How do you choose the Correct Target Rifle Bullet to use in your Rifle? TR Shooting in the UK is done using the 308 Winchester Cartridge with a bullet subject to a maximum weight limitation of 156 grains. Bullet Manufactures are all competing for a larger share of a growing market, driven by the growing interest in long range precision shooting around the world. There are many very good .308 diameter 155 grain bullets currently in the marketplace from major manufacturers such as Sierra, Berger, Lapua, Nosler, Hornady, and Optimus HBC Projectiles.
Which bullet(s) should you choose?
This article is not meant to be a definitive technical guide to Precision Shooting, it is only meant to increase the awareness of the factors that should influence the shooter’s bullet choice. Before I start off, I need to thank my shooting friends on both sides of the Atlantic, who have kindly shared some ‘trade secrets’, learned through many years of successful shooting at the international level. Without their contributions and willingness to share their deep subject knowledge it would not have been possible for me to write this article.
Identify your shooting requirements
Are you deciding for yourself or a team or another group?
If deciding for a team or club, do you have an informal team with a mixture of barrels and chambers or do you have a formal team with standardized equipment? If you are deciding as an individual, do you have more than one rifle or more specifically, more than one chamber? If you are choosing a single bullet that is going to group well in a collection of rifles with different chambers, different twist barrels, and different degrees of barrel wear, a more ‘forgiving’ bullet design may rank high on your shortlist.
NRA Target or ICRFA?
The NRA TR Target used at Bisley is regulated to allow a good shooter who uses an average rifle and average ammunition the chance of shooting an HPS. Target size is adjusted from time to time based on statistics. In theory, good scores can be achieved using ‘average’ bullets. The ICFRA Target is quite small in comparison, thus group size needs to be small. The size of the Bull on a 1000 Yard ICFRA Target is 2 minutes, and when you think about it, you quickly realise that there is not much room for error. Every possible factor that can be controlled should be examined and addressed. Using bullets that are consistent in terms of weight, shape, size and jacket thickness is a good starting point. All bullets are not created equal. Some manufactures tolerate a wider variation in weight and dimensions than others.
How much shooting are you or your team going to do?
If you shoot a relatively small quantity of handloaded ammunition, then cost is not a major concern. If you go through thousands of rounds per year, then using a less expensive bullet, if only during practise, could mean achieving savings to contribute towards other shooting consumables such as barrels and air fare. If this the case then you may want to overlook brand loyalty and look for a good value-performance solution. Once you have decided on a bullet, look for 500 or 1000 count packaging to keep your costs down.
Are you trying to duplicate GGG Ammunition (Issued at the Imperial Meeting) Characteristics?
The Target Rifle Imperial Meeting at Bisley is shot with issued ammunition manufactured by GGG using the Sierra 2155. My partner will only train using GGG ammunition until after the Imperial Meeting, then she will switch to hand loaded ammunition. She wants to make sure that her rifles will work with issue ammunition at the Imperial Meeting, and wants to be familiar with the characteristics of GGG going into the Meeting. This reasoning is perfectly valid.
On the other hand, I train for the Imperial Meeting with hand loaded ammunition closely duplicating GGG velocity using the Sierra 2155 Bullet. The reason for this is I am focused more on discovering errors in my technique and wind reading, and need my ammunition to be as accurate and predictable as possible. I need to know that my shot will go where I am pointing the rifle.
Although GGG manufactures great 308 Winchester 155 grain ammunition, a hand load developed to suite the characteristics of a particular rifle can yield better results. The characteristics of GGG issue ammunition can be duplicated using the Sierra 2155 or the Nosler 155grn .308 Custom Competition which is a very close copy of the Sierra 2155. There are different opinions on which these has bullets has better consistency. The Nosler is made using the highly regarded J4 Bullet Jacket, which just happens to be the same bullet jacket used by Berger. If the wall thickness of the bullet jacket is not uniform across the entire diameter, an imbalance is created as the bullet spins, resulting in an increase in group size on the target. In addition, runout or non-concentricity will result in larger group sizes as well.
Do you have a specific long range requirement you are trying to address?
