I’ve been handloading for decades.  It is an enjoyable activity in its own right, albeit one that carries some safety considerations, and needs concentration and care.  Over the years, reading the many reloading guides and talking to more experienced handloaders, I have determined a process that I believe is well-matched to the needs of hunters.  I did not invent anything that follows.  It is a logical sequence of good, common sense information from the public domain developed and shared by well-known experienced reloaders.

A lot of the reloading information available is written for shooters who are into benchrest and long-range shooting.  These folks need the utmost accuracy for their shooting and the reloading guides often go into the detail they require to achieve that.  Hunters do not need that degree of finesse for handling their ammo.  How do I define a hunter?  It is somebody carrying a light sporting rifle, mostly on foot, through the bush seeking a particular prey animal.  When such opportunities arise, the shot has to be from a hastily assumed (often awkward and uncomfortable) position at a guessed range.  Often it is also in dull twilight conditions with a cold wind blowing and a swarm of midges chewing on your exposed parts.  Not the comfort of the covered concrete stand at your local SSAA range with your range known to within a few centimetres.

Even if the rifle has amazing benchrest accuracy, few hunters are capable of consistently delivering groups under 2MOA under such varying field conditions.  For that reason, the accuracy benchmark for hunting rifle accuracy has often been quoted as 1 to 2 MOA.  Nevertheless, most handloaders aspire to the best accuracy they can achieve and sub-MOA is a common goal.

So, if we aspire to handloading the most accurate ammo for our lightweight hunting rifle, what steps are necessary to achieve that 1MOA, or better, goal?

The First Step – Choice of Projectile

In developing a handload you must choose the type of projectile you intend to use in your rifle.  The load you develop will be specific to that projectile and your rifle.  The fact that you may have different projectiles that are all the same weight is irrelevant.  There can be subtle differences in the geometry of the projectiles that could lead to excessive pressure on firing for some, but not others.  Handloads for each projectile must be worked up independently for each one.  Having said that, your choice of projectile should be tailored to the game you intend to hunt with it.  For this example, I am using a 55 grain polymer-tipped projectile for the 223 Remington.

Second Step – Determine the Maximum Seating Depth

The first constraint to be aware of is the length of the magazine in your rifle.  If you want the ability to cycle your ammo straight from the magazine then that will determine the maximum cartridge length.  I once went through the procedure of establishing the most accurate handload for my rifle only to discover on my first hunting trip that my ammo was a few millimetres too long to fit in the magazine!  All my testing had been single-shot feed at the range.  That is now the first thing I check with any new rifle.

For hunting rifles, you do not want to load ammo that engages the rifling on chambering.  That will avoid the risk of having a round chambered, and extracted without being fired, leaving a projectile stuck in your barrel.  Having determined the overall length of the cartridge that just touches the rifling, as below, and assuming your magazine length is adequate, you are ready to proceed.  Your starting point is to set up your press to seat your bullets 10 or 20 thousandths of an inch off the lands.  That will be the longest cartridge you should ever load for that projectile in that rifle.  Your testing of various bullet seating depths will step-way from that, being more deeply seated in the case for shorter overall cartridge length.

You will need a fired case that has not yet been re-sized and de-primed.  Because the case has not been re-sized, projectiles will slide easily and loosely into the neck.  Press the case neck against a hard surface to slightly flatten it on one side.  That will be enough to hold the projectile while you determine at what depth it meets the rifling on chambering.  By hand, push a projectile a little ways into the neck of the case.  Take a permanent marking pen and colour most of the exposed projectile.  Place a little lubricant on the front part of the projectile.  That will make it less likely to stick in the rifling. Then carefully chamber the round in your rifle, closing the action.  Likewise, carefully extract the shell.  Sometimes, the projectile will remain in the rifling from where it can be removed with a gentle tap from a cleaning rod pushed down from the muzzle.

Close inspection of the inked projectile will show you where the rifling engaged it, and the mark where it was pushed into the crimped case neck.  Gently, by eye, you can ease the projectile back into the case neck to match the scratch lines in the ink.  The overall length of the cartridge, where the projectile just touches the rifling, is now in your hands.  Measure that with your callipers and record.  It is a good idea to repeat the exercise a few times for assurance.

Step Three – Choice of Propellant

I have a range of reloading guides on my bookshelf, plus I also make use of a number of website loading databases.  My go-to guide these days is the ADI World Class Handloaders’ Guide.  No matter what my reference source is, I always cross-check against a couple of other reloading guides.  A point to note here is that ADI’s propellants are widely used around the world, but marketed and known by other names.  Also, other powder makers products can be very similar in performance.  The powders listed here, for safety sake, should not be considered exact but rather close approximations within 5%.  The following table gives a few of the major equivalent propellants for ADI products.

