06-18-2013, 01:29 PM
I am going to commit a heresy now (puts flame suit on)...
The 6.5 mm Grendel is a good round. As is, it is demonstrably better than any 5.56 mm variant, although somewhat heavier. A reluctance to increase the war fighter's combat load makes it a difficult sell the Grendel as a 5.56 mm replacement. Arguably, the best case for adopting the Grendel, is if it can be made to exceed the performance of 7.62 mm M80 ball in a smaller, lighter package. That way you kill two birds with one stone. You also reduce the training burden, the logistics burden and the need to buy AR15s and AR10s, because a single weapon type suffices.
To get the Grendel evaluated by the military, you need to develop a military spec version than can easily and cheaply be mass-produced. However, as a comparison of military-spec mass-produced M855 5.56 mm rounds versus match grade Mk 262 5.56 mm rounds shows, most military spec rounds lack the same performance as high quality match loadings in the same caliber. So, if you put a regular 6.5 mm FMJ bullet in the existing Grendel case, you will get a drop in range and terminal effectiveness, especially if you fire it from anything less than a 24" barrel. But...
- For EU members of NATO to adopt the 6.5 mm Grendel, it will require a FMJ projectile.
- Most military users will want to shoot it from weapons with 16" barrels or shorter.
- You'll also need a tracer for use in machine guns.
- Tracer rounds are likely to be longer than standard ball rounds so will use up more cartridge volume further limiting performance.
In other words, the degradation in performance that comes from militarising any cartridge is likely to prevent the Grendel from being a close match for 7.62 mm NATO. This shouldn't come as a surprise. Bill Alexander never set out to develop a new military caliber; he wanted to create a more powerful hunting cartridge that would fit the action length of existing 5.56 mm platforms. However, with relatively little further development, the Grendel could become not just a viable military cartridge, but a perfect one-size fits all solution. To do so, it needs the following refinements:
- A purpose designed military projectile designed along the same lines of the M855A1 EPR, i.e. a steel core and copper jacket, to provide good barrier penetration and terminal effectiveness
- The above requirement is likely to reduce maximum projectile weight to 108 g / 7 g (there is no reason why you couldn't have a special 9 g tungsten loading for sniping and AP work) bullet design could easily be made to compensate for a lower than 123 grains weight and so lethality should not be compromised
- The requirement to include a tracer round mandates a longer case, say 43 mm versus the current 39 mm, in order to accommodate the necessary quantity of propellant
- An even longer case, say 46 mm, with at least a 40 grains capacity, would accommodate sufficient powder for the Grendel to comprehensively overmatch 7.62 mm.
All of these requirements can be achieved with a round that is substantially smaller and lighter than the .260 Remington, 6.5 Creedmoor or 6.5 x 47 Lapua. It should be possible to get the weight down to 17 g for a 108 grains / 7 g loading and maybe 18 g for an 123 grains / 8 g loading.
The downside is that a revised Grendel would no longer fit the action length of the M4 and other AR15 designs. But, it would easily fit the action length of an AR10 platform. The overall weight increase versus a 5.56 mm weapon is about 1.1 lb and the reduction versus a 7.62 mm weapon is about the same.
In addition to giving ordinary squad riflemen a quantum leap in range and effective firepower, the Grendel could reduce the amount of weight carried for the SAW by 25%-30% assuming a total cartridge weight of 17-18 grams versus 24 g for 7.62 mm. Once you make a Grendel with a polymer case, it should weigh pretty close to a brass 5.56 mm round.
An FN SCAR-H in 7.62 mm is not heavy. In fact, it is lighter than the standard 5.56 mm L85A2 assault rifle used by the British Army. A 6.5 mm SCAR-M rifle would be lighter still, but the real weight saving would come with an FN 7.62 mm Minimi (Mk46 LMG) re-barrelled in 6.5 mm.
The 6.5 mm Grendel is a good round. As is, it is demonstrably better than any 5.56 mm variant, although somewhat heavier. A reluctance to increase the war fighter's combat load makes it a difficult sell the Grendel as a 5.56 mm replacement. Arguably, the best case for adopting the Grendel, is if it can be made to exceed the performance of 7.62 mm M80 ball in a smaller, lighter package. That way you kill two birds with one stone. You also reduce the training burden, the logistics burden and the need to buy AR15s and AR10s, because a single weapon type suffices.
To get the Grendel evaluated by the military, you need to develop a military spec version than can easily and cheaply be mass-produced. However, as a comparison of military-spec mass-produced M855 5.56 mm rounds versus match grade Mk 262 5.56 mm rounds shows, most military spec rounds lack the same performance as high quality match loadings in the same caliber. So, if you put a regular 6.5 mm FMJ bullet in the existing Grendel case, you will get a drop in range and terminal effectiveness, especially if you fire it from anything less than a 24" barrel. But...
- For EU members of NATO to adopt the 6.5 mm Grendel, it will require a FMJ projectile.
- Most military users will want to shoot it from weapons with 16" barrels or shorter.
- You'll also need a tracer for use in machine guns.
- Tracer rounds are likely to be longer than standard ball rounds so will use up more cartridge volume further limiting performance.
In other words, the degradation in performance that comes from militarising any cartridge is likely to prevent the Grendel from being a close match for 7.62 mm NATO. This shouldn't come as a surprise. Bill Alexander never set out to develop a new military caliber; he wanted to create a more powerful hunting cartridge that would fit the action length of existing 5.56 mm platforms. However, with relatively little further development, the Grendel could become not just a viable military cartridge, but a perfect one-size fits all solution. To do so, it needs the following refinements:
- A purpose designed military projectile designed along the same lines of the M855A1 EPR, i.e. a steel core and copper jacket, to provide good barrier penetration and terminal effectiveness
- The above requirement is likely to reduce maximum projectile weight to 108 g / 7 g (there is no reason why you couldn't have a special 9 g tungsten loading for sniping and AP work) bullet design could easily be made to compensate for a lower than 123 grains weight and so lethality should not be compromised
- The requirement to include a tracer round mandates a longer case, say 43 mm versus the current 39 mm, in order to accommodate the necessary quantity of propellant
- An even longer case, say 46 mm, with at least a 40 grains capacity, would accommodate sufficient powder for the Grendel to comprehensively overmatch 7.62 mm.
All of these requirements can be achieved with a round that is substantially smaller and lighter than the .260 Remington, 6.5 Creedmoor or 6.5 x 47 Lapua. It should be possible to get the weight down to 17 g for a 108 grains / 7 g loading and maybe 18 g for an 123 grains / 8 g loading.
The downside is that a revised Grendel would no longer fit the action length of the M4 and other AR15 designs. But, it would easily fit the action length of an AR10 platform. The overall weight increase versus a 5.56 mm weapon is about 1.1 lb and the reduction versus a 7.62 mm weapon is about the same.
In addition to giving ordinary squad riflemen a quantum leap in range and effective firepower, the Grendel could reduce the amount of weight carried for the SAW by 25%-30% assuming a total cartridge weight of 17-18 grams versus 24 g for 7.62 mm. Once you make a Grendel with a polymer case, it should weigh pretty close to a brass 5.56 mm round.
An FN SCAR-H in 7.62 mm is not heavy. In fact, it is lighter than the standard 5.56 mm L85A2 assault rifle used by the British Army. A 6.5 mm SCAR-M rifle would be lighter still, but the real weight saving would come with an FN 7.62 mm Minimi (Mk46 LMG) re-barrelled in 6.5 mm.