If you require a dedicated load for use in long range competitions where competitor supplied ammunition is allowed, then you need to carefully consider the different characteristics of different .308 155 grain bullets. Bullet characteristics can be compared and described by a number called Ballistic Coefficient. The BC of a bullet is measured under laboratory conditions. There are different methods used to describe the BC of a bullet, two of which are G1 and G7. A great video description is available here BC Explained. Given a collection of bullets of the same weight and calibre, all shot at the same muzzle velocity at the same time, the bullet with the highest BC will arrive at the target first because it will have retained more velocity along the way. Less flight time in the air, translates to less time exposed to the effects of wind and other atmospheric variables.
For example, using the G7 method, a Sierra 2155 travelling at an optimistic 3000fps at the muzzle will be deflected 99.1 inches in a 9 o’clock 10 mph crosswind at 1,000 yards. A 155 Berger VLD Target travelling at the same muzzle velocity under the same conditions will be deflected only 90.3 inches. It does not sound like a big difference, but in real life conditions with varying wind velocity and angle, the difference can put you on the inside of the circle instead of the outside. A higher BC bullet will also be less effected by head and tail winds reducing elevation variation at long range.
Higher BC’s are achieved by reducing drag, hence the term Very Low Drag (VLD). A few decades ago, I was introduced to VLD bullets from JLK, a lesser known American bullet manufacturer. Back in the day, JLK’s were noted for their ability to retain velocity at long range, and not user friendliness. The JLK was a specialist bullet back then, satisfying shooters experimenting in using light calibre cartridges at long range. JLK raised shooter awareness as to what was technically possible at the time, and in my opinion, advanced bullet design and development.
Reducing drag is primarily accomplished by designing a bullet ogive (the area between where the full .308 diameter section transitions to the ‘point’ or meplat) that offers as little resistance to movement through air at high speed as possible. There are three major types of ogive design used in match bullets today; the secant, the tangent, and the hybrid. Simple drawings, charts, and a practical explanation of the different ogive types written by a qualified Professional Ballistician, Brian Litz can be found in this Ogive Comparison.
VLD bullets, with a secant type ogive are generally more sensitive to ‘jump’ than traditional tangential type ogives, due to the fact that the design does not initially ‘self-centre’ in the rifling upon firing because of the sharper angles built into the design. To be effective some VLD bullets may require a ‘positive’ seating into the barrel lands to overcome this issue, sometimes described as ‘bullet jam’, as opposed to ‘bullet jump’.
Although common in other shooting disciplines and in other countries, you probably won’t want to down the ‘jam’ road for practical reasons, such as safe unloading at the point. If a bullet is ‘stuck’ in the barrel lands when the rifle is unloaded, the powder in the case will usually spill over the action floor and the locking lug recesses, possibly causing the rifle to be temporarily unusable making you especially unpopular with your wind coach if you are in team shoot when it happens.
The Hybrid design is a relatively new innovation, attempting to offer the best of both secant and tangential types in an attempt to offer VLD but with less sensitivity to bullet seating. The portion of the ogive that will be the first part of the bullet that makes contact with the rifling upon firing the shot has a tangential design. Forward from this the ogive design reverts to the secant type.
I should mention two other significant factors in reducing drag. First the bullet tip or meplat. During manufacture of Hollow Point Boat Tail bullets, the jacket is swaged to form the bullet tip. This process leaves relatively rough edges and variation from bullet to bullet. Some shooters ‘point’ their bullets in an attempt to create uniform meplats and possibly achieve higher BC.
Bullet manufacturers have tried to improve bullet uniformity by using a polymer tip. An example of this is the Sierra 7755 .308 155grn Tipped MatchKing. The additional manufacturing steps involving the tip increase bullet cost. Up until a few years ago, tipped bullets were thought to have issues with uniformity and there were questions about tips possibly melting or otherwise being torn off the bullet during flight. Modern polymers have addressed these issues.
The last significant factor is the boat tail angle. The final geometry of the bullet, after the ogive and bearing band have been finalized remains is made up of the boat tail. General consensus seems to be that gentle boat tails should be longer as opposed to shorter. The longer the boat tail is, the shallower the angle to the bearing band, reducing drag.