 

ADI Hodgdon IMR
Trail Boss   Trail Boss
AS50N International 700X
AP70N Universal SR 7625
AP100   SR 4756
AR2205 H4227 / H110 IMR 4227
AR2207 H4198 IMR 4198
AR2219 H322  
Bench Mark 2 BENCHMARK IMR 3031
Bench Mark 8208   IMR 8208 XBR
AR2206 BLC(2)  
AR2206H H4895 IMR 4895
AR2208 Varget IMR 4064
AR2209 H414 / H4350 IMR 4350
AR2213SC H4831  
AR2217 H1000  
AR2225 Retumbo  
AR2218 H870 / H50BMG  

 

After referring to your handloading guide, select the propellant appropriate for your choice of projectile.  For the 55 grain Ballistic Tip, there are some good options.  In this case, I opted for the versatile and reliable AR2208.  Over the decades, I have found it to be a particularly accurate propellant in the 223 Remington.

Starting with the listed minimum load, I load three cartridge lots at each weight, going up in 0.5 grain increments.  Normally, I stop short of the listed maximum load until I have assessed what pressure is being developed in my sequence of reloads.  At the rifle range, I put up a batch of targets at 100 yards (or metres depending on your location).  For this initial testing of varying propellant charge, you need to maintain the same seating depth for all your handloaded cartridges.  Just what that depth is does not matter so much on this first run, so long as it is less than the depth where the projectile meets the rifling, that you determined first up.  If you want to be specific, the standard SAAMI length is a good choice.

Starting with the lightest loadings, I fire each three-round batch at individual targets so that there is no confusion in the groups.  As I extract each fired shell I note the ease of extraction then inspect the case head for any visible signs of pressure, such as primer flattening and ejector marks.  I use a micrometre to measure the head diameter in several spots around the shell (cases are not uniformly circular, so take three readings and average them).  Any expansion over 0.5 thousandths of an inch is an indicator of high pressure.  Sticky, tight extraction from your rifle is the very last sign of pressure and occurs after you will have detected excessive pressures from head diameter measurements.  This is true for any cartridge reloading, but especially so for magnum calibres.

The attached graphs of my load testing in the 257 Weatherby Magnum show how dangerous pressures can sometimes be encountered well within the recommended loading range listed in your guide.  Every rifle and load combination is potentially unique.  For the same rifle and projectile, the AR2217 loading escalated rapidly in pressure whereas the AR2213SC loading was fine right up to the maximum recommended charge.  That is why you start at the listed minimum charge and increase your load in increments, always looking for signs of pressure.

If there are no signs of excessive pressure, I will eventually test loads right up to the maximum.  However, reloaders should never exceed the maximum listed loadings, even if you believe there are no signs of excessive pressure in your loads to that point.

With measurements of each three-shot group, I like to plot the data.  For me, that gives me a better feel for the accuracy variation with propellant load.  In this example, loading 55 grain poly tips in the 223 Rem, the rifle clearly preferred the lower powder charge.  With another rifle, but the same loading, it may well have shown a preference for the maximum loading.  Each load and rifle combination is different; that is why it is important to methodically test each one.

Step Four – Finding the Optimum Seating Depth

Now that you have found the optimum propellant charge, you can further refine your rifle’s accuracy by testing variation in the projectile seating depth.  Holding the propellant charge constant at the optimum level (25.5 grains AR2208 in this case), load up another batch three-shot lots.  Starting at your maximum cartridge length, each successive three-shot lot should have the projectile seated 20, or 30, thousandths of an inch deeper in the case.  Conventional wisdom mostly had it that the best accuracy is achieved when the projectile is seated somewhere in the range of 20 to 50 thousandths of an inch short of the rifling.  In my experience, that is not a hard and fast rule.  I have had many rifles that shot nice tight groups only when the projectile was seated 150 thou, or more, short of the lands.  The vertical green line is the magazine length in the rifle I tested the loads in – the rounds needed to be seated 110 thou or more off the lands to feed and gave better accuracy anyway.

Step Five – Finalising the Rifle’s Sighting for Hunting

With your optimum handload now determined, you are ready to go hunting.  My recommendation is to sight your rifle so that the trajectory peaks no more than 50mm above your line of sight.  For most game animals, in field conditions, that means you can just place the crosshairs on your point of aim and fire without having to worry about allowing for any sighting variations.  In just about all calibres and rifles with normal telescopic sight mounting, that means your group at the 100 yard range should be centred about 45mm (1.75 inches) above your point of aim.