Capability of 308 out of 16" AR10?

Dashunde · December 9, 2018, 04:19 PM

I'm on the fence picking optics for my new RR Predator 16".
(I have another similar thread that has guided me to this point, so far)

I'd like to know if a quality 16" 308 is *worthy* of a 4-12x40 (Nikon P-308 $300) or 4-16x42 (Nikon M-308 $400)??

I'll definitely go with a 1-6x24 for 100-400 yards, and I've not yet completely ruled out a EOTech holo for ~100 yards.
(Very much seeking lightweight options for a holo sight)

I'm really wondering if a shorty 308 can make good use of 12+ magnification optic?

jmr40 · December 9, 2018, 04:35 PM

I don't know how much difference 2 more inches of barrel makes, but my 18" Ruger Predator is about 50-60 fps slower than my 22" rifles.

I can do anything I need to do with a 308 with 6X to 9X on the upper end. I don't see the need for 12X unless you are shooting very small varmints at long range with an extremely accurate rifle. I'd think a 1-6X scope would do fine well past 400 yards, and a 16" barrel will get you well past 400 yards.

Mobuck · December 9, 2018, 04:36 PM

"I'd like to know if a quality 16" 308 is *worthy* of a 4-12x40 "

IMHO---NO
Unless you plan to do most of your shooting beyond 400 yards, I see zero need for a 12X scope on ANYTHING but especially something like a 16" .308.
It doesn't take a long barrel to be accurate but it does take bore length to generate velocity required to send ballistically efficient bullets long distances.

disseminator · December 9, 2018, 04:48 PM

I'd go with the 1-6 myself.

big al hunter · December 9, 2018, 04:56 PM

Quote:

I'm really wondering if a shorty 308 can make good use of 12+ magnification optic?

That is a personal decision that only you can make....but I will try to help you decide.

It is still a rifle, and you are not loosing that much velocity. For me it is not the cartridge that determines the power of the optics. The target size and distance are of more importance. Small targets at long range need more power. I have a 22 LR with a 6-16 power scope. For what I do with it I would have as much fun using iron sights....but I have another 22 for that. This set up is great for plinking empty shotgun shell casings at 25 yards, hunting grouse, and punching holes in paper while my hunting rifles cool down The scope makes it easy for my kids to use the rifle too. (They are young and still learning)

You didn't say what your intended use is. But I assume since you listed multiple sight types that you haven't decided, or you plan to switch sights for the task at hand.. Are you planning to use this rifle for a specific purpose?

Road_Clam · December 9, 2018, 05:15 PM

I'm in agreement with big al , OP needs to first realistically determine max shooting distances and size of targets. A standard NRA target uses a 6 MOA black area relative to distance. (a 100 yd target is 6" dia black, and a 300 yd target is 18" dia black) so for 100-200 yds a 6x or 8x optic is all that's really needed. However trying to ring a 6" gong at 300 yds you will be better served with 12-16X. Remember if unsure of distances and target size , you can always dial down magnification on a higher power scope, you can't dial "up" a fixed power scope. If I had a 16" AR10 I would probably run a nice 4-12X as a good "all around" <300 yd combo. A 16" .30 cal rifle can reach 500 yds with good consistency, not sure I would be confident with a 16" bbl beyond 500 yds. I shoot a lot of different rifle/ scope combos out to 600 yds regularly, and i've shot 1K a few times. These are strictly just my opinions.

TX Nimrod · December 9, 2018, 05:57 PM

Here is actual velocity data from the same .308 barrel cut off in increments, not guesses. Velocity depends on the load too. The OP hasn’t bother to tell us the use of his rifle, so how can we tell him if a 12x scope is appropriate for his use.

https://rifleshooter.com/2014/12/308...ty-28-to-16-5/

.

Dashunde · December 9, 2018, 08:20 PM

Thanks all.. use is light weight, *all purpose* 308 (if such a thing exists).

I'm really just wondering if a 4-16x40 or 42mm is worth messing with on a 16" 308?
If not I'll continue to focus on optics up to 600 yard max.

raimius · December 9, 2018, 08:21 PM

If you are going for small targets at extended distances, yes, a good scope is valuable. (I'd even say most people would suggest a step up from the scopes you listed, if you plan to do a lot of work past 500yds.)

Usually, .308 is considered about an 800yd cartridge, for precision shooting. Most loadings will drop subsonic in that neighborhood, which with many bullets means a reduction in accuracy. Using a longer barrel (to a point), will give you more velocity, which will keep the bullet supersonic to a longer distance. That is why you see a lot of 6 or 6.5mm chambered guns for long-range shooting these days.

