I was wondering if anyone shoots to 1,000 plus with a creedmore, and what bullet do they use?  Does anyone use a 123, or is it mainly 129-140 range?   This bullet would be fired from a 20" barrel, and would be shot at distances from 100 - 1,300 yards.   It would not be used for hunting, just paper and steel.  I took my 175 grain 308 sierra matchkings to a little over 1,000, they do it but you can tell they are out of gas.  My friend was shooting his 7mm-300 and obviously a 190 at 3250 performs slightly better at those ranges.  I am working on a 300 Norma mag for my Barrett but I wanted to get into creedmore for a few months before I go that big.  
At longer ranges
-Does anyone use a 123 grain?  If so, what bullet

-is 129-130 worth it or should I skip to heavier if 123 is not heavy enough?

-For anyone that uses a creedmore at decent distances what is your favorite bullet?

-Is everyone used mainly AR10s or bolt guns?

Haven’t loaded any 123’s to do a definitive test yet.

My suspicion is they’d be too light for ELR, but flat and fast for MR.

Every BBL is unique, however my Creedmoor really likes the Hornady140 ELD-M’s easily sub MOA at 1000.

Rubicon,
           What is your barrel length and what kind of velocities are you getting with the 140s?

Hornady 140 eldm at 2740 fps gets the job done.  I've loaded the 147s Eldm and berger 144 hybrids and couldnt get good accuracy with resonable effort.  The 140s shoot so good I just stuck with them.  

When I was shooting factory Prime to get brass the Norma 130 shot well.

Edited to say the above was bolt gun 24" barrel.  I also used the 140 eldm in a .260 20" barrel at around 2690 with good results

I had no problems hitting out to 1000 yards with Berger 140 gr Hybrids and Hornady 140 and 147 gr ELD-Ms.

use the highest BC you can get.  I shoot the Hornady 147 ELD m

22” BA premium

Approximately 2750

20” bolt gun here, tried the 129 ablr, 147 eld and finally the Berger 130 hybrids. 147’s shoot great but couldn’t get about 2500, 129 did ok but the Berger’s is what I settled on at 2745 avg velocity with staball 6.5. To me unless your going 24” plus barrel I’d stick 130’s or under for that distance.

I've had both my 20" T3x CTR and my 18" AR-10 out to 1300 m effectively while shooting 140 grain ELD-Ms.

The 20" CTR achieves 2630 fps muzzle velocity. The 18" AR-10 achieves 2600 fps muzzle velocity. The elevation holds were pretty easy to dial in, but the wind was kicking my ass at full distance. I could nail the 1000 m steel plate pretty consistently. It was a 4ish MOA plate if I remember correctly.

My 22" factory remington barrel has easily shot to 1,200 with 140 gr ELD-M. I'm getting just under 2,700 fps with factory ammo. I haven't had an opportunity to shoot farther but I have no hesitation to do so if I get the chance. However, if your rifle shoots it well I'd probably stick to something like the Berger 130s to retain some velocity. I wouldn't go lighter than that, though. The BC of lighter rounds starts becoming a problem before you get to 1,000.

ETA: Like Rob said, you can get better performance out of your existing 308 by shooting a more modern round through it.