6.5 Grendel vs. 6.8 SPC

[awittmer]

I have never seen a 6.5 bolt gun, but would be interested in knowing if one is made. Is there a special reason you want to go with a bolt vs the AR platform? I believe some custom shop could make a 6.5 bolt gun for you but the money factor might not be pretty.

I have no real reason as to why i would want a bolt gun over an AR platform, just think it would be unique. Although the cost im sure is going to be much higher for a bolt gun, but who knows! im going to my local gunsmith tomorrow to get prices on both an upper for an AR platform as well as possibly pricing out a bolt gun!

 

[melensdad]

. . . I heard that the short comings of the 6.8 had been addressed by twist rate and tweaking loadings. You guys are saying the 6.8 is still a Volvo?

Good follow up questions.

"Is the 6.8 still a Volvo": Yes. That is simple math. The ballistic coefficient of the 6.8 115 grain bullet is only .340. The holy grail in aerodynamics is to have the bullet over .500 for its ballistic coefficient. That means the bullet is very aerodynamic. The standard 123 grain bullet for the Grendel starts out at .542 for its BC. In simple terms .340 = VOLVO or flying brick, but .542 = F1 race car.

As for the "twist rate" question: It is true that by slowing down the twist rate of the barrels they have decreases pressures a bit and that allows for a slightly hotter load. But that means a couple things. First, the recoil energy with the hotter load gets even worse, the standard 6.8SPC load already had more recoil energy than the weak in the knees 5.56 mil-spec rounds, pump it up and it generates even more. Secondly even with a SLIGHT velocity gain, you are still pushing out something with the aerodynamics of a late 1970's Volvo 240 DL sedan. So you are still pushing a brick through the air and expecting it to perform. Not gonna happen.

Now the simple solution would be to put a longer bullet into the 6.8 SPC but the case, being long and skinny, can't accept a long 270 caliber bullet and have it seat/crimp/fit properly because the shoulder it too far forward in an attempt to gain more powder capacity.

So what you have in the new "hotloaded" or some might call it "improved" 6.8SPC is a round with additional recoil energy when compared to the 6.5 Grendel, that pushes a short fat bullet pretty hard for the first 200 yards and then it dramatically slows down and runs out of energy.

Simply looking at the energy levels of the two rounds in question its pretty simple to pick the Grendel over the SPC.

ENERGY FIGURES PER ROUND FOR EACH CALIBER:
YDS - 6.5 Grendel - 6.8 SPC - 7.62NATO
100 - 1609# - 1498# - 2084#
200 - 1397# - 1191# - 1779#
300 - 1206# - 938# - 1509#
400 - 1037# - 730# 1274#
500 - 888# - 565# - 1072#
600 - 758# - 440# - 899#
700 - 646# - 352# - 756#
800 - 550# - 294# - 639#
900 - 471# - 256# - 570#

Sorry that a hand typed chart doesn't format really well but you get the idea.

The BLUE numbers indicate the approximate range where the bullet falls below the 1000 foot pounds of energy number. For the 6.8 SPC that distance is roughly 250 yards. For the 6.5 Grendel its roughly 450 yards. So you get almost TWICE the ethical hunting distance out of a Grendel as you get out of the 6.8SPC.

The RED numbers indicate the distance at which the range falls below the military standard of 500 foot pounds of energy. I guess the military figures that 500 # of energy will disable a man but hunters figure that 1000 # of energy will cleanly kill a typical game animal? Anyway the 6.5 Grendel's effective military range, using the 500# of energy number, is 850 yards while the 6.8SPC can muster only 550 yards.

All of these are compared to the 7.62 NATO, 175 grain round.

 

[awittmer]

What twist rate would you recommend for a grendel 22inch barrel as mostly just a bench gun?

 

[melensdad]

What twist rate would you recommend for a grendel 22inch barrel as mostly just a bench gun?

Alexander Arms, the developers of the original 6.5 Grendel provide us the answer to this question. On their shorter barrel guns they offer barrels with twist rates of 1:8 and on their longer barrel guns they run the barrels with a twist rate of 1:9. Their logic for this is actually very interesting, they argue that the longer barrels produce higher velocity and to stabilize the bullet at the higher velocities they slow down the twist rate to 1 turn in 9". They recommend this twist rate for bullets between 90 and 130 grains (which seems to be about 98% of the Grendel loads).

For consideration, they do not test their 6.5 Grendel guns for grouping sizes at 100 yards, but rather test them at 200 yards. They also suggest that a bullet stabilized for 200+ yards may still be in the process of stabilization at distances as short as 100 yards, especially for the longer, heavier bullets. Long heavy bullets take longer to stabilize and the twist rate required to stabilize it at 100 yards, they argue, would not be suitable for long distance shooting accuracy. As you are asking about a 22 inch barrel and bench shooting then I can only presume you are looking for a gun barrel that would put small groups on target at long range.

 

[malern28us]

My yellow Grendel has a 19" barrel, which is the shortest barrel I own in that cartridge. The Grendel picks up velocity with barrel length and while it still puts out a whole lot more energy than the 5.56 out of a short barrel that is not what I personally wanted. I'd think a 16" barrel Grendel would be a great pig gun out to about 300 yards, but out of a 19" barrel it probably is a great pig gun to 400 yards. Me, I don't shoot that far (yet) but when I started playing with the Grendel cartridge it was because I really want to try to push out to 600 yards and beyond.

As for reloading, no you don't need to reload. Wolf offers a 120 grain MTP round that can be had for about 75 cents a shot and it delivers pretty darn good accuracy. Their 123grain jacketed soft point would be suitable for deer size game and is accurate enough for hunting, its probably a 2 MOA round and I've gotten that for 50 to 60 cents a shot (depending on the deal, quantity ordered, etc).

