Working with the Marlin T900-Series Small Bore

Though not the sole manufacturer, Marlin’s reputation for accurate barrels dates to 1875 when it first produced Ballard single-shot rifles. A legend in its time (and still), the rifle was designed and patented (#33,631) by C. H. Ballard. During the Civil War, the U. S. purchased over 1,000 Ballard carbines and discovered they were capable of firing 18 rounds per minute.

In 1864, a patent (#41,166) was awarded to Merwin and Brey for a device allowing the loading of Ballards with either fixed cartridges or powder and ball. J. M. Marlin didn’t use this patent on his Ballards. He secured a patent of his own (#159,592) for a reversible firing pin. Prior to 1875, the Ballard was used only with rimfire ammunition. Marlin’s patent brought centerfire cartridges into the Ballard arsenal, and the centerfire begat smokeless steel barrels in 1893.

These added a significant safety factor to the mild-steel tubes employed for low-intensity rounds including the blackpowder cartridges used in the M1893B. The "B" stood for "Blackpowder only," and the stamp "Special Smokeless Steel" is found only on Marlin M1893, M1892, and M27 rifles. All Ballard barrels were made by the cut-rifling process.

In brief, it involved drilling a hole through the center of a steel bar, reaming it out to bore (land) diameter, and pulling a cutter through that was preset to match the twist and caliber. It was slow going, requiring 30 minutes or more just for the rifling. In 1950, Marlin began to test and study Remington barrels that used a technique called "button rifling," known well in Europe and to a lesser degree here. The button method is accomplished by pulling or pushing a hardened swedge through a barrel.

Advantages proved to be uniformity of rifling shape, lengthened tool life, uniformity in bore and groove finish, dimensional uniformity, and reduced time. Barrel rifling took only 2 to 5 seconds! Marlin adopted the button method in 1953. In 1954, the company introduced its .22-caliber Micro- Groove barrels after perfecting a design for rifling that was eventually patented by T. R. Robinson (#3,100,358).

By 1956, all Marlin barrels carried the Micro-Groove mark, and they carry it today with the exception of cowboy-action models. The latter are still cut-rifled to better serve the soft lead, reduced power loads of the sport. Basically, the Micro-Groove barrel has a plurality of grooves, not cut as deep as broached grooves, and there’s little doubt it is the best thing that ever happened to Marlin rimfire bolt rifles.

There’s also little doubt the trigger systems on these guns left much to Other models in the 900-Series are tube-fed, while the M15 is a single-shot. All are rimfires and share the same new trigger system.

Figure 1. be desired in terms of creep and weight of pull. This older system is shown here in the schematic for the Model 880 (see Figure 1). It’s so simple that I’ve never understood some gunsmith’s concerns regarding subjecting it to a "trigger job." The sear (#31) contacts the striker (#33). When the trigger (#45) is pulled, the sear is depressed, releases the striker, and it is propelled forward by the striker spring (#42) to impact the firing pin (#11).

Merely smoothing the sear/striker interface will ease pull and creep. Polishing the striker, its tunnel in the bolt, and the OD of the striker spring will combine to speed up lock time. Marlin engineers have been very aware of the dissatisfaction with the trigger for some time so they’ve redesigned it for the T900 series (see the exploded drawing on page 5 ). The mechanism no longer hangs from a stud at the rear of the receiver as it has since the 1950s and 1960s.

The trigger group is nowa unit held to the receiver by a half-dovetail cutout and a single screw. The unit houses the trigger spring, sear spring, sear, safety lever, safety-lever spring, and broke crisply at 3-3/4 pounds out of the box on NRA weights. Below left and When uncocking the bolt for disassembly, the cocking knob is inserted in the receiver and the bolt is turned counterclockwise. After reassembly, the bolt is turned clockwise to cock it prior to reinstallation in the receiver.

Opposite page top: This schematic applies to all 900-Series rimfire rifles. Those specific to the Model 925 are identified in sub drawings (A); Model 928 parts are shown in sub drawings (B) and (E); Model 981 in sub drawing (C); and Model 15 in drawing (D). Field Stripping For clip-fed bolt-actions, start with the clip out and the chamber empty. Remove the bolt by raising the cocking lever, pulling the trigger, and drawing the bolt completely to the rear.

