I think most of the differences have been well covered in the previous posts, but here goes a summary (apologies for any redundant statements). Regarding my expertise, I was a RESO trained Lt who went through Phase training in Gagetown‘s CTC the first year that they had C7‘s instead of the FNC1A1 (Ironically, our section LMG‘s were still the FNC2 - a heavy barrel version of the the FN with a 30 round magazine. But, I digress...)
1. Heavier barrel to aid in dissapating heat, and thus retaining better accuracy.
2. The furniture (butt and forestock) are made of either different compounds (butt) or heavier plastic (forestock) to deal with winter temperatures and avoid cracking or breaking as a result of the cold.
3. The original C7 (iron sights and carrying handle) did not have a windage adjustment knob on the rear sight like the M16A2 does.
4. The C7 has a removable trigger guard to allow trigger access while wearing bulky winter mitts (I‘m don‘t think the M16A2 has this feature - forgive me if I‘m mistaken).
5. Regarding plastic magazines: These were (sadly) an original feature of the C7. The idea was that in time of war, they would come pre-loaded. The reality was that they were sadly lacking in most respects. The lips of the magazine, exposed to the heat of the weapon near the breach, would frequently break. As you removed a partially filled magazine from the weapon, bullets would fountain up into the air.
It was in Bosnia that needs of the troops finally overcame the bureaucracy. The plastic magazine was flat out unacceptable, and entire battalions doing work up training in the States would buy (using money from their own pocket) metal thirty round magazines to take over with them.
An interesting aside to this is that as 30 round mags became illegal in Canada, a number of units tried to confiscate the privately owned metal mags on returning to Canada to add to their unit weapons inventory. I knew several guys who literally threw them away or destroyed them rather than give up something that the army had refused to supply them with.
6. Regarding double feeds: This frequently happens when firing at a rapid rate (either on repitition or just quick semi-auto) while using a 30 round mag that is actually loaded with 30 rounds. It was common practice to only load 28 rounds, as this seemed to ease the spring tension feeding rounds enough to mostly avoid double feeds into the weapon.
Regards,
Max
