AR15.Com Archives
 7.62 x 51 and 16" barrels
Bradd_D  [Team Member]
2/21/2006 8:48:48 PM
I'm considering a DSA Para Congo and I'm wondering if 7.62 x 51 is worth anything out of a 16" barrel.
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keller  [Member]
2/21/2006 9:16:45 PM
Go for 18" youll get full powder burn. Plus factory para barrels are around 17.7' long.
survivorman  [Member]
2/21/2006 9:29:34 PM
does it matter really if your getting hit by a bullet especially 308 if it came from a 16in barrel or an 18in barrel? get what you like and god willing you will never have to use it on any poor bastard
Bradd_D  [Team Member]
2/21/2006 9:53:56 PM

Originally Posted By survivorman:
does it matter really if your getting hit by a bullet especially 308 if it came from a 16in barrel or an 18in barrel? get what you like and god willing you will never have to use it on any poor bastard



Good point, but if it's no more effective than 7.62 x 39, then I'll just stick to the AK.
SHIVAN  [Team Member]
2/21/2006 9:55:36 PM
With NATO surplus ammo you are looking at 147gr doing +/- 2600fps....

Is that better than an AK?
jwise  [Member]
2/23/2006 1:38:43 AM

Originally Posted By SHIVAN:
With NATO surplus ammo you are looking at 147gr doing +/- 2600fps....

Is that better than an AK?



I don't know, but I sure would like to find out. I've always thought a .308 out of a 16" barrel was a waste of a good cartridge. If I'm wrong, I would really like to know.

ORinTX  [Team Member]
2/23/2006 1:49:52 AM
I'd like to hear opinions on this too.

I've always though 16 would be too short for that cartridge.
Achilles1  [Member]
2/23/2006 2:00:39 AM
It won't matter as much with the two inches shorter of the 16 inch 7.62x51mm barrel at all your normal battle rifle ranges, it's out farther that little more will make the difference. Out to 500 is one thing, but out to 800 is another. If your not going to try and shoot that far, than why worry? The manueverability around obstacles is where that extra 2 inches shorter makes the difference. Which is more important?
Yojimbo  [Team Member]
2/23/2006 9:37:49 AM
I always thought that an 18" should be the minium for a .308 but then sometime ago someone here posted some ballistics info on TAP 155gr from 16" barrel and IIRC, it was fragmenting all the way to around 400 yards!

After reading that I decided that it didn't really matter and that the 16" barrel would get the job done if you chose the right ammo...
ar-wrench  [Member]
2/23/2006 9:47:58 AM
You won't lose that much as opposed to an 18". I have a 16 incher, and called Sierra about the effects of a 16" barrel and what to expect from some of their bullets.

The loss wasn't as much as I expected (of course, I forgot to write the info down, and this was 10 years ago), IIRC the reduction in MV was less than 100fps.

One thing about the short 7.62NATO rifles, they are LOUD!

Wanna shoot my short rifle (again), I'll probably bring it to the shoot.



TxLewis  [Team Member]
2/23/2006 10:02:27 AM
My ar10Tc is a 16". I get good accurate results out to 600 yds with 147gr hirtenberger.

I do not feel underarmed with my 16" barrel, expecially knowing how accurate it is.

TXL
DevL  [Member]
2/23/2006 10:57:55 AM

Originally Posted By Bradd_D:

Originally Posted By survivorman:
does it matter really if your getting hit by a bullet especially 308 if it came from a 16in barrel or an 18in barrel? get what you like and god willing you will never have to use it on any poor bastard



Good point, but if it's no more effective than 7.62 x 39, then I'll just stick to the AK.



This would be possible how? Are you talking a 14" bareld .308 to a 20" barreled 7.62x39 or something? I have never understood this "no better than 7.62x39" concept with short .308 barrels.
SHIVAN  [Team Member]
2/23/2006 11:59:52 AM
I had a secondary question about this:

Even assuming similar velocities, which we know isn't correct, how does the AK round overcome the excellent BC's of the the .308 bullets?
VSP  [Member]
2/23/2006 1:03:24 PM
Bradd,
Put either one in the center of a man's chest and your problem will be solved.

