Richard Boothroyd’s Blog

One of my buddies is one of those “get things done” types. He made successful 50 BP Express cartridges from brass tube soldered to lathe turned heads, and 375H&H bullet jackets from 5.56 fired cases. That included making all the dies.

His latest foray into case conversion is 45 Auto Rim. For those who don’t know the 45 Auto Rim is the 45 ACP with a rim for use in revolvers. In WW1 the Americans couldn’t produce enough 1911 pistols so both Colt and S&W made revolvers for the 45 ACP. To confuse matters both are known as Model 1917. Half moon clips were used, but later brass was made with a rim. It is a very thick rim because headspace needed for the 45 ACP case rim plus the half moon clip.

45 Auto Rim is not easy to come by so my buddy decided it was time to make some cases for his S&W Model 1917. This is how he did it. He turned a plug to be held in the three jaw chuck, so dimensioned to be a close fit to the inside of the case, ie the case is pushed on tight enough to be secure for light machining. The rim is turned off, in fact the head of the case is turned to 10mm diameter for a length of 2.29mm that being rim thickness. That’s all there is to the preparation of the 45 ACP case.

To make the rims a piece of brass rod is chucked in the lathe and faced off. The OD is turned to rim diameter. A 10mm hole is drilled down the middle, and the rims which are no more than washers of a particular size are parted off. Thickness is not so critical that it can’t be controlled with a vernier caliper.

The rims are then soldered to the cases. I am somewhat confused about that. I know that fabricating cases is done by soldering head to tube but I would have thought that solder temperature especially silver solder is so far above the annealing temperature of brass that it would leave the head too soft for safety. But it seems to work as the cartridges he showed me were on their fifth loading.

As he didn’t have a shellholder he made a simple Lee Loader type die, so we don’t yet know whether the soldered rims will resist pulling off in the loading press. He is also quick to concede that it is not a precise job at this point, although the cartridges shoot well enough and looked pretty good to me. He says that for bigger volumes it would be worth making better and more precise tooling, which is easy to make.

But there you go, a real live example of what can be done.

[Originally posted to SATalkGuns -- Admin]

While ruminating about this and that I got to thinking about case life. It could be argued that if you get 15 rounds out of a 308 case, cost per round is so low that there’s not much to be saved by extending it to 20 or 25 rounds. In any case, my interest is what happens if brass is not available ? So it is worth exploring I reckon.

Rifle cases usually fail by splitting at the neck, but neck tension has become too weak by then anyway. They fail at the neck because brass hardens and gets brittle by working, and the sizing and expanding that causes work hardening is most violent at the neck. Rifle case necks are first sized down then expanded back up to the required size by the expander plug. Sizing them down and then up again work hardens them a lot. So why not just size them down to the diameter required and dispense with the expander plug ? Because of tolerances in cases. The die maker doesn’t know what the case wall thickness will be, so he must make his dies to handle the thinnest walls likely to be encountered. If he doesn’t, his dies will not size thin walled cases far enough to hold a bullet. Dies are therefore all made on the tight side. The result is that all cases, and thick walled cases especially, are sized too much, and the only way to get them to end up the desired size is to fit the die with an expander plug.

I have some Sako 308 cases fired in my rifle and some PMP cases fired in another rifle. The Sako necks all measure 0.404 OD and the PMP all 0.406. Cases expand to fill the chamber when fired then shrink slightly because of elasticity or “spring” of the brass. The small difference in these cases shows only that the chamber necks of the rifles are slightly different, which is to be expected.

I use both RCBS dies and a Lee Target Model Loader. The Target Loader neck sizes only, and the necks, when captured in the sizing die, are reamed with the reamer that is part of the Target Loader kit. The case necks are thus uniform in thickness and concentric. The sizing die reduces the neck to the desired diameter, ie there is no expander plug..