**44 AMP** · December 9, 2018, 08:29 PM

A couple of points to consider, people like to look closely at the target, and a high power variable allows this. However, it is almost a given that if you ever need to use the rifle in a hurry, the scope will be set on it's highest power.

Unless you train yourself rigorously to ALWAYS turn the scope down to low power after shooting is done.

The other point is that when you get above 9x EVERYTHING gets magnified more. From heat shimmer to the jarring effect of your heartbeat on the crosshairs.

I use a 6-18x and a 6-24x on varmint rifles, and while its nice to crank it up to get a good look, I turn it down to 9x or lower to actually shoot.

3-9x works well for a wide range of uses, and for rifles used in deep woods situations 2-7x is better and a 1.5-4x is about ideal.

Everyone is different, but I've always felt that if you can't see it to hit it at 9x or lower, you shouldn't be shooting it.

mehavey · December 9, 2018, 08:59 PM

I can confirm TX_Nimrod's article on the carbine-length AR-1-(like) ballistics, including the (~300yd) 8" gong point-blank range.

Since I regard 4X as a "standard" benchmark for 100yds -- especially in a sub-minute capable rifle -- I'd suggest the 4-12X to be a good choice.

stagpanther · December 10, 2018, 02:46 AM

I'm old, bad eyes. My motto--no such thing as too much magnification (except at close range). If you are expecting sub-MOA at 600--then I'd be thinking about more than even 3 x 9. I have a 4 x 12 on my AR 10 carbine and I never feel it's too much at 100 yds. Might be an issue if CQB is part of your plan--but a "do-it-all" gun is generally going to be a jumble of sub-optimal compromises in my experience.

I generally go for "simplest approach to doing one thing well" because that's about all I'm capable of.

Wyosmith · December 10, 2018, 09:50 AM

I, my wife and a few friends I have loaned the rifle to have killed elk (several of them) with my Mossberg 18" MVP. No problem at all.

I have owned quite a few 308s in my life, and I still own 2. A Ruger SR762 (16.5") and the above Mossberg.

I have chronographed the ones I have owned as well as both of those I still own with various ammo. I have found that 20 to 25 FPS per second is the average difference from a 16" up to a 22 inch barrel, and past 22 " you gain about 18-22 fps at 25" and 26" I never had a 308 with a barrel longer then 26"

None of that made any difference on deer antelope or elk.

Drm50 · December 10, 2018, 10:38 AM

I had a 788 Rem that had a buldge in the barrel from previous owner shooting it with a obstruction. I had it cut off and ended up with 171/4" barrel. I had a 6x on it and it shot under 1" at 100yds with Rem factory 150gr.

5whiskey · December 10, 2018, 11:06 AM

I have 1st and 2nd round hits on targets at 1k yards with an M1A CQB. It had a 16" barrel. About a dozen witnesses at Camp Butner to prove it. So the answer is... yes, that snubby is capable of stretching legs of a 12x scope. It wasn't my rifle, and I didn't think it was feasible (possible but not likely). So, the instructor pulled his rifle out and handed it to me, telling me to have at it. Lo and behold, the thing would do it.

That being said, it is not the best tool for the job and if you don't foresee yourself shooting further than 400 yards with it a 6x scope will suit you well.

Dashunde · December 10, 2018, 04:34 PM

Thanks for all the info and perspective everyone.

Seems the 1-8x24 Vortex might be just about right and a better balance of most all factors?
It bumps up the magnification from 6x to 8x for a bit more versatility and it comes with a decent mount.

Mobuck · December 10, 2018, 09:42 PM

8x-24 is going to limit your low light usage.

MarkCO · December 10, 2018, 10:04 PM

My 16" .308, which I mostly use for 3Gun, wears a Burris XTRII 1-8. For me, it is about perfect for a .308 gas gun. I shot a few 1000 yard matches, a few deer and a few pigs with it, but mostly I am shooting targets from about 70 to 600 yards.

Please don't buy a Strike Eagle. It won't last and it has a lot of parallax, almost useless past 200 unless you like to spray and pray.

eastbank · December 11, 2018, 04:17 AM

what size was the target you had first and second hits on at a thousand yards?

Mobuck · December 11, 2018, 07:59 AM

"So, the instructor pulled his rifle out and handed it to me, telling me to have at it. Lo and behold, the thing would do it."

And so will numerous other platforms once zeroed for the range. This discounts the fact that 40-50 yards closer or farther would result in a miss.

