Upgrade your Blue Line Pump shotgun with our extended magazine tube.
This essential add-on increases your round count, keeping you ready for action whether you’re at the range or in a tactical scenario. Built for durability and a flawless fit, it ensures reliable performance and smooth feeding with every shot.
+1 - 3.5 inches long
Comes with our:
- CNC Machined Green No-Jam Delrin Mag Follower
- Million Cycle Count Spring & 3 Position Front Sling Mount.
CNC Milled from a solid block of 4140 steel.
Finish: Cerakote Graphite Black.
100% Made in Canada.
Why one-piece construction matters
Every multi-piece magazine extension has at least three components: a cap, a tube body, and a nut. Each junction is a potential failure point - a gap where a shell rim can catch, a seam where the bore stops being perfectly round, a thread junction that loosens under recoil.
Conventional tubes are made from extruded or DOM tubing. That means a weld seam running the length of the bore. When we machine from solid barstock, the bore is perfectly round from end to end because it was cut that way, not formed and welded.
There is no cap to unscrew. No nut to back off. No seam for a shell to catch on. One piece. One continuous bore from the threads into a lead end - the same approach used in barrel manufacturing.
Why we machine from 4140 barstock
Magazine tubes live under the gun, at the front of the gun, where they hit things. Door frames. Truck beds. Barricades. Obstacle courses. A thin-wall aluminum or extruded steel tube that dents on contact is a reliability problem waiting to happen - a dent in the bore is a jam you can't clear in the field.
4140 is the same chromoly steel used in most shotgun barrels. We machine from custom-sized barstock using specialized CNC tooling developed over eight to nine months of R&D just to get the process repeatable.
The weight difference between our machined steel and a machined aluminum equivalent is measured in ounces, not pounds. Nobody takes aluminum suppressors into the field. This is the same principle.
Proprietary threading that actually fits
Factory magazine tubes have notoriously inconsistent threading. Remington uses different thread pitches across generations. Mossberg, Winchester, Benelli, and Beretta all have their own specs, and the quality control on factory tubes - even from the big three - varies widely.
We developed a proprietary hybrid thread design engineered to account for the manufacturing variation across generations and models of the major shotgun brands. The result: a tube that threads on cleanly without being so loose that it compromises the bore.
Every tube is laser-engraved with the exact model and length - Mossberg 590 +2, Remington 870 +1 - so there is zero ambiguity about what goes on what gun.
Premium finish, not a shortcut
Every SJ Hardware magazine extension is Cerakote finished. Not phosphate. Not black oxide.
Phosphate was a World War I solution for giving bare steel the ability to absorb oil so it doesn't rust. It works. It is also what you use when cost is the primary driver.
Cerakote is harder, more corrosion-resistant, and looks like it belongs on a firearm that costs what yours cost. Standard finish is black. Factory-matched Cerakote colors are available for popular models - including the Benelli M4, Beretta 1301, and Stoeger M3K - at no additional charge.
