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-   -   5.56 sniper rounds? (http://www.firearmstalk.com/forums/f30/5-56-sniper-rounds-51597/)

Vincine 11-11-2011 02:06 PM

5.56 sniper rounds?
 
So I’m looking over the Federal Ammunition ballistic charts (neat free software) and it seems that at 300 yards (the longest range near me) there's only small differences between the .223 & .308 in; bullet drift @ 5 mph, bullet drop, and bullet velocity.

However;
the .308s have around 30% more foot pounds at 300 yards (1,700 f-ps) than the .223s have at the barrel (1,300 f-ps)!

Item: The Philippine Marine Corps Scout Snipers use DPMS AR-15s (24" Heavy Stainless Steel Ultra Match barrel w/a 1/8.5" twist) chambered for 5.56 (65-75 gr.), not 7.62.

(I don't know what the standard barrel length is this data is generated from, but it seems that after 20" you've more than reached diminishing returns as far as increasing muzzle velocity with additional length. I'd be surprised if 24" barrels are used.)

Granted, you’re not going get 1k yd ranges, or even 500 yds, in the rain forest. Still with all the lions and tigers and bears, Oh my! in the jungle, you (me) would think you’d (me again) want something that had more than a few hundred foot pounds left in it when it hit the target. Especially if it has to fly through branches & leaves & battle jackets and stuff without being deflected.

Discuss.

jpattersonnh 11-11-2011 02:44 PM

Although you may not see an advantage in certain systems, My Varmint rifle in .223 has a 24" barrel. W/ no gas being bled off it is still can reach out there. W' a FMJ it has a habit of tumbling more at lower velocities, so at 500 yards w/ a velocity of 1675 and retained energy 342fp the 55gr bullet will tumble almost upon impact. At this point 4" of penetration center mass will either kill or severely wound an enemy combatant. 300 yards would be a long shot in a dense jungle, But what is classified as a jungle may suprise you. There may be 500 yards shots that present themselves.

JonM 11-11-2011 03:32 PM

if you have ever carried a 5.56 chambered rifle through a jungle and also tried carrying a 308 you will quickly understand the advantage of the 5.56.

if i was going to combat i wouldnt want a 308 unless i was using a beltfed or a sniper type bolt rifle. the weight you save is better used to carry water.

the 5.56 in a 20" barrel is a proven man stopper. its a devastating round. when you shrink the barrel down below 20 and the range starts getting out there around 300+ you start having issues especially with heavier bullets like the SS109 in the 14.5" M4 carbine. this where the issue of the 556 comes from.

while a shorty barrel is great for troops who are spending a lot of time in vehicles or are doing urban combat at very close ranges once the distance gets out there a little 300ish or so the M4 falls on its face.

the rise of the 6.8 and 30 cal solutions started showing up but the weight factor creeps back in and you still have issues at longer ranges.

the military has tried over and over to re-invent the M16-A1 and so far has not succeeded. thats why my goto is a very light weight AR15A1 20" rifle using 55grn fmj.

Vincine 11-11-2011 11:50 PM

Quote:

Originally Posted by JonM (Post 625034)
if you have ever carried a 5.56 chambered rifle through a jungle and also tried carrying a 308 you will quickly understand the advantage of the 5.56.

I just did that, sort of (not really).

I took a drive to VT and visited a few shops. I got to heft a .308 AR 15 w/24” SS heavy barrel. DPMS I think. That thing is heavier than my car! I’ve got a compact car, but still. Geez! They also had a 20” there and they showed me the proper way to do arm curls with it. You wouldn’t think 4” would make much of a difference, but the 20” felt half as heavy as the 24” and it that was still heavier than my car. The DPMS spec sheets says they’re about 10-11 pounds. I don’t believe it.

I know the Filipinos are tough, but I can’t see any sniper dragging these monsters through the jungle.

I have a new appreciation for the 7.5 lb. bolt action, regardless of the ballistic charts.

Vincine 11-11-2011 11:54 PM

Quote:

Originally Posted by jpattersonnh (Post 625001)
Although you may not see an advantage in certain systems, . . (snip) . . There may be 500 yards shots that present themselves.

