By Emile Smit
I recently bought a Tikka T3 rifle in .308 Winchester, after doing a lot of research about various rifle manufacturers and calibers. I was looking for an all-round rifle and calibre that would be suited to hunting the majority of plains game in South Africa. Although there are many great all-round calibers that would have sufficed, the venerable .308 Winchester was my preferred choice.
The Tikka T3 got the nod as it was lighter that the other rifles that I was interested in and they are known to be very accurate out of the box. I know a lot of people prefer a heavier rifle which ensures a steadier aim and a reduction in recoil, but I prefer to carry a light rifle when I am walking long distances in the bush.
Even before I took ownership of the rifle, I was advised by many people to reload my own ammunition when the time comes, in order to achieve optimum accuracy with my rifle and with the added benefit of savings costs. I applied for my firearm license at the SAPS and after a few months my application for the Tikka was approved.
I then obtained my own re-loading equipment and I was ready to load my own ammunition. When I started out I referred to the Somchem (a South African propellant manufacturer) booklet and I loaded from the suggested minimum load upwards in 0.5 grain increments, to 0.5 grains below the specified maximum.
This method is called the “ladder method”, where you shoot multiple 5 shot groupings with different loads (in 0.5gr increments), after which you pick the smallest grouping to develop further. You can then fine tune the load by shooting additional 5 shot groupings with minor changes in the load and the COL (cartridge overall length). This is then done until a 5 shot grouping with the desired MOA accuracy is obtained. This is however dangerous as the only signs of high pressure are visible signs and there is no other indication of pressure.
After getting good results at the range with 150gr Hornady Interbond bullets, Hornady unfortunately stopped producing them. I was then advised to opt for Nosler Accubond bullets, but there weren’t any available in South Africa at the time. I then went for Nosler BT (Ballistic Tips) which was the closest thing that I could get to the Accubond bullets. This however meant that I had to start over from scratch with my load development. At this stage I had probably shot more than 200 rounds of ammunition (+- R3000) with no load (or grouping) to show for it.
I learned the hard way that the R2300 for QuickLOAD from JMS Arms is more than worthwhile, as the cost of brass, propellant and bullets don’t come cheap. My goal was to shoot as few as possible rounds of ammunition on the range in order to get the most accurate load for my rifle. This was my main motivation behind acquiring QuickLOAD as I had already paid my school fees.
The QuickLOAD software assists the re-loader to understand certain important aspects such as pressures, velocities, effects and the importance of changing a single variable in the reloading procedure. Keep in mind that each rifle is different; it doesn’t matter if they are both of the same caliber, have the same specifications or is from the same manufacturer.
All rifles have different chamber dimensions, maximum cartridge lengths etc., thus the rifles will handle pressure differently. So NEVER give someone a load which worked in your rifle and expect the same for his, as this has led to many injuries and exploded guns.
In order to calibrate a QuickLOAD, the following information is needed:
Rifle and Caliber: Tikka T3 in .308 Winchester
Bullet: Barnes TTSX BT 150gr
Brass: Lapua Cases – H20 volume: 54.95gr
Barrel length: 570mm
Measured COL: 71.71mm
Primer: Fiocchi large rifle primer
Propellant: Somchem S321
Case length: 50.95mm
Average velocity: 2601fps with 41.5gr S321
When you open QuickLOAD the following screen will appear:
On the left hand side of the screen, you will find a drop down field (Selected Cartridge) where you can select the desired cartridge. When you select this cartridge, in this case .308Win. (SAAMI), the data fields below will change to adapt to the specifications of the chosen calibre. This is relevant to the maximum pressure; core sectional bore area, the groove calibre etc.
Now select the required bullet (Selected Bullet) to continue. In this case it is .308, 150, ‘Barnes TTSX’BT 30875. The data fields below will again populate with regard to the selected bullet’s specifications. The affected fields will be, bullet length, the bullet diameter etc.
