The past few months have seen some interesting developments in terms of new ammunition technology with the notable appearance of polymer bullets. An October 2015 article in American Rifleman provided some details on the Polycase ARX ammunition. But what is the big deal about this new technology? Is this really interesting? Is it going to make any difference in the shooter community?
I ventured to explore this theme further in relationship with Ecomass Technologies, a company involved in the manufacturing of polymer projectiles. As described in the above referenced article, the projectiles are composed of copper powder and a nylon-like polymer matrix. They are produced through an injection molding process similar to that of a LEGO block.
The initial driver in manufacturing such projectiles was to produce a lead-free bullet as mandated in certain military and law enforcement applications. As a matter of fact, the US Army replaced its green-tipped 5.56mm x 45mm NATO, M855 standard ball cartridge in June 2010 with the new lead-free, or ‘green’, M855A1 cartridge.
The physics
Copper has a density of 8.96 compared to 11.3 for lead and when copper powder is used in combination with polymers to yield material suitable for projectiles, the end density is around 6. This very significant difference in density results in light projectiles which are dimensionally large in relationship to their weight in grains. A polymer projectile for 9mm Luger weighs in the range of 80 to 90 grains compared to 115 to 124 grains for a lead bullet. However, the polymer projectile is about 30% larger in size.
When considering these projectiles for reloading, an immediate challenge appears for calibers such as 9mm where case capacity is limited. Considering the maximum OAL of a 9mm Luger, more than 50% of the case capacity is occupied by the bullet compared to ca. 30% for a conventional lead projectile. The problem is compounded by the fact that larger amounts of powder are necessary to provide sufficient power for cycling firearms in their stock configuration.
With such ‘off the charts’ parameters, manufacturers have generally not offered polymer bullets as components and focused on factory or professionally reloaded ammunition. I am thankful to Ecomass for keeping an open mind and for allowing me to experiment with their projectiles.
The performance
A simple statement could just be ‘it feels different’. Other comments from experienced shooters have been ‘Wow, I cannot believe this’. Because of the reduced bullet weight and possibly other parameters related to the material, polymer ammunition shoots extremely soft. With such a reduction in felt recoil, polymer ammunition is likely to gain high popularity with recoil sensitive shooters such as junior and less experienced shooters.
But there is more. Due to their composition, these polymer bullets are frangible so they will disintegrate upon impact on a hard object. This is a very desirable behavior when shooting at steel plates as it eliminates the danger of bullet fragments bouncing back and hitting shooters and bystanders.
A considerable amount of work was devoted to developing loads for Ecomass projectiles. Our efforts focused on the 9mm Luger using the 89 grain Ecomass bullet. Upon thorough analysis, proper choice of powders and careful practice, we were able to develop accurate, reliable and practical training loads with velocities in the 1,300fps range.
For experienced shooters who want to race, polymer ammunition is perfectly setup to provide fast recovery between shots. Taking a Springfield Armory 1911 in 9mm with a good trigger and optics, one can turn a $1,000 production pistol into a $4,000 race gun. Going beyond felt recoil, polymer ammunition provides excellent accuracy, minimal barrel wear and extremely clean functioning.
The limitations
The low recoil is obtained as a trade-off of momentum for energy resulting in relatively low power factors. Certain competitions mandate power factors for various divisions and polymer ammunition is likely to fall short of the requirements. The relatively powerful Polycase Inceptor RNP advertises 1,425 fps for an 84 grain bullet resulting in a power factor just under 120. Our reloads were typically in the 115 range.
The economics
Because copper is significantly more expensive than lead, the manufacturing cost of polymer projectiles is inherently more expensive their lead-based counterpart. However, given some of the advantages detailed above, it is quite possible that polymer projectiles gain in popularity. They may also play a significant part in the transition toward ‘green’ materials, which are already mandated for water fowls and other hunting applications.
I am thankful to all my friends who took the time and shared their equipment (chronograph, guns, benchmark ammunition and more) towards this learning experience. They also lent their hands to provide extremely valuable feedback in the course of shooting a large panel of ammunition. I am also thankful to Ecomass Technologies for providing several hundred projectiles for load development and testing. I strongly encourage shooters of all skill levels to try polymer projectiles and draw their own conclusions.