.Anyhow, that’s the bare bones. There’s a lot more to it, so I don’t where the notion comes from that it’s simple. But maybe I’m too much of a perfectionist.[Originally posted to SATalkGuns -- Admin]