Range Report - 6.5 Grendel PDW 7.5 Inch Barrel - Printable Version +- 6.5 Grendel Forum (https://65grendel.com) +-- Forum: 6.5 GRENDEL DISCUSSION FORUMS (https://65grendel.com/forumdisplay.php?fid=3) +--- Forum: 6.5 Grendel ARs and Other Semi-Autos (https://65grendel.com/forumdisplay.php?fid=8) +--- Thread: Range Report - 6.5 Grendel PDW 7.5 Inch Barrel (/showthread.php?tid=23161)

Range Report - 6.5 Grendel PDW 7.5 Inch Barrel - depletedyourcranium - 04-05-2021 Here's my quick range report on my PDW-Grendel build from the other thread. I decided to do a new thread since that last one was getting side tracked by a yet another caliber war... Anyway, over the weekend I was able to do some initial testing of the barrel and got some chronograph data with a couple of loads. Although the total barrel is 8.5 inches, I'm going to refer to it as a 7.5 inch barrel from here on out since that's the actual length from the breech to the end rifling surface and most accurately describes it's performance, that way no one is going to confuse these velocities with a proper 8.5 inch barrel... if anyone ever goes that route. Here's a pic of the setup to give you an idea on just how short the overall package is: 16.25 inches folded 24.5 inches to the first brace position. 26.5 inches with the brace fully extended. Now, onto the data. All shooting was done from the prone, bag supported on the rail, chronograph positioned about 10 feet from the muzzle. Chrono was a Caldwell Ballistic Precision with the wings installed. Temps were about 50°F, elevation about 1400 above msl. No idea on pressure or humidity or anything like that. Hornady Black 123 grain ELD-M: 1917 1914 1917 1890 1919 Mean Velocity: 1911 fps SD: 15.09 Hornady American Gunner 123 grain HPBT 1868 1910 1909 1911 1849 Mean Velocity: 1889 fps SD: 29.00 Wolf Military Classic 100 grain FMJBT 2090 2162 2113 2141 2182 Mean Velocity: 2138 fps SD: 33.01 Another note on the Wolf load, I did some more shooting through the chrono later and the Wolf seemed to either measure right around 2050 or 2150 and not much in between. Goes to the general QC issues we've all learned to expect from the steel case imports. So anyway, as far as these numbers it tells me that 7.5 inches is the absolute shortest I would consider going in 6.5 Grendel. I was expecting pretty low velocities but hoping for maybe 100 fps faster than what I was getting. Perhaps a 5r rifled barrel could have got these up another 50 fps. For my purposes with this gun and what I got the barrel for, I'm still likely within a level of terminal effectiveness and range I'm satisfied with for such a small package... but just barely. Essentially it's the same power level of an M1 carbine at the muzzle and will carry a little more energy downrange than one. Considering this was replacing a 9mm PCC in this role, for me it's nice step up in power and moderate increase in range at the cost of a little weight and lots of noise/flash. Speaking of muzzle blast, which is pretty difficult to objectively quantify... so far it wasn't as bad as I was expecting. I wasn't getting that teeth jarring concussion that you typically get with something like a 5.56 pistol and it seemed comparable to shooting my 12 inch Grendel, though I didn't shoot it that day. I did notice the blast a lot more in prone, there was significant kick up of debris but, again, I didn't shoot my 12 that day to compare. The only time I noticed significant flash in my sight picture was with the Hornady Black ELD-M, and it was huuuge. I was shooting outdoors in the daylight but I was in the shadow of the hill around 1800 local, so it was a little dim all around. The Hornady AG and the Wolf MC did not have that effect and the flash went pretty much unnoticed. Here's the best image I could get of the flash from a video clip of me shooting. I'd say, at least with the Wolf MC I was shooting in the vid, it was pretty comparable to the 12 inch: Range Report - 6.5 Grendel PDW 7.5 Inch Barrel - depletedyourcranium - 04-05-2021 Now, on to some quick groupings. I didn't spend a lot of time (or ammo) doing this as this is far from a bench rest build but I wanted to be able to extrapolate what I could expect down range from each of these loads. I was only shooting at a limited 30 yards with a circle dot Holosun and milspec trigger, so it's still not a great representation of mechanical accuracy... but I shot prone from a rest with the brace supported so it was fairly stable. 