VSP
CitySlicker  [Team Member]
2/23/2006 4:20:08 PM
According to Dr. Roberts, 16" to 18" is optimal barrel length for a .308.

Personally, I would go with 18" but you should go with what best suits you and your needs.
fossil_fuel  [Team Member]
2/23/2006 5:34:29 PM

Originally Posted By CitySlicker:
According to Dr. Roberts, 16" to 18" is optimal barrel length for a .308.

Personally, I would go with 18" but you should go with what best suits you and your needs.



do you have a link where he explains his reasoning on this? i'd like to see what dr roberts has to say about the issue.
CitySlicker  [Team Member]
2/23/2006 5:36:19 PM

Originally Posted By fossil_fuel:

Originally Posted By CitySlicker:
According to Dr. Roberts, 16" to 18" is optimal barrel length for a .308.

Personally, I would go with 18" but you should go with what best suits you and your needs.



do you have a link where he explains his reasoning on this? i'd like to see what dr roberts has to say about the issue.



It was quite recently actually; perhaps in the Ammunition Forum. I'll see what I can do.

Gamma762  [Team Member]
2/23/2006 5:41:59 PM

Originally Posted By CitySlicker:

Originally Posted By fossil_fuel:

Originally Posted By CitySlicker:
According to Dr. Roberts, 16" to 18" is optimal barrel length for a .308.
Personally, I would go with 18" but you should go with what best suits you and your needs.


do you have a link where he explains his reasoning on this? i'd like to see what dr roberts has to say about the issue.


It was quite recently actually; perhaps in the Ammunition Forum. I'll see what I can do.


Guess those 17 3/8" FAL barrels were right all along
Bradd_D  [Team Member]
2/23/2006 5:58:03 PM

Originally Posted By ar-wrench:
Wanna shoot my short rifle (again), I'll probably bring it to the shoot.






I'll never turn down an opportunity to shoot the FR-8.

Bradd_D  [Team Member]
2/23/2006 6:00:58 PM

Originally Posted By DevL:

Originally Posted By Bradd_D:

Originally Posted By survivorman:
does it matter really if your getting hit by a bullet especially 308 if it came from a 16in barrel or an 18in barrel? get what you like and god willing you will never have to use it on any poor bastard



Good point, but if it's no more effective than 7.62 x 39, then I'll just stick to the AK.



This would be possible how? Are you talking a 14" bareld .308 to a 20" barreled 7.62x39 or something? I have never understood this "no better than 7.62x39" concept with short .308 barrels.



I wasn't suggesting it was possible at all. I'm really not up on the ballistics of either one. My question is simply at the practical engagement ranges of these 16" rifles what will the 7.62 x 51 do that the 7.62 x 39 won't?
Bradd_D  [Team Member]
2/23/2006 6:01:36 PM

Originally Posted By SHIVAN:
I had a secondary question about this:

Even assuming similar velocities, which we know isn't correct, how does the AK round overcome the excellent BC's of the the .308 bullets?



And how would that come into play at the practical engagement ranges of these rifles?
Bradd_D  [Team Member]
2/23/2006 6:02:06 PM

Originally Posted By VSP:
Bradd,
Put either one in the center of a man's chest and your problem will be solved.

VSP



If that's the case, I'll just stick to the M4.
glazer1972  [Team Member]
2/23/2006 6:59:29 PM
I would pick the 18" barrel myself if I was going to get a Congo.
cobrasks  [Member]
2/23/2006 7:46:43 PM


I wasn't suggesting it was possible at all. I'm really not up on the ballistics of either one. My question is simply at the practical engagement ranges of these 16" rifles what will the 7.62 x 51 do that the 7.62 x 39 won't?




