EC Internal Barrel-Thread Inspection Card
Shop-controlled record. Use with the work order and controlling drawing. This card may also be useful to other qualified shops.
Planning reference—not a machining specification. Current instructions and drawings for the actual barrel, firearm, muzzle device, mount, piston, or adapter always supersede this EC document. Confirm thread class, finished major and pitch diameters, root form, relief, length, shoulder geometry, torque, and alignment requirements before work.
| Characteristic | Requirement | Measured | Instrument / method | Result |
|---|---|---|---|---|
| Finished barrel OD | ||||
| Thread major | ||||
| Pitch diameter / class | ||||
| Root / optional relief | ||||
| Thread length | ||||
| Relief width | ||||
| Radial shoulder | ||||
| Radial wall | ||||
| Shoulder / face runout | ||||
| Device alignment / clearance |
□ Bore/chamber clear□ Profile/material accepted□ Crown protected/finished□ Device fit verified□ Timing/clearance verified□ Alignment verified