Next totally back out the front takedown screw (#59), rear takedown screw (#60), and the trigger-guard screw (#65) in that order. Grasp the stock, lightly rap the barrel upward on a padded work surface, and separate the action from the wood. To prevent damage, do your rapping about 8 to 10 inches back from the muzzle. With tube-fed bolt-actions, first draw out the inner magazine tube. Drift the magazine-ring pin (#36) out in either direction, and pull the outer magazine tube free of the feed throat.

Remove the bolt and stock as with clip-fed models. About the Schematic and Calibers The drawing here is primarily the Model 925 but references all 900- Series models. The differences be-

Marlin T900-Series Bolt-Action Rimfire Rifle (Specifications subject to change without notice) A B 1: Barrel** 2: Barrel Retaining Pin 3: Breech Bolt Assembly Pin 4: Breech Bolt, Front* 5: Breech Bolt, Rear* 6: Bullseye*** 7: Buttplate/Butt Pad*** 8: Buttplate Screw (2) 9: Cartridge Lifter 10: Cartridge Lifter Base 11: Cartridge Lifter Base Screw 12: Cartridge Lifter and Ejector Spring 13: Cartridge Lifter Pivot Pin 14: Cartridge Lifter Spring 15: Ejector 16: Extractor*** 17: Feed Ramp/Feed Throat 18: Feed Throat Assembly Pin 19: Firing Pin* 20: Firing Pin Spring 21: Front Sight Base 22: Front Sight Base Screw tween the 925 and those models are identified by lettered insets in the schematic.

With the 925, the feed ramp has a D A 23: Front Sight Hood 24: Front Sight Insert 25: Magazine, Complete 26: Magazine Guard Plate 27: Magazine Guard Plate Screw (2) 28: Magazine Guide 29: Magazine Guide/Latch Assembly Pin 30: Magazine Guide Pivot Pin 31: Magazine Guide Screw 32: Magazine Latch 33: Magazine Latch and Ejector 34: Magazine Latch Screw 35: Magazine Mounting Bracket 36: Magazine Mounting Bracket Screw 37: Magazine Tube Band 38: Magazine Tube Band Pin 39: Magazine Tube Inside Assembly 40: Magazine Tube Outside 41: Rear Sight Assembly 42: Rear Sight Base 43: Rear Sight Base with Elevator 44: Rear Sight Elevator 45: Rear Sight Folding Leaf 46: Receiver** 47: Safety* short nose and is an integral part of the trigger housing.

The feed ramp and cartridge lifter of the 928 are separate (Inset B) and attach to the C E 48: Sear* 49: Sear and Safety Pivot 50: Sear Spring 51: Stock 52: Striker 53: Striker Assembly Pin 54: Striker Cam Bushing 55: Striker Cam Pin 56: Striker Knob 57: Striker Retaining Screw 58: Striker Sleeve 59: Striker Spring 60: Swivel Stud, Front 61: Swivel Stud, Nut 62: Swivel Stud, Rear 63: Takedown Screw, Front 64: Takedown Screw, Rear 65: Takedown Screw, Stud 66: Trigger* 67: Trigger Guard 68: Trigger Guard Screw 69: Trigger Pivot 70: Trigger Spring 71: Trigger Stud** *Restricted availability; qualified gunsmith only. **Factory only. ***Non-restricted.

May require some final fitting. trigger housing, as do the same components of the 981 (D). In the 925, the ejector is integrated with the magazine latch (A), while the 928 ejector is

Care must be taken to avoid fracturing the part during removal and replacement. located as shown in Inset F. The feedramp Eappears only in the singleshot Model 15. The clip-fed 925 is available in .22 Long Rifle only; the 928 tube-fed is .22 Magnum only; and the 981 accepts .22 Short, Long, and Long Rifle. Coming down the pike is chambering for the brand new .17/.22 LR. That’s an LR case necked down to .17, and not to be confused with the .17 HMR. The latter may happen later on, too.

