Target Sports

HANDLOADING: SHORT AND STOUT PART TWO

Created on 14th May 2009

In part two of his series on WSSMs, LAURIE HOLLAND considers data, tools and handloading procedures for these cartridges

LET'S MOVE onto loading the cartridges, starting with data sources, then tools, procedures, and finally bullet and powder combinations. I should mention the rifles I was loading for, as this had a bearing on component choice. A Winchester 70 Stealth II did the job for the .243WSSM, while the .223WSSM test batches were fired through a custom-built job generously loaned by the Southern Gun Company. The factory Winchester rifle was a conventional turn-bolt using a 26" hammer-forged semi-heavy barrel with 10" rifling twist and chromed bore. The .223WSSM rifle was a straight-pull SSR-10 (based on the Armalite AR10 T rifle) which also had a 26" barrel, in this case a heavy Krieger match effort with a one turn in 8" rifling twist (as opposed to the standard 10"). Unfortunately, straight-pull operation and WSSMs don't go together well, poor primary extraction causing these fat cases to stick in the chamber before maximum pressures are achieved. Even with the Winchester, I could easily judge what pressures were doing by the effort that was required for me to lift the bolt handle and achieve primary extraction.

Data

There is less loads data available for this pair than some. Barnes, Hornady, Speer, and Nosler cover them in their latest manuals, while Hodgdon (which includes Winchester and IMR powders) has a comprehensive data map in its magazine format Annual Manual, and also most usefully online through its Reloading Data Centre, accessed through the website www.hodgdon.com. Hodgdon is also one of the few that covers heavier bullets for this cartridge with a selection of loads for the 69gn and 77gn Sierra Match Kings. The only comparable information is from Hornady for its 75gn A-Max match projectile. The Sierra 77gn and 80gn bullets need a faster rifling twist than the standard 10", and I imagine the 75gn A-Max ideally does too.

So far as .243WSSM data is concerned, loads for 55gn to 100gn sporting bullets is the norm, and Hornady includes its 105gn A-Max match bullet although it requires a faster rifling twist rate. If short of data, you can always look up that for the .243WCF, which should be safe given the two designs have near-identical case capacity, and the WSSM is allowed another 5,000psi over its older sibling. That's the theory anyway, and it worked that way in most examples I found where a bullet-powder combination is quoted for both cartridges. However, not always - for instance, Speer quotes 45.5gn Viht N560 as its maximum for the .243WCF with 100-105gn bullets, but reduces that to 42gn for the WSSM. (Vihtavuori quotes 47.7gn of this powder for the .243WCF with the 100gn Hornady BTSP, so blithely assuming you could load the WSSM up to just short of 50gn of N560 with any old 100gn bullet would be most unwise!) Hornady warns that these cartridges see sudden pressure rises with small charge increases, and my experience bears this out, so be doubly aware.

I ran every load combination through QuickLOAD before use and reduced one or two published loads which looked as if they'd produce pressures on the high side - I didn't want to be loading anything up at the full 65,000psi, especially for the SSR-10, where I knew I'd never get the bolt open! The software was also used for checking out potential combinations not listed in the manuals. Results usually worked out on the range near the prediction for the .243 version, but again not invariably, and if there was a major discrepancy it often produced higher pressures and velocities rather than lower. As will be seen, it was well out, and in the ‘wrong' direction too for some .223WSSM load combinations.

So far as powders go, data is provided for some fast- to mid-burning range types, in particular Hodgdon H4895 and VarGet, but the majority of loads are for slow burners - IMR/Hodgdon 4350 and slower burning through to magnum rifle powders. With all but the lightest bullets, powders in the 4350, N160, 4831, N560 class give the highest velocities in the data tables. This was particularly so with the .223 version, unsurprising given its low expansion ratio. What can you expect? Hodgdon's top .223WSSM MVs for the 69gn Match King run at 3,450 to 3,500fps from a 24" barrel, so one can expect 3,600fps from a custom-built rifle with a 28" or 30" tube. The top 95-100gn bullet .243WSSM prediction comes from the current Nosler manual at 3,177fps from a 24" barrel using IMR-4350, 100fps more than .243WCF with the same powder. Remember that .223WSSM MVs with bullets up to 75gn will exceed allowed velocities (3,275fps) on all MoD ranges, the Bisley complex and some private ranges that have been certified with standard MoD range restrictions, likewise the .243WSSM with lighter bullets.

