Retained Energy by Range and Where Each Cartridge Drops Below the Threshold Figures
Muzzle energy and impact energy are different numbers and the threshold figures get quoted against both. A 6.5 Creedmoor 140gr from a 20in barrel starts at 2,101 ft-lb, falls below 1,500 at 303 yards and below 1,000 at 639. The 1,000 ft-lb figure has a traceable regulatory origin; the 1,500 figure does not.
A 6.5 Creedmoor 140gr load from a 20in barrel leaves the muzzle with 2,101 ft-lb. It is below 1,500 ft-lb by 303 yards and below 1,000 ft-lb by 639. A .308 Winchester 150gr from the same barrel starts higher, at 2,518 ft-lb, and crosses both thresholds sooner — 300 and 514 yards — because it sheds velocity faster.
That inversion is the whole reason this page exists. Muzzle energy ranks cartridges one way and retained energy at any real distance ranks them differently, sometimes in reverse. When a threshold figure gets quoted against muzzle energy, as marketing tends to do, it produces a very different answer than when it is applied at the distance the shot is actually taken, which is what everyone else means. The gap between those two readings is often several hundred yards.
Below: 24 loads resolved from 0 to 600 yards at one declared rig, the exact range each one crosses 1,500 and 1,000 ft-lb, and a provenance table naming where those two threshold numbers actually came from. One of them is a published regulation. The other is a magazine convention that has been repeated until it sounds official.
What this page is and is not
Scope note, stated up front because it matters. This site publishes the arithmetic of the projectile: velocity, momentum, recoil, stability, trajectory and impact energy. That is where our competence ends and the page ends with it.
What a given energy figure means once the bullet arrives is not our subject. We stop at impact and we stop there deliberately. Everything downstream of the moment the projectile lands is somebody else's page, and it is not arithmetic, so we will not pretend it is.
So read the columns below as what they are — the kinetic energy the projectile still carries at a stated distance, computed from a stated starting condition — and read the threshold figures as published conventions with a stated origin, not as a verdict on anything. Where a threshold has legal force, we say which jurisdiction and you should check the current regulation yourself, because these change.
Where the threshold figures actually come from
Both numbers get quoted with total confidence and neither is usually sourced. Here is what can be traced.
Figure Stated as Traceable origin Conditions it was stated under Status 1,000 ft-lb Minimum for large game Colorado Parks and Wildlife rifle regulations, which set a minimum energy figure measured at 100 yards alongside minimum calibre and bullet weight Measured at 100 yards, not at the muzzle and not at the shot Regulatory in at least one US state; verify current text before relying on it 1,500 ft-lb Minimum for elk-class game No traceable regulatory or institutional origin; appears in sporting press and reloading manuals from the mid-20th century onward Never stated with a distance in the original usages Convention only — widely repeated, nowhere published as a standard 500 ft-lb Minimum for deer-sized game Circulates in the same press tradition as the 1,500 figure Unstated Convention only Momentum-based figures Alternatives to energy thresholds Various proprietary formulas published by individual authors and manufacturers Each defined differently; not mutually convertible Proprietary — cannot be compared across sources Manufacturer energy claims Printed on ammunition boxes SAAMI-length test barrels, length usually not printed on the box Test barrel typically longer than any production rifle Real but not transferable to your rifle without a barrel-length correction Use the status column to weight how much authority to give a number someone quotes at you. Only the first row has published force anywhere, and only at 100 yards. The critical detail in row one is the distance. Colorado's figure is specified at 100 yards, which is a real, checkable, reproducible condition. That is a well-constructed regulation. Almost everybody who repeats the 1,000 ft-lb number drops the distance, at which point it becomes ambiguous enough to be meaningless — a .30-30 clears it at the muzzle and fails it at 200 yards, and both statements are true.
The 1,500 figure has no such anchor. It may be good advice, bad advice or neither; what it is not is a standard, and it should never be quoted as though somebody measured something to arrive at it.
