CZ 527 American barrel twist?

Hi all
I have a CZ American 223 moly barrel and plastic stock which I purchased in about 2008 new. It has been a bugger to get a load to shoot well, and my goto is a sierra 53 BTHP. I thought it was a 1/12 twist but I have read recently that they changed 1/9 in 2002. Just wondering if the owners of CZs like my one have confirmed the barrel twist in theirs? I tried 55s but it didn't like them at all, which I have read is typical however they will shoot 64gn+ projectiles well. Keen to know your thoughts.
Many thanks
Ruger7mm

Have a couple of 527 barrels in 223. Both are 1:9 twist. Shoot both 53gr V-max, 52gr and 69gr Targex without issue.
However I should mention that neither are on CZ actions!

I have a 2007 1in9 sporter and later heavy varmint also 1/9

I have 1in9 that came with the plastic rubber coated stock.
Swapped stock to walnut one I made.
Barrel chopped to 17".
60gr sierra TMK is my go to bullet, am using BM 2 powder. 65gr sierra gk is equally as accurate but not as pretty looking.
Tried the 64gr TGK aka gamechanger but couldnt make them group.
NRF.

Hi all
Thanks for the replies, I will dig out some 64 gn projectiles and start playing. As it didn't like 55s I didn't go heavier, however I read on another forum where is was a regular outcome not liking the 55s. I have been using 748 with the 53 bthp, and what are your recommendations for 64grainers? Many thanks for your advice.
Ruger7mm

I find the 62gr Hornady soft points shoot very well in my 527, better knock down power than the 55gr on goats and deer.

I actually thought they were all 1:12 twist until 2012...

I have one from 2008 too, and it shoots 45 grain tsx and 55 grainers very well and also the 70 grain Speer.

My take off is stamped 1:9 from the factory, not sure what date.

Thanks for the replies everyone, I'll be trying a few 60-64 gn projectiles in it to see how it goes. I'll report back.
Cheers
Ruger7mm

Mine shoots the 68gr HPBT Hornadies real good, but does not like the 69gr Sierras much.