Jim Watson · December 11, 2018, 08:57 AM

Just get a March 2.5-25 and cover all the bases.

MarkCO · December 11, 2018, 09:01 AM

Quote:

Originally Posted by eastbank

what size was the target you had first and second hits on at a thousand yards?

18" gong at 1040. Last week, went 8 for 10. 6 and 8 were the misses.

bman940 · December 11, 2018, 11:13 AM

I'd check out Nikon's new M-Tactical 3-12x42 MOA/MRAD reticle scope. It'll do all you want it to for under $400. Dial in your distance or use the Spot On for holdovers, you are good to go. I will be putting one on a CMMG 7.62 that I have very shortly. I have used to 3-12 to shoot to 600 yards before going 5 for 5 on a 10 inch gong and also hitting a soda can.

Bottom Gun · December 11, 2018, 07:42 PM

I would be tempted to look at a compact scope. Leupold makes a 2 1/2-8X that would be perfect for a carbine. I have one mounted on one of my hunting rifles and have found it to be a perfect woods scope with good FOV and enough magnification available to reach out a bit.

JJ45 · December 12, 2018, 05:20 AM

Isn't anyone concerned about weight and bulk?....a handling consideration? Probably depends on intended use which the OP didn't say.

If it's a 16", it's pretty much carbine length, short, light, fast handling and IMO a low powered variable or better yet a high quality fixed 4x or 6X would compliment the weapon.

You can do some good work with a low powered scope and some of you guys know what I mean if you've tried it.

December 9, 2018, 04:19 PM	#1
Dashunde Senior Member Join Date: December 22, 2004 Posts: 2,018	Capability of 308 out of 16" AR10? I'm on the fence picking optics for my new RR Predator 16". (I have another similar thread that has guided me to this point, so far) I'd like to know if a quality 16" 308 is worthy of a 4-12x40 (Nikon P-308 $300) or 4-16x42 (Nikon M-308 $400)?? I'll definitely go with a 1-6x24 for 100-400 yards, and I've not yet completely ruled out a EOTech holo for ~100 yards. (Very much seeking lightweight options for a holo sight) I'm really wondering if a shorty 308 can make good use of 12+ magnification optic? Last edited by Dashunde; December 9, 2018 at 04:25 PM.

December 9, 2018, 04:35 PM	#2
jmr40 Senior Member Join Date: June 15, 2008 Location: Georgia Posts: 10,805	I don't know how much difference 2 more inches of barrel makes, but my 18" Ruger Predator is about 50-60 fps slower than my 22" rifles. I can do anything I need to do with a 308 with 6X to 9X on the upper end. I don't see the need for 12X unless you are shooting very small varmints at long range with an extremely accurate rifle. I'd think a 1-6X scope would do fine well past 400 yards, and a 16" barrel will get you well past 400 yards. __________________ "If you're still doing things the same way you were doing them 10 years ago, you're doing it wrong" Winston Churchill

December 9, 2018, 05:15 PM	#6
Road_Clam Senior Member Join Date: November 21, 2013 Location: New Hampshire Posts: 1,695	I'm in agreement with big al , OP needs to first realistically determine max shooting distances and size of targets. A standard NRA target uses a 6 MOA black area relative to distance. (a 100 yd target is 6" dia black, and a 300 yd target is 18" dia black) so for 100-200 yds a 6x or 8x optic is all that's really needed. However trying to ring a 6" gong at 300 yds you will be better served with 12-16X. Remember if unsure of distances and target size , you can always dial down magnification on a higher power scope, you can't dial "up" a fixed power scope. If I had a 16" AR10 I would probably run a nice 4-12X as a good "all around" <300 yd combo. A 16" .30 cal rifle can reach 500 yds with good consistency, not sure I would be confident with a 16" bbl beyond 500 yds. I shoot a lot of different rifle/ scope combos out to 600 yds regularly, and i've shot 1K a few times. These are strictly just my opinions. __________________ "To be old an wise you must have been young and stupid"

December 9, 2018, 08:29 PM	#10
44 AMP Staff Join Date: March 11, 2006 Location: Upper US Posts: 28,812	A couple of points to consider, people like to look closely at the target, and a high power variable allows this. However, it is almost a given that if you ever need to use the rifle in a hurry, the scope will be set on it's highest power. Unless you train yourself rigorously to ALWAYS turn the scope down to low power after shooting is done. The other point is that when you get above 9x EVERYTHING gets magnified more. From heat shimmer to the jarring effect of your heartbeat on the crosshairs. I use a 6-18x and a 6-24x on varmint rifles, and while its nice to crank it up to get a good look, I turn it down to 9x or lower to actually shoot. 3-9x works well for a wide range of uses, and for rifles used in deep woods situations 2-7x is better and a 1.5-4x is about ideal. Everyone is different, but I've always felt that if you can't see it to hit it at 9x or lower, you shouldn't be shooting it. __________________ All else being equal (and it almost never is) bigger bullets tend to work better.

