|For those interested in still trying resurrect a politically-sacrificed dead horse,
SSK has come up with a new contender in the "5.56mm-just-won't-cut-it-anymore" debate.
http://www.sskindustries.com/6_5mpc.htm>here it is courtesy of SSK's website
The 6.5 MPC (Multi Purpose Cartridge) is a SSK development urged by Brian Hormberg (USMC) based on the 5.56 cartridge shortened and opened to 6.5 MM and the same OAL as the 5.56. In the M-16-AR-15 rifles it utilizes the 5.56 bolt and magazines as well as all other parts except the barrel itself. Its design adapts it to a short Close Quarter Battle rifle with a 12? barrel moving a 107 6.5 SMK at 2400 FPS with superior full auto controllability and excellent accuracy. The 12? barrel model easily puts it into the realistic 300+ yard combat category and longer barrels stretch that realistic combat range considerably further.
Factory ammunition is not yet available for the 6.5 MPC; however we are working on that. Ready to load brass and dies are in stock.
The 120 grain BT is near maximum bullet weight for good performance. 85 grain is about the least weight for good performance. Some 140 grain bullets may be used but ballistically are counterproductive.
There is a good article in the latest (Summer 2006) Special Weapons For Military and Police magazine (by Stan Crist, pp 64-67 & p 89),
$6.95 @ US newsstand price (displays until Nov 2006, so lots of time yet)
http://www.special-weapons-magazine.com/>here's the magazine at its website, with additional ordering info and back issue information
this new round was developed to match the existing overall length of the 5.56mm ammunition, which it shares the same (albeit modified) case with, to still be able to fit all current 5.56mm hardware (magazines, belt-feed links, etc), with the only necessary change being a new barrel in this new caliber.
It will match per-round capacity of all 5.56mm rounds (20 & 30 round clips, C-Mag 100 round drums, 200 round M249 cassettes, etc), the only difference being a slight weight increase (62-gr typical for 5.56 NATO vs 95-gr typical for 6.5 MPC)
One of the oft-suggested more favorable replacements for the 5.56, the Remington 6.8mm SPC (which doesn't stack comparably in standard 5.56 magazines, allowing only 25 rounds instead of 30), compares as follows:
keeping the same weight, it breaks down to:
5.56mm NATO- 10x30-rd mags = 300 rounds.
6.5mm MPC - 9x30-rd mags = 270 rounds.
6.8mm SPC - 7x25-rd mags = 175 rounds.
Now the Remington 6.8mm SPC is said to offer the most superior performance in "5.56mm-compatible" hardware (can still use standard magazines, etc), while its closest competitor, the 6.5mm Grendell, has to have everything modified to accomodate its considerably-different cartridge profile (although offering much superior performance at extended ranges, with some suggestions putting its performance on par with 7.62mm NATO but in a smaller package).
As for sheer round performance, p 89 of the magazine has a nice comparison chart, between the 5.56 62-gr NATO, 6.5 95-gr MPC and 6.8 115-gr SPC.
At 200m range (within CQB), the 6.5 has more than 250 foot-lbs advantage (14.5" barrel) over the 5.56.
At 500m range, the 6.5 still retains just shy of a 200 ft-lb advantage over the 5.56.
Stan Crist's article raises the issue that the round (6.5mm MPC) was designed with regards to field reports suggesting that 5.56 from 14.5" (and shorter, CQB) barrels was proving to lack the 5.56's potential it had from longer barrels which could exploit the high velecoity needed to make the round truly incapacitive (leading many to adopt the view that "controlled pairs" would overcome any definciencies on the single, lowered-velocity (when fired from shorter barrels) 5.56 ammunition. But that of course effectively reduces the number of engagements: what's the advantage of carrying 300 rounds when you can, by the "controlled pairs" book, only sustain 150 engagements?)
There were numerous "official" suggestions/recommendations that the current 5.56mm NATO was proving "adequate" in current operations (with the higher-performance Mk262 round not being standard en-masse issue as compared to the typical 5.56 NATO.)
But of course, this coming from the same administration who initially thought unarmored logistics vehicles and Humvess and troops lacking body armor would be sufficient and adequate-enough to complete the Iraq mission also.
Now, we've all heard the arguments that "nobody wants to cough up the money to retool the most-commonly-used small arms ammunition/weapons in the midst of the current conflict."
But SSK's new solution suggests only a barrel change (to the new caliber) is needed, with all other componenets of the M-4/M-16 AR family and M249 series LMG/SAW being fully compatible (gun loads, recoil stresses, ammo mags, etc).
Now, there are reports from the field (bot