The Idea. Barrel length is a hot topic of conversation for those who own a 6.5 Grendel as well as those wanting to own one. The most common question I hear is “Do you recommend an 18″ or 20″ barrel?”. I’ve always felt that the ideal barrel length really depends on the primary application. To determine if a certain barrel length will suite your needs though, you’re going to need performance data. What velocity will I get with a certain barrel and load? How much energy will my bullet have at a given range? How much do I gain or lose by going from one length barrel to another? That’s the point of this project. To gather and ultimately share data in a format that you’ll hopefully find useful.
The Plan. What I’ve decided to do is take the four most common lengths of 6.5 Grendel barrels and shoot through them the eight most common and readily available factory loads on the market to see how they perform. Measure velocities, calculate energy and trajectories and then post the results for you to reference. I’m not sure if this has ever been done before, but I haven’t seen anything quite like it. The barrels I’m using are 16″, 18″, 20″ and 22″ Liberty barrels made by Satern in Iowa. The ammunition I’m using is listed below.
- Wolf Military Classic (Steel) 100 grain FMJ
- Hornady American Gunner 123 grain BTHP
- Hornady Black 123 grain ELD-M
- Hornady Custom 123 grain SST
- Federal Fusion 120 grain SP
- Federal American Eagle 90 grain TNT JHP
- Federal Gold Medal Berger 130 grain OTM
- Federal American Eagle 120 grain OTM
Just as a quick note, none of this is meant to be definitive. I plan to run my tests through several barrels of each length, but whichever barrel you have might perform a little bit differently. Your elevation, temperature and barometric pressure will vary from my testing conditions as well. I wouldn’t argue with someone who has measured results different from my own. But hopefully I can find some good bits of data that will be useful to you.
First Range Trip. The first step in my project was to collect velocity data. On my first range trip, I fired five rounds of each of the above eight loads through my chronograph with the 16″, 18″, 20″ and 22″ barrels. It’s worth pointing out that a mere five rounds per load per barrel is going to be far from conclusive evidence of much of anything, but this is only the first range trip.
Results. Since the data collected so far is such a small sample size, I’m going to wait until I’ve taken a couple more trips to post most of the information. But let me share a couple of things I found. It’s not going to come as a surprise to you that the fastest average string came out of the 22″ barrel with the Federal American Eagle 90 grain TNT’s. Those came in at 2,965 FPS. The slowest average string came out of the 16″ barrel with the Federal Gold Medal Berger 130 grain OTM. Those measured 2,272 FPS. Again, no surprise. But it’s still interesting how a difference in barrel length and load can change the measured velocity so drastically…in this case by nearly 700 FPS. I also noted that when averaging all of the loads, velocity increased about 25 FPS per inch of barrel length. There’s much more data to collect, but day number one was a good start.