LINED or HONED
Frequently Asked Questions — Monobloc® Barrel Bore Options
One starts more accurate. The other stays where it started.
// The Short Answer
Triple honing is the surface the bullet rides. Chrome lining puts a different one on top of it.
Our standard Monobloc® barrel is 416 stainless, button rifled, then triple honed — and that honing is not a cosmetic step. It’s what produces a bore whose dimensions and finish are consistent from chamber to crown, which is most of what makes a barrel shoot. Chrome lining is a plating deposited into that finished bore, and the difficulty has always been the same one: it is genuinely hard to plate the inside of a rifled barrel to exactly the same thickness all the way down. Wherever the plating varies, your carefully honed uniformity varies with it. That is the mechanism behind chrome lining’s reputation among match shooters, and it’s why national match barrels have traditionally been left unlined. What chrome buys in return is real and worth understanding: substantially better resistance to throat erosion, which is what eventually ends a barrel’s accurate life. One thing worth being clear about up front — the chrome-lined option is the same 416 stainless Monobloc® blank, lined. It is not a different, cheaper barrel with a plating on it.
// Uniformity Is The Whole Argument
Plating a rifled bore evenly is a harder problem than it sounds.
Chrome is deposited electrically, and deposition rate depends on the distance between the electrode and the surface being plated. In a rifled bore that distance changes constantly — lands are closer, grooves are further. Doing it well requires an electrode formed as a reverse of the rifling and held precisely centered and oriented down the whole length of the barrel; the quality of the result depends directly on how well that is controlled. The bore also has to be rifled slightly oversize so that, once plated, it finishes within tolerance.
When it isn’t controlled well, you get thick and thin spots, softened rifling corners, and a bore that is less uniform than the one the honing produced. This is the reason match barrels have historically been unlined — the U.S. military’s own sniper variants of the M14 used unlined barrels precisely because they shot better. Note the shape of that claim, though: the problem is plating variability, not chrome itself. At least one well-regarded barrel maker now produces a match-grade chrome-lined AR barrel and credits a more consistent, uniform lining process for it. Done to a high standard, the gap narrows a great deal.
Which leaves a genuine trade rather than a right answer. A triple-honed match bore starts with the higher accuracy potential. A chrome-lined bore resists throat erosion far better — commonly cited at two to three times — and throat erosion is what actually ends a barrel’s useful accuracy. One barrel starts higher. The other holds its starting point longer. Which matters more depends entirely on what the rifle does for a living. Pick the curve, not the number.
| Standard Monobloc® (match) | Chrome-lined Monobloc® | |
|---|---|---|
| Barrel steel | 416 stainless | 416 stainless — the same blank |
| Construction | Monobloc® — gas block milled into the blank | Monobloc® — gas block milled into the blank |
| Rifling | Button rifled | Button rifled |
| Chambering | 5.56×45mm NATO | 5.56×45mm NATO |
| Bore surface | Triple-honed steel — the honed finish is what the bullet rides | Hard chrome plated over the rifled bore |
| Bore uniformity | Set by the honing operation | Set by honing, then modified by plating thickness variation |
| Starting accuracy | Higher potential | Good; depends heavily on lining quality |
| Throat erosion resistance | Normal for stainless | Substantially better — commonly cited 2–3× |
| Corrosion resistance | 416 stainless is already corrosion resistant | Bore protection added on top of the same stainless |
| Fouling | Normal cleaning | Resists carbon buildup |
| Solvent caution | None specific | Avoid prolonged soaks in ammonia-based copper solvents |
| Availability | Standard across the series | Limited additional option |
| Best for | Precision, competition, deliberate fire | High round count, sustained fire, harsh environments |
// Questions We Get Asked
Why exactly does chrome lining cost accuracy?
Three related reasons, all of them about uniformity rather than the chrome itself:
- Plating thickness varies. Deposition depends on electrode distance, and in a rifled bore that distance changes between lands and grooves and along the barrel’s length. Perfect evenness is difficult.
- It covers the honed finish. Triple honing exists to produce a specific surface. Plate over it and the bullet no longer rides that surface — it rides the plating.
- Rifling corners soften. Plating tends to build at edges, which can round the crisp land-to-groove transitions that engrave the bullet consistently.
How much accuracy are we talking about?
A commonly cited figure is a quarter to half a minute of angle added to group size where plating thickness isn’t tightly controlled. We’d treat that as an indication rather than a specification — the honest answer is that it depends almost entirely on the quality of the lining, and the range between a poor one and an excellent one is wider than the average difference.
So is chrome lining just worse?