I sized a few fired cases that had previously had their necks uniformed as described above with both the RCBS dies and the Target Loader. After sizing in the Target Loader neck OD is 0.397. After sizing in the RCBS die it is 0.398. Pretty much the same which is to be expected as that is about the diameter needed to grip the seated bullet. That tells us that the amount of normal sizing required is 7 - 9 thousandths. The interesting point, however, is that cases sized with the RCBS die without it’s expander plug are 0.390 OD. Therefore, in addition to 7 - 9 thou of normal sizing the RCBS die is taking them down another 8 thousandths, and to make matters worse is then stretching them up 8 thousandths.

The amount of working of the brass is therefore three times as much in the RCBS dies as in the Lee Target die. The solution ? I reckon it is a good idea to lap the die neck out to the diameter that will size the necks to the same diameter that is presently left by the expander plug. In the case of my 308 that would be 0.398, ie an enlargement of 8 thousandths. Obviously it would differ slightly from other rifles, dies and brass. I have not yet done it but I plan to.

Of course, neck life can be extended by annealing, which I recommend. But it is not a matter of either/or, as both these methods can be used. I have no info as to how much this will extend case life but I suspect that it will be quite a lot.

Something else to bear in mind, not directly related to the above, is that cases with split necks are not necessarily useless. All cases with the parent 7 x 57 head can be made into shorter cases like 45 ACP and possibly others I haven’t thought of. Some of this forum will be aware of the 458 x two inch which is simply a 458 Win shortened for use in LA carbines. MV is under 2000PS but still greatly exceeds old calibres like the Martini Henry and don’t forget that the MH was effective at ranges well beyond 300m. Any of the belted magnum cases can be used for the 458 x two inch.

Case conversion is a topic all on it’s own, but there is hardly a cartridge that can’t be made from another, and hardly a case that can’t be altered to another calibre. The lesson ? Don’t throw away brass, even if it’s a calibre you don’t shoot, or even if the neck is split. You never know when you or someone else might need it.

Same goes for berdan brass. It can be converted to boxer.

[Originally posted to SATalkGuns -- Admin]

I might have mentioned that my buddy Richard B has made bullet dies. He said they were only experimental to prove the viability of making the dies and the bullets and were thus a bit crude at this stage. Today he showed me some 243 bullets he made from 22RF cases and some 30 cal jackets drawn from an old hot water geyser. As he said the bullets were not perfect, for example they had a slight annular depression where you’d find the extractor groove on a rimless case. That’s due to some imprecision in the drawing die. As he said, it’s just a matter of matching the die exactly to the 22 cases. But they were good enough to shoot, and he fired some with respectable accuracy in the circumstances.

The 30 cal jackets were drawn from discs cut from a hot water cylinder. They were longer than needed and were very nice, no cracks or splits despite having been annealed only once before the first draw. Because of that, the corners of the bases were quite generously rounded. But that was the only fault if it can be called a fault.

The quality of both was such that he has proved the viability of drawing jackets and making bullets, and making the dies to do it. There seems to be very little to do with firearms and ammo that can’t be done by amateurs if the will is there. Now, who knows exactly, from actual experience, how to make primer compounds and propellants ?

[Originally posted to SATalkGuns -- Admin]

We are all familiar with the golden rule of gunfights that one must have a gun. But I reckon the real golden rule is to have a gun that works. I’ve seen plenty that don’t. I previously told the story of a revolver belonging to a friend of my wife’s that wouldn’t fire more than one round in ten the first time she took it to the range. It is an Astra and was easily fixed by adjusting the hammer spring compression by means of the adjusting disc inside the grip. The important point however, is that she had had the gun for several years without ever having fired it. What’s worse is that her mother who had bequeathed it to her had never fired it, nor had it’s first owner, her aunt ( mother’s sister ). It had been kept as a dysfunctional defense piece for 35 years in all.

The present owner also complained that the cylinder was a bit “sticky” on opening. I didn’t notice any obvious problem on casual inspection so she soldiered on with it until it got worse and I was forced to do something. The screw in the cylinder release catch is not in the centre, that is the catch is asymmetric about the screw. It was the wrong way round, and being thus closer to the recoil shield it was limiting forward movement hence the slight resistance of the cylinder when opening. There was enough movement of the catch to allow the cylinder to open, but only just.

