35-06 vs. 35 Whelen

Blue Sky repatriated a quantity of surplus Garand rifles in the 60s. The rifle colloquially known as the Garand was offically designated by the US Government as "U.S. Rifle, Cal 30, M1".  Their barrels were removed as unserviceable and rebored and rifled to 9 mm or 35 cal. Apparently this reworking was done overseas as the twist rate is exactly 1:38 cm or approximately 1:15+ in. This was a time of growing popularity for the 35 Whelen. After spending decades in a storage they were sold as inexpensive barrels by High Standard.

Most, if not all, of the barrels failed inspection using a 30'06 nogo gauge (the head space gauge Brownells sells for the 35 Whelen). This was probably caused by the cleaning up of the chamber due to wear in their former caliber. At the time these barrels were reworked, the 35 Whelen was still a wildcat with no SAAMI standard. Therefore head space wasn't a consideration. Then Remington came along and domesticated the 35 Whelen in 1987 and SAAMI standards were established. Now things get interesting.

Today there is a standard to which all 35 Whelen chambers are cut, all brass is formed and all factory ammo manufactured. These reworked 35 cal USGI barrels do not meet the SAAMI standard. A dangerous situation can occur if a rifleman were to feed rounds of Remington factory ammo into these barrels with their excessive head space. The oprod can bend or even worse, the case can separate letting hot gases escape back into the shooter's face.

To a seasoned wildcat reloader, head space is something dealt with on a routine basis. And this reloader will know how to adjust loading techniques to form a safe and accurate load. However, not every reloader meets this standard. Thus the moniker 35-06 was coined  to reference the nonstandard 35 Whelen wildcat cartridge of yore as opposed to the modern SAAMI standard 35 Whelen cartridge currently available.

If you do not fully understand the information presented above, please do not even CONSIDER building one of these Garand conversions!