Target Sports

BALLISTIC THEORY: THE MOTHER LOAD

Created on 14th May 2009

ROGER BAKER takes a look at the load of all loads, which weighs a massive 500gn

Ballistic theory, so they say, would send a glass eye to sleep. It promises much to its students, though. Currently there is so much testing going on here, mostly in Freedom Arms revolvers, you'd think there was little time left for speculation. But thanks to FA's long cylinders, there's a chance of developing a most unorthodox - critics may say odd - round, and a potentially formidable performer for Long Range duty. Just consider for a moment a perfect load, printing point-of-aim on a target 200yd distant, 22" high at 100yd (at that distance the sighting is no more than a six o'clock picture with a tad of white space above the sights), and under 6ft low (less than half of the norm) at 300yd. It sounds too good to be true, doesn't it?

Just to ratchet up this quest for the Grail, recoil in our perfect load has to be pleasant. The good old heavy-bullet subsonic formula of 1,100fps is attainable but not necessary. Recoil would be uncomfortable, some ¾ of full-chat 454 Casull at 1550ft/lb or so. However, at a more modest velocity of 900fps muzzle energy is under 950ft/lb, the level of standard .44 Magnum home loads.

More good news: the retained energy is excellent. It's 874ft/lb at 100yd then 807 and 745ft/lb at the greater distances. Can this miraculous round be built? Yes it can. Will it chamber? Yes, it will. So what's the bad news then? There's always some. Well, and I hesitate to type this, the bullet has to weigh more than 500gn and have the pistol diameter of .452".

Now I can almost sense your disappointment, just when you thought this was going somewhere. You shake your head and move on to the next page - but wait a moment and take a look at this beast. It's a nominal 520gn. Indeed, working to Elmer Keith's old recipe of one part tin to 16 parts lead that's very close to what it would weigh. In Lyman #2 alloy it would throw at 510g or a little less. These just cast here and pictured weigh 515gn - a traditional round-nose-flat point Colt 45 is shown in front for comparison.

The mould is a stock item, believe it or not, sold by NEI Handtools Inc of El Paso, Texas. This one is all steel (or as NEI list it on the bill, iron) except for the screws securing the mould handles, which is a bit puzzling. NEI sells alloy versions of its moulds. Lighter and cheaper, they might suit casters used to Lee Precision products rather more. Most moulds without the sprue-cutter weigh half a pound or so. Some get to 10oz; the NEI weighs in at 15oz. Its sprue-cutter - which wants to be a safe door in Fort Knox when it grows up - weighs 3½oz on its own!

Its prodigious weight enables the mould to retain more heat than standard models so watch out for overheating. The best way of preventing this is by using another mould alongside it. This tops up your stock of a useful bullet. In fact I had to cast for stock in a ratio of two or even three-to-one on occasions to keep the big mould down to a reasonable temperature.

It's too large to fit Saeco and Lyman handles. They have a built-in ‘ramp' which lends a precise fit to some moulds mounted on them. I used RCBS handles with their straight tines and the fit was excellent with the mould's halves swinging very freely and meeting one another effortlessly when they are closing.

Sizing and lubricating

The bullets threw at half-a-thousandth over spec at .4525" making them close to ideal for rolling in Liquid Alox. Minimal sizing to .452" would produce no distortion of the driving bands but sharpen their edges slightly - an almost perfect result.

During colder months the bullet lubricants supplied by Lyman and RCBS can be rather hard and troublesome in use. I've had the O-ring in a Lube-a-Matic torn off on a couple of occasions bringing operations to a dead (and exceedingly messy) stop.

Two solutions are (a) a lube heater - Lyman sells a superb one which not only fits all mainstream presses but actually improves their anchorage to the bench - and (b) a much softer and more biddable stick of lubricant made in the old NRA of America formula of Alox and beeswax. It was produced by Lyman for decades; nowadays they have replaced it with something more high-tech and the ‘traditional' product comes from Lee Precision.

Headspacing

This is the ease and precision with which ammunition fits its intended chamber. It requires a spent case with its used primer still in place in order to create a dummy round. Using primed or charged cases (i.e. live ammo) to test headspacing is reckless. It's bad practice, hazardous and not to be contemplated. The spent primer serves to protect firing pins which could come to harm if they descend on thin air when the trigger is used to test cylinder rotation.