It was a simple to reverse it. But that was not the end of it, because a few months later it exhibited the same fault. The screw had worked loose enough for the catch to rotate 180 degrees into the position that had caused the problem first time. And to be fair to the owner it was not apparent to casual inspection. That is, although it had worked loose enough to cause the problem it was not obviously loose except to close inspection. Indeed, if I hadn’t had the first experience with it I probably would not have found it quickly the second time.

The lesson? Screws work loose. It pays to keep a small set of screwdrivers to fit all screws on your guns and to regularly check the screws.

It is surprising how many people seem not to grasp the importance of this reliability issue. Maybe they think waving it at the perps will be enough. I was on RO duty last week. We had a new member on the range, a guy of about 40 with a CZ ( Model 70 I think ) in 7.65 auto. It failed to feed about every fourth or fifth round. A casual glance suggested the mag lips judging from the angle at which the cartridges presented to the feed ramp. I pointed out to the guy, in case it wasn’t obvious, that it was no better than a paper weight as a defense piece and that he should get it fixed or better yet get a better gun, notwithstanding the FCA. For heaven’s sake there’s some good stuff out there for nothing if one takes some trouble to look. Not long ago Strand Guns had a Sig Sauer P220 for R2200 asking price. Somebody was smart enough to buy it.

That same day, a long time member and experienced shooter and handloader had feed problems with his Beretta 92. Not as bad as the CZ but enough to render it useless as a defense piece. I noted that he was shooting handloads loaded with the RCBS 124 grain conical flat point seated a hell of a long way out. Whether that was the problem who knows, testing it with better loaded rounds might have shown it up, but he’s not the sort of guy to accept any suggestion that his loads might be at fault. Could also have been too light a load not cycling the slide properly. Whatever it is, an experienced shooter shouldn’t be having reliability problems with his primary defense piece.

Reliability is paramount. By far the important thing in a gunfight is that the gun must work, calibre is much less important, as a 22 that works beats a 155mm howitzer that doesn’t.

[Originally posted to SATalkGuns -- Admin]

Members of this forum will know that I don’t like what I consider oversize scopes. There is of course difference of opinion as to what constitutes too big and there are some who think that very big is not necessarily a handicap. But making due allowance for opinion some scopes are ridiculous. I recently fitted a Swarovski 4-12×50 to a dainty little Sako sporter in 22-250. Scope was so damn big it dwarfed the rifle and would have been more suitable for an artillery piece.

It was so long that with the objective bell almost wedged into the front ring it barely cleared the rear iron sight. The lens cap couldn’t be fitted, not only because of the rear sight but also because the 55mm diameter objective bell was only 1mm above the barrel. Furthermore, the scope was so long and so limited as so fore-aft adjustment because of the aforementioned factors that eye relief was very much on the short side.

Why do people buy such unsuitable scopes ? Don’t they give any thought to matching it to the rifle both in terms of it’s bulk and intended use ? The customer paid 10K for it and considered it a bargain. He could have had a more suitable and probably more durable Leupold for a quarter the money.

Which brings me to another point that I have also mentioned before. He didn’t buy the scope from us, he bought it from a camera shop that advertises in Magnum. The camera shop doesn’t know how to fit them even if its possession of the rifle was legal, so the guys buy pricy scopes and bring them to us for fitting. I consider it humiliating to earn R300 for doing the serious job of ring lapping and precision fitting when somebody else has cleaned a grand or two profit for just selling it. I reckon we could sell Leupold for the same or less than the camera shop and include the fitting in the price. But my boss won’t go for it, says they are too expensive to stock, and is content to take the crumbs and leave the real profit to camera shops.

I guess there’s nobody to blame but me. I’d consider selling Leupold myself but I wouldn’t get the sales without significant advertising costs that would make it not viable, and possession of customers’ rifles in my private capacity would be legally questionable anyway.