Tools and techniques

The WSSMs have a few peculiarities insofar as mechanical aspects are concerned. Dies are no problem - all major manufacturers produce sets, although until very recently all sizer dies were of the full-length type. I used Redding dies for .223WSSM, these loaned to me by Bob Clark of Southern Gun alongside the rifle, and a Hornady set for the .243 version. Full-length case sizing required no undue effort despite the abnormally heavy case construction, this due at least in part to there being relatively little case-body expansion with both rifles tightly chambered. It's important to adjust the sizer die in the press to set fired case shoulders back marginally, a couple of thou in SSR-type rifles to ensure the bolt locks up fully, but no further or one risks creating excessive headspace. I found that adjusting the Redding sizer die to the default position where it is in hard contact with the shellholder set the shoulders back far too much for the SSR-10 and it had to be unscrewed a fair way. Conversely, the Hornady die/Winchester chamber were a perfect match at the usual setting in resizing .243WSSM cases.

A combination of 21 thou thick case-neck walls and the standard factory die dimensions produced a very tight bullet fit in the case, especially with the nickel-plated .243WSSM Supreme cases. This amount of bullet pull is very undesirable from the point of view of accuracy and consistency, not to mention case life as an over-tight neck-to-bullet fit stresses and quickly hardens the brass. Seating bullets in the .223 version saw noticeable variations in the effort needed on the press-handle so bullet-pull will be equally variable - again not good.

Talking about the energy needed to push (or pull) the bullet out of the case-neck, I had to do this with some rounds for reasons that will become evident. Thanks to the deep bullet seating needed by the rifles' throat set-ups, a press-mounted collet-type puller wouldn't work as there was insufficient parallel bullet surface to grip. No matter, I thought, just dig the old inertia hammer-type tool out, but this was a no-go as well - the WSSM body was too fat for the cavity in the puller body! In the end, I had to go back to the oldest method around: putting the cartridge in the press with a pair of pliers sitting flat on top instead of a die. You grab the bullet before lowering the ram to pull the cartridge apart, ruining the bullets of course.

The fat case also stopped me using a Lee Auto-Prime, as it wouldn't fit. The hand-held Hornady magazine priming tool does the job as it has a different front-end arrangement employing a press-shellholder, and I primed cases with one of these tools latterly. Before that, I had to find the redundant priming arm for my Lee Classic Cast press and do the job that way, a method I've never liked. I've already mentioned the burrs and spikes around primer flash-holes on the inside of cases. These were removed with a couple of twists of a Lyman flash-hole reamer, the only preparation work carried out apart from chamfering case-mouths.

The short, fat case shape caused some other minor problems - hole-diameter/depth in standard loading blocks and powder funnel tube fit. Most powder funnel designs will see the bottom edge of the drop tube hit the broad case shoulders before the case mouth makes a seal with the internal bevel letting some powder kernels run down the outside of the neck. One also needs WSM/WSSM cartridge boxes as these cartridges are too fat for the MTM RM50 box and similar. I used this company's 22-cartridge WSM/WSSM boxes, but being designed for the half-inch longer WSM, they have excessive internal height for the shorter number. This means cartridges can fall out of the partitions if the box is inverted. (The answer is a layer of expanding polystyrene foam material in the case-lid.)

With 20-round boxes, test cartridges were loaded in four batches each of five rounds, instead of my usual five by five. As always, all powder charges were individually weighed on a set of RCBS 10-10 scales. With the nature of these cartridges, range-time constraints, and their reputation as barrel burners, I sometimes had to use higher than ideal starting charges on the .243 calibre version. I also had to raise the weights in coarser steps than I would have ideally preferred, usually 1gn steps with a half-grain between the top pair. With no information for many .223WSSM combinations, using somebody else's expensive custom rifle, and the primary extraction problem, I was very cautious indeed with starting loads and normally increased charges in half-grain steps. Despite all precautions, I had to curtail testing with four batches, two of each calibre, for excessive pressures evidenced by very hard extraction, badly-cratered primers, and suchlike. This is unprecedented: I've never suffered such a high incidence of pressure problems from any other cartridge I've worked with!

Components and results

Starting off with the .223, I tried a few loads with lighter 55gn and 69gn bullets as well as the 77gn and 80gn Sierras that the 8" twist barrel really merited. Faster burners (by WSSM standards) are generally recommended for 55gn bullets so I tried Hodgdon Varget and Viht N150 in the only three combinations loaded and accuracy was neither good nor dreadful at around the inch. I didn't manage to see what the FMJs were travelling at, but the old Nosler 55gn Solid Base (predecessor to the Ballistic Tip) achieved an impressive 3,870fps with the top load. Accuracy deteriorated at that speed, and better results were obtained at 3,800fps or less. One is really spinning these bullets quickly in this rifling twist at such velocities which doesn't make for top performance.

