I am just getting into this and am wondering what is the best barrel lenth for the
7mm-08 cartrige I am assuming since it is a .308 case a longer barrel will not be required to get maximum performance.
I think 20 to 22 inches is the best length for handling and velocity. A few more inches will net you a bit more FPS but not near what you think, like 25 FPS per inch. A lot of that depends on what powder is used.
I read an article a few years back that took a 7mm 08 with a 26" inch barrel and shot 10 rounds (I believe) and averaged the velocity and then cut 1" off the barrel and recrowned and then shot 10 more and averaged etc. They went down to like 18" one inch at a time. I remember doing the math in my head and it worked out to just 17 fps per inch velocity loss with the largest losses comming as the barrel got shorter. Even getting down below 20 inches the losses were only 25 FPS or so.
I had always believed that the losses were much greater and that article changed my mind. I really liked this evalution because it was from the same barrel with the same ammo so that variable was eliminated.
I would personally go with a 22" barrel if it is a carry rifle.
I read a few article where they take an inch off and compare velocities, they only used one load to check though. Would it make a bigger difference if they used a slow powder AND a fast powder load? Seams like this would be a fairer way of checking lightbulb
The optimal speed powder used for a 24" barrel would still be the optimal speed powder for a 18" barrel. The faster powder than optimal speed powder would be slower at 24" and at 18". However, at 18" the faster powder would give far less of a fireball and that might be desirable even if you give up 50 fps.
I ordered my ULA w/a 24". When it came time to replace the barrel I went to a Pacnor 25" for improved balance.
There was no noticeable velocity increase using the same 140 TSX/Varget combination. Accuracy, on the other hand, went from 7/8" to 3/8". Nothing to do with barrel length, just an exceptional barrel for a hunting rifle.
My load chronos at an average of 3008 fps @ my home elevation of 6803'.