December 10, 2018, 02:46 AM	#12
stagpanther Senior Member Join Date: March 2, 2014 Posts: 11,770	I'm old, bad eyes. My motto--no such thing as too much magnification (except at close range). If you are expecting sub-MOA at 600--then I'd be thinking about more than even 3 x 9. I have a 4 x 12 on my AR 10 carbine and I never feel it's too much at 100 yds. Might be an issue if CQB is part of your plan--but a "do-it-all" gun is generally going to be a jumble of sub-optimal compromises in my experience. I generally go for "simplest approach to doing one thing well" because that's about all I'm capable of. __________________ "Everyone speaks gun."--Robert O'Neill *I am NOT an expert--I do not have any formal experience or certification in firearms use or testing; use any information I post at your own risk!*

December 9, 2018, 04:36 PM	#3
Mobuck Junior member Join Date: February 2, 2010 Posts: 6,846	"I'd like to know if a quality 16" 308 is worthy of a 4-12x40 " IMHO---NO Unless you plan to do most of your shooting beyond 400 yards, I see zero need for a 12X scope on ANYTHING but especially something like a 16" .308. It doesn't take a long barrel to be accurate but it does take bore length to generate velocity required to send ballistically efficient bullets long distances.

December 9, 2018, 04:48 PM	#4
disseminator Senior Member Join Date: November 26, 2016 Location: Minnesota Posts: 960	I'd go with the 1-6 myself.

December 9, 2018, 05:57 PM	#7
TX Nimrod Senior Member Join Date: November 27, 2009 Location: Zona Posts: 423	Here is actual velocity data from the same .308 barrel cut off in increments, not guesses. Velocity depends on the load too. The OP hasn’t bother to tell us the use of his rifle, so how can we tell him if a 12x scope is appropriate for his use. https://rifleshooter.com/2014/12/308...ty-28-to-16-5/ .

December 9, 2018, 08:20 PM	#8
Dashunde Senior Member Join Date: December 22, 2004 Posts: 2,018	Thanks all.. use is light weight, all purpose 308 (if such a thing exists). I'm really just wondering if a 4-16x40 or 42mm is worth messing with on a 16" 308? If not I'll continue to focus on optics up to 600 yard max.

December 9, 2018, 08:21 PM	#9
raimius Senior Member Join Date: January 27, 2008 Posts: 2,199	If you are going for small targets at extended distances, yes, a good scope is valuable. (I'd even say most people would suggest a step up from the scopes you listed, if you plan to do a lot of work past 500yds.) Usually, .308 is considered about an 800yd cartridge, for precision shooting. Most loadings will drop subsonic in that neighborhood, which with many bullets means a reduction in accuracy. Using a longer barrel (to a point), will give you more velocity, which will keep the bullet supersonic to a longer distance. That is why you see a lot of 6 or 6.5mm chambered guns for long-range shooting these days.

December 9, 2018, 08:59 PM	#11
mehavey Senior Member Join Date: June 17, 2010 Location: Virginia Posts: 6,883	I can confirm TX_Nimrod's article on the carbine-length AR-1-(like) ballistics, including the (~300yd) 8" gong point-blank range. Since I regard 4X as a "standard" benchmark for 100yds -- especially in a sub-minute capable rifle -- I'd suggest the 4-12X to be a good choice.

December 10, 2018, 09:50 AM	#13
Wyosmith Senior Member Join Date: December 29, 2010 Location: Shoshoni Wyoming Posts: 2,713	I, my wife and a few friends I have loaned the rifle to have killed elk (several of them) with my Mossberg 18" MVP. No problem at all. I have owned quite a few 308s in my life, and I still own 2. A Ruger SR762 (16.5") and the above Mossberg. I have chronographed the ones I have owned as well as both of those I still own with various ammo. I have found that 20 to 25 FPS per second is the average difference from a 16" up to a 22 inch barrel, and past 22 " you gain about 18-22 fps at 25" and 26" I never had a 308 with a barrel longer then 26" None of that made any difference on deer antelope or elk.