Actually, out of a 16 inch rifle the 6.5 and 6.8 are almost identical twins out to 300 m. Its with the longer barrel lengths the 6.5 has a big advantage. I dont shoot past 300 meters currently and dont want to carry a 20 inch barrel AR just to have a long distance advantage.

 

[melensdad]

Melensdad- Do any of your 6.5 rifles have a 16 inch or under barrel length? If so how does it perform? I've researched the 6.5 grendel, and it sounds like a great cartridge, I just need to learn to reload.

My yellow Grendel has a 19" barrel, which is the shortest barrel I own in that cartridge. The Grendel picks up velocity with barrel length and while it still puts out a whole lot more energy than the 5.56 out of a short barrel that is not what I personally wanted. I'd think a 16" barrel Grendel would be a great pig gun out to about 300 yards, but out of a 19" barrel it probably is a great pig gun to 400 yards. Me, I don't shoot that far (yet) but when I started playing with the Grendel cartridge it was because I really want to try to push out to 600 yards and beyond.

As for reloading, no you don't need to reload. Wolf offers a 120 grain MTP round that can be had for about 75 cents a shot and it delivers pretty darn good accuracy. Their 123grain jacketed soft point would be suitable for deer size game and is accurate enough for hunting, its probably a 2 MOA round and I've gotten that for 50 to 60 cents a shot (depending on the deal, quantity ordered, etc).

Actually, out of a 16 inch rifle the 6.5 and 6.8 are almost identical twins out to 300 m. Its with the longer barrel lengths the 6.5 has a big advantage. I dont shoot past 300 meters currently and dont want to carry a 20 inch barrel AR just to have a long distance advantage.

As for the ballistic data out of a 16" barrel comparing a 6.8 to a 6.5 the edge still favors the 6.5 for several reasons. First the 6.5 offers a much wider range of bullet weights and bullet choices. Some say they are roughly equal out to 300 meters the reality is that in every weight compared out to those ranges, the 6.5 offers better ballistics and a wider choice of bullet construction for target, hunting or defense. The 6.5 still delivers more energy and more velocity, even if the differences are not as large as when compared in longer barrels. The military charts posted below are showing data using 16" barrels.

While some folks don't want to carry a 20" barrel, there are people asking questions about even LONGER barrels. One of the beautiful things about the 6.5 Grendel is that it is a good round out of most any barrel length you can shoot it through. It is a very versatile round; that is probably why so many Grendel owners have guns in MULTIPLE barrel lengths.

Its also interesting to see that some of the folks here are looking to build bolt action 6.5 Grendels, I'd guess those would be most common in barrel lengths in the 18 to 20 in range if they are hunting bolt actions. But interest in bolt actions for the Grendel shows even more of the versatility of this round and the appeal goes beyond the tactical and target gun crowds.

Its pretty rare to find a round that works as a 16" CQB battle round, a 400 yard Elk round, 1000 yard target round and has recoil mild enough to be comfortably shot by a teenage girl. The 6.5 Grendel does all that

 

[malern28us]

I would refer you to the 6.8 FAQ section at Innovative Tactical Systems LLC, Made in USA, AR 15 uppers, piston operated tactical upper, 5.56, 6.8spc, custom precision barrels if you are saying there isnt any bullet selection for the 6.8. Someone was even nice enough to line them all up and take a picture.
Btw, how does the 6.5 perform out of a 10.5 barrel in a CQB platform?
I would also question how old is the data you post? Is it before the 2 recent changes to the 6.8 chamber? Were they measured from a 6.8 with a 1:11.25 twist? Testing has shown that the twist of the barrel greatly affects the 6.8

 

[awittmer]

While at a local gunshop this weekend, talked to a gentlemen who had a great knowledge and was a good source of information. I was originally interested in a 6.5Grendel in a Bolt gun. This gentlemen refered me to a website for a company out of Seymour,IN. This company integrates a bolt action gun into the AR platform, i believe they use a Remington 700 action for their guns.
Anyways....
Here is the website
“The Original Tube Gun”

Also Refer to another website:
6mmbr.com for information on the Grendel as well as other cartridges.

 

[melensdad]

While at a local gunshop this weekend, talked to a gentlemen who had a great knowledge and was a good source of information. I was originally interested in a 6.5Grendel in a Bolt gun. This gentlemen refered me to a website for a company out of Seymour,IN. This company integrates a bolt action gun into the AR platform, i believe they use a Remington 700 action for their guns.
Anyways....
Here is the website
“The Original Tube Gun”

Also Refer to another website:
6mmbr.com for information on the Grendel as well as other cartridges.

You may also want to consider the TUBBS rifle. David Tubbs is the holder of many different long distance records and designed a rifle that is very similar to the TUBE GUN rifle. Here is his website => DavidTubb.com.html

Realize that the TUBE GUN and the TUBBS rifle look like an AR15, they are not AR15 based guns but rather are guns in and of themselves. Awesome guns for target use, I may add.

 

[Scotmak]

neither of these are legal for deer hunting thought, right?

 

[dross]

neither of these are legal for deer hunting thought, right?

Out here in Colorado, they are.

 

[melensdad]

neither of these are legal for deer hunting thought, right?

They are not generally legal for deer in Indiana. If you have your own land and a DNR depredation tag you can use them but that is not available to the general public.

 

[neraph]

They are not generally legal for deer in Indiana. If you have your own land and a DNR depredation tag you can use them but that is not available to the general public.

Or you could build an AR pistol.

 

[worksalot]

I would pick up the 6.5 grendel wait I already did. I love my grendel but I like the extra range.