Load Development for a new rifle
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- Last updated: 29/12/2020
It’s amazing the time and effort it takes to make a rifle really shoot well, and often you just stumble over a good load. Having a well thought out and repeatable procedure will ultimately pay dividends downrange. You have to start somewhere and that is usually thinking about the relationship between barrel, bullet and load components, you basically want all to be in harmony.
People tend to go too mad over choice, I try to stick to as few components as possible, and target these to a point that creates accuracy. For example, cases and primers, I tend to stick to the best and then vary the other components around these. I only change these if a promising load is emerging and I want to see if a hotter/longer burn primer or different case will shrink the groups further.
I use virgin brass, usually Lapua, but Nosler Custom and Hornady are excellent too. Keep the brand the same for the load development and you will be ok. You must weigh and inspect each case, putting aside any outliers that may negatively affect group sizes.
Only change one variable at a time, and shoot enough groups to give a meaningful set of data. Many people use a set procedure and analyse results with charts and percentage means etc. Personally, I ascertain the load density and max noncompressed charge. Any good reloading manual is an essential starting point but the Quickload Ballistic program is very good at predicting initial loads and barrel timings from a potentially accurate load. It saves a lot of wasted time tediously loading ammunition that just is not suitable. It’s not infallible as the condition of bore, rifling twist, primers, chamber dimensions etc will make a difference.
To find the true H20 capacity of my cases, I weigh an empty case with Blu Tack in the primer hole, fill with water so a meniscus is evident and then re-weigh and subtract the empty case weight to get the capacity. Then, I can work from a safe 80% load density starting load and work up, letting the case and chronograph tell me how the velocity and pressure are doing. I then go through all my case prep procedures (which would be a whole other article) to make sure the case is perfect, thus eliminating it as a variable.
Consistency from load to load, eliminating one variable at a time and taking good notes is essential. One change may counteract the effectiveness of another, so split the load regime into step by step tasks.
It is important to shoot enough of one type of reload to get a good statistical result. One quality group does not make a good load, if it looks promising, load at least ten 3-shot groups (my wildcat calibres burn through barrels!), 5-shot groups for comp. Then work on that load to finesse it.
The advancement of bullet design has been one of the biggest contributors to better accuracy, but you can assist them on their way by making sure they enter the bore correctly. Alignment tools are essential as a consistent load is no good if it puts the bullet down the barrel sideways!
Getting the projectile to seat straight in the case and enter correctly i.e. concentric to the rifling, is the key factor to me. Fireformed cases and subsequent reloading can certainly help in this respect. For every 1 thou run out of bullets, group sizes can increase exponentially, often 0.25” at a time.
I have outlined neck turning and bullet alignment tool processes before in previous articles, but it is wise to check for badly fitting seating or sizing dies that will undo all your hard work. I like to neck turn and then use hand dies, so I can feel the brass move and so can consistently feel the seating process. I can then put aside any odd feeling loads.
Another important consideration is getting that bullet to leave the bore when the barrel is moving at its least (barrel timing), so between the nodes or oscillations of the barrel’s free movement. You should have a series of targets that have a smaller and larger group size that is mimicking your barrels nodes and troughs when testing progressive loads.
If a load shows potential then you can enter that data into Quickload and it will work out all powder/bullet combinations for that same barrel timing. It helps to eliminate loads that you might load that just won’t work. You will find that quite a few powder/ bullet combinations match the perfect barrel vibration, and to test all of these is foolish. I settle on the bullet I want to use for fox, crow or deer then choose a powder I have plenty of. I then change the other variables like powder weight and seating depth.
Personally, I try not to vary the powder or primers too much, usually, two or three suitable powders (correct burn rate for the chosen bullet weight) are sufficient. In regards to primers, these are the last thing I vary. I usually use Federal Match, large or small primers, as I have bought a larger batch of each and know their consistent nature.
To neck-size or full-length resize brass is always a contentious issue. Some rifles chambers just prefer one type of procedure over another. Full-length is certainly popular these days and also ensures ease of extraction, but I still like neck sizing on tight necked or wildcat rifles. An uneven neck expands differently to seal the chamber and therefore produces pressure and velocity differences. Any neck wall thickness that has a variation of 0.0015 or more should start the alarm bells ringing.
Seating depth and the relationship between the bullet and the rifling is one of the biggest factors concerning consistent accuracy. Along with that bullet entering the rifling perfectly straight or parallel to the bore axis. That is largely why custom rifles shoot better than factory ones, as the match grade barrels and action to bore alignment, chamber etc are held to far better tolerances than a factory rifle.
Never assume anything in this game, just because one bullet shoots better at 0.025 thou off the lands doesn’t mean another will. Just look at VLD or some all-copper projectiles; as pressure issues and bullet length often means they shoot better way off the lands, often 60 to 100 thou! This is counter-intuitive to most reloaders. Just because two bullets are the same weight doesn’t mean they have the same amount of bearing surface.
My reloading procedure is sometimes called the ladder principle. It’s just a series of progressive steps that include the increase in powder or the decrease in seating depth to ascertain any difference in group size.
There are a few techniques that help with a good load, and one is powder swirling, or case banging to settle the powder. Alternatively, you can use a long powder drop tube, it’s amazing how much the powder settles as the air gaps are removed. Also, try to measure your bullets base-to-ogive measurement, as it’s amazing much bullets of the same type can vary. I use a Sinclair Bullet Comparator Gauge which eliminates suspect bullets that can cause those unexplained fliers.
Just an overview to start you on the path of making better loads, but in the end, it is all about data and methodical step by step trial and error. Finding that magic load makes it all worthwhile in the end.
Step 1: I load three lots of 3-shot groups with one bullet type at one seating depth, usually 0.015 thou off the lands. One powder type but starting at the minimum load and working up 0.5-grains for larger calibres or 0.25-grains for pressure-sensitive smaller calibres.
Step 2: Average the results, be honest.
Step 3: With the most promising load, try five, 3-shot groups to check again.
Step 4: If it’s still good, start to alter the seating depth, 5 thou at a time, be brave, go right down to 60 thou off and work up to near touching the lands if the pressure signs are still ok.
Step 5: If a smaller group size is achieved but there is still room for development, then I would start to think about a different primer and see if there is any further improvement.
Step 6: I would consider changing the powder to one of similar burn rate above and below the promising group to see what happens.
Step 7: Lastly, I would alter the bullet, but you may need to start the procedure again.
JMS Sporting - Quickload ballistic Program -www.quickload.co.uk
Norman Clark - Reload Supplies - www.normanclarkgunsmith.com
Hannam’s - Reload Supplies – www.hannamsreloading.com
Edgar Brothers - Hornady & Alliant powders - shootingsports.edgarbrothers.com