So, I bought a 224 Valk upper

[ed308]

The SAAMI chamber is suppose to work better with factory ammo do to less jump. Don't think I've read of anyone getting good groups with a long freebore chamber and factory ammo. That's why I was in no rush to build my Valkyrie since I have a long freebore barrel and my reloading equipment wasn't setup after I moved over the summer.

[marine6680]

From the talk I hear... The heavy bullets need more than 1/7 twist. The 90gr stuff and heavier needs 1/6.5 twist. They just don't stabilize and get good groups in 1/7 twist.

If you stick to the 77gr bullets, you would gain velocity, and be stable.

[stagpanther]

From the talk I hear... The heavy bullets need more than 1/7 twist. The 90gr stuff and heavier needs 1/6.5 twist. They just don't stabilize and get good groups in 1/7 twist.

If you stick to the 77gr bullets, you would gain velocity, and be stable.

I have loaded several types of 90 +/- gr bullets for use in the PSA 1:7 barrel--it's hit or miss, so to speak, whether or not they can stabilize--but if loaded a bit long with the right powder it can definitely be done. Given a choice before buying though--I'd definitely recommend a 6.5 twist or better (and a minimum 22" with rifle xl gas system). I personally think more than just the twist is affecting the stability as mentioned in my "last" thread. If the bullet can't get "a good running start" no amount of twist +/- is going to completely and consistently compensate for that.