It is a frustrating situation, as I believe that the nature of the trade is changing rapidly. The days of selling budget priced pistols are over. In future most customers will be those who have hung onto a gun or two, and they will be what I call the serious people who spend some money on their sport. It will be a much higher level trade with demanding customers and only those dealers that provide knowledge, expertise and service at that level will get the business.

But that’s just my rant for the month. Need to let off some steam occasionally.

[Originally posted to SATalkGuns -- Admin]

Making sizing dies is not difficult, just slow and painstaking. Richard Bowman and I have made a few, partly for the hell of it, partly because it seems silly to pay for such things if you’ve got a lathe, and partly because it’s a good idea to develop the skill for making things. Who knows what one might need to make ?

I’m not going to delve into the finer nitty gritty at this stage, I’ll just explain the bare bones of it. Basically it is a simple lathe job in which a piece of suitable steel is turned to outside dimensions and the bore drilled, bored and polished, or is you can afford the reamer drilled reamed and polished.

Reaming is the easiest, quickest and most accurate method. But reamers are not made exactly to bullet size. An adjustable reamer is best. I have found that they can be adjusted very finely to ream out exactly to size. The hole must be drilled 0.20mm smaller to leave enough meat for the reamer to remove without leaving the tool marks of the drill. The reamer will leave a mirror finish. I have made dies at least as smoth or smoother than factory dies. There’s no harm in polishing the reamed bore with 1000 or 1500 grit, which will leave a finish best described as optical.

But expanding reamers are about R500 each. Machine reamers are about one third of that and available in 0.01mm increments. That makes possible a reamed hole only a few microns smaller than desired, which can be brought to size by polishing.

To avoid even that cost I recently made a die by drilling to about 0.50mm under size and machining with a boring tool almost to size, and finishing by polishing. The reason for boring is that a properly sharpened boring tool will leave a finer finish that a twist drill and therefore requires less polishing. The danger with polishing is that it is easy to end up with a hole that is tapered or oval or both. In the even I bored too big and ended up with a die too big. But the exercise proved the practicality of the method. Polishing removed three thousandths of diameter ( 1.50 thousandths all round = about 40 microns ). I went through all the grits from 220 to 1500. I used wet or dry paper attached with masking tape to a wood dowel. The circumferential polishing was done with an electric drill, the lengthwise polishing by hand.

Tests with a small hole gauge showed that the bore was parallel and concentric within very close limits and the finish was optical.
The only real difficulty with this simple method is that one must start three or four thou under for polishing, but there’s no reliable way to predetermine how much metal is being removed. It has to be regularly tested with a small hole gauge, and you don’t want to get to final size with 320 grit. On the other hand you don’t want to end up one thou small after the 1500 grit. So there’s a lot of feel and cut and try about it. And in the worst case you might make two or even three before you get it right.

But the point is that it works. And each success in making such an item adds to experience gained when it comes to the next.

[Originally posted to SATalkGuns -- Admin]

Further to the matter of home workshop activities, let me make it clear that I am not a pro, I am an amateur with a good bit of practical gunsmithing experience. There are others who know a lot more than I about gunsmithing, machining and toolmaking. But until they come forward I’ll continue to offer bits and pieces occasionally. Although my methods may not be the best they are all tested and proven to work.

There are all sorts of little devices that are not too expensive and can be useful out of all proportion to their cost. It is useful to know which those are because we amateurs don’t usually have the bucks particularly for machine tools and expensive accessories so we must get good bang for each buck we spend.

A very useful and versatile item is the micrometer head, which is a micrometer thimble and spindle with no caliper and opposite anvil. It is intended for holding in a fixture for controlling the movement of the work or a tool. Possible uses would fill a book. It can be used as a comparator, which is a simple table and column that usually holds a plunger type dial gauge. The purpose is to measure the thickness of a workpiece on the table. It is a small item, the table usually being only a few centimetres each way. A respectable one can easily be made, and a mike head used instead of a dial gauge.

