On Savage rifles, there is usually enough movement to ensure fairly uniform contact between the two locking lugs
and their shoulders in the receiver.
The "A" in the serial number was used to separate the 3rd Model 1890 receivers from those of the 1st and 2nd models (which had internal locking lugs
for the bolt, rather than the external lugs).
I then coated the rear surfaces of both locking lugs
on the bolt with Dykem machinist layout fluid.
As the slide moved rearward, the stud/slot turns the barrel slightly clockwise to free three locking lugs
from their recesses in the slide.
Wilson also recommends checking the engagement of the twin locking lugs
with their recesses in the slide.
Sako's famous action sports three locking lugs
and mechanical ejector.
What we did find was a small sliver of steel atop the locking lugs
on the barrel that had sheared off the lug recesses in the slide and the cause was readily apparent.
The bolt body and the locking lugs
must pass through the shim.
The Model 70 features dual, opposing locking lugs
; a full-length, rotating claw extractor; a fixed, mechanical ejector; a three-position wing-type safety; and a box magazine.
The hallmarks of this Mauser's action were its dual-opposing forward locking lugs
; controlled-round-feed, in which the cartridge feeds up out of the magazine against the bolt face, where it is trapped or held in place by the extractor and carried or "controlled" into the chamber; a long extractor with a wide surface grabbing the cartridge rim; and a fixed-blade ejector in the rear action ring, operating through a slot in the bolt face.
The action of the 1920 shows the influence of the Mauser 98 and '03 Springfield, with two forward locking lugs
, long external extractor and controlled-round feeding.
The first step is to simply check your bolt to ensure it fits the receiver and you have good contact between the locking lugs
on the bolt body and the lug seats in the receiver.