October 2013

300 WinMag

And so it came to pass that I found myself badly in need* of a flat rifle. Not one that’s been under a truck, mind, but one with a flat trajectory, for use at distances further than the 100m or so that my collection of leverguns are capable of.

So I asked around, and found a new barreled action in 300 WinMag. Perfect. Got an endorsement letter (as a dedicated hunter) from Kaapjag, applied for the licence, waited about four months, got the licence and the gun.

Reading up on the Howa, I came across this page which explains how to adjust the trigger. But the first step is, take the whole thing apart and clean it up. Get the gunk out, and also lightly sand the relevant surfaces to smooth things out.

[When I find the pictures I took I’ll post them here. I suspect they’re on a memstick that crashed. Suffice to say, the inside of the trigger assembly was dirty!]

Johan van Niekerk out in Plattekloof makes awesome stocks. Unfortunately he didn’t have a template for the long Howa action, only for the short one. So I had to wait while he ordered a stock from the ‘states to use as a template. Took from February until June, but I am way happy with the result.

He epoxy bedded the action, put in two aliminium pillars where the action screws go through the stock, and added two crossbolts (you can see the holes, roughly in line with the scope rings).

The scope is a 3-9 Redfield Revolution with the Accu-Range BDC reticle.

Load development

A factory round is made to a specification — typically that set by the Sporting Arms and Ammunition Manufacturers’ Institute (SAAMI). When handloading, you have a bit more leeway — your hard limits are not the paper specification, but the actual rifle in your hands.

1. Pick a bullet. Every time you change the bullet, you have to revisit all the points below. In my case, I picked the Sierra 180 grain Game King. While the Match King might be more accurate, I’m developing a hunting load here, and in general match bullets are totally unsuited to hunting.

2. Cartridge Overall Length (COL). The cartridge has to fit in the chamber of the gun. The bullet can’t protrude to where the lands of the rifling starts, because it takes the pressure of the exploding powder to force the bullet into those lands and grooves, engraving the lands on the bullet which then impart spin on it.

In general, it’s good to seat the bullet about 10 thou (0.001″ 0.010″ or a quarter of a millimeter) away from where it would contact the lands, so that it has a short “jump” before it hits the rifling. Varying this distance can also improve accuracy.

There’s also a second hard limit that’s sometimes overlooked, and that is that you preferably want your ammo to fit in your magazine. Sometimes, this is not a problem, and there’s plenty space in the magazine, other times, not so much.

So, step the first. Load a bullet in an empty case, just deep enough to hold it in place. See whether this combination fits in your chamber. If not, seat the bullet a little deeper until you can close the bolt. Measure the COL, either to the tip of the bullet or (better) using something like a Stoney Point bullet comparator.

This is the maximum length cartridge that will fit my chamber — about 3.540″. The caliper shows the SAAMI spec 300 WinMag COL of 3.340″. The Howa has a very long throat, obviously.

So far so good, but does this monstrosity fit in the magazine? Not a chance.

Step the second. Continue seating the bullet until it fits in your magazine.

There we go. That fits my magazine.

Notice the other nice thing? All other things being equal (hint: they never are) you want the whole neck of the case to be in contact with the bullet, which means that it should be aligned with the parallel sides of the bullet, which start just after the boat tail and at some stage stop being parallel by turning into the bullet ogive. The pic above shows the IMO optimal seating depth relative to the case neck for a boat tail bullet. Further in and you’re encroaching on your powder space, also at some stage the front end of the case neck stops contacting the bullet (not really an issue with a short neck like this, more of an issue with something like the 30-30). Further out and not all of the case neck is gripping the bullet.

3. Pick a load. The general rule of thumb is, get as many data points as possible, then start low and work up. The Somchem manual lists 60.8 to 67.5 grains S365, 67.5 to 75 grains S361 and 68.5 to 73.5 grains S385 for a 180 grain bullet. I started at 66.6 grains S365 and worked up to 69 grains. The first (3 shot) group was just under an inch at 100m, but a bit slow at 2880 fps. More powder didn’t really give better groups, until the groups started opening up at 68 grains and 2980 fps.

So I switched to S385. 74 grains (which is over the Somchem max, I know) gave 3040 fps and this:

Yes, I know. It’s a fluke. But it’s a pretty fluke.

* People would argue, but I’m calling it a need, so there.

The slow unwinding.

There was a time when a (well-do-do, granted) man-in-the-street could travel at twice the speed of sound, 18km above the earth, as often as he wanted. Ten years ago today, we lost that. The Concorde made its last passenger flight.

