barrel length questions

DarryH

Private
Full Member
Minuteman
Mar 9, 2005
3
1
Omaha, Nebraska
I am considering a .224 Valkyrie rifle. This will mostly shoot paper or steel at ranges 600 yards and beyond. Leaning towards a bolt action, possibly Mossberg's new gun. Will a 20" barrel get all available velocity or will I need 22" to 24" ??? initially factory loads, then reloads. Thank you.
 
For factory loads you will need all the length you can get to squeeze out FPS. In my opinion 24" is the minimum. I have a 26" on my Valkyrie bolt gun. Factory Hornady 88s are averaging 2724fps. I'm working on a load for the 95gr SMKs one node is right at 2700fps and I haven't hit and pressure signs yet pushing over 2750fps.
 
I've read quite a few studies/ experiments on this topic, and it seems that barrel length vs. velocity is affected differently between not only different cartridges, but also different powder/bullet combinations within cartridges. Short answer that i've found is more than a 20in. bbl is probably needed but maybe not a 26in. if you are reloading. If you reload, you can use a faster burning powder in a shorter barrel and get your velocity up vs. a slower burning powder. In other words, yes a longer barrel will give you more velocity because you can use a slower powder and put more of it in your case or ensure that all powder in factory loads is being burned before the bullet exits. Silencer Tech did an interesting experiment the other day with a 6.5CM and actually got more velocity at 24in. than they did at 26in. and 25in., but that was just one bullet/powder combination.
 
Not sure if this is still something you are following but I ended up with an 18" Ballistic Advantage 1:7 twist barrel on my 224V. I mainly run suppressed so overall length was my biggest consideration. I reload so I am able to get 2750 out of my 18" barrel running 82gr Berger's. On a recent trip I was able to get a few hits at 1100 yards. That is right at transonic distance for me according to Applied Ballistics app.