Greeting, SAW Gunner!
I've owned a Springfield Armory SAR 48, and have shot extensively several H&K 91/CETME 7.62 NATO rifles. My association with competitve military rifle shooters and armourers bring the following comments.
To summarize experiences and help you to decide:
1. The Springfield Armory SAR 48 was imported from Brazil and used Imbel military production (makers of small arms for the Brazilian military). At last info, SA changed to US-made investment cast receivers and military surplus metric FN FAL parts from various countries. This, due to the "assault rifle" import ban of 1994.
2. The FN FAL rifle is an outstanding design, often branded "the Free World's Right Arm". It was the most numerous rifle design and adopted by more non-communist block countries than any other before the 7.62x51 NATO was dropped in favor of 5.56x45 NATO. They come in English inch-standard (US, Canadian, British, Australian) and metric standard (German, Belgian, Dutch, South American, etc). The originals were totally machined steel, but later FN production (and the US-made receivers) went to investment casting as a cost-saving measure.
3. The FAL design is gas-operated, a BIG plus if you use military surplus ammo or handloads. The sample I had functioned flawlessly for several thousands of rounds using mil surplus and handloads. Accuracy was typically 1 1/2" to 2" at 100 yards using almost any surplus ball ammo (US, Canadian, British, Rhodesian, South African, Spanish, British, Portugese). The best groups were with match-quality handloads using the 168 grain boattail Sierra MatchKing. It would often group under 1 1/2" at 100 yards. The FN design is considered adequate, but not superior in sand and dust climates and operating conditions. The UK version went to zig-zag machined cuts on the bolt carrier to increase sand and dust reliability.
4. Accurizing is very practicable. There were (are) gunsmiths that specialized in accurizing this design for match competition shooting. Re-fitting recoil shoulders, bolts, hinges, and trigger work is the usual procedure. Better quality iron sights will improve your shooting too. Peter Kokalis did a very nice article for Soldier of Fortune Magazine on the SAR 48 back in the middle-to-late 1980's.
5. Accoutrements and accessories are still cheap and plentiful: magazines, scopes/mounts, cleaning kits, etc are readily available from Gun LIst and Shotgun News advertisers.
6. The G-3/CETME design is a roller-locked delayed blowback design, and is much less friendly for handloaders.
7. The nations that adopted the G-3/CETME design include: Germany, Norway, Greech, Iran, Thailand, Saudi Arabia, Spain, Portugal, etc. Many of these user nations bought the gun and manufacturing rights under "technology transfer" contracts that set up toolling and assisted manufacture in the customer country. The design is considered to be very reliable in sand and dust conditions and climates.
8. The stamped sheet metal design, while certainly high quality and practical, makes for a heavy and ungainly weapon. The sights are crude and of limited utility. The fluted chamber and violent ejection makes reloading a challenge. The telescoping stock is sturdy and conveniernt. A nasty remark I've heard about the H&K/CETME is that it was the world's first "throwaway assault rifle".
9. If American user comments are any indication, the quality of the recently available CETME rifles are iffy. You may, however, get a good one that needs minimum work to be reliable. A properly fitted HK is extremely reliable with mil ball ammo. Accuracy should be more than adequate for a battel rifle. Don't expect $10,000 PSG1 sniper rifle accuracy from your surplus G3/CETME.
10. Finish. The original FN was ordnance enamel-coated phospate coated steel. "Painted" finishes are a real turn-off for most American shooters, but are imminently practical for high humidity, tropical climates, and are very durable and protective. The H&K production was phosphated steel with epoxy overcoat. Extremely attractive and durable. I don't know what current H&K/CETEME clone finishes are.
Summary: If I were to decide between the FN or H&K/CETME rifles today, I would still unhesitatingly choose the FN or SAR 48. It's simply better made and generates more pride of ownership.
If you have any additional questions, feel free to send me private mail.
HTH
John