December 10, 2018, 10:38 AM	#14
Drm50 Senior Member Join Date: November 10, 2014 Posts: 1,378	I had a 788 Rem that had a buldge in the barrel from previous owner shooting it with a obstruction. I had it cut off and ended up with 171/4" barrel. I had a 6x on it and it shot under 1" at 100yds with Rem factory 150gr.

December 10, 2018, 11:06 AM	#15
5whiskey Senior Member Join Date: October 23, 2005 Location: US Posts: 3,652	I have 1st and 2nd round hits on targets at 1k yards with an M1A CQB. It had a 16" barrel. About a dozen witnesses at Camp Butner to prove it. So the answer is... yes, that snubby is capable of stretching legs of a 12x scope. It wasn't my rifle, and I didn't think it was feasible (possible but not likely). So, the instructor pulled his rifle out and handed it to me, telling me to have at it. Lo and behold, the thing would do it. That being said, it is not the best tool for the job and if you don't foresee yourself shooting further than 400 yards with it a 6x scope will suit you well. __________________ Support the NRA-ILA Auction, ends 03/09/2018 https://thefiringline.com/forums/sho...d.php?t=593946

December 10, 2018, 04:34 PM	#16
Dashunde Senior Member Join Date: December 22, 2004 Posts: 2,018	Thanks for all the info and perspective everyone. Seems the 1-8x24 Vortex might be just about right and a better balance of most all factors? It bumps up the magnification from 6x to 8x for a bit more versatility and it comes with a decent mount.

December 10, 2018, 09:42 PM	#17
Mobuck Junior member Join Date: February 2, 2010 Posts: 6,846	8x-24 is going to limit your low light usage.

December 10, 2018, 10:04 PM	#18
MarkCO Senior Member Join Date: October 21, 1998 Location: Colorado, USA Posts: 4,307	My 16" .308, which I mostly use for 3Gun, wears a Burris XTRII 1-8. For me, it is about perfect for a .308 gas gun. I shot a few 1000 yard matches, a few deer and a few pigs with it, but mostly I am shooting targets from about 70 to 600 yards. Please don't buy a Strike Eagle. It won't last and it has a lot of parallax, almost useless past 200 unless you like to spray and pray. __________________ Good Shooting, MarkCO www.CarbonArms.us

December 11, 2018, 04:17 AM	#19
eastbank Senior Member Join Date: February 7, 2008 Location: pa. Posts: 2,450	what size was the target you had first and second hits on at a thousand yards?

December 11, 2018, 07:59 AM	#20
Mobuck Junior member Join Date: February 2, 2010 Posts: 6,846	"So, the instructor pulled his rifle out and handed it to me, telling me to have at it. Lo and behold, the thing would do it." And so will numerous other platforms once zeroed for the range. This discounts the fact that 40-50 yards closer or farther would result in a miss.

December 11, 2018, 08:57 AM	#21
Jim Watson Senior Member Join Date: October 25, 2001 Location: Alabama Posts: 18,535	Just get a March 2.5-25 and cover all the bases.

December 11, 2018, 11:13 AM	#23
bman940 Senior Member Join Date: August 29, 2010 Location: N. Texas Posts: 170	I'd check out Nikon's new M-Tactical 3-12x42 MOA/MRAD reticle scope. It'll do all you want it to for under $400. Dial in your distance or use the Spot On for holdovers, you are good to go. I will be putting one on a CMMG 7.62 that I have very shortly. I have used to 3-12 to shoot to 600 yards before going 5 for 5 on a 10 inch gong and also hitting a soda can.

December 11, 2018, 07:42 PM	#24
Bottom Gun Senior Member Join Date: October 13, 1998 Location: Arizona Territory Posts: 1,092	I would be tempted to look at a compact scope. Leupold makes a 2 1/2-8X that would be perfect for a carbine. I have one mounted on one of my hunting rifles and have found it to be a perfect woods scope with good FOV and enough magnification available to reach out a bit. __________________ NRA Life Member Mechanical engineers have their moments.

December 12, 2018, 05:20 AM	#25
JJ45 Senior Member Join Date: June 8, 2015 Posts: 908	Isn't anyone concerned about weight and bulk?....a handling consideration? Probably depends on intended use which the OP didn't say. If it's a 16", it's pretty much carbine length, short, light, fast handling and IMO a low powered variable or better yet a high quality fixed 4x or 6X would compliment the weapon. You can do some good work with a low powered scope and some of you guys know what I mean if you've tried it.

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