This quote, from ten years ago, hits it right on the button:

The Roman Empire crested at Hadrian’s Wall and thereafter retreated slowly, step-by-step, so gradually that few people noticed that with every year, there was a little less.

The Western Empire, did we crest at the Moon? If we did, surely the death of Concorde is akin to the last of Rome’s Legions departing Britain. And the most troubling sign is not that Concorde is no more, but that we watch it’s passing with such complacency.

We’re throwing away the future. We have seen the stars, and meekly followed the State back to our mud puddles and sandboxes.

Then, in 2011, the Space Shuttle made its last flight ever. With no replacement.

Right now, we have people like SpaceX and Virgin working hard to get back to where we were. Back into space, back on the moon (we were last there in 1972 — are you spotting the pattern here?) and beyond.

I fear that we are living at the crest, and I hope that I am wrong.


(This blog post partly inspired* by Spider Robinson’s In the Olden Days (pdf and online). Go read.)

* I doubt that “inspired” is really the right word.

Kitchen counter revisited

Back in 2008 we knocked out the wall between the kitchen and the living area. The idea has always been to put a counter surface on there, it’s just that I wasn’t quite sure how to do it so… I didn’t.

Until a few weeks ago, when Tanya mentioned that with Jessica’s 18th birthday (cocktail) party coming up, it would be nice to have a counter…

So I got my arse in gear.

Started with a couple of templates, ordered MDF mostly-cut-to-size and with the appropriate edges rounded. Not that they got it right, but it was close enough.

Then I carefully marked the boards and routed them to size against a straight edge and… it didn’t work out right. No idea why. Out by about two mm on the outside edge. FSCK.

So I routed it back further and glued in a false piece and repeated the operation, but starting about 5mm oversize and coming in via router and then belt sander, half a mm at a time.

That’s probably as good as it gets.

Covered the two pieces in wrapping paper for the party (I didn’t want stains on the wood before I seal it, and staining and sealing will be a slow process since I need to try to match the postform kitchen counter colour).

And that’s what it looks like at the moment.

I’ll tie the two pieces together with dowels or biscuits, maybe a screw underneath to hold things together. The polyurethane wood glue dries to almost the right colour so that should be OK… I hope.

Fortune 32:16 and the longevity of floppies

Way back when, back in 1987, I was studying engineering over at the University of Stellenbosch, and I read about this thing called BIX, the Byte (magazine) Information eXchange.

So I went over to Professor Krezinski at the Computer Science department and asked him nicely to let an engineer play with their toys and to my surprise he agreed. Gave me access to the building and organised an account on the DG, which was connected to some magic elf (X.25?) boxes which in turn connected to… BIX. Where I spent some time (not a whole lot, my father’s credit card was paying for my time) chatting to some very bright people. This was when smileys still looked like ^_^ and {^_^} (Hello jdow, wherever you are)

But there were other interesting computers in the lab (on the third floor, ISTR). Specifically, an AT&T 3B2 and a Fortune 32:16.  And since I was designing a 68000-based computer at the time, I copied all the Fortune disks, thinking maybe, some day,  I can make some of this stuff run on my machine.

That day has not yet come :-)

But I recently found those floppies again, and copied them using Dave Dunfield’s ImageDisk 1.18. And they were all still 100% readable (OK, on one floppy the jacket had warped, I had to remove the disk and stick it in a cleaning disk jacket to read it).

Bitsavers have some documentation online, and from this it’s clear that Fortune Systems never intended the user to poke around under the hood. Apart from the 68000 processor, I can’t find any details online about the chips used, the amount of ROM on the motherboard, or anything like that (Unleashing a hex editor at the diagnostics software shows mention of a Z-80 processor, as well as “CTC” and “SIO” and “dual port RAM” — sounds like an I/O device.  There was apparently also some kind of an MMU).

Anyway, here are my disk images. Disks are 80 track, with five sectors of 1024 bytes each per side.

I’m not too sure how useful these will be, since this 2005 posting to ClassicCmp states that

They also had a reasonably effective copy-protection scheme.
Uninstalled Fortune software on distribution media was encrypted using
a key known to Fortune and to Fortune's installation program.  When
you installed software from the distribution media, the software would
be decrypted and then re-encrypted using a key based on the
motherboard serial number for storage on the hard disk (so you
couldn't just copy the executables from your system to some other
system: installed software only ran on the system on which it had been
installed); and of course the installer marked the distribution medium
as "installed" so you couldn't just go install it again somewhere