By now you should see that getting the best out of these low drag bullets will require some experimentation and testing on your part.
Here are some things to consider:
First, remember that these modern bullets still weigh 155 grains and if they have a sharper nose, then the mass that would have been in the nose has to be added somewhere else. This can be achieved by lengthening the bearing band area (full .308 portion) of the bullet. Lengthening the bearing band causes more resistance as bullet travels down the barrel, hence increasing pressure. Consider using a slower powder or a least a different load as compared to a bullet with a relatively short bearing band.
Many Target Rifles in the UK are chambered to shoot issued GGG ammunition with 0.030″ – .035″ jump. This may be a consideration when choosing one of the high BC Bullets.
I once owned a rifle with a relatively ‘short’ chamber that shot the Sierra 2155 perfectly well. When I tested the Lapua 155 Scenar (excellent bullet), I found that due to the longer length of the Lapua bearing band, while seated at a reasonable depth, the base of the bullet protruded deeply into the case, well into the shoulder, effectively reducing case capacity. My chamber configuration limited use of the Lapua 155 to short range with reduced loads.
For reasons similar to this, many specially configured long range rifles are chambered with custom reamers, optimized for a specific bullet/cartridge case combination chosen in advance of the rifle being built. There are companies that cater to this activity, and one very good one can be seen here https://pacifictoolandgauge.com/. It starts with determining where you want the base of the bullet to end up in the finally assembled cartridge. Ideally you want the line where the bullet bearing band transitions to the boat tail to sit slightly above the case neck/shoulder transition junction. When designing a chamber, you start with this in mind and carefully calculate each of the other dimensions.
Thirdly, you cannot simply expect to throw a load together at roughly 2.80″ OAL and go shooting as you can with more forgiving tangential bullets. Getting the ‘jump’ just right will probably take experimentation and testing at long range. When the Sierra 2156 was first introduced, I purchased a large quantity for my own use. After testing many different loading combinations including many different seating depths, I just could not make it work in my rifle and gave up on the bullet. Two years later I accidentally came across mention of the Sierra 2156 on a US shooting forum referencing the use of a large ‘jump’, well outside of my normal range of testing. I tested a batch with this ‘big jump’ on Stickledown Range, and surprisingly saw very nice groups at thousand yards.
Last, but not least, is the twist rate of your rifle barrel. The original 1 in 13″ twist rate that was so commonly used to shoot 155 grain bullets in the past may not be fast enough to properly stabilize these high BC bullets. High BC bullets can be long. Both length and weight have to be taken into account when calculating the Gyroscopic Stability Factor of a bullet. Using the Berger Twist Rate Stability Calculator and choosing some sample .308 155 grain bullets, you can check to see if Berger considers your rifling twist fast enough to fully stabilize their bullet. The calculator reduces the ‘Advertised’ BC as part of the calculation if your twist is not considered fast enough. For example, Berger recommend a minimum twist rate of 1 in 12″ for their 155 Target VLD Bullet to be fully stabilized and provide its maximum BC shot with a muzzle velocity of 2950 fps. Berger recommend a twist rate of 1 in 11.5″ for their 155 Target Hybrid at the same velocity. This does not completely exclude using high BC bullets in a rifle with a slower twist, it just means that you will not be getting the full benefit from high BC. Berger openly shares twist rate data whereas Sierra and Nosler both use 1 in 10″ barrels for their loading data and do not currently provide a twist calculator.
Conclusion - Choosing the Correct Target Rifle Bullet
By now you have gathered that it is not a one size fits all situation. You need to look at your requirements and try to prioritise them. You also need to consider any potential limitations with your chambering and twist rate.
What is your primary goal in loading ammunition for Target Rifle shooting?
Are you loading ammunition for training for the Imperial Meeting?
Are you trying to budget for a new barrel along the way and your next international shooting trip?
Have you built a special long range rifle to win open matches and are determined to get lots of V’s at 1,000 yards and are prepared to invest some time in load development and testing?
Are you an enthusiastic Target Rifle shooter that enjoys reloading and simply wishes to extract the best performance from your rifle possible?
The good news is that with a little thought and experimentation you can accomplish any of these goals.
Good luck and good shooting.