Battle for light precision supremacy: The Recce Rifle Vs. The SPR

[ALCOAR]

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[Warg]

Not a concern of Trident's or mine but...does the 18" barrelled SPR offer any advantage in terms of killing/wounding potential (lack of better words) at longer distances? Would that lead the military to choose the longer bbl for extended shots at range or is that where another caliber comes into play (.308)?

This is a good question, particularly in light of newer loadings, more portable rifles and improved optics.

Take a look at the ballistics table below using MK262 round in 16" vs 18" BBL. The MVs were obtained using chrono data from the Hide and entered into JB Ballistics. Rock's barrels may differ from this, but probably not appreciably so.



At 500 yards the delta in energy is only 34 ft lbs, decreasing to 6 ft lbs at 1000y. The bullet goes subsonic right at 800y in the 16" and 830y in the 18" (not shown in the table). There's obvioulsy more drop from the 16", but nothing a good optic and shooter couldn't overcome. In effect, they're very damn close.

Given the above, I'd easily go with the lighter 16" Reece, but FWIW, I wouldn't feel comfortable trying to take down a BG with < 500 ft lbs of energy at 500+ yds. Then again, I'm not a sniper

EDIT ABOVE- forgot to mention that the ballistics data were derived at sea level, 59 degrees, 29.92 pressure, yada yada. Speed of sound, trajectory, etc will vary with changes in pressure, temp and altitude.

[Silver_2325]

This is possibly the coolest most informative thread I have ever read. Congrats, you win the internet.

[strambo]

I wouldn't feel comfortable trying to take down a BG with < 500 ft lbs of energy at 500+ yds.

Well, if you have a need to engage at that range...you don't have to drop them with the immediacy required when they are across the room.

Eliminating their ability to hit you back at 500 and taking them out of the fight is sufficient.

Sure, bigger is better, but a 5.56 to the torso out to 800 will probably render them combat ineffective at least.

[shootist~]

Trident,

Good shooting.

Another interesting thing to look for when you get a chronograph is the relative differences in velocity between the SS barrels and chrome lined barrels.

You might see more difference than common wisdom would indicate. In my very limited testing, I see a full 100 fps difference, +/- very little, between a 16" Noveske N4 CL barrel and an 18" Noveske SPR barrel. I've seen similar results in one thread somewhere, btw - his included Mk262; mine is with a 77 gr SMK reload. Possibly something unique to Noveske's SPR, but maybe not. BTW, the N4 barrel's velocity is pretty standard, based on a comparison to some posted results from others.

If this carries over in a similar way to the 16" SS vs 16" CL, or the more relevant standard M4, it would mean the Reece has more going for it than just accuracy.

[Silver_2325]

Well, if you have a need to engage at that range...you don't have to drop them with the immediacy required when they are across the room.

Eliminating their ability to hit you back at 500 and taking them out of the fight is sufficient.

Sure, bigger is better, but a 5.56 to the torso out to 800 will probably render them combat ineffective at least.

Well said. And if they dont immediately go down they are surely moving slow enough for a double tap.

[ALCOAR]

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[MistWolf]

It's not the sub-sonic range that kills long range accuracy, it's the trans-sonic range, where the bullet is travelling just at the speed of sound. This is where the most turbulence is encountered. Some parts of the airflow will be sub-sonic while another part will be supersonic. This is where the boat-tail really earns it's keep, getting the bullet through the trans-sonic range more smoothly. Once the bullet drops to sub-sonic velocities, it's flight path once more becomes smooth.

So in reality, the maximum effective range for precision isn't where the bullet drops to sub-sonic velocities, it's where it drops to transonic velocities. Bullets launched at subsonic speeds remain stable and accurate until they lose enough velocity to fall out of the sky or lose enough RPM to start wobbling

[ALCOAR]

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[hikeeba]

Good stuff, Trident. Hope you have fun shooting today!