NRA Safety Notice re No 4 7.62mm Conversions
This is the current stance of the NRA safety warning which first appeared in the Summer NRA Journal:
Safety Notice
Enfield No 4 Rifle Conversions to 7.62mm
A safety warning concerning the use of Enfield No 4 Rifle actions converted to 7.62mm was published in the Summer Journal.
After further consideration of all factors influencing safety of these conversions and consultation with the Birmingham Proof Master, the following advice must be adhered to in respect of the use of Enfield No 4 conversions:
• Owners of Enfield No 4 actioned rifles converted to 7.62mm currently proofed to 19 tons per square inch are strongly advised to have them re-proofed to the current CIP standard (requiring a minimum mean proof pressure of 5190 bar) which allows the use of CIP approved ammunition with a Maximum Average Working Pressure (MAWP) of 4150 Bar.
• Conversions retaining their original Enfield barrel or a replacement barrel as manufactured by RSAF Enfield are safe to use with commercial CIP approved ammunition, which complies with a MAWP of 4150 bar, loaded with any weight of bullet, providing they carry a valid proof mark, and are still in the same condition as when submitted for proof.
• Conversions fitted with any other make of barrel (such as Ferlach, Maddco, Krieger etc) should be checked by a competent gunsmith to determine the throat diameter of the chamber/barrel fitted before use.
• Conversions where the throat diameter is less than the CIP specification of 0.311” but not smaller than 0.3085” must not be used with ammunition which exceeds 3650 Bar MAWP when fired in a SAAMI/CIP pressure barrel.
• Conversions which have been checked and found to comply with Rule 150 may safely be used with any ammunition supplied by the NRA including the 155 grain Radway Green Cartridge, 155 grain RUAG Cartridge or any other commercial CIP Approved cartridges loaded with bullets of any weight provided that the ammunition pressure does not exceed 3650 Bar when measured in a CIP standard barrel.
• Owners of Enfield No 4 actioned rifles converted to 7.62mm who are uncertain as to the proof status of the rifle should have it checked by a competent gunsmith.
• Owners of Enfield No 4 actioned rifles in any calibre are strongly advised not to use them in wet weather or without removing all traces of oil from action and chamber prior to shooting.
• Enfield No 4 rifles which are fitted with a barrel which has a throat diameter less than 0.3085” must not be used on Bisley Ranges.
• Ammunition loaded with bullets of any weight which are of greater diameter than the throat diameter of the barrel must not under any circumstances be used on Bisley Ranges in any rifle or barrel of any manufacture.