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IS 7549:1975 is the Indian Standard (BIS) for timber half-wrought for sporting rifles. This standard specifies the requirements for half-wrought timber blanks used for manufacturing stocks for sporting rifles. It covers the material (primarily walnut), dimensions, tolerances, permissible defects, moisture content, and marking for the semi-finished wood components.
! The species of timber, typically Indian Walnut (Juglans regia), is critical for achieving the desired strength, stability, and aesthetic.
! Careful inspection of grain direction and for defects like knots, splits, or cross-grains is essential, especially around the grip and action areas, as these can lead to catastrophic failure during use.
! Verification of moisture content is crucial to prevent warping or cracking of the finished rifle stock.
Wood, Walnut, Black (Juglans Nigra), Gunstock Blanks
Covers quality, seasoning, and defect requirements for walnut gunstock blanks for military rifles.
DIN 68366:1957-03Deutsches Institut für Normung, Germany
HighWithdrawn
Holz für Gewehrschäfte; Gütebedingungen (Wood for gun stocks; quality requirements)
Specifies quality conditions for walnut wood specifically intended for the manufacture of gun stocks.
NHLA Rules for the Measurement and Inspection of Hardwood and CypressNational Hardwood Lumber Association, USA
LowCurrent
Rules for the Measurement and Inspection of Hardwood and Cypress
Defines grading for general hardwood lumber, which is the raw material before being cut into specific gunstock blanks.
Key Differences
≠IS 7549 specifies Juglans regia (English/Persian Walnut), whereas key international counterparts like MIL-W-6058D specify Juglans nigra (American Black Walnut), which has different density, color, and grain characteristics.
≠The Indian standard is for 'sporting rifles', where appearance can be a factor, and includes a Grade II allowing minor aesthetic defects. Military specifications like MIL-W-6058D are for service rifles, prioritizing absolute structural integrity and interchangeability over appearance, hence having stricter defect criteria.
≠IS 7549 specifies a moisture content of 12% ± 2% (10-14%), while MIL-W-6058D requires a tighter and lower range of 9% to 12%.
≠While IS 7549 (Grade I) and MIL-W-6058D both prohibit knots, the Indian standard provides a lower grade (Grade II) which permits small, sound knots up to 5mm in specific zones. The military standard has no such allowance.
Key Similarities
≈Both IS 7549 and equivalent international standards mandate the use of walnut (Juglans genus) as the primary timber, recognizing its optimal balance of strength, stability, and workability for gunstocks.
≈A critical shared requirement is the control of grain orientation. All standards specify that the grain must run parallel to the length of the stock, with a maximum slope (e.g., 1 in 15), especially through the narrow grip or wrist area, to ensure maximum strength.
≈All standards strictly limit or prohibit the presence of strength-reducing defects such as splits, decay, insect damage, and cross-grain.
≈Both the IS code and international equivalents require the timber blanks to be properly seasoned to a stable moisture content to prevent warping, checking, and cracking in the finished rifle stock.
Parameter Comparison
Parameter
IS Value
International
Source
Primary Timber Species
Juglans regia (English/Persian Walnut)
Juglans nigra (American Black Walnut)
MIL-W-6058D
Moisture Content
12% ± 2% (10-14%)
9% to 12%
MIL-W-6058D
Minimum Density
560 kg/m³ at 12% moisture content
Specific gravity not less than 0.50 (approx. 560 kg/m³ at 12% MC)
MIL-W-6058D
Maximum Grain Slope
Slope shall not exceed 1 in 15
Slope of grain shall not be greater than 1 inch in 15 inches
MIL-W-6058D
Sapwood Allowance
Grade I: None. Grade II: Permitted on certain surfaces up to 10mm width.
Sapwood shall not be permitted.
MIL-W-6058D
Knot Allowance
Grade II allows sound intergrown knots up to 5mm in designated zones.
Blanks shall be free from knots.
MIL-W-6058D
End Sealant Specification
Prescribes a paraffin wax, rosin, and lamp black mixture (8:1:1) or equivalent.
Must conform to a separate military specification for coatings (MIL-C-13610).
MIL-W-6058D
⚠ Verify details from original standards before use
Key Values3
Quick Reference Values
Maximum permissible moisture content12%
Minimum seasoning period for air seasoning12 months
Minimum slope of grain in the 'hand' (grip) section1 in 15