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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.
This is possibly the coolest most informative thread I have ever read. Congrats, you win the internet.
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.
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.
Well said. And if they dont immediately go down they are surely moving slow enough for a double tap.
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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
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Good stuff, Trident. Hope you have fun shooting today!
Nice project. Im looking forward to seeing your results. I’m guessing there’s not going to be that much difference between the barrel lengths. If you want to get a good accurate velocity reading without messing with a chrono you might consider Atragg software. It runs on a PDA or I think there’s an iPhone version. It calculates MV based on bullet drop and has been pretty damn accurate in my experience. You can also have it build a MV curve based on atmospherics.
Here’s something to consider when getting wrapped up on the specific definitions of these rifles. Terms like SPR, DMR, recce etc seem to have somewhat different definitions on the internet and in the military. On the internet they seem to describe semi-specific builds. In the military, at least within my experience, the terms are used to describe weapon employment as well as the weapon itself. I’ve heard a Mk 17 with a Nightforce mounted on it described as an SPR: an automatic mid range rifle. The M110 is also kind of an SPR. The sniper qualified guys are generally given some leeway to decide what they want to use as an “SPR”. Likewise a DMR is just a fire team or squad organic mid range rifle. It could be a M14 for instance. Not teying to get off topic, just food for thought.
Anyway great project. Should be fun.
I realize that, hence my use of “goes subsonic”. That point on the ballistics chart can be used as a rough guide to indicate the transonic envelope. Since this thread is in the General Discussion section that point is certainly worth mentioning, however.
I am still surprised at the 30 yard difference between the two.
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Nice shooting! Thanks for the viddys too.
Are the OnTarget calculated MOA results based on 100Y or your 267?
Honestly, the difference is what you make it. I can put some high power glass and a bipod a on 16" SS barreled upper and call it an SPR or I can put a 1-4x scope and vertical grip on a 18" SS barreled upper and call it a Recce.
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Nice rifles and a good thread. I think because the “Recce” was a “concept” of a “sniper M4” rather than the SPR that had a specific component list, it makes it harder to get the differences.
I really don’t see much of a difference between a 16" and 18" rifle with comparable barrels. The difference is really more in the optics. I like the “concept” of a Recce that has the low power variable (although there are a lot of new scopes out now that run from 1 mag to 10 mag) allows the shooter to use the 16" for a close range weapon easily and then switch to enough magnification to make hits at range.
Apples to apples I really don’t think that a 16" vs. 18" with the same magnification scope are significantly different.
My idea was to have an 18" SPR with a long(er) range scope, in this case a 4.5-14 Leupold MK4 and a 16" Recce with a mid range scope, in this case a 1.5-5 Leupold MK4.
Bravo Company 18" SPR and Daniel Defense 16" Recce
With these two, really the optics make the difference. You could literally (and I have) switch the scopes and not really be able to tell the difference between them.
It is interesting what Kyle Defoor said about the two, in another thread here.
After owning and shooting both a lot, I think Kyle is right the 16" Recce is a more practical rifle than the 18" SPR.
Regards,
Cameron
Interesting. Great quote. Nice rifles Cameron…as usual. Great thread you have here Alex and all involved
This really isn’t how a minute of angle works. A minute of angle is the same arc length at any given distance in degrees, or 1/60 of one degree (one minute of one degree). The actual measurement comes out to 1.024 inches at 100 yards, but simplified it is 1 inch at 100 yards. One minute of angle at 800 yards is roughly 8 inches in diameter, center of bullet to center of bullet.
We had a rare spring day with decent wind conditions for a change. I made it out and chronographed some Mk262 as well as my 77 gr reload.
Temp: Low 60s
Altitude: 5,000
Wind: Crossing to quartering, mostly 5-10 mph.
10’ from a PACT Chronograph
BH Mk262: (Red Box)
18" Noveske SPR Barrel Cold/Dirty Bbl.
Rainer Comp, 13" VTAC XTR Rail. (This is a build, not a complete rifle). 9 shots fired. 10 intended, but user error or the Chronograph start/stop leads caused an no-read on #1.
Avg - 2,814 fps
H - 2,833
L - 2,783
SD - 15.9
Mk262: (Red Box)
14.5" DD LW Barrel Cold/Dirty Bbl.
Rainer Comp, 11" Troy XTR Rail.
Avg - 2,672
H - 2,682
L - 2,655
SD - 11.9
18" Noveske SPR Barrel Cool/Dirty Bbl.
77 grain SMK Reload (24.0 TAC in 2nd loaded LC brass.)
Avg - 2,674
H - 2,702
L - 2,643
SD - 16.2
The 77 gr SMK reload in the SPR bbl at 711 Yds (650 Meters):
1st was windage shot (a miss off the right edge) then the next 8 of 9 were hits on my 12"x18" pistol gong. Fired from a concrete bench using an Atlas Bi-pod. No butt bag.
