20 Inch Chainsaw Chain: Complete Fitment Guide for Every Brand Australia | Farm & Acre Co
Twenty inches is where chainsaws get serious. A 20 inch bar handles big firewood rounds, fence posts, felling medium trees, and proper farm work. It's the standard bar length for saws in the 50–80cc range — your Stihl Farm Boss with a long bar, your Husqvarna 455 or 460 Rancher, your Echo Timber Wolf.
But 20 inch chains vary more than you'd expect between brands. Here's every common 20 inch chain spec.
20 Inch Chain Specs by Brand
| Model | Pitch | Gauge | Drive Links | Chain Type |
|-------|-------|-------|-------------|------------|
MS 271 Farm Boss | .325" | .063" | 81 | Semi chisel |
|MS 290 Farm Boss | .325" | .063" | 81 | Semi chisel |
MS 291 Farm Boss | .325" | .063" | 81 | Semi chisel |
MS 311 | 3/8" | .050" | 72 | Semi chisel |
MS 362 | 3/8" | .050" | 72 | Full chisel |
MS 391 | 3/8" | .050" | 72 | Semi chisel |
MS 440 | 3/8" | .050" | 72 | Full chisel |
MS 441 | 3/8" | .050" | 72 | Full chisel |
MS 460 | 3/8" | .050" | 72 | Full chisel |
MS 461 | 3/8" | .050" | 72 | Full chisel |
MS 500i | 3/8" | .050" | 72 | Full chisel |
Two groups: The Farm Boss models (MS 271/290/291) use .325" pitch .063" gauge 81DL. Everything else uses 3/8" pitch .050" gauge 72DL. These are completely different chains.
| Model | Pitch | Gauge | Drive Links | Chain Type |
|-------|-------|-------|-------------|------------|
450 | .325" | .050" | 80 | Semi chisel |
450 Rancher | 3/8" | .050" | 72 | Semi chisel |
455 Rancher | 3/8" | .050" | 72 | Semi chisel |
460 Rancher | 3/8" | .050" | 72 | Semi chisel |
465 Rancher | 3/8" | .050" | 72 | Semi chisel |
555 | 3/8" | .050" | 72 | Full chisel |
562 XP | 3/8" | .050" | 72 | Full chisel |
365 | 3/8" | .050" | 72 | Full chisel |
372 XP | 3/8" | .050" | 72 | Full chisel |
572 XP | 3/8" | .058" | 72 | Full chisel |
Watch out: The Husqvarna 450 (non-Rancher) uses .325" pitch with 80 drive links. The 450 Rancher and everything above uses 3/8" pitch with 72 drive links. And the 572 XP uses a thicker .058" gauge.
Echo 20" Chainsaws
| Model | Pitch | Gauge | Drive Links | Chain Type |
|-------|-------|-------|-------------|------------|
CS-490 | 3/8" | .050" | 70 | Semi chisel |
CS-501P | 3/8" | .050" | 70 | Full chisel |
CS-590 Timber Wolf | 3/8" | .050" | 70 | Semi chisel |
CS-620P | 3/8" | .050" | 70 | Full chisel |
Echo 20" saws all use 3/8" .050" but with 70 drive links — different from the 72DL used by Stihl and Husqvarna on the same pitch and gauge. The pitch and gauge match, but the chain length is different.
Full Boar 20" Chainsaw
| Model | Pitch | Gauge | Drive Links | Chain Type |
|-------|-------|-------|-------------|------------|
FBPC-5320 (53cc) | .325" | .050" | 78 | Semi chisel |
The Full Boar 20" uses .325" pitch with .050" gauge — same pitch as some Husqvarna models but with a different drive link count (78 vs 80). Always count your drive links.
Milwaukee 20" Chainsaw
| Model | Pitch | Gauge | Drive Links | Chain Type |
|-------|-------|-------|-------------|------------|
M18 FUEL 20" Dual Battery (2827-22) | .325" | .050" | 78 | Semi chisel |
Same specs as the Full Boar 20".
