Despite all the posts...
In order to reduce manufacturing costs in the face of higher labour rates, rifles manufactured from 1964 to 1992 differed from early Model 70s in the following ways:
The bolt was changed significantly. The bolt face was enclosed so that it fully surrounded the cartridge rim, in a similar way to the Remington 700 bolt. While cheaper to manufacture than the undercut bolt face needed for controlled feed actions, it is also stronger, providing more support to the cartridge case head, and better contains escaping gases in the event of a case rupture. The new bolt also differed from the old in that it was manufactured in 2 pieces (bolt-handle/collar and the bolt body[7]) and then brazed together.
The Mauser-inspired, non-rotating claw extractor (incompatible with a fully enclosed bolt head) was eliminated, and replaced with a small wedge-shaped extractor located within a lug of the bolt head. This type of extractor does not engage the cartridge rim as it rises from the magazine into the action, but rather clips over the cartridge rim after the cartridge has been pushed into the chamber and the bolt handle is turned down. This system is more vulnerable than the old system to jamming or being inadvertently closed on an empty breech (i.e. failing to load a new round) if operated under duress, especially if the rifle is held upside down or on its side. In addition, the old extractor design served to stabilize the bolt while the action was open; without it, the new bolt did not have any such stabilization, and wobbled while fully open. This has since been fixed in later rifles, but it was nevertheless an obvious departure and certainly less elegant in function than the earlier models, which allowed the rifle to chamber cartidges smoothly from any position.
Barrels were now rifled by hammer forging, rather than the more costly process of being cut by hand.
The machined steel trigger guard and floor plate were replaced with parts stamped from an aluminium alloy to reduce weight using the assembly from the pre-1964 Featherweight version.
Some earlier models featured walnut stocks with checkering that was impressed onto the wood rather than cut into it as on the early Model 70s, further reducing manufacturing costs at the expense of a less positive grip on the rifle, particularly if the shooter is wearing gloves.
Last edited by Spotshooter; 12/17/14.