A couple of 69gn Match King combinations were also tried with Hodgdon H4350 and4350 and H4831sc, the latter producing velocities rather lower than those predicted by Hodgdon. My top load of 44gn gave a ‘mere' 3,310fps, but this was still way above what QuickLOAD had estimated - 3,065fps allied to 35,721psi, PMax. So I could have gone a bit higher towards Hodgdon's 46.5gn maximum, albeit at the expense of possible extraction problems. However, before I'd discovered how far QuickLOAD underestimated pressures in this cartridge, I'd loaded up some 77 Match Kings with Hodgdon H4350 using an apparently conservative starting load of 40.5gn, which the software said would produce 2,954fps and a bit over 38,000psi. Well, the first shot saw a pierced primer, and I was very wary of QuickLOAD's WSSM predictions after that! Naturally, no more were fired and the bullets were subsequently pulled. (Actually, Hodgdon lists the combination and its maximum is 39.5gn, but interestingly the equivalent IMR powder has a much higher maximum of 43.7gn.) I had another batch where pressures became uncomfortably high, my excuse being the use of Viht N160 which has no data for heavy bullets. 44gn produced 3,460fps and hard extraction with the 80gn Sierra, while another ½gn produced warning signs, so that was another few ‘pulled'. I subsequently tried the powder with lower loads (41 + 42gn) and they gave no trouble with reasonable accuracy, but produced excessively large velocity spreads (96 and 71fps). In fact, MV spreads were on the large side across the board with the .223 version, a feature I'll put down at least partly to brass quality, but perhaps also to not being able to use maximum loads because of straight-pull operation.

Overall, Hodgdon H4831 gave the best results. My other favourite combination was the 77gn Sierra with Alliant Reloder 19, a relatively mild load of 41gn giving good results at 3,136fps, again with a large spread (65fps). I did try still slower burning powders than H4831 - H1000 and Viht N165 - but they gave poor results. Virtually all 223 loads tried produced badly-sooted cases, suggesting they were on the light side, but even so, the top loads
usually saw me have difficulty in retracting the SSR-10's bolt. Fighting the rifle between shots doesn't help one's bench-shooting technique, or group-size!

.243 conundrum

The story with this cartridge in the ‘Stealth II' started when I'd been impressed by the rifle and cartridge and bought one about four years ago. A load comprising the Hornady 87gn hollow-point boattail seemed to perform well out to 600yd, but that was on standard NRA TR targets. Things have moved on a long way from 1MOA V-bulls and over double that size for the five-ring for those of us shooting supported and scoped rifles. Even then, I noticed two untoward things - a tendency for accuracy to drop off after a number of shots, and the occasional, usually lateral, flier. The former was put down to the scope bases constantly loosening irrespective of the amount of Loctite used on their screws. This was rectified with a Ken Farrell Weaver rail epoxy-glued and bedded onto the receiver as well as it being screwed down, but it didn't provide a solution. I eventually came to the conclusion the Winchester hammer-forged barrel was a ‘fouler', so accuracy drops off rapidly unless it is cleaned every few rounds. I've read this of other late manufacture Winchesters, and of course what we didn't know four years ago was that the famous New Haven factory was on its last legs with hardly any staff still employed there. Owner FN-Herstal was transferring work elsewhere and planned to close the New England facility, a fate it has since suffered. This state of affairs usually does little for product quality.

Trying my ‘good' 87gn loads from the bench showed they weren't half as good as I'd thought either, so the hunt was on for better combinations. I tried lots of powders with the 70gn Sierra Match King bullet that had performed so well for me in a heavy-barrel .243WCF Parker-Hale M87 ex-police rifle, also a few 90gn Lapua Scenar combinations, but didn't find what I was looking for. I eventually decided the rifle would never give match accuracy and took the decision to use sporting bullets that suit the type of shooting this cartridge is most likely to be used for. Incidentally, I duplicated a small range of 70gn Sierra plus Viht N130 loads that had worked brilliantly in the M87's well-worn barrel (also 26") to see how MVs compared. The WSSM gave a consistent additional 90-100fps or around 3% velocity for each charge weight. This was comparing a nearly new and short-throated WSSM barrel to a well-used .243WCF example where the bullets had to make a large jump to the rifling. It confirmed my view that the two cartridges give more or less identical ballistics if loads and barrel specs are the same. That, however, is not to say they necessarily behave the same way with some powders - I believe the WSSM version to be considerably less tolerant when top loads are approached than with the older cartridge, and they should therefore be approached with extreme caution.

Next month, I'll let you know if I found a bullet that would perform in the .243WSSM as well as giving full results for this version. I'll also recount how the barrel dramatically stopped performing, and pass on my appreciation of these two fat hotshot cartridges. Next month's topics will also include some new precision loading tools, the Sinclair Premium neck turning tool, new carbide turner mandrels and die body and the Whidden Gunworks bullet pointing die, as part of a future evaluation of the benefits (if any) of case selection and preparation in an accurate but not full benchrest standard .260 Rem calibre heavy-barrel rifle.