The next step is to adjust the cartridge length and case length (the standard default length is already visible) to your specific load.
Change the default barrel length to match that of your own rifle, this is measured from the bolt face to the crown of the barrel (make use of a cleaning rod).
The next and final variable to be altered on the left hand of the screen is the maximum case capacity overflow. Measure the H20 volume of a few fire formed cases, taking into consideration that the water must be exactly level with the case mouth. Add one teaspoon of Sunlight dishwashing liquid in the water, as this helps the water not to bulge over the mouth of the case. Use a minimum average of 5 cases, which is then measured in grains. An electronic scale will be needed in order to weigh the brass.
Weigh the empty fire formed brass first and then weigh the brass filled with water. After doing this you can subtract the empty weight from the full weight. The answer will then give you the H20 volume of each case. Please remember to number each case before weighing them, or you will not get accurate results (for obvious reasons).
We then move over to the right hand side of the screen. Here the first option available is to select the powder/propellant that you are using (Selected Propellant). You will see that all the fields beneath the propellant are greyed out; this is the properties of the powder (we will go into more detail about this at a later stage).
Insert the charge into the field beneath the propellant property and press calculate on both sides. The results will now appear in the fields at the bottom of the screen.
A few important numbers to take into account are the following:
Pressure max – If you go into red, it’s getting dangerous.
Filling of the case – Performs better close to 100%.
Ballistic efficiency – It is best above 30%.
It is important to understand the roles which each of the individual variables play in the outcome of the proposed load. Only then will you also understand what influence the variables have on the pressure, velocity etc. of the selected calibre and bullet.
Step 8 (Advanced Calibration)
The first thing that we need to talk about is OBT (Optimal barrel time combustion) and what it means. Each rifle barrel has a specific node or nodes where the rifle will perform at its best. QuickLOAD helps you to predict the velocity that you must achieve in order to get to one of these nodes in your rifle with a certain bullet.
First make sure that all your variables (step 1 to 7) have been entered correctly. Prepare 5 rounds at a safe charge (the prescribed minimum) and make use of a chronograph to capture the speed of the bullet which will then enable you to calculate an average velocity for the load. After calculating an average speed, enter the data in QuickLOAD as well as the charge weight that you used to get the speed.
You will see that the velocity you get from the chrony might differ from the velocity (fps) that QuickLOAD initially predicted. This can be due to a number of reasons such as: different batches of propellant, a tight barrel, the twist rate of the barrel, different types of primers etc. We now have to calibrate the propellant to give the same speed as what we measured with the chrony at the range.
Click on the hand with the pencil icon next to the propellant selection field, this will open the previously hidden fields below to be edited. We will only change the Burning rate factor (Ba) up and down to get to the range velocity.
The next step is to calculate the node or OBT. This is done by entering your barrel length in an Excel calculation sheet which will then display your different nodes. Your goal is to reach the highest node without exceeding the maximum pressure. This is done by increasing and decreasing your charge weight which changes your OBT in the process in order to match one of the nodes calculated in the spreadsheet.
As you can see, node 5 can be reached at a velocity of 2657fps and a projected charged weight of 42.5gr.
Please be advised this is just a brief overview of QuickLOAD, merely to demonstrate that it’s not as complicated as it seems to some. The software is definitely worth every cent, especially if you have more than one rifle and you wish to reload different bullets weights for each rifle.
Remember that it is absolutely essential to own a chronograph before acquiring QuickLOAD, as you have to measure the speed of your bullets, otherwise QuickLOAD will be of no use. Also remember that the chrony has to be placed 5m from the muzzle of your rifle and that there should not be any direct sunlight on the chrony itself when measuring speeds.
*Please note that neither I or Guns and Fly Fishing will be liable for any damages, injury or fatality caused by making use of the above-mentioned information. All information regarding the QuickLOAD software and the reloading of ammunition is used at your own risk. It is advised that you seek professional assistance before attempting to use QuickLOAD or to reload ammunition.
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