A .308 rifle with a 1:11.25" twist rate is actually right in the sweet spot for medium-weight bullets, but it can still handle a broad range.

Here's how it breaks down:

Lighter bullets (147 155 gr)

This twist will stabilize them fine, but you may not get the absolute best long-range performance compared to a faster twist because lighter bullets lose velocity and energy quicker in flight.

At short to mid ranges (inside ~600 yards), they'll perform very well and often give higher muzzle velocity and flatter trajectory.

Medium-weight bullets (165 175 gr)   Ideal for 1:11.25

This is the weight range your twist is optimized for.

Bullets like the 168 gr SMK or 175 gr SMK are extremely popular in precision .308 rifles with this twist, balancing stability, accuracy, and wind resistance.

Heavier bullets (190+ gr)

The twist can stabilize some heavier match bullets (up to ~190 200 gr), but as you get heavier, you may see reduced velocity and possibly less-than-perfect stability, especially at lower temperatures or longer distances.

If you consistently shoot heavy bullets (200+ gr) or subsonics, a faster twist like 1:10 would be preferable.

Bottom line:
Your 1:11.25" twist will perform best with medium-weight bullets around 165 175 grains.
If you want maximum versatility and longer-range stability in .308, 175 gr is a safe bet. If you're shooting under 600 yards and want speed, 155 168 gr will shine.

If you tell me what your target distance is, I can recommend an exact grain weight and bullet type for your setup.

Originally Posted By Vikingsouthpaw:
That is an oddball twist rate.  It was developed to shoot 155 gr. Palma projectiles on National Match Courses.  It may be too slow.