The reference rig for the matrix
One barrel length for all 24 rows, so they can be ranked against each other. 20 inches, chosen because it is a length that genuinely exists in every one of these chamberings — you can buy a 20in AR, a 20in bolt gun and a 20in .300 Blackout, which is not true of 24 inches.
- Barrel: 20in for every row, muzzle velocities stated per load
- Atmosphere: sea level, 59F, 29.92 inHg
- Model: point-mass with constant G1 BC, standard G1 drag function
- Energy: bullet weight in grains multiplied by velocity squared, divided by 450,437
- Threshold columns: the range at which each load first falls below the stated figure
If your barrel is longer or shorter, correct the muzzle velocity first and everything else follows. Rough rates: 25 to 30 fps per inch for standard rifle cartridges, 15 to 20 fps per inch for .300 Blackout and other short-barrel-optimised rounds above about 10 inches, and 35 to 45 fps per inch for belted magnums, which have the most powder still burning at the muzzle.
Energy scales with the square of velocity, so a 5 percent velocity loss is a 10 percent energy loss. That is why the barrel-length correction is not optional here in the way it almost is for drop inside 300 yards.
Retained energy, 24 loads, 0 to 600 yards
All figures in ft-lb, all from the declared 20in barrel. Ordered roughly by muzzle energy within class.
Load MV (fps) G1 BC 0 50 100 150 200 250 300 350 400 450 500 550 600 .223 Rem 55gr FMJ 3,240 0.243 1,282 1,121 976 850 736 634 543 464 393 333 280 237 201 5.56 M855 62gr 3,020 0.304 1,255 1,124 1,007 898 800 710 627 553 486 426 372 325 284 .223 Rem 77gr OTM 2,750 0.372 1,293 1,178 1,073 975 885 800 722 651 585 525 470 421 376 .300 BLK 110gr 2,400 0.290 1,407 1,240 1,089 954 832 724 628 545 473 412 362 321 290 .300 BLK 125gr 2,250 0.345 1,405 1,259 1,128 1,006 896 796 707 627 556 495 442 397 361 7.62x39 123gr 2,350 0.295 1,508 1,331 1,171 1,026 897 781 679 590 514 449 396 353 320 .350 Legend 170gr 2,200 0.240 1,827 1,558 1,323 1,118 941 793 669 570 494 437 394 361 334 .30-30 Win 150gr 2,390 0.218 1,902 1,605 1,350 1,126 934 773 640 534 453 393 350 318 292 .45-70 Govt 405gr 1,330 0.281 1,590 1,386 1,221 1,093 994 915 851 797 750 708 671 637 605 6.5 Grendel 123gr 2,580 0.506 1,818 1,695 1,580 1,471 1,368 1,271 1,179 1,092 1,011 935 863 796 734 6mm ARC 108gr 2,750 0.536 1,813 1,701 1,595 1,493 1,397 1,307 1,220 1,138 1,061 988 918 853 792 .243 Win 100gr 2,900 0.405 1,867 1,717 1,580 1,450 1,329 1,217 1,111 1,013 921 837 759 687 621 6.5 Creedmoor 140gr 2,600 0.646 2,101 1,990 1,884 1,783 1,686 1,593 1,504 1,419 1,338 1,260 1,187 1,116 1,049 7mm-08 Rem 140gr 2,750 0.485 2,350 2,190 2,039 1,897 1,762 1,635 1,515 1,401 1,295 1,195 1,102 1,014 933 .308 Win 150gr 2,750 0.415 2,518 2,319 2,132 1,957 1,795 1,643 1,499 1,368 1,245 1,131 1,026 930 842 .308 Win 175gr 2,550 0.505 2,526 2,356 2,194 2,041 1,897 1,762 1,633 1,512 1,399 1,293 1,193 1,100 1,014 .270 Win 130gr 2,960 0.460 2,529 2,350 2,185 2,029 1,882 1,743 1,612 1,489 1,374 1,265 1,164 1,069 980 .450 Bushmaster 250gr 2,200 0.210 2,686 2,240 1,854 1,529 1,254 1,033 857 726 632 565 513 472 437 6.5 PRC 143gr 2,880 0.625 2,633 2,496 2,363 2,237 2,117 2,002 1,892 1,786 1,685 1,589 1,497 1,409 1,325 .30-06 Sprg 180gr 2,650 0.507 2,806 2,621 2,444 2,278 2,121 1,972 1,832 1,699 1,574 1,457 1,346 1,243 1,148 7mm Rem Mag 160gr 2,850 0.531 2,885 2,706 