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Reflection on the 6.8 SPC II

2.9K views 16 replies 4 participants last post by  Dallas53  
#1 · (Edited)
:beatingdeadhorse:
I own a 6.8 SPC II upper. I considered trading it off to consolidate calibers, but decided to think through it a bit more before casting it aside. In the end, I chose to keep the upper.

Objection 1: why own a 6.8 SPC II at all? An AR-10 .308 hits harder, reaches further, and with the .30 cal, "there's no replacement for displacement".

Reply 1: what is the intended purpose for the rifle? If the purpose is a hunting rifle for deer and smaller, the 6.8 SPC II is effective beyond 300 yards. In the places I hunt, there are only a finite number of places which offer even a 200-250 yard shot. Therefore, the 6.8 can kill any deer within my hunting radius. It also does so with less recoil, shares a really nice lower, and weighs less than the AR-10.

If hunting and shooting really long range, go .308 (or .260). Basically, not 6.8.

Objection 2: the bullet is smaller than the .308, you're giving up wound size

Reply 2: The .270 (.277) is a well established hunting bullet. The bullets will rock the critters. In addition to wound size, you also give up recoil. Shot placement is #1 priority. If you're flinching with the AR-10, you're going to miss more shots.

Objection 3: The ballistics suck compared to the 6.5 Grendel, why not just go 6.5 instead of 6.8 and get the better ballistics.

Reply 3: the ballistics advantage of the 6.5 Grendel is real. Again, what is the intended purpose? If punching paper, or ringing gongs, the 6.5 has an advantage. If hunting, the 6.8 has a better bullet selection, and factory ammo availability.

Objection 4: it's too expensive to shoot, the .308 and 5.56 is cheaper.

Reply 5a: What is the intended purpose? If buying quality hunting ammo (Like Hornady), the 6.8 is the same or less expensive than .308 when ordering off the internet. The 5.56 is less expensive. If hunting, will 1 box of premium hunting ammo per year break your bank? If the intended purpose is tactical, plinking, or target shooting, 5.56 wins hands down.

Reply 5B: the 6.8 has a large selection of quality bullets for reloaders. Not so much for the 6.5 Grendel.

Objection 6: 6.8 ammo is hard to find

Reply 6: so is .22LR, so what? 6.5 Grendel is not carried at the local Walmart either. Most of the big-box store ammo that is carried is garbage anyways, and it's expensive for what you get. Go to ammoseek and you'll find decent prices.

Objection 7: Now there's another caliber to be stocked. It's not efficient or good.

Reply 7: when ammo is available, it can be ordered and mailed to your doorstep.
When there's a run on ammo, the 5.56/.308 guys have much more heartburn keeping rifles fed.

Objection 8: the caliber doesn't seem very accurate.

Reply 8: Even "if" true, a 2 MOA gun will put bullets into a 6" diameter circle at 300 yards.

Objection 9: there are not the ammo choices out there like there are for 5.56 or .308

Reply 9: there is a reasonable selection of components and factory ammo. Even if an "ideal" pet factory load is not found, a 1.5" grouping rifle is still sufficient for hunting to 300 yards. For punching paper, handloading is the way to go. That said, if focused on punching paper, the .308 and 556 shine in spades 6.5 Grendel if you're primarily a target shooter AND a reloader. There's less 6.5Grendel than 6.8 SPC ammo on the shelves.
 
#2 ·
Reply 5B: the 6.8 has a large selection of quality bullets for reloaders. Not so much for the 6.5 Grendel
IMO, to be an effective "hunting" round the 6.8 needs to use bullets 115gr or less and be designed to expand at it's anemic velocities. That rules out most of the .277 hunting bullets and leaves only a few.

Barnes has come to the 6.8 rescue and manufactures a few, the rest, not so much.

Looking at Midways .277 bullet selection It appears that without "Barnes" there are only 3 other bullets that will Hunt in the 6.8, 110gr Pro Hunter, 90 and 100gr Nosler.

I have my doubts about the 110gr Pro Hunter, If it was designed for the 6.8 great, but it is a 270 Win bullet then it is designed for much higher velocities then the 6.8 can produce.

IMO, the 6.8 suffers from the same lack of Hunting bullets as does the Grendel, maybe even more so.

http://www.midwayusa.com/s?targetLo...A1%2Ccustomertypeid%3A1%29&Nrpp=48&Ns=p_metric_sales_velocity%7C1&Ntpc=1&Ntpr=1
 
#3 ·
It's important to ask first, what is the maximum distance you Need to shoot?

If your hunting is realistically 100 yards, velocity isn't much of a concern

My understanding is that the velocity will be in the 2000 fps range at around 250 yards.

Looking at this chart of .30 bullets (I'm making the assumption the expansion velocities are similar), it looks like 1900-2000 fps is the point where some bullets aren't expanding

http://stevespages.com/jpg/bestbullet.jpg

Second is the actual application. To the concern there's not enough bullet options for the hunting application:
How many different hunting bullet options are necessary to find one that's able to achieve ~2.5" or better MOA in a particular rifle?

To use an analogy, I have a 444 Marlin and took 2 deer at 100 yards with it. At the range, it shoots about 2-1/4" groups. it's MPBR is about 225 yards. It's deadly and effective when used within it's limits. There's not a superabundance of hunting bullets for the 444 (most or pistol bullets), but there doesn't need to be. Find one that works, and go with it.

It's not a long-distance shooter, and it's not a 1/4" tack driver - nor does it need to be.

This is not directed at you mseric.

