Load Development

Load Development is the process of figuring out just what exactly you need to put into your hand loaded cartridges in order to make them shoot the best out of your gun. All guns are not capable of benchrest quality shooting; but the better tuned your ammunition is to your gun, the better it will shoot. This process is not magical; but it does take time, perseverance, and the ability to understand what is happening and how to improve the ammunition. Here you will learn how to tune your reloaded ammunition to shoot the best from your gun.

      Before we get into the heart of tuning your ammunition I strongly encourage you to read the safety precautions for reloading. You must be cautious when in the load development process and watch very carefully for any type of pressure signs. IF YOU SEE ANY OF THESE PRESSURE SIGNS STOP SHOOTING THAT LOAD I recommend never trying a load developed for someone else’s gun, and never giving ammunition made for your gun to someone else. It probably won’t shoot well and could be over pressure for the different gun. It only takes one high pressure load to damage your gun, and although it is rare it does happen. Do not gamble with your safety.

      There are as many ways to find a good load as there people that hand load, but the basic process involves 5 steps:

           Choose your components

           Measure your chamber

           Find the best velocity/ powder charge

           Find the best C.O.L. (cartridge overall length)

           Fine Tune

      I recently did a load development for my Remington 700 with 175 grain Sierra Matchking bullets. After much trial and error on this step (4 different powders) I found that IMR 4350 works very well for this bullet. All the pictures are from that process. I have since done a load development with the same bullet and IMR 4895, and it works even better than the IMR 4350.

Choose Your Components

      The first step in the load development process is determining the components you want to use and purchasing them. Think carefully about what you will be doing with your gun, what type of gun you have, and how frequently you shoot before committing large sums of money to components. I recommend starting out with 100-200 of your chosen bullets, a single box of primers, some brass cases of your chosen brand, and one or a few different kinds of powder that are all listed in your reloading manual for your cartridge. This should give you enough components to determine if you can make a good load with them without committing yourself to 500 bullets that just won’t shoot. You may want to start out with only one type of powder as well for the same reason, it is much easier to buy more powder than to get rid of what you have but don’t need. After some period of time you will have accumulated more than enough of the individual components needed to go through a full load development process without buying many more.

      When choosing your bullet make sure you take into account what you are going to use the bullet for. There are many different kinds of bullets for each caliber, make sure you get one that will suit your purpose be that competition, hunting, varmints, or whatever. Always make sure to get the correct size bullet for your caliber, consult your loading manual to determine the correct size. Also take into account the weight and length of the bullet you buy, certain bullet weights and lengths will shoot better in certain barrel twist rates. If you aren’t sure what bullet weight or type you are looking for check in your loading manual, or give the bullet manufacturer of your choice a call. They will be happy to answer any questions you may have about their products. Click here to learn more about bullets

      For my load development I chose the 175 grain Sierra Matchking bullets in .308” diameter. I was looking for a target load that would do well for me in competition out to 600-1000 yards. This bullet is very well known for winning competitions.

      Choosing a gun powder is every bit as important as choosing a bullet, so give careful consideration to what type of powder you buy. Make sure that the powder you buy is listed in your loading manual under the bullet weight that you chose. Most loading manuals will give you between 6 and 20+ different kinds of powders for a certain bullet weight in a chosen caliber. I generally try to stick to the middle to slower burning rates for powders, although a gun with a short barrel may need a slightly faster powder. Nearly all loading manuals have the powder listed from fastest burning rate at the top, to slowest at the bottom; but you will need to verify that in your loading manual. Click here to learn more about gunpowder

      I had a number of different powders left over from when I developed my .308 Winchester hunting load, but none of those powders did exceptionally well with this new bullet. I tried IMR 4064, IMR 4320, Varget, H 4895, and finally decided on IMR 4350. The IMR 4350 is a very slow powder and did give me some low velocities, but it also gave me the tightest grouping and most consistent results. I have since opted to change over to IMR 4895, which gave me even more impressive results than the IMR 4350.

      Primer’s are important as well, however, they do not require as much thought when choosing. Just make sure you get the right type for your chosen cartridge. Many reloading component companies offer very high quality primers, I have used and liked Winchester, Federal, and CCI primers. I haven’t had any issues out of any of the brands I’ve tried. Click here to learn more about primers I use CCI benchrest large rifle primer’s exclusively in my .308 Win, they work very well for me.

     You will also need to select your cases as well. Any of your big name reloading component companies that offer brass cases will be of generally good quality. The higher priced custom cases like Lapua may last longer and shoot more accurately, but Winchester, Hornady and others are also very good. I use Winchester brass in my gun, and it does very well with a little TLC. Click here to learn more about brass cases

Measure your chamber

After you have purchased your components, and before you start your load development, you will need to measure the chamber of your gun. The maximum chamber length is also called the maximum C.O.L. (cartridge overall length). It is a crucial measurement to know as it is as long as you will want to load your bullets for two primary reasons. The first is high pressure, if you make your cases to long they may develop too much initial resistance in the barrel. This will cause higher than normal pressures. The second reason occurs when trying to remove an unfired cartridge from the chamber. Sometimes a bullet that has been jammed into the lands will unseat upon removal and spill powder all over everywhere. That leaves you with a mess, and a bullet stuck in your barrel. Click here to learn about measuring your rifle’s chamber.

If you are going to load your ammunition into a magazine you will need to determine the magazine's maximum C.O.L. instead of your chamber's. Do this by gradually seating an un-primed, un-charged cartridge shorter until it fits and feeds correctly. In nearly all cases the magazine's maximum C.O.L. will be less than the chamber's.

