§ Fitment Guide
Mac Allister M4MTP33 chain size & replacement chart
The Mac Allister M4MTP33 takes a 3/8" Low Profile™ pitch, 1.3mm gauge chain. Below: every factory bar length with its exact drive-link count, cross-referenced to Oregon part numbers, plus the OEM parts list.
Fitment matrix
| Bar length | Pitch | Gauge | Drive links | Oregon chains | Bars / combos |
|---|---|---|---|---|---|
| 25cm | 3/8" Low Profile™ | 1.3mm | — | 56426891P040E91PX040E91VXL040E | — |
Source: Oregon part-finder (EU), retrieved 2026-07-06. Part numbers link to the manufacturer's spec page. Always confirm drive-link count against your current chain before ordering.
How to confirm the fit
- Read your bar. The pitch and gauge are stamped on the guide bar near the saw body — e.g.
3/8" LP .050". - Count drive links. Lay the old chain flat and count the teeth that ride inside the bar groove. This number must match exactly; length in inches is not enough.
- Match all three. Pitch, gauge and drive-link count all have to agree with a row in the table above. Two of three is not a fit.
Watch: how to identify chain pitch and gauge
Oregon Products: Identifying Chain Pitch and Chain Gauge Official video from Oregon Products, the manufacturer behind the cross-reference part numbers above.
Official Mac Allister resources
- Mac Allister manuals (B&Q customer support) — owner's manual for the M4MTP33, including tensioning and maintenance intervals.
FAQ
What size chain does a Mac Allister M4MTP33 take?
The Mac Allister M4MTP33 runs a 3/8" Low Profile™ pitch, 1.3mm gauge chain. Available bar lengths: 25cm. Match the drive-link count to your bar (see the table above).
How do I know which gauge my M4MTP33 chain is?
Check the number stamped on your guide bar near the tail, or measure the drive-link thickness with calipers. Common gauges for the M4MTP33 are 1.3mm.
Can I put a longer bar on my Mac Allister M4MTP33?
Oregon lists 25cm bars for the M4MTP33. Stay within this range — a longer bar than the engine is rated for cuts slowly and accelerates wear.