Thought about the caliber for LR
The new season is approaching and we all begin to think about the new equipment. And its most important part is the choice of a suitable caliber for the purpose. So I tried to think about it. What and why I expect from my caliber...
As I mentioned in the article about ammo - there has been a great deal of recent development. Manufacturers are giving us new and better bullets. And so there are changes in the caliber selection...
In the picture are the bullets from left:
6mm Sierra MK 110grs / BC G1 .617
6,5mm Hornady ELD-M 140grs / BC G1 .646
6,5mm Sierra MK 142grs / BC G1 .626
6,5mm Sierra MK 150grs / BC G1 .713
7mm Sierra MK 197 / BC G1 .780
7,62mm Sierra HPBT 168grs / BC G1 .462 (standard for years but look at the new ones)
7,62mm Sierra TMK 168grs / BC G1 .535
But what does that actually change? What are our caliber requirements at all?
For us is important to hit the target precisely... And this can helps us:
- a low recoil. To be able to track our hits just after the shot (especially when shooting at metal targets). It also allows us to maintain better a quality position and make fewer mistakes thanks to a good position. Low recoil is the key... The lighter the bullet - the lower the recoil. Unfortunately there is a higher influence on the projectile by the wind. So they are a bit of a contradictory requirement.
- high bullet velocity - and hence a flatter ballistic curve. This will help us make fewer correction errors. In addition there is a very important factor - influencing the projectile by wind. The faster the bullet is the less the wind will affect it. When shooting at longer distances the wind estimation and the proper wind correction is crucial... - high Ballistic Coefficient. The higher it is the less the bullet loses its speed.
These requirements are somewhat contradictory at some points. So there will always be a compromise... It would be ideal to shoot the heaviest bullet with the highest BC as fast as possible - and with even the smallest recoil. Unfortunately it is not possible. And also - heavy and fast bullet is a heavy burden on the barrel and its life is rapidly declining.
The question is what precision we want at what distance. The longer the distance is the more will play the role influencing of the projectile by the wind...
Ammo by caliber from left:
.223 Remington (5,56x45) - very high bullet velocity (around 1000 m/s for light bullets) low recoil. Unfortunately the bullets are very light and do not have a very high ballistic coefficient. But within 300m distance you can get good results.
6mm Norma BR - medium speed for heavier bullets with high BC (around 820 m/s). Extremely accurate up to 500m with very low recoil. Over 500m wind plays a major role.
6,5 Creedmoor - medium speed for heavier bullets with high BC (around 840 m/s). Accurate up to 1000m. Wind correction is significantly smaller than the .308 Win and the recoil is significantly lower.
6,5 PRC - it's like Creedmoor on steroids... High speed even with heavy bullets with excellent BC (around 900 m/s). New caliber especially in Europe. But the potential is there. It should be accurate enough to 1250m. With good muzzle brake the recoil should be lower than the .308 Win.
.308 Winchester (7,62x51) - medium velocity for medium bullets with lower BC (around 820 m/s). New types of bullets already have BC above .500. Good accuracy up to 700m. At greater distances very affected by the wind.
6,5x55SE - medium speed for heavier bullets with high BC (around 860 m/s). Accurate up to 1000m. Compared to 6.5 Creedmoor it has a slightly higher speed.
7mm Practical - our project for ELR. Very high speed with heavy bullets with high BC (around 930 m/s with very long barrel). Here we are at the edge... But for 1000 meters in the wind I feel like a cheater - it almost does not affect the bullet... But we have this caliber for longer distances - we will try to attack 2000m. The recoil of a our heavy rifle is very manageable (more enjoyable than .308 Win).
.300 Winchester Magnum - high speed for medium-heavy bullets with decent BC (around 900 m/s). From this parent case comes our 7mm project... Higher recoil.
338 Lapua Magnum (only the case. I have no bullets currently...) - high speed for heavy bullets with high BC (around 900 m/s). Heavy hitter for shooting up to 2000m. Higher recoil.
One thing can be seen in the picture. Manufacturers have found that shorter cartridges are more efficient but with a larger diameter. And they made new calibers of this type recently. In addition it is simply the fact that manufacturers are also trying to make some short Magnums to be used in Short Action systems. This is just a trend.
The lower recoil can be achieved both by a higher weight of the weapon and a good muzzle brake. I'm preparing a test of several types of brakes - I'm hoping for an interesting comparison... The positive effect of the muzzle brake is also beneficial with calibers where the recoil is low on itself. It's just much easier to manage the recoil. "Recoil Management is the name of the game". It is the key to success for dynamic shooting (especially when shooting metal targets). Heavy weapons with powerful brakes and calibers with a weaker recoil and with a flat ballistic curve have dominated this sport...
For the new season after a longer thought - we chose several different calibers...
6mm Norma BR (or one of its variant) - for accurate shooting up to 500m. These calibers are just great. High accuracy with low recoil and less gunpowder - this is the music for my ears...
6,5 Creedmoor - today I can say that this is (from my point of view) an ideal universal cartridge. It is easy to reload and can handle the Long Range. We have verified ourselves this season. We've replaced the .308 Win and I'm pretty sure we will not come back. This 6.5mm (as well as the others - 6.5x47, 260 Rem, 6.5x55) simply does everything as .308 Win - but better, more accurately, faster, for longer distances, with less recoil, with less wind influence and for less money...
6,5 PRC - I just want to try it. It should be like another 6.5mm - just a little faster and hopefully able to hit for longer distances... It's not really a Magnum but it's more than Standard.
7mm Practical (I would probably name it 7 PRC to match it with the smaller one...). We will just finish this project. I am convinced that it has the potential among Magnums. The recoil is very pleasant. After fifty rounds I do not feel any fatigue and do not make more mistakes than usual.
And what caliber do You plan for the new season?
Not only to members of our team we can offer help or advice when choosing the right ammunition. We already have some experience and results with it... Do not be afraid to contact us.