Well, to answer the first Q, "What part of the trigger will i have to replace? I dont want to file or grind anything, I am willing to buy the correct part and set for the trigger! please tell me where i can get a complete trigger assembly that is drop in without any grinding or sanding or filing!" like I said, Century is typically ruining part of the trigger assembly...unfortunately, it's a part that's integral to the lower...not a replacement part...that's why you have to replace the whole lower. BTW, you don't have to replace the furniture, just the metal. Also BTW, in order to be "legal" you need to make sure that the new lower has a US made trigger, hammer and sear...not the one that will come with the lower. You may be lucky and get US parts in the lower from Century and just move them over to the new lower.
Your second question. Watch Shotgun News for ads, check
http://www.dsarms.com , Federal Arms,
http://www.gunthings.com and about a half dozen other places.
http://www.falfiles.com forums will help you locate parts.
NOTE: Century has often shipped "L1A1" rifles with metric lowers! If this is true, you might not need to change lowers at all! Check yours to see! Is the safety a round know type or a "gas pedal" type? The Inch types had the gas pedal. Also, the metric lower will have most of the trigger assembly in the receiver, with only the trigger return spring in the pistol grip...the inch gun has more stuff in the pistol grip. ALSO, the inch gun will have a metal plate that's part of the triggerguard that goes down the face of the pistol grip. That's perhaps the MOST definitave thing to look for.
As far as a "drop in" trigger assembly, you can wish in one hand and **** in another...see which one fills up faster. There is no such animal. Here's the trigger advice that I received by someone here a while ago.
To work the trigger down to a 3.5 - 3.25lb pull replace trigger return
spring (the one behind the pistol grip) with a Wolfe .200 OD, .025 wire
diameter cut 14 coils long (from Brownell's #69 spring assortment $9.50).
Replace hammer spring with a Wolfe .255 OD, .035 wire dia. cut 36 coils
long (from Brownell's #71 assortment $9.50). Note: Both springs must be
replaced TOGETHER! Trigger should break clean at 3.25 - 3.5 lbs. DSA US
trigger & hammer kit seems to break the cleanest with no creep. FSE trigger
& hammer kit will need minor smoothing with stones. Hesse trigger & hammer
kits will need MAJOR stoning to get trigger creap in the ballpark.
As always -- be safe. Test trigger to be sure hammer does not follow bolt
back. This setup works in my guns with DSA, FSE, and HESSE trigger kit.
PS. Even if you don't stone the hammer hook and sear (and some folks would
rather have a smith do it for them anyway), just replacing the springs as
indicated above will greatly reduce trigger weight. However, if you have
any doubts about your skills in this matter, PLEASE seek out a qualified
gunsmith to do it for you!
: Always remember the three most important rules when working on triggers:
: 1. SAFETY ALWAYS
: 2. SAFETY ALWAYS
: 3. SAFETY ALWAYS
Did this work for me? Not quite. My hammer spring didn't have enough tension to force the hammer against the sear when I followed these directions. I wound up putting the original hammer spring back in. The trigger isn't perfect, it's about 7 lbs...but at least it's crisp and reliable. I just did not have the reliability I wanted out of the 3.5# job. BTW, the measurements here are final...you should start with the springs longer than this and work down. Always test your work in a safe area. Also, only load TWO rounds at a time when final testing your trigger. A full auto FAL gets attention.