OK, so I decided to lighten up my SIG 556 SWAT. I ordered a 551 handguard and short receiver rail to replace the SWAT railed handguards. Here are the official numbers.
SWAT handguard: 1lb 3.0oz = 19.0oz
551 handguard and rail: 9.1oz
Weight savings: 9.9oz
Not a big difference really, but the problem with railed handguards is that they tend to gather accessories. For instance rail covers, lights, grips, lasers, etc.
Mine was fairly modestly outfitted with a light, small grip, and fairly small XTM and ladder rail covers.
so actual weight savings for me is 34.3oz-9.1oz = 25.2oz or 1.575lb a little over a pound and a half. All up front where the SIG 556 is needs the weight loss the most.
My 556 now balances a lot better. Still not as light as an M4 type AR, but I like the feel a lot better now.
I like top heavy womenz...