What rifle? 55 grain. 1/12?

frank_1947 11-18-2011 11:35 PM

the guy shooting it is the sniper not the rifle , what are you trying to accomplish, 500 yard shots , you can get what ever you want , do you want great accuracy, like a rifle a trained sniper would use , would be similar to a benchrest gun, most of what the marines use as snipe is based on rem 700 they are now going to 300 win mag i just read this 10 minutes ago they will get better ballistics as opposed to 338L

Sniper03 11-19-2011 12:37 AM

Vincine,

First of all I would not recomend the 1:12 twist barrels due to the fact they do not stabilize any round much over 55 gr. over that weight they have a tendency to have keyhole strikes on a target at 100 yards. While the 1:9s from 55-Max of 69-72 gr., 1:8s which most heavy barreled varmint, predator and light sniper rifles are chambered for can handle 55s up to 80 gr. I have had two Rock River 20" 1:8 A-4 Varmints that would shoot 1/4 MOA when I had a good day. It would shoot 80 gr. if you want to hand load the rounds individually. Then there is the 1:7s which will also handle from 55 up. As far as the 20" vs the 24" it will not take you long if you pack them around to figure out which one you would rather pack. The 24 is a great bench gun bit fairly front heavy holding it off the bench. But do not take this wrong they are good shooters.

03

Vincine 11-19-2011 01:56 AM

Quote:

Originally Posted by Vincine (Post 625401)
I have a new appreciation for the 7.5 lb. bolt action, regardless of the ballistic charts.

Marksmanship = practice. Practice = ammunition. Ammunition = $$.

5.56x45mm Military Lake City 62 Grain M855 Penetrator 3025 fps
1,000 rounds of 5.56 @ $320 = $.03 per round.

So I looked for a bolt action that could handle 5.56 (and .223). However none are to be found. I looked at .223 Remington Varmint/Target 700s (among others). I emailed Remington, they emailed back:
“Any rifle chambered for .223 Remington cannot safely fire 5.56 NATO ammunition. The brass, case dimensions, and pressures are too high/large in 5.56 NATO ammunition for .223 Remington chamberings to handle.”
Similar results on 5.56 vs. .223 from various websites.

I investigated .223 ammunition (all are 62 gr for apples to apples comparison).

.223 Remington TulAmmo 62 Grain Hollow Point 3025 fps
500 rounds of .223 @ $101 = $.05 per round
However many give this ammunition very poor reviews

.223 Remington Fiocchi Rifle Shooting Dynamics Full Metal Jacket Boat Tail 62 Grain 3000 fps.
50 rounds @ $18.50 = $.37 per round
This is the lowest cost equivalent rounds from the same site as the Lake City. It is twelve times the cost of the M855.

Most of the .223 is much more expensive than the 5.56.

The only rifles that publicly state that either 5.56 & .223 would be fine, are some of the AR 15s. No bolt actions.

This is correct?

Vincine 11-19-2011 01:59 AM

Quote:

Originally Posted by Sniper03 (Post 631177)
First of all I would not recomend the 1:12. . . (snip) . . .But do not take this wrong they are good shooters.

Thank you for all this!

I have been looking at the Rock Rivers. May I ask why the A4 Varmint? And not the EOP Varmint, Predator Pursuit or Coyote Rifles.May I ask why the A4 Varmint? And not the 20" EOP Varmint, Predator Pursuit (lightest) or Coyote 'flavors'.

trip286 11-19-2011 02:01 AM

Good lawd, here we go again.

The thread, let me paraphrase, and OP-please correct me if I'm wrong, a discussion of the advantages/disadvantages of .308 vs 5.56. The thought just happened to be brought on while browsing ballistics data.

There is no question here as to what magic rifle/round combination will magically make the OP a "sniper".

Now, Question to the OP. Am I right in my assessment of the situation? Or are you really looking for that magic combo? I ask because there was another thread where one of the members I'm fond of was getting completely and totally flamed over this same issue. I tried my best to stick up for him, but the offending party was having none of it, and continued bashing him for being a wannabe sniper.

If the question is about that magic round/rifle combo, it doesn't exist.


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