Find the best velocity/ powder charge

      This step is where the differences in load development processes begin. My technique is as follows:

      I start finding the best powder charge by first determining what my maximum powder charge is. I will take 3 to 4 loading manual’s data for the powder/bullet weight combination I am using and use the average as my maximum charge. All of the manuals come up with different maximum charges due to the minute differences in their particular tests. These could include different primers and different brand bullets of the same weight. For the IMR 4350 in my .308 Winchester my maximum charge was 50.0 grains. That actually turned out to be more than would fit in my cases, so I had to load down a bit more than I normally would during load development.

      After choosing a maximum charge I load 5 cases each with 90%, 92%, 94%, 96%, and 98% of the maximum charge (these are loaded to factory recommended C.O.L.). I don’t initially load right up to the max in case I want to tune the 98% load up, doing so will usually put me right up near max. For the IMR 4350 I wound up loading 43.0, 44.0, 45.0, 46.0, and 47.0 grains. 47.0 grains was a compression load, and 48.0 grains would change the C.O.L. due to too much compression of the powder. I shot these using as perfect form and technique as I am able, then analyzed the results.

      When I analyze the targets during load development I am looking for a similar point of impact on the targets to either side of the smallest group. This shows that the bullet is exiting the barrel at a very similar point in the barrels vibration. All barrels vibrate at different frequencies with different bullet velocities (adjusted with the powder charge). The whole trick of load development is to find a powder charge that directly correlates to those barrel harmonics. If you find that sweet spot (sometimes there is more than 1) with the right powder burn rate the results are outstanding.

The first target in the picture is obviously the best group, but the velocity was too low for my liking. This round is supposed to make it out to 1000 yards if I need it too, and that just wasn’t strong enough to cut it. Target 5 was the next best, and for this stage of the game I’ll take it to continue development with. I don’t have a higher charge target to compare point of impact too, but it was very close the fourth targets impact, so that will have to work. This is just a rough charge for now anyways.

Now that I have my rough charge of 47.0 grains, I load -.4gr, -.2gr, at that charge, +.2gr, and +.4gr. This gives me a good spread of charges very close together which is helpful for finding where the exact sweet spot is. After loading those 25 new cartridges at factory C.O.L. and shooting them, I then analyze my targets again.

The first target is the best group size so I chose that as my powder charge. Point of impact is very similar for all groups, so it didn’t have much factor in the decision. The charge I came up with for this load was 46.6 grains of IMR 4350. If I were to not find any really great results with this powder I would simply switch powders over, then start back at 90% and work a new charge up using the same load development process. I wound up doing just that 4 times before deciding on the IMR 4350, then I ran out of IMR 4350 and had to do it again with IMR 4895. The IMR 4895 wound up being a better powder anyways, so I didn’t mind it at all. I prefer to have more than one good load worked up for a given bullet just in case I have problems finding that one powder that worked the best.

If you have a chronograph this step in load development can become much simpler as you will know what velocity your gun really likes for that bullet. Load a new powder back up to that velocity sweet spot and you will be very close to your ideal charge (use a few shots of incrementally increasing powder charges to make sure you are not getting pressure signs at that velocity). The burn rate of the powder alone can change the accuracy substantially. You can also come back to very close to the same velocity based on your load manuals information if it shows the charges required for 100 fps increments with your bullet (not all loading manuals do this, some only give min and max loads). Just look in your manual at where the first powder charges sweet spot was for velocity, then look for the same velocity in your new powder. When comparing the IMR 4350 and IMR 4895 sweet spots I wound up with a 10fps difference.

Find the Best C.O.L. (Cartridge Overall Length)

Now that I have my powder charge chosen I load incrementally longer cartridges from the factory recommended C.O.L. out to my maximum chamber length. I use .020” increments for this test because the throat of my rifle is very long. Use a smaller increment if you need to. The reason I choose a powder charge prior to finding my best C.O.L. is because of how the targets are analyzed. The charge is chosen for small group size and point of impact. The C.O.L. is chosen only by group size. When doing load development you want to do the rough tuning first (charge), then fine tune (C.O.L.).

I loaded up 5 progressively longer loads, 5 cartridges each, and shot them. Here is the target.

Targets 2 and 3 were the best, with target 3 coming out slightly ahead. I had one shot on target 3 that I called bad, so I left it out of my decision. Based on this load development for the 175 grain Sierra Matchking my best load is 46.6 grains of IMR 4350, seated at 2.860”. As you can see, that left me with a just slightly larger than .5” group which is certainly acceptable in my book.

Fine Tune

After picking your best C.O.L. in the previous step you should have a very good shooting load. You can either load up a bunch of these and shoot them as is, or if you are like me and never quite content you can try tweaking the load just a tiny bit at a time. I tend to try tweaking .1 grain up or down and .005” up or down at a time and see if the load tightens up any. It may or may not improve, but you won’t know unless you try it. Unfortunately I was running very low on IMR 4350 at the time of writing this, so I have not been able to tweak this load yet. Given that I was unable to find any more IMR 4350 I wound up doing a load development with IMR 4895 instead and I am getting phenomenal results. I’m still working on tweaking the IMR 4895 load, but it is doing very well.

That is my load development process. It is an important step, and I think it is most of the fun in reloading. My opinion is that the level of accuracy achieved from handloading should always be better than factory ammunition, and the more accurate the load the more skillful the handloader (and shooter, of course). My current standard for a load is it has to shoot under a .6” group regularly, and smaller is always better. All rifles and shooter’s are not capable of this level of accuracy, make sure you strive for what you can achieve.

Other very popular methods of load development include the Audette Ladder Test and the Optimum Charge Weight Method. My main issue with both of these methods is that they must be done at longer ranges (200-300 yards+) for best results. I only have access to a 100 yard range, so these methods are poorly suited to me. These methods will lead you to a very good (possibly the same) load if you have access to a longer range than I.

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