Subsonic 308 question

[sic65stang]

I currently load 10.5 trailboss for an 18" 308 for subsonic. I am going to begin to work on a load for a 24" 308 and I am wondering if I start at the 10.5, more? less? Wouldnt the BBL legnth increase the MV or because of the trailboss would I need to put in more powder? Thanks for any thoughts.

 

[bohem]

Subsonics can be fussy from rifle to rifle. When I change barrels I recheck the subsonic loads by starting high and working down to the previous load. Having to hammer out a stuck bullet sucks big time so a modicum of caution will pay dividends over the first time you have to do this.

I'd suggest starting at 11.2-11.4gr and working back down. You're likely going to have a different accuracy node on the subsonics in the 18 vs. 24 inch barrel anyway, so it's not out of the question to do the work from scratch to start.