2,538 2,378 2,227 2,084 1,947 1,817 1,694 1,578 1,468 1,364 1,266 .300 Win Mag 180gr 2,870 0.507 3,292 3,079 2,879 2,691 2,511 2,341 2,180 2,028 1,885 1,749 1,621 1,501 1,388 .300 PRC 212gr 2,780 0.673 3,637 3,457 3,286 3,121 2,963 2,811 2,665 2,526 2,391 2,263 2,140 2,022 1,909 .338 Lapua Mag 250gr 2,830 0.675 4,445 4,227 4,019 3,819 3,629 3,445 3,268 3,099 2,935 2,780 2,631 2,487 2,351 Find your load, then read across to the distance you actually shoot. Comparing muzzle columns tells you almost nothing useful; comparing the 300 or 400 column tells you a great deal. Two rows demonstrate the point better than any argument. The .450 Bushmaster starts at 2,686 ft-lb — more than a .308 with 150gr — and is down to 857 ft-lb by 300 yards, where the .308 still has 1,499. A BC of 0.210 does that. Meanwhile the .45-70, which starts lowest of any of the big-bore rows at 1,590 ft-lb, is still carrying 605 ft-lb at 600 yards, more than the .30-30 that started 300 ft-lb ahead of it, because the heavy 405gr slug retains what it has.
The 6.5 Grendel and 6mm ARC rows are the other instructive pair. Both start under 1,850 ft-lb, well behind .308 and .30-06. By 600 yards the Grendel is at 734 and the ARC at 792, against .308's 842 — a gap that has closed from nearly 700 ft-lb at the muzzle to under 100. Ballistic coefficient is a slow-acting advantage and it compounds.
Threshold ranges, ranked
The single column most people came looking for: the distance at which each load first falls under each figure, from the declared 20in barrel.
Load Muzzle energy Below 1,500 ft-lb at Below 1,000 ft-lb at Note .338 Lapua Mag 250gr 4,445 979 yd 1,313 yd — .300 PRC 212gr 3,637 805 yd 1,137 yd — .300 Win Mag 180gr 3,292 551 yd 804 yd — 7mm Rem Mag 160gr 2,885 486 yd 756 yd — .30-06 Sprg 180gr 2,806 432 yd 685 yd — 6.5 PRC 143gr 2,633 499 yd 823 yd Beats .30-06 past 400 on both thresholds .308 Win 175gr 2,526 356 yd 609 yd — .270 Win 130gr 2,529 346 yd 589 yd — .308 Win 150gr 2,518 300 yd 514 yd Lower BC costs it 56 yd against the 175gr 7mm-08 Rem 140gr 2,350 307 yd 559 yd — 6.5 Creedmoor 140gr 2,101 303 yd 639 yd Beats .308 150gr on the 1,000 ft-lb line by 125 yd .450 Bushmaster 250gr 2,686 155 yd 259 yd Highest muzzle energy of any sub-300yd row .30-30 Win 150gr 1,902 70 yd 182 yd — .243 Win 100gr 1,867 131 yd 357 yd — .350 Legend 170gr 1,827 62 yd 183 yd — 6.5 Grendel 123gr 1,818 137 yd 407 yd — 6mm ARC 108gr 1,813 147 yd 442 yd — .45-70 Govt 405gr 1,590 21 yd 197 yd Still carries 605 ft-lb at 600 yd 7.62x39 123gr 1,508 2 yd 160 yd — .300 BLK 110gr 1,407 never 133 yd Below 1,500 at the muzzle .300 BLK 125gr 1,405 never 153 yd Below 1,500 at the muzzle .223 Rem 77gr OTM 1,293 never 137 yd Below 1,500 at the muzzle .223 Rem 55gr FMJ 1,282 never 92 yd Below 1,500 at the muzzle 5.56 M855 62gr 1,255 never 103 yd Below 1,500 at the muzzle Read this against the provenance table above, not on its own. A threshold crossing is only meaningful once you know which threshold, stated by whom, at what distance. The 6.5 Creedmoor row is the one that gets argued about, so here it is in numbers. It starts 417 ft-lb behind a .308 150gr and crosses the 1,000 ft-lb line 125 yards further out. Both facts are true simultaneously and which one matters depends entirely on where the threshold gets applied. That is the entire cartridge debate, and it evaporates the moment you fix the distance.
