Need ammo selections for my .223 CZ527 Carbine.

[HogSniper2]

I bought a CZ527 Carbine in .223 for groundhogs.  Everything about this rifle is great (this coming from a longtime Remington rifle owner/user).  Except trying to get it zero'd.  It seems it doesn't like the heavier grain ammo.  This is what I've tried at 100 yards: Win USA 55 gr., Rem 55 gr., and Amer. Eagle 50 gr.  I'm thinking with the 1:9 twist a box of lighter Hornady 40 gr. V-Max should do better.  Is it possible this particular model rifle prefers a lighter grain or were my Remington 700's (which I know have longer barrels) just dead-on accurate?

[jeclif]

I thought the carbine was 1 in 12 twist

[Badnews Bob]

It is only the kevlar varmit is 1-9. Your carbine is probably gonna shoot the 45 to 55 gr rounds the best, The 40s might just be the ticket. Give the winchester white box a go they seem to shoot good outta most anything.

[mcwoodduck]

Try the RFemington/ UMC 45 grain JHP.  They come in a 200 pack and work great out of all three of my 223's.  None are a CZ yet but one is on the list. 
How do you like your carbine?

[HogSniper2]

Well, it appears this little carbine likes the lighter grain rounds.  Here's my target with the 40 grain Hornady V-Max.  This is the best I can do.  I know afterwards two groundhogs weren't too happy with the accuracy.  The longest shot was paced off at 155 paces.  I'm not sure how much further it could reach accurately.  And your right, the twist is 1:12.  I had a 50/50 shot at the right answer and choose the wrong one.  I'm beginning to like this rifle over my Remington's.  The single set trigger is unbelievably light.  Too light if you're not ready.