Short answer: a chrome-lined barrel has chrome applied to the bore and chamber and is the traditional military choice. A nitride (QPQ) barrel has its steel surface hardened by a salt-bath process, inside and out. A stainless barrel, usually 416R, is chosen for match accuracy and can be left untreated. For a standard 16-inch build, a 4150 barrel with a QPQ nitride finish from a reputable maker, such as the Faxon Gunner or Ballistic Advantage Modern Series, is a good-value default. All the performance claims here come from the makers, not independent tests.
Chrome-lined vs nitride vs stainless barrels
| Chrome-lined | Nitride (QPQ, salt bath) | Stainless (416R) | |
|---|---|---|---|
| What it is | Chrome applied to the bore and chamber | Nitrogen and carbon diffused into the steel surface, bore and exterior | Untreated match steel, "in the white", or treated |
| Usual steel | 4150 chrome-moly-vanadium | 4150 CMV or 416R stainless | 416R or 410 stainless |
| Outside finish | Typically phosphate | Black, matte | Bare, or nitrided |
| Makers say | Durable, easy to clean, used on military rifles; Criterion says its match chrome-lined barrels are hand-lapped | Hardens the steel itself; corrosion resistant inside and out | Match-grade accuracy |
| Example | FN 15 TAC3 (16 in government profile) | Faxon Duty Gunner, 4150 CMV, QPQ bore and exterior | Criterion 416R barrels |
Descriptions are from Criterion Barrels' technical articles on chrome lining vs salt-bath nitriding and barrel life (both from 2017), Faxon, Ballistic Advantage and FN, read October 2026. Criterion sells both finishes, so treat its comparison as a maker's view. We found no independent test data.
Chrome-lined barrels
Chrome lining is a treatment of the bore and chamber. Criterion says it has been used for decades on military rifles and that the exterior is typically phosphate. It also says chrome-lined barrels have an "undeserved reputation" for being less accurate because traditional lining varies the bore, and that it hand-laps its own. FN's 15 TAC3 is a common example: a 16-inch government-profile, chrome-lined, cold-hammer-forged barrel in a CMV steel (DIN 21CrMoV5-11) that FN says is magnetic-particle inspected. Criterion also notes the mil-spec accuracy standard is 4.5 MOA at 100 yards on an M16A4.
Nitride (QPQ) barrels
Salt-bath nitriding, also called ferritic nitrocarburizing or QPQ, diffuses nitrogen and carbon into the surface so the steel itself is hardened, and it blackens the surface. The Faxon Duty Series 16 inch Gunner is a 4150 CMV barrel with salt-bath QPQ nitride on the bore and exterior, 1.37 lb, 1:8 twist, with an M4 feed ramp extension installed at 150 ft-lb, pinned and headspaced. Ballistic Advantage's Modern Series is 4150 CMV with a QPQ finish; its chrome-lined barrels are a different line. Criterion warns that results vary with how a maker does it: extension torque timing, bath temperature and how the bore is machined before nitriding all matter.
Stainless barrels
Stainless 416R is the match-barrel steel. Criterion calls an untreated one "in the white", and sells nitrided 416R barrels too. Stainless suits precision builds; our barrel profiles and twist rate guide covers the other choices that affect accuracy.
Chrome-lined and nitride barrels, with today's prices
Lowest price across the stores we track:
FN America 5.56 16 in mid-length barrel, chrome lined, black phosphate
Pros
- Chrome lined
- FN, 16 in mid-length
Cons
- Costs more than most nitride barrels here
Chrome-lined
Brownells BRN-4/M27 16.5 in medium chrome-lined barrel
Pros
- Chrome lined, phosphate finish
- 16.5 in medium profile
Cons
- Costs more than most nitride barrels here
Chrome-lined
Faxon Gunner 14.5 in mid-length barrel, 4150 QPQ
Pros
- 4150 steel with a QPQ nitride finish
- Gunner profile
Cons
- Under 16 inches: read our short-barrel rifle guide first
Nitride
Ballistic Advantage Modern Series 14.5 in carbine barrel, QPQ
Pros
- 4150 CMV with QPQ
- QPQ-coated feed ramp extension
Cons
- No chrome-lined bore
Nitride
Diamondback 16 in 1:8 black nitride barrel
Pros
- Black nitride finish
- Low price
Cons
- Few published specs
Budget nitride
Stainless barrels, with today's prices
Odin Works medium profile stainless barrel, 16.1 in
Pros
- Stainless steel
- Medium profile
Cons
- Few published specs here
Stainless
Criterion 18 in AR-10 rifle-gas barrel, .308, 416R stainless
Pros
- 416R stainless from a maker that publishes its process
Cons
- AR-10 size, not an AR-15 barrel
Stainless (AR-10)
How to choose
- Plain build, best value: a 4150 CMV barrel with a QPQ nitride finish.
- Duty-style, traditional: a chrome-lined barrel, as on FN's rifles.
- Precision: a stainless 416R barrel; see our 5.56 ballistics chart for what the barrel length and load do.
- Check the maker. Criterion warns that cheap nitriding can be done badly. Buy from a maker that lists its steel and process, as Faxon does.
Compare every AR-15 barrel by price, browse chrome-lined barrels, and plan the rifle in the AR-15 builder.
Frequently asked questions
Is chrome-lined or nitride better for an AR-15?
Both are durable, and makers say either can be accurate. Chrome lining is the traditional military treatment; nitriding hardens the steel itself, inside and out.
What does QPQ mean on an AR-15 barrel?
Quench-polish-quench, a salt-bath nitride treatment of the steel surface. Faxon's Gunner barrels are QPQ nitrided on the bore and exterior.
Is a chrome-lined barrel less accurate?
It can be if the lining is applied unevenly, according to Criterion, which says its hand-lapped chrome-lined barrels avoid that. The mil-spec standard is 4.5 MOA at 100 yards.
How long does a chrome-lined or nitrided barrel last?
Criterion says either treatment can double or triple an untreated barrel's service life; it is the maker's estimate, not a test.
Is a stainless barrel better than a chrome-moly one?
Stainless 416R is the match-barrel steel and suits precision builds; a treated 4150 barrel is the usual choice for a general-purpose rifle.
What steel are AR-15 barrels made from?
Most are 4150 chrome-moly-vanadium: Faxon and Ballistic Advantage list it, and FN uses a CMV grade (DIN 21CrMoV5-11). Match barrels are often 416R stainless, as Criterion lists.