3 shot group with Hornady Black - 2.1 MOA. I know I pulled that left shot, so it should have been a little tighter than what you see here... probably closer to 1.5 MOA. 3 shot group with Hornady AG - 2.3 MOA. I've never gotten good groups out of this stuff with almost anything. Usually marginally better than Wolf. I typically don't do 3 shot groups for accuracy testing... 5 shot groups are where its at. However, given these unprecedented times I chose to save a little ammo and sacrifice my values here. I did do 5 shot groups of the Wolf MC, though as I have much more of the stuff. 5 shot group with Wolf MC - 2.5 MOA. This is typically what I get out of the Wolf MC in most barrels, so that's good. This is primarily (like most of my guns) a steel case blaster so I'm pleased with that. So, bottom line I think is that this is bottom end on what a few people would consider for 6.5 Grendel for velocity, and below what many would consider at all. This would get you expansion on most modern hunting bullets only to about 200 yards, so you're losing quite a bit of range to even a 12 inch barrel. Moreover, if you're in the suppressor game I think that 7.5 inches would fall below what most cans are rated for. So overall there's not a great use case for going this short. It does handle well, but so does my 12. It does fit in my bag now without being broken down... but honestly you're probably be better off just getting a bigger bag than a small barrel. I didn't chronograph my 10.5 inchers that day, that's probably my next step to give me that in between piece of data between the 12s and the 7.5 inch. Range Report - 6.5 Grendel PDW 7.5 Inch Barrel - BluntForceTrauma - 04-05-2021 Fun stuff! Cool experiment. Eye-opening when compared favorably with a .30 Carbine. Range Report - 6.5 Grendel PDW 7.5 Inch Barrel - BlogSarge - 04-05-2021 Thanks for taking the time to compile this. I like the short ARs (I have a 5” 9mm, 6” and 8” 300blk) for handy, close work. Many folks note that you are limited to ‘just’ a few hundred yards with them before you are unlikely to get expansion. But seriously, how many realistic situations will we get into when we need to go farther? And at farther ranges, at least you can still put hits on target but with less expansion. That’d just be like using FMJ, but still, hits are hits at crunch time. Nice looking build, and ideal for your close range blaster. Range Report - 6.5 Grendel PDW 7.5 Inch Barrel - kmon - 04-05-2021 Looking good, figured blast and flame would be more and that is a pretty good ball out there in the shade. If I were using this for defense or hunting, te 129gr LRAB that expands down to 1300 and really expands well at 1500 would be a good choice, give up probably 100 to 150fps but get more expansion with secondary projectiles in the target object. Range Report - 6.5 Grendel PDW 7.5 Inch Barrel - A5BLASTER - 04-06-2021 Congrats on the grendel sir. Fold those brace ears in and the brace will shoulder and bag much better. Range Report - 6.5 Grendel PDW 7.5 Inch Barrel - James Young - 11-30-2022 Thanks for sharing this. I have been looking for info on short barreled Grendels below 10". Is the barrel 7.5" or 8.5" by the normal way you'd see it retailing? Like a listed 18" barrel, would be what by your standard? The velocities are certainly lower than I had hoped. I had estimated 7.5" to have ~2,040 with 123gr. Range Report - 6.5 Grendel PDW 7.5 Inch Barrel - LRRPF52 - 11-30-2022 That is cool. I’ve been thinking about a 9” Grendel PDW, currently finishing up a 10.5”. I used a Honey Badger PDW kit on mine, just needs to be Cerakoted. Everything else is already Cerakoted FDE. I’m at 24” Collapsed with no muzzle device. It’s been in the works for years, just haven’t had it at the top of my list. If you can get any 90gr TNT Federal factory load, try that.