Out of stock
SKU: E01630
UPC: 082442875347
MPN: E01630
The Beretta Stock Drop Adjustment Kit (MPN E01630) is the B-Fast shim system that lets a shooter tune the fit of a Beretta semi-auto shotgun instead of settling for factory geometry. It works by swapping the shim plate between the receiver and the stock, changing where the comb sits relative to your eye. Wing shooters chasing a cleaner sight picture, clays competitors, and anyone mounting the gun inconsistently benefit from getting drop and cast right. If you've searched for a Beretta A300 shim adjustment chart, this is the hardware those charts reference. Browse related shotgun action parts to round out a fitting project.
Per Beretta specifications, the B-Fast system covers a wide adjustment window: up to 11 mm of height change parallel to the tower axis, up to 6 inches of drop, up to 11 degrees of rotation relative to the axis perpendicular to stock drop, and up to 13 mm of lateral cast perpendicular to the stock. That range lets you correct both drop and cast, whether you shoot high with too much comb or need cast-off to line the rib up under your dominant eye. The redesigned locking screws seat tightly against the towers for a solid fit that holds zero of adjustment under recoil. Because the shims are keyed, each plate corresponds to a specific drop and cast value, which is what those A300 fitting charts map out step by step.
Use this kit when a Beretta A300, 390, 391, 3901, or similar semi-auto doesn't shoot where you look. Set your point of aim, note whether the pattern prints high, low, or off to one side, and select the shim that moves the comb toward center. Cast changes handle left-eye or right-eye dominance and shoulder pocket differences. It's a straightforward swap with a takedown of the stock and the included locking screws. For more fitting and repair hardware, see our stock parts and firearm parts selection.
Yes. The A300 Outlander adjusts for drop and cast the same way the 390, 391, and 3901 do, so the B-Fast shim system applies. Match your drop and cast readings to the shim plate and follow the same fitting steps referenced in the A300 shim adjustment chart.
The shim plate sits between the receiver and the stock and changes comb height, drop, and cast. Per Beretta specifications the system covers up to 11 mm of height, 6 inches of drop, 11 degrees of rotation, and 13 mm of lateral cast, letting you line the rib up under your dominant eye.
Pattern the gun first. If it prints high, you need more drop; if it shoots off to one side, adjust cast. Beretta's fitting charts map each shim plate to a specific drop and cast value. Note where your pattern lands relative to point of aim, then choose the shim that moves it toward center.
Installation involves removing the stock, swapping the shim plate, and torquing the included locking screws against the towers. The new locking screws are designed to seat tightly for a secure fit that holds under recoil. No proprietary tooling beyond standard stock takedown hardware is required.
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