A bullet seated in .45 Colt brass to an overall length of 1" chambered like a dream. Another in a Hornady 454 Casull case produced the tiniest imaginable bulge in the thicker, stronger case wall. It was almost invisible to the eye and just discernible to a light stroke of the thumb, but it couldn't be fitted in the Freedom Arms revolver's cylinder. It just won't play without fine precision in all its facets. This meant it had to be brand new .45 Colt brass, to be used once only and then discarded or demoted to lighter duties.

Handloading

As you might imagine, the burning room within the case is limited. It is this factor rather than data manuals that will decide how much propellant can be dispensed. The choice remaining to the loader on the press is burning speed. By tradition the slowest powders are natural bedfellows to the heaviest bullets. There are two contradictions. Unlike the usual option of heavy gas-checks, the 515gn is plain-cast and in long-barrelled revolvers slow. Hot Magnum powders may erode the bases, and in the right quantities might not generate enough energy for good groups. Instinct suggests that a medium-slow propellant has the best chance of success. The velocity required is quite modest, well below four figures. The trick is to avoid a steep pressure curve. And there is no need to meet Silhouette criteria in this.

Accurate Arms # 7 powder is approximately equivalent to Blue Dot in burning speed and currently easy to get. (The disruption to shooting supplies caused by Middle Eastern conflicts is pretty dire at the time of writing). It's made with very fine granules for easy dispense on the loading press. All in all it seemed the best starter.

My measurements indicated that there was about 12gn of room in the case. A sensible start would be 10.4g, about 85% of maximum. Chronograph testing showed muzzle velocity of 908fps with no signs of excess pressure. The spent case ejected easily, the primer hadn't backed-up and there was no darkening of the brass. The powder charge was no more than an educated guess.

Adding ½gn to 10.9g delivered 926fps, an insignificant additional 18fps. However, the spent case refused to eject without a lot of grunt, indicating that not all was joy in the chamber. I took the hint and went back to the original load.

The results

Allowing for every eventuality, I prepared the ammunition in a variety of ways. Some bullets were sized to 1/1000" under at .451". They were certain to obdurate in a long barrel and had a chance of chambering in 454 Casull brass (you never know!). They made even less of a bulge in the case but still wouldn't chamber, so I put the assembled but uncrimped rounds through a case-resizing die.

Pulling the first of the batch, there was no bullet distortion that I could see. To some extent, though, both sizes of bullet had lifted out of the case mouth. After that it was simple to re-seat the bullet and crimp the case - chambering was effortless. Both diameters were seated in .45 Colt brass too, and I gave half of those the round-resizing treatment as well, just to see if it made a difference.

Although ammunition using very heavy bullets is always destined for long range use, initial zeroing is best attempted at standard pistol distances. What may be just a few inches of error at 25m will have you entirely outside a target - even a 2x4ft Wessex rectangle - at 100m. You'll be hitting sand somewhere with no idea of the sight-correction necessary for centring. Closer zeroing wasn't problem-free though, as Iron Sight Gun Works Silhouette sights, never intendedfor 25m aiming, didn't come down low enough for this load.

I had to choose a point-of-aim a few inches beneath the bottom of the roundel. It was a kind of six o'clock picture with loads of white on top, and the low figure 3 seemed about right.

Yes, it's haphazard, no, it's not perfect, but at times we just have to get on with it. The initial results (with smaller holes than I expected from the bullet's profile) are shown here. It so happens that the two highest were sized to .451", but don't believe that this indicates a trend. The variation was within the firer's error, particularly when aiming off.

Once the Range Officer had retrieved and witnessed the first target it was time to see what variations would result from bullet-sizing, round-sizing and the differences between brass cases. There seemed to be none.

At first I intended to keep detailed records of the behaviour of every variant, but it became pointless. The results show there are some fliers, my error again, but a high percentage of the 95 rounds occupy one hole.

An early conclusion is that with bullets this big we are relieved of many technical challenges. Whether we use a favourite propellant or a new one, whatever we size it to (or if we don't bother with a bottle of Alox handy!) and however we treat the finished ammunition, sheer length and weight are likely to deliver high quality results. Recoil was moderate all the way through and no variant showed any sign of pressure.

This development has possibly taken the heavy-bullet-low-velocity tactic as far as it's going to go. It may not in the end prove to be the answer - but it makes an additional and interesting entry in that never-ending quest for the mother load.

BALLISTIC THEORY: THE MOTHER LOAD

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BALLISTIC THEORY: THE MOTHER LOAD

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