A mike head can be mounted on a bracket on a lathe bed for precise control of carriage movement. I use one mounted on the cross slide of my Myford for controlling compound slide travel for threading, especially for small threads. I bring the tool up to the point where a feeler gauge will fit between the tool and the work. Why not bring the tool into contact with the work ? Because feed screw pressure and a sharp tool make it difficult to judge, ie the tool can dig in without my realising it. Hence the feeler gauge trick. Then I bring the micrometer anvil into contact with the corner of the compound slide which is set to 29.50 degrees for metric threads. The mike then controls the depth of cut. More accurate than the lathe feed dials or visual judgement.

I also use it for getting finishing cuts very close to size before final checking with a conventional mike. Yes I know that can be done with the lathe dials but this baby does it better and more accurately. With a lathe turned collar it can serve as a depth mike.

As I have mentioned screw cutting, not much real nitty gritty has been published. Most lathe users are scared of it, but it’s easy once you know how. There are two little books that give chapter and verse. “Screw Cutting in the Lathe” by Martin Cleeve is the most complete and detailed exposition I have seen. I found it invaluable. “Drills Taps and Dies” by Tubal Cain is about thread cutting with hand tools and covers it in extreme detail. This particular book explains the various British, US an Metric threads, and has a very useful set of charts of drill sizes.

It should be understood that the drill diameter usually given on the box of a tap set is not the only size that can be used and often may not be the best choice. It has to do with thread engagement. A nut and bolt or a screw and it’s tapped hole seldom if ever need 100% engagement. In most cases 60% engagement provides 90% of pull out strength and much easier cutting. Tapping a hole for 100% engagement needs three or four times as much torque as 60 or 75% engagement and is a common cause of tap breakage in small sizes below 4mm or so. Tubal Cain’s book provides the engagement % for various drill sizes for each thread diameter.

Although a close running fit of screw and hole are seldom necessary it is sometimes nice if only for the satisfaction of that nice “close fit” feel especially if it is an operating screw in a jig or tool one has made. The best way to achieve that is by tapping a hole in a piece of scrap to use as a gauge for the male thread if it is being lathe turned. When you approach finished size the tapped hole becomes the gauge and the job is done when the gauge screws freely but not loosely on to the male thread. I have made some very nice screws this way.

Note that drill size is more critical for small holes. That’s because the thread “teeth” are smaller on smaller diameter threads. Drills come in 0.10mm increments. 0.10 makes a much bigger difference in thread engagement in a 3mm thread than a 6mm. On a standard 3mm metric thread the thread is only 0.30mm deep. A difference of 0.10mm drill dia is one sixth of thread depth. With the metric fine threads it is worse. On the very small threads it might sometimes be necessary to resort to a drill in the 0.05 increment class because two drills only 0.10mm apart might cause insufficient engagement one way or so tight as to risk tap breakage the other way. 0.10mm Increments are not usually available at hardware stores but are usually available at engineering supply shops. 0.05 drills are usually a special order item.

I have not mentioned dies because I seldom use them. Almost never in fact. Dies are expensive and a different one is needed for each thread. A lathe on the other hand can cut any pitch thread any diameter. Well, not all lathes can, some will thread only in their primary language ie metric or imperial. My Myford will cut both without special gearing.

[Originally posted to SATalkGuns -- Admin]

We hobbyists have to make do with the equipment we have, which is often limited in capability. So methods sometimes need to be devised that will get more accuracy from a machine than it is theoretically capable of. What follows will not be new to many, but it may provide a glimpse of what can be done with simple equipment for those who are just starting into this hobby.

I make sprue cutters for Lee six cavity bullet moulds because the factory sprue cutters don’t work. Not many will want to make sprue cutters but the method can be used for lots of other things. I refer to drilling holes in a dead straight line and accurately spaced on a cheap hardware store drill press. How accurate ? Within two thousandths easily ( 50 microns ) and within one thou ( 25 microns ) with a lot of care.

Why does it need special methods ? Because cheap drill presses usually have considerable spindle run out. Mine can be seen and felt and it is quite impossible to drill a hole accurately to position. It doesn’t matter for most home workshop purposes because 99% of holes don’t need to be closer than half a millimetre.

