One of my closest friends has two 6.5 Creedmoor rifles made by Surgeon Rifles that he has tried a couple different barrel sizes on. He started with a 26″ barrel, because that is what Surgeon typically used but lately we’ve been shooting in more practical/tactical long-range competitions where you have to carry the rifle for miles every day … so he wanted to lighten the load. He was also planning to add a suppressor to his rifle, and a 26″ barrel + 9″ suppressor makes for a pretty long and cumbersome rifle. He eventually rebarrelled to a 22″ barrel, which he loves. Both of the barrels were big, heavy, Krieger #10 contours with 1:8 twists (and both rifles could shoot 10 shot groups under 1/2″ … mostly in one ragged hole).
He mentioned that he’d searched online to see what barrel lengths people were using for the 6.5 Creedmoor cartridge and get an idea for what kind of velocity he would be sacrificing, and saw a lot of debate … but not a lot of helpful information. The new Berger Bullets Reloading Manual said you could expect a change of about 25 fps per inch (see excerpt image). So he was expecting 100 fps loss, but that is not what happened. So we thought it’d be helpful to share what he found. He regularly shot each barrel length over an Oehler 35P chronograph, which is a professional grade chronograph and one of the most accurate ones made. He kept really good documentation on the velocities, and here is what he found.
6.5 Creedmoor with 26″ Barrel
This is the original configuration he tried, because it was the one Surgeon typically makes. Here are the velocities he found:
- 2805 fps – This was his muzzle velocity was out of a brand new barrel (without a suppressor attached)
- 2860 fps – His barrel sped up a little as the barrel broke in, and this is what his muzzle velocity was after 1,200 rounds out of the 26″ barrel (again, this was without a suppressor attached). This is the point where he rebarrelled, but he inspected the the barrel guys with a borescope with a professional gunsmith at Surgeon and based on the barrel wear they estimated this was about 1/2 way of the accurate barrel life.
6.5 Creedmoor with 22″ Barrel
- 2760 fps – This was the 1st velocities recorded with the brand new 22″ barrel (without a suppressor attached). He was ecstatic to see this, because he was expected more than 100 fps of velocity loss with 4″ less barrel, based on the estimates in Berger’s new reloading manual.
- 2805 fps – This is what he is now getting after 800 rounds, with the barrel completely broken in and no suppressor attached.
- 2833 fps – He has since started using a Thunder Beast 30P-1 suppressor with his 22″ barrel, and the added 9″ of length the suppressor adds has helped his muzzle velocity a little as well.
So ultimately, after he added the suppressor he only lost 27 fps with 4″ less barrel. That essentially means he only has 2/10 more vertical adjustment of a mil at 1,000 yards, and wind drift is virtually identical. In return he has a lighter, more maneuverable rifle … and he couldn’t be more happy with that trade.