How-To Guides
Everything you need to start shooting well and make smart hardware decisions — written for real beginners and improving shooters.
Rifle Recoil Chart: 48 Cartridges at One Declared Weight, Then Solved for Yours
At a declared 8.00 lb rifle, .223 Remington with a 55 gr bullet at 3,240 fps produces 3.5 ft-lb of free recoil, .308 Winchester with a 168 gr bullet produces 16.6 ft-lb, and .300 Win Mag with a 180 gr bullet produces 30.4 ft-lb. Those three can be ranked against each other because every row was solved at the same weight, the same load data and the same powder-gas convention. Change the rifle weight and every number moves, which is why the solver matters more than the table.
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Barrel Twist Rate Chart, Rebuilt Around Bullet Length Instead of Bullet Weight
Gyroscopic stability is decided by bullet length, not bullet weight, and the two disagree often enough to matter. 62 gr M855 measures about 0.906 in — the same as a 69 gr match bullet — so it needs the same twist despite being seven grains lighter, and a 62 gr solid copper bullet at about 1.010 in needs a faster twist than either. Aim for a Miller stability factor between 1.4 and 2.0 on your coldest expected day, not your warmest.
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300 Blackout Velocity by Barrel Length: What Each Inch From 7.5 to 16 Inches Is Worth
A 110 gr supersonic 300 BLK load loses roughly 233 fps going from a 16 in barrel to a 7.5 in one, but the loss is not linear — about 17 fps per inch between 14.5 and 16 in, about 40 fps per inch below 8.5 in. Subsonic loads move far less, around 90 fps across the same range, which is why the cartridge works in short barrels at all. A 190 gr load leaving a 16 in barrel at 1,140 fps is already supersonic and needs a shorter barrel or a different load.
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Muzzle Brake vs Compensator vs Flash Hider: What Each One Trades Away
A good multi-port brake removes 25 to 35 percent of recoil impulse at the reference rig, which the maker will print as 44 to 58 percent because energy scales with the square of momentum. Both figures are arithmetically true; only the impulse figure describes what your shoulder receives. Flash hiders do essentially nothing for recoil, compensators fight muzzle rise rather than rearward push, and every brake buys its performance with 6 to 12 dB of extra blast aimed at whoever is standing beside you.
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Every Muzzle Thread Pitch, and the Ones Manufacturers Break
AR-15 barrels in 5.56 are 1/2x28 and AR-10 barrels in .308 are 5/8x24, and those two cover most of the market — but .300 BLK is also 5/8x24 despite living on an AR-15, 9mm AR barrels are often 1/2x36, and AK pattern rifles use left-hand metric threads. Measure the major diameter with calipers and the pitch with a gauge before you order anything, because a 1/2x28 device on a .30 caliber bore is a device strike waiting to happen.
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AR-15 Buffer Weight, Spring Rate and Gas Length That Cycle Together
A carbine buffer is 3.0 oz, H is 3.8, H2 is 4.6, H3 is 5.4 and a rifle buffer is about 5.0 oz, and one step of roughly 0.8 oz moves ejection about one hour on the clock. But buffer mass is the last thing to change, not the first — barrel length, gas system length and port diameter set the problem, and a buffer only trims the answer. Brass at 4 to 5 o'clock unsuppressed and 3 to 4 o'clock suppressed means the rifle is in tune.
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6.5 Creedmoor to 1,000 Yards, Corrected for Your Barrel and Your Altitude
From a 24in barrel at sea level and 59F, a 140gr ELD Match at 2,710 fps drops 53.3in at 500 yards and 320in at 1,000, holding 1,484 fps and 685 ft-lb. Cut the barrel to 20in and 1,000-yard drop grows to 352in; move to 8,000ft and it shrinks to 280in. The box card is one point on that surface, not the surface.
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MOA, MRAD and Dot Size in One Conversion Table
1 MOA is 1.047in at 100 yards; 1 mil is 3.6in at 100 yards. A 1/4 MOA click moves impact 0.262in per 100 yards, a 0.1 mil click moves it 0.36in. The same arithmetic governs reticle subtension, which is why a 2 MOA dot covers 2.09in at 100 yards and completely hides a 6in plate at 287.
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Red Dot Footprints and Which Slide, Mount or Rail Each One Bolts To
There are roughly eight footprint families in common use and several near-clones that will bolt up but not stay bolted. What separates them is whether the pattern has load-bearing recoil lugs or asks the two screws to carry the recoil alone. Match footprint, screw length and torque, or the pattern that fits today shears a screw at round 400.
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Pick an AR-15 Zero by the Miss You Can Live With: 25, 36, 50 and 100 Yards Compared
With a 2.60in sight height and 55gr M193, a 50-yard zero keeps every impact inside 3 inches of the dot from the muzzle to 266 yards. A 36-yard zero rises 4.7 inches at 170 and busts a 6-inch target at 93 — but it holds a 10-inch target to 336. The right zero depends entirely on target size, which is why the argument never ends.
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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.
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Diagnosing an AR-15 From the Evidence It Leaves — Brass, Primers, Bolt and Mount
Ejection at 1 to 2 o'clock means over-gassed; 7 to 9 means short-stroking. Brass smeared on the case mouth is bolt-over-base from a weak spring, and a zero that walks 2 inches after 200 rounds is almost always a mount at the wrong torque rather than an optic fault. Read the evidence, run one confirming test, then change one part.
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