Baumr-AG 20" Chainsaws
| Model | Pitch | Gauge | Drive Links | Chain Type |
|-------|-------|-------|-------------|------------|
SX82 (82cc) | 3/8" | .058" | 72 | Semi chisel |
Uses a thicker .058" gauge — same as the Husqvarna 572 XP.
Makita 20" Chainsaws
| Model | Pitch | Gauge | Drive Links | Chain Type |
|-------|-------|-------|-------------|------------|
EA5000P | 3/8" | .050" | 70 | Semi chisel |
Same specs as Echo 20" models.
The Most Common 20 Inch Chains
Chain 1: 3/8", .050", 72DL — The Universal Farm Chain
The single most common 20 inch chain. Fits: Stihl MS 311/362/391/440/441/460/461/500i, Husqvarna 450 Rancher/455/460/465/555/562 XP/365/372 XP.
If your saw is 50cc+ with a 20 inch bar and runs 3/8" pitch, there's a good chance this is your chain.
Chain 2: 3/8", .050", 70DL — The Echo/Makita Chain
Fits: Echo CS-490/501P/590/620P, Makita EA5000P.
Same pitch and gauge as Chain 1, but two fewer drive links. You cannot interchange 70DL and 72DL chains — one will be too short or too long.
Chain 3: .325", .063", 81DL — The Stihl Farm Boss Chain
Fits: Stihl MS 271/290/291 Farm Boss with 20" bar.
This is Stihl-specific. The .063" gauge is thicker than what Husqvarna uses, and 81 drive links doesn't match any other brand.
Chain 4: .325", .050", 78–80DL — The .325" Consumer Chain
Fits: Husqvarna 450 (80DL), Full Boar FBPC-5320 (78DL), Milwaukee M18 FUEL 20" (78DL).
Note the drive link difference — 78 vs 80. Check yours carefully.
Chain 5: 3/8", .058", 72DL — The Heavy-Duty Chain
Fits: Husqvarna 572 XP, Baumr-AG SX82.
Thicker gauge for more powerful saws. Not interchangeable with .050" gauge chains.
Stihl Farm Boss Trap: .325" vs 3/8" on 20" Bars
This catches people out regularly. If you have a Stihl with a 20 inch bar, the chain depends on which model:
MS 271/290/291 Farm Boss: .325" pitch, .063" gauge, 81DL
MS 311/362/391/440+: 3/8" pitch, .050" gauge, 72DL
These are completely different chains. The drive sprocket on your saw is set up for one pitch or the other — fitting the wrong one won't work and could be dangerous.
How to tell: Check the bar markings, or look at the drive sprocket teeth. .325" teeth are visibly smaller than 3/8" teeth.
Which Chain Type for a 20 Inch Saw?
A 20 inch bar on a 50cc+ saw is a proper work tool. Chain type matters here.
Semi Chisel — The All-Rounder
Best for: farm firewood, cleanup, mixed use, dirty timber, Australian hardwood. This is the default recommendation for most farmers.
Full Chisel — The Performance Option
Best for: felling clean timber, milling, professional forestry work. Cuts faster but dulls quicker in dirty conditions.
Tungsten Carbide — The Endurance Option
Best for: hardwood firewood (ironbark, box, red gum), land clearing, dirty timber, anyone tired of constant sharpening. Costs more upfront but the edge lasts 10x longer.
For a 20 inch saw cutting Australian hardwood, tungsten carbide semi chisel is the premium combination. You'll process a trailer load of firewood without stopping to sharpen.
How to Confirm Your 20" Chain Size
1. Check the bar — stamped numbers near the tip or base show pitch, gauge, and drive links
2. Count the drive links on the old chain — most reliable method
3. Check the sprocket — smaller teeth = .325" pitch, larger teeth = 3/8" pitch
Need a 20 inch chain? Browse our chainsaw chains and bars all common 20 inch sizes in standard and tungsten carbide.
Not sure which one? Send us your model number or a photo of your bar — call Aaron 0431 183 421 or email us farmandacreco@gmail.com
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