A modification of the original Mk12 SPR, the Holland rifle features a shorter barrel and collapsible carbine stock. The Douglas Stainless Steel barrel was used by US Navy and USMC on Mk12 Mod 0, Mod 1 and Mod H rifles. The Douglas barrel is match grade button broached stainless, handcrafted by Compass Lake Engineering specifically for Charlie's. Compass Lake (CLE) makes some of the best match grade profiled barrels, and historically has been a supplier to the US Military during the Global War on Terror. The Douglas barrel has a CLE chamber, which is very much like a 5.56 NATO or .223 Wylde, but crafted for precision shooting.
If you are outfitting a Mk12 Mod H, then Charlie's is your spot for all things Mk12.
The profile on the Mod H Douglas barrel is made to accept an Allen Engineering short or long collar and muzzle brake. If Ops Inc. #12 style suppressor is anticipated, it is recommended that the brake be installed with the suppressor to check the alignment and the distance. AEM5 suppressors are made to certain tolerances, and Allen Engineering provides shims and a spacer to time the suppressor to the brake.