Guest Post: Allabaster
*** Editor's Note: This is the first of the new guest posts. Fair warning... these gun posts are not going to be written for everyone. This isn't mass market stuff. This is gun nerd eggheadery. Big time. If you want dumbed down mass market crap... there are plenty of places to find it. Sometimes you'll even find it here. But this is one of the few places you will find articles like this. Also... you will find some unique spelling here. Allabaster is an aussie. Deal with it.***
Few things can bring about humility and clarity of thought than being forced to recant from an opinion derived from logic and reason when it is contradicted by the empirical results of practiced application of the before mentioned logic and reason. To stubbornly cling to the questionable fruits of your abstract faculties in spite of the witness of your lying eyes is little more than an exercise in self indulgent hubris.
Therefore being a man who has learned, via the unapologetic hammer of reality’s consequences, to be wary of his own sense of creeping hubris from spates of overactive abstract analysis, I have recanted my position of the ideal twist rate for the 223 Remington in a practical game and varmint rifle.
Now the 223 Remington, being an almost interchangeable round with the 5.56x45mm NATO round standardized in the 1950’s, was always going to have far greater focus of attention placed upon it than other cartridge offerings due to the economies of scale and dedicated platforms that flow to the sporting shooter market from widespread military applications. For this reason it is adapted to game, target, varmint and battle rifle applications with a far greater variety of projectile designs and weights than would ever be afforded a cartridge without the benefits of widespread popularity beyond its own inherit virtues.
The former NATO standard, the 308 Winchester (7.62x51mm), has less in the way of variation of ideal projectile weights, and therefore barrel twists, for intended use as the typical 155 to 175 grain weights are as popular for hunting projectiles as they are for the target variety.
Now my own recantation, mentioned many paragraphs passed, involves the belief that every 223 made should be equipped with a 1 in 8 or thereabouts twist rate to take advantage of all projectiles up to around 75 grains with their superior ballistic properties and sectional densities. This was my firm, somewhat informed, opinion until circumstances conspired against me during my reasonable priced bolt-action 223 varmint build of a few years ago.
The rifle in question, which I have written of many times before, is my Howa 1500 varmint. I have been very impressed with this model of rifle for its relatively modest price and high potential for consistent accuracy out of the box. The only non aesthetic downside I could detect at the time of planning my build was the lack of barrel twist options, namely the 1 in 12 for the 223, which would in turn restrict the range of projectiles I could reliably stabilize. Ultimately the monetary handicap known as “being a student” forced me to blunt my high minded and fast twist aspirations and accept the everyman’s lot in both life and rifle barrels.
With the rifle intended to target varmints out to 400m I decided upon the Hornady V-Max line of projectiles and had great results with the 50gr boat tail version in both snap target matches and with predictability of shot placement in the field. However this projectile had its own inherit limitations as it, and most other projectiles of its kind, are intended to be used in everything from a 22-250 to a 222. This meant the projectile’s ogive shape had to accommodate the throat length of many possible cartridges across the board, not just the 223 dimensions for which it was being used in my case. Consequently the ogive shape is quite angled and less aerodynamic that it could potentially be given the projectile weight.
A relatively new 53gr V-Max offering from Hornady however makes the most of the popular 1 in 12 twist 223 combination. By being intended for use only in the 223, the new projectile can replicate the ogive dimensions of the 75 gr A-Max target projectile. This provides a marked ballistic co-efficient (BC) increase of .290 for the 53gr vs .242 of the 50gr for a very modest weight gain. This does not provide the BC of a 68 grain target projectile, whose BC of around .350 requires a 1 in 9 twist rate, but it mitigates the gap in BC which is predominantly caused by the ‘one size fits all’ nature of most 22 cal projectiles.
What this effectively means is that for a 223 rifle is that projectiles with a length and weight beyond what a 1 in 12 twist can stabilise offer only a real benefit for those who intend for their 223 to engage in extended distance target applications where the improved ballistic properties are the major deciding factor. For any rifle that is intended for use on game or varmint the lack of access to the high BC heavy projectile is not a relevant limitation as such projectiles are not intended for use on either, although they may be arguably be used in a reduced capacity.
It is my hope that there will be, one day, a greater variety of popular chambering specific projectiles released to the market which will open new possibilities for the hand loader to make the most of their common rifle configurations.
