Daniel, this Ruger RPR has a thread pitch of 5/8x24. Barrel = 20" 4140 Chrome-Moly Steel Cold Hammer Forged Barrel, Medium Contour Profile, 1:10" Right Hand Twist Rate, 5R Rifling and thread pitch of 5/8x24.

308 model or he Ruger Precision has 5/8 X 24 threads. Its quite a shooter, and gets some very good reviews.

5/8"-24 see ******StockFolding, Adjustable Length of Pull and Comb Height
FinishType III Hard Coat Anodized
Barrel Length20"
BarrelCold Hammer-Forged, 5R Rifling
*******Thread Pattern5/8"-24
Twist1:10" RH
Grooves5
Weight9.8 lb.
Capacity10
Height7.30"
Overall Length39.25"-42.75"
Length of Pull12" - 15.50"
Folded Length31.60"
Width3.30"
Suggested Retail$1599.00
ruger.com/products/precisionRifle/specSheets/18028.html

5/8 24