The .450 Bushmaster row is the mirror image. Second-highest muzzle energy on the non-magnum list, and it drops under 1,000 ft-lb at 259 yards — sooner than a 6.5 Grendel that started 868 ft-lb behind. Straight-wall cartridges are engineered for a specific regulatory context and a short range band, and their energy figures should never be compared to a bottleneck round at the muzzle.
Muzzle energy versus impact energy, in yards
Here is the gap the introduction promised, made concrete. Take a claim of the form 'this cartridge makes 1,500 ft-lb' and ask where.
Load Muzzle At 100 yd At 200 yd At 300 yd Energy retained at 300 yd .300 Win Mag 180gr 3,292 2,879 2,511 2,180 66% .300 PRC 212gr 3,637 3,286 2,963 2,665 73% 6.5 Creedmoor 140gr 2,101 1,884 1,686 1,504 72% .308 Win 150gr 2,518 2,132 1,795 1,499 60% .450 Bushmaster 250gr 2,686 1,854 1,254 857 32% .30-30 Win 150gr 1,902 1,350 934 640 34% .45-70 Govt 405gr 1,590 1,221 994 851 54% 6.5 Grendel 123gr 1,818 1,580 1,368 1,179 65% The last column is the honest measure of a cartridge's efficiency. Anything above about 70 percent is a genuinely good long-range performer; anything under 40 percent is a short-range cartridge no matter what its muzzle figure says. Retention percentage is the number nobody prints and it is more informative than muzzle energy by a wide margin. The .300 PRC keeps 73 percent of its energy to 300 yards. The .450 Bushmaster keeps 32. Those two cartridges are not in the same conversation at any distance past about 150 yards, and the muzzle-energy comparison actively conceals that.
It is also why quoting a threshold against muzzle energy is not just imprecise, it inverts the ranking. On muzzle energy the .450 outranks the 6.5 Creedmoor by 585 ft-lb. At 300 yards the Creedmoor is ahead by 647. Same two loads, same table, opposite conclusions, and the only thing that changed was where you looked.
Correcting the whole matrix to your rifle
Three inputs move every number above. Apply them in this order.
- Barrel length. Correct muzzle velocity first at the rates given earlier, then recompute energy as weight in grains times velocity squared over 450,437. A 4in shortfall on a standard cartridge is roughly 100 fps and roughly 7 percent of muzzle energy.
- Altitude and temperature. Thinner air means less drag and more retained energy downrange. At 6,000 ft you gain roughly 4 to 6 percent retained energy at 400 yards over sea level for a typical bottleneck load, and the threshold ranges extend accordingly.
- Actual BC of your bullet, not the class average. Manufacturers publish both G1 and G7 for match bullets; use G7 with a G7 solver if you have it. Substituting a hunting bullet's real BC for a match figure can move a threshold range by 50 yards or more.
- Chronographed velocity beats all of the above. If you have a chronograph, ten shots over it replaces every rule of thumb on this page.
One thing worth resisting: adjusting the threshold instead of the trajectory. If your load crosses a figure sooner than you would like, the honest response is to note the distance and decide what to do with that information — not to go looking for a different published threshold that your load happens to clear. Both threshold figures on this page circulate in several variants precisely because people do that.