No, and we’d be misleading you if we let that stand. Chrome lining solves a problem match barrels don’t solve: it dramatically slows throat erosion, which is what kills a barrel’s accuracy over a service life. A match barrel that starts at half a minute and is finished at four thousand rounds may be the worse choice for a rifle that will see twenty thousand.
What does triple honing actually do?
It refines the bore after rifling — multiple passes that bring the surface finish and the dimensional consistency to a level button rifling alone doesn’t reach. A bore that measures the same and feels the same from chamber to crown is what lets a bullet be engraved and released identically every shot. That consistency is what you’re buying in a match barrel.
Do I need chrome for corrosion resistance?
Less than you would with a chrome-moly barrel. Both of our bores are 416 stainless, which already resists corrosion far better than carbon steel — stainless is not rust-proof, but it removes much of the historical argument for lining. Chrome here is additive protection on an already corrosion-resistant barrel, which is why erosion life, not corrosion, is the real reason to consider it.
Which barrel lasts longer?
The chrome-lined one, in accurate-life terms, and by a meaningful margin under hard use. But be careful with round-count numbers — published figures swing wildly because they depend on ammunition, rate of fire, and how hot the barrel gets. A barrel cooled between strings outlives an identical one that gets mag-dumped, regardless of what’s in the bore.
Does chrome change how I clean it?
Mostly it makes cleaning easier — carbon releases more readily from a hard smooth plating. One real caution: avoid leaving aggressive ammonia-based copper solvents sitting in a chrome-lined bore. Chrome is bonded over an underlayer, and prolonged ammonia exposure can work at that bond through any imperfection. Clean it, don’t soak it.
What happens at the chamber and throat?
Reaming a chamber removes plating in the reamed area, so chamber and throat treatment is part of how a lined barrel is made rather than an afterthought. It’s one more reason lining quality is a manufacturing question: the barrel has to be rifled slightly oversize and finished to spec with the plating in place.
Can a chrome-lined barrel be match grade?
Yes — a well-regarded maker now offers exactly that and credits a more uniform lining process. It’s worth knowing because it locates the problem correctly: the historical accuracy penalty is a plating-consistency problem, not a law of physics. Good lining costs more and is harder to do, which is why it isn’t universal.
Why is the unlined barrel your standard?
Because the Monobloc® series is built around accuracy and consistency, and for the way most of our customers use these rifles the honed 416 stainless bore is the better answer. Chrome lining is offered as a limited additional option for the cases where erosion life outweighs starting accuracy. It is not a cheaper alternative — it’s the same 416 stainless Monobloc® barrel with an extra process performed on it, which is a common industry shortcut we deliberately don’t take.
Does the Monobloc construction change any of this?
Not the lining question itself. The Monobloc® advantage is that the gas block is milled into the barrel blank rather than clamped on, so the barrel heats and expands more evenly — that benefit applies to either bore equally. Your bore choice and your barrel architecture are two separate decisions.
Which should I order?
Answer honestly about how the rifle will actually be used, not how you imagine using it:
- Standard triple-honed match bore — precision work, competition, deliberate fire, and anyone who cares most about the smallest group the rifle can print. This is the default for good reason.
- Chrome-lined — very high round count, sustained or rapid strings, duty and agency rifles, marine or tropical environments, and anyone who would rather have consistent-enough accuracy for twenty thousand rounds than excellent accuracy for five.
- Not sure? Tell us your annual round count, how fast you shoot it, and where it lives. Most shooters overestimate the first and underestimate how much the third matters.
// What This Comparison Cannot Settle
The bore is one variable in a system with several.
- The accuracy gap is not a constant. It’s a function of lining quality. A well-lined barrel and a poorly lined one differ from each other more than the average lined barrel differs from an unlined one.
- Barrel-life numbers are soft. Published round counts vary by a factor of several depending on ammunition, cadence, and heat. Treat any specific figure — including ones we’ve cited — as a range.
- Ammunition outweighs both. Velocity spread and bullet consistency drive vertical dispersion at distance more than bore treatment does. A chrome-lined barrel fed good handloads will outshoot a match barrel fed indifferent ammunition.
- Neither choice makes a rifle accurate. Chamber concentricity, the crown, the barrel joint, and the shooter all still have to be right.
- Throat erosion eventually wins. Every barrel is consumable. Lining changes the slope of that curve; it doesn’t remove it.
// What You Get
Your build record names the barrel — length, gas system, bore treatment, and the headspace gauging result for your bolt against it. Whichever bore you chose, the barrel came off the same Monobloc® architecture with the gas block milled into the blank, and it left here with a Zerust VCI protector in it. If you’re deciding between the two, call us and describe the rifle’s job rather than its aspirations — we’ll tell you which one we’d build for that, including when the answer is the one that costs less.
One starts higher. One stays longer.