There are two requirements to get good accuracy. First the spindle run out must be eliminated ie the drill bit must not wander even slightly. That is accomplished by a drill guide bushing which is a little precision made item that costs about R25. Mine fits a 4mm twist drill and is such a close fit that there is no run out. It is carried in an easily made bracket. The second requirement is a means of positioning the work and shifting it’s position by a measured amount.

Here’s how it is done. My drill press is small. Stands on the bench and is small and light enough to carry around. A similar press costs no more than R300. It’s table is about 150 x 150mm. Take a piece of bright drawn flat, size not critical, try 6 x 25 x 250mm long. Drill a series of holes so it can be bolted to the drill table in whatever position needed. This is a “fence” against which the work is positioned and slid back and forth as required. Somewhere near the middle you need a tapped hole to attach the guide bushing bracket. The bracket is a simple arm that carries the guide bushing just a bit higher than the work, and must have some adjustment of “reach” to accomodate work of different sizes. Various lengths of arm can be made as needed. It is bolted to the fence with the bushing positioned over the hole in the middle of the table and directly under the chuck.

Any hole drilled in a piece of flat stock held against the fence will be exactly the same distance from the edge of the work, for the reason that the fence and the bushing will not move. Consequently a series of holes will be in a perfect straight line. Spacing the holes where you want them is done by vernier caliper. After the first hole is drilled and the work is still clamped to the table, measure the distance from the end of the workpiece to the end of the fence. The work can then be moved a measured distance to the next hole by altering the vernier reading by the required amount.

Any errors are not cumulative because hole number six is measured from hole number one not hole number five.

This is much simpler in a picture than a written explanation. It is so simple to make and to use that it is almost a joke.

This is just one way in which great accuracy can be accomplished with simple equipment. There are many others.

[Originally posted to SATalkGuns -- Admin]

Thanks to those who commented on my little posting about lathe turned cases. My buddy has just made a small batch of ten Martini cases. He necks them down in a single pass without annealing them first. He is of course aware that that is not a good technique but it is still in the early stages. The interesting point is that they can be necked in a single pass without any apparent problem. For proper production necking will be in two passes, annealed before first pass, and before and after second pass.

At this stage there is considerable variance in neck wall thickness but that’s because no great effort at concentricity has been made. For dimensionally consistent cases some fairly decent jigs will need to be made.

The cases made thus far are however so good as to prove the practicality of the method. John D pointed out that Martini cases are OK with the straight drilled interior volume as no more than that is needed for a practical powder charge. Brett N suggested that chamber inserts are a better idea and less work. Both points are taken. The objective however was more than just making cases for the Martini, it was another step in the development of the ability to make what is needed if it cannot be easily obtained otherwise. As my friend put it yesterday, ” We are getting closer to the position in which we can make just about anything.”

[Originally posted to SATalkGuns -- Admin]

I might have mentioned before that I have a buddy who is very good at making things. He is also a collector and shooting enthusiast. Has half a dozen Martini Henrys. You will all know that modern Martini cases are lathe turned, at least all those I’ve seen are. They are usually turned from the solid with a straight hole drilled down the middle for the powder space, ie very thick walls because it is difficult to machine a cavity anything but straight.

I have a case made by North Devon Firearm Service that was first machined straight on the outside, or maybe slightly tapered, and the neck formed by reducing in a series of dies, and annealed at every stage. The discolouration of annealing is visible. That makes a case with a full interior volume.

My buddy has just done the same. Turned the case in exactly that way and made the dies for reducing the neck. The resulting case is a trifle rough as it is just an experiment at this stage. But it is good enough to shoot, and good enough that the dies just need a bit of smoothing to get them dead right. I have no doubt that with a bit of work he will make cases as good as the NDFS case which is beautifully made.

This is the guy that makes such things as 50BP Express ammo by soldering a machined case head to tube body he has reduced to size also in dies he made.

As he says, never say die, anything is possible.

[Originally posted to SATalkGuns -- Admin]