Developing Hunting Handloads
By Chuck Hawks
This article explains how I develop hunting handloads for my rifles. Conveniently, as I write these words, I am in the process of developing a general-purpose big game load for my Merkel K3 Stutzen carbine. (You can find a review of this rifle on the Product Review Page.) The K3 is a takedown, single shot rifle that fits in a valise type hard case. It is chambered for the 7mm-08 Remington cartridge. I consider the K3 Stutzen to be the ultimate travel rifle for out of state hunts and that is the purpose for which I am developing a reload. I will use the 7mm-08 Merkel as an example in this article, but the same process works for any caliber of big game hunting rifle.
Remember that I am developing a big game hunting load, not a varmint or match load. The longest shot that I am likely take at a big game animal is around 200 yards, so I need a load that provides a maximum point blank range of at least 200 yards and adequate killing power at that distance. I am looking for 100% reliability under all conditions and quick, humane kills rather than extreme accuracy. Big game animals, after all, provide at least a 9-10 inch heart/lung target area.
It is actually preferable to use factory loaded ammunition in a travel rifle due to NTSB regulations that all ammunition must be transported in original factory packaging. Almost all 7mm-08 factory loads from the big ammunition manufacturers come with 139-140 grain bullets and I have already tried a wide selection of factory loads in this rifle. Unfortunately, my K3 is not at its best with bullets of that weight, so I am forced to reload. (Always pay attention to what your rifle tells you at the range.) At least I have saved a good supply of factory ammo boxes in which to put my travel reloads.
When working up reloads, my procedure is initially to choose the weight of bullet that I want to use and the velocity that I think I need for the application I have in mind. In this case, the purpose is a load for a "go to" travel rifle that will be used for hunting all CXP2 game and maybe, under favorable conditions, the smaller CXP3 species. Since my rifle does not seem to like 139-140 grain bullets and I may use the K3 on relatively large game for the caliber, I will try 150-154 grain bullets. As long as I choose a bullet designed to provide the terminal performance (controlled expansion) required for my purposes, this bullet weight should be ideal.
A little basic research in reloading manuals reveals that, with most powders, a maximum or near maximum hunting load for a 150 grain bullet in the 7mm-08 typically yields a muzzle velocity (MV) of around 2700 fps from a 24-26 inch test barrel. The Merkel's relatively short 19.7" barrel means that I should expect an actual MV, in my rifle, of around 2600 fps with those loads. That is sufficient for my needs in terms of both trajectory and killing power.
My next step is to pick three suitable 150 grain bullets to test in my rifle. What I am initially looking for in a bullet is terminal performance and local availability. I like to be able to buy bullets over the counter at my local sporting goods store. In this case, I happen to have some appropriate bullets on hand, so I will try them first. These include the Hornady 154 grain InterLock SP, Nosler 150 grain Partition spitzer and Winchester 150 grain Power Point spitzer.
Then I need to choose three suitable powders. In this case, I will try IMR 4064, Varget and IMR 4350. There are other equally applicable powders, but I have these three on hand.
I have pretty much standardized my primer brands as Winchester and CCI to limit the number of variables in load development. (These are the easiest brands to buy "over the counter" where I live.) I use Winchester primers if that is what the reloading manual specifies and CCI as a substitute for everything else.
I am now ready to start loading. I will pick one of the three selected powders and load 10 cartridges with each of the three bullets (30 total rounds). I take the specific powder charge directly from the applicable reloading manual. I use full-length resized brass and I seat the bullets to the specified cartridge overall length (COL).
I don't try to customize the bullet seating depth for a specific rifle (the K3 in this case), because I believe that hunting cartridges should work correctly in all rifles, not just one. Experience has taught me that sometimes another hunter may need to borrow some of my cartridges in the field, or I may need to borrow some of his. In any case, I own more than one rifle in most calibers and I am constantly reviewing new rifles for Guns and Shooting Online.
The next step is to get to a rifle range and shoot the trial loads from a bench rest at 100 yards (or 100 meters, depending on how the range is measured). 10 cartridges lets me shoot three, three-shot groups with each load and leaves one spare cartridge to "make-up" a called flyer. I will be shooting a total of 30 shots from the bench rest. Maximum concentration is necessary here, as what I am looking for is the best average group size each load can deliver. I want to eliminate the human factor as much as possible. I use a Lead Sled DFT for most of my test shooting, as it provides a steady rest and it saves wear and tear on my shoulder by greatly attenuating recoil. I measure the resulting groups (center to center) and save the targets for future reference. Remember to record the load data on each target.
On my next trip to the rifle range, I will repeat the same procedure with the second of my three chosen powders. The final test powder will require a third trip to the range. I find that it is easier to maintain the high level of concentration required for 30 shots per trip to the range than to try to shoot 90 rounds at one sitting.
Once I have test targets for all three bullets and all three powders in hand I can start to eliminate some of the combinations. I want groups to average not more than 2" at 100 yards and I'd prefer to see a 1.5" average. I will usually find a couple of bullet/powder combinations that merit further testing. I then load 20 cartridges using each of these combinations for the second stage of testing. This will require another trip or two to the rifle range, this time shooting five shot groups to increase the reliability of the results. At the end of those shooting sessions, I can usually choose a good load for my hunting rifle.
Of course, on rare occasions, none of the initial loads meet my expectations. In that case, I will extend my bullet search to other brands and, if necessary, other bullet weights. Usually I will try other bullets (first) and then (second) other powders, or slightly different powder charges. Remember, MV is a basic requirement, so there is not too much latitude in powder charge, but there is some. The last variable I experiment with (in desperation) is primers. Only rarely, for me at least, has the primer made an appreciable difference in accuracy. Unlike target shooters, I am usually not worried about tenths of a MOA.
Developing a good hunting load for your rifle is usually not difficult. You need to determine practical goals for the load you are developing. Once you have defined what you need, success is mostly a matter of patience and a logical, methodical approach.
Copyright 2008, 2016 by Chuck Hawks. All rights reserved.