Turn cover into concealment.


At 100 yards shoot 7.62 X 39 mm at a double thick dumpster ,a stack of cinder blocks,
a stack of firewood,a medium sized tree ,or through some other thick item .

Now try it with 7.62 X 51 mm.

Which one would have killed a target behind that cover ?

I think most guys here would be really surprised at what the 7.62 X 51 mm can
shoot through that 7.62 X 39 mm and 5.56 do not.

From the standpoint of how much ammo one man can carry ,I think 7.62 X 51 mm
is about as large of a cartridge as one person can carry enough ammo for.

Remember ,people like to hide behind stuff !
ar-wrench  [Member]
2/23/2006 7:52:32 PM

Originally Posted By Bradd_D:

Originally Posted By ar-wrench:
Wanna shoot my short rifle (again), I'll probably bring it to the shoot.






I'll never turn down an opportunity to shoot the FR-8.




It has been born again as a scout rifle, sweet.
5subslr5  [Team Member]
2/23/2006 8:23:13 PM

Originally Posted By keller:
Go for 18" youll get full powder burn. Plus factory para barrels are around 17.7' long.




+1




5sub
SHIVAN  [Team Member]
2/23/2006 9:13:35 PM

Originally Posted By Bradd_D:

Originally Posted By SHIVAN:
I had a secondary question about this:

Even assuming similar velocities, which we know isn't correct, how does the AK round overcome the excellent BC's of the the .308 bullets?



And how would that come into play at the practical engagement ranges of these rifles?



My thoughts?

Allows for versatility from even a short barrel 7.62NATO. Engagements out to 500yds would require less adjustment and the bullet would be less susceptible to wind drift.

I actually meant to indicate BC and sectional density. With higher sectional density usually indicating better penetration on target.

Bradd_D  [Team Member]
2/23/2006 9:18:02 PM

Originally Posted By SHIVAN:

Originally Posted By Bradd_D:

Originally Posted By SHIVAN:
I had a secondary question about this:

Even assuming similar velocities, which we know isn't correct, how does the AK round overcome the excellent BC's of the the .308 bullets?



And how would that come into play at the practical engagement ranges of these rifles?



My thoughts?

Allows for versatility from even a short barrel 7.62NATO. Engagements out to 500yds would require less adjustment and the bullet would be less susceptible to wind drift.

I actually meant to indicate BC and sectional density. With higher sectional density usually indicating better penetration on target.




Ok...I'll buy that.
jwise  [Member]
2/23/2006 11:32:11 PM

Originally Posted By cobrasks:


I wasn't suggesting it was possible at all. I'm really not up on the ballistics of either one. My question is simply at the practical engagement ranges of these 16" rifles what will the 7.62 x 51 do that the 7.62 x 39 won't?




Turn cover into concealment.


Remember ,people like to hide behind stuff !



Ok, that is the best argument I've heard for a 16" .308.

In fact, that is one of the reasons I like the AK over the AR for SOME situations. The 7.62X39 punches through more stuff and still has the "oomph" to take down a target. The 5.56 may make it through, but it is now a .22lr. Just ask the guy an FBI agent shot 5 times with an M4 through a windshield. He's fine... I was there.

triburst1  [Team Member]
2/24/2006 8:32:04 AM

Originally Posted By jwise:
Just ask the guy an FBI agent shot 5 times with an M4 through a windshield. He's fine... I was there.




He is a lucky motherfucker.
dablues  [Team Member]
2/24/2006 11:40:29 AM

One thing about the short 7.62NATO rifles, they are LOUD!


What he said!

As far as the impact out of a sixteen inch goes, regular 147 grain ball ammo shatters head sized rocks at 100 yards, repeated impact will punch its way through a rail road tie plate, and a 150 grain Nosler partition dropped a doe very nicely this season. It is way more energy than an AK round
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