Detailed Disassembly The bolt is disassembled by holding onto the rear, and turning the front in either direction to separate the two components. When you raised the handle to remove the bolt, you cocked the bolt. You have to uncock it before further takedown. Insert the striker knob (#52) in the rear of the receiver with the strikercam pin (#51) between the forked slot (see photo). Turn the bolt counterclockwise to uncock it and take the pressure off the striker spring.

Now and not before can you undo the striker-retaining screw (#53) and dump the assembly from the bolt. No additional disassembly of the Marlin’s striker group (#48, 49 and 50) should be undertaken. The extractor (#14) snaps on to the blade farther in between them. When the arms are far enough apart to clear their slots in the bolt, use a finger to push up on the extractor. Once the extractor has been removed, the firing pin (#17) and spring (#18) will drop out.

The pin is restricted because it has a bevel milled to a specified angle at its end. So don’t lose it. The Trigger Group Refer to the photos and don’t panic, I’m not going to tell you how to take it apart. That’s not reality. Reality is when a customer stands across from you with a plastic bag of parts, a sorry expression, and a plea to undo what he has done. The trigger groups for all 900-Series rifles are the same. The only diffront end of the bolt.

Don’t reach for your handydandy pliers to pop it off unless you want to kill it. There’s a better, safer way. Insert the flat blade of a screwdriver between the extractor arms. Slowly push them apart by pushing the ferences have already been pointed out in the paragraph on the schematic. Feed throats and cartridge carriers are caliber-specific. And they merely attach to the trigger housing with a pin or two. Fundamentally, then, the Marlin’s trigger group is held together by two identical pins.

The pins are held to the housing by a pair of E-clips. When the customer with the plastic bag disassembled the trigger "to make it work better," he probably lost the clips and the whole mechanism fell apart. Tell him you’ll have it "tomorrow," and have a small vise with padded jaws standing by to act as your assistant. Initially, you’ll focus on the side of the housing with the squared, milledout recess. Slip the safety washer on one of the pins. The washer is actually around, wavy-looking spring.

Slip the safety lever on the same pin with the small hole in the lever body facing the front of the housing. Slide the sear into the housing so it protrudes from the top. Align the holes and push the

The washer under the upper pivot pin is actually a flat, round spring. That’s the sear extending above the casting to the right of the safety lever. lever/washer pin through the sear. Secure what you have in the vise, sear upwards. Now press in hard on the pin until you see a groove show up on the opposite side of the housing. Place an E-clip on the curved milled area of the housing, and push the clip into the groove. You may need the help of a screwdriver to do so.

Rotate the safety lever so the small hole extends beyond the base of the housing. Insert the small leg of the safety-lever spring into the small hole from underneath the lever body. Move the lever into a position that lets you readily insert the long leg of the spring into its housing hole. Turn the housing upside down. You should be looking at the underside of the sear. Rest the trigger/searspring on the sear. Examine the trigger. There’s a metal, stamped portion to the rear that looks like a tab.

That tab and the trigger/sear spring must meet, then you slide the trigger into the housing. Push the trigger forward a little with your thumb to align the pivot-pin hole and start in the pin. Move the safety lever a little toward the "safe" position. The lever body has to clear the head of the pin when you push the pin down against the housing. Now release the safety and install the lower E-clip. The trigger assembly has been reassembled. It is disassembled in reverse.

And if you lose an E-clip in the process, worry not. The clips area standard dimension and can be found at most hardware stores. Final Reassembly Tip When reinstalling the trigger assembly on the receiver, place a dab of grease in the sear-spring hole on the sear. This will aid in keeping the spring (#46) in place. The other end of the spring fits into a hole in the receiver.

Tilt the housing to insert the spring into that hole, push down against the spring, and simultaneously push the dovetail end of the housing into the half-dovetail cut in the bottom of the receiver. Keep pushing down until you’re sure the housing is mated with the flat of the dovetail cut, and release the assembly. Spring pressure will retain it while you reinstall the housing screw. That’s about all there is to it. But don’t forget to give the customer back his plastic bag….