It's like the 30-06 guys who bash the .308 because it doesn't shoot 180gr+ bullets, the 45-70 guys who poo-poo the 444 because of some pistol bullets. I get the same feeling with the 6.8. People will ***** and poo-poo. It'll get the job done within its limitations, and the shooters.
 
#4 ·
I worked at a NASA satellite tracking station. Only one actual NASA guy there, the rest of us were contractors.

The NASA rep was a very smart guy ( which should go without saying ). He had a philosophy:

Never Lose Capability

If you have the ability to do a thing, cling to it. you never know when the need will come around again.

you have the capability to shoot 6.8 SPCII, bought, paid for, tested and proven. what would you gain by losing that?
 
#5 ·
If your hunting is realistically 100 yards, velocity isn't much of a concern

My understanding is that the velocity will be in the 2000 fps range at around 250 yards.
That would depend on a number of factors, Bullet weight and barrel length to name two.

Lets look at some actual load data for the 6.8.

Hodgdon lists bullet weights from 85gr to 115gr.
http://www.hodgdonreloading.com/data/rifle

Nosler lists bullets weights from 85gr to 115gr as well.

Lets narrow these bullet weights down to actual Hunting bullets by eliminating the Competition, Match and varmint bullets.

Looking at Midways site that selection becomes very limited.
http://www.midwayusa.com/up-to-130-grains/br?cid=22099

IMO, if you are going to hunt "deer" sized game with the 6.8, one should use a bullet designed for the 6.8 Velocities and that narrows the selection down even more.

Nosler data for the 110gr Accubond list a max velocity of 2543 fired from a 20 inch barrel. We can calculate (guess) on the bullet velocity as the bullet travels down range.

at 250 yards that bullet will be traveling about 1985fps.

If we reduce the barrel length to the more common 16 inch barrel, that 250 yard velocity is only, 1880fps.

it looks like 1900-2000 fps is the point where some bullets aren't expanding
So, with a 16 inch barrel, to maintain 2000 fps, you would have to stay under 175 yards for reliable expansion using a conventional bullet.

Now if you were to select a bullet that was designed for the anemic velocities of the 6.8, you could expect to increase that reliable expansion distance.
 
#6 ·
Several years ago I was in search of a .308 Whitetail bullet for my 7.62 x 39.

I found what I was looking for in the Sierra .308 125gr Pro Hunter, or at least I thought I did.

Looking at load data for other 30 caliber cartridges I found this same 125gr bullet being used in the Big Boys, the 300 Mag and the 300 Short Mag, pushing Muzzle velocities in excess of 3500fps.

I contacted Sierra and asked if this 125gr Pro Hunter would be good Whitetail bullet fired from a 7.62 x 39. His response was rather short, but to the point.

No, That bullet was designed for much higher velocities than the 7.62 x 39 can produce. It will work, but more than likely, it will not expand and just "pencil through".

I will assume that the .277 110gr Pro Hunter suffers from the same "tough" jacket, being designed to hold up to the 3500+ velocities produced by some of the 270 Big Boys.

My point, just because a bullet has the correct diameter, does not automatically mean it will be the correct Hunting bullet.

Don't get me wrong, I am not poo-pooing the 6.8.

I am just pointing out that the 6.8, like the Grendel and also the Blackout, suffer greatly in "Hunting" bullet selection.
 
#7 ·
18" barrel, 250 yards 1900 fps, standard Nosler bullet = good to go.

This conversation was helpful for me. I better understand the limitations now.
 
#8 ·
18" barrel, 250 yards 1900 fps, standard Nosler bullet = good to go.

This conversation was helpful for me. I better understand the limitations now.
Nosler offers several different bullet weights and styles, Accubonds, Ballistic Tips, Partitions, Bonded SP, Competition and all copper E-Tech.

Care to tell us what Nosler bullet you are referring to?
 
#9 · (Edited)
Standard factory ammo using 90gr bonded solid base should meet the requirements safely (250 yards, 18" barrel, good expansion). The 2840 muzzle velocity from the manufacturer is probably optimistic, and the barrel length is probably from 20".

From Nosler:
http://www.ableammo.com/catalog/nos...60.html?utm_source=ammoseek&utm_medium=feed&utm_term=ammo&utm_campaign=ammoseek


From SSA:
https://www.cheaperthandirt.com/pro...c-nosler-bonded-solid-base-90-grain-2840-fps-20-round-box-75020-804879116806.do
 
#10 ·
#12 ·
Point being, if you want the maximum range with the 6.8 cartridges limitations, there are real-world factory loaded options for hunting. If you want to use heavier .277 bullets (110+)you can, and you give up range.
 
#14 ·
Yup, ya caught me.

I was cherry picking.

I had no point, cept to cherry pick your point apart.

Thanks, I'll try and behave better next time we talk.
 
#15 ·
I found a whopping 4 bullets that can achieve high velocities. I overstated bullet availability. There should be a self-flagellation icon :eek:

On the bright side, I know now to leave my shelf full of 110/120 bullets at home when I go hunting :eek:

You do know, now I have to go buy new ammo based on this discussion :)
 
#17 ·
I think you have to factor in all the variables when making a choice in bullet selection. a bullet that performs great in a 30-06 or a 300 Win. Mag. may not perform as great in a 300 Blackout due to muzzle velocity differences.

the 300 Blackout was originally designed as heavier round used in the AR platform with a suppressor. I suspect that some of the bullet manufacturers haven't got caught up with making bullets that work for hunting as the lower velocities of that round yet. just like some of the others as well.