Mag Housing and Barrel Jacket Assembly (short & long setups)
In 2003, BRP CORP, CORP, along with the help he lp of the original inventor, inve ntor, John Stemple, manufactured the rst Stemple Takedown Takedown Gun (STG) setups. These are complete accessory packages for unmodied/ transferable Stemple 76/45 machine gun receiver tubes. These “takedown” systems of interlocking subassemblies can be easily attached to and removed from the 76/45 receiver. This method of assembly is ATF ATF approved. These machineguns machineg uns are fully transferable transfer able to individuals.
Finnish KP31-based Setups The Stemple 76/45 is roughly a 45ACP version of the 9mm S&W 76. The S&W 76 design was heavily inspired by the Swedish K/Carl Gustov M45. The M45 uses the same barrels and magazines as the Swedish M37. The M37 is a short-barreled version of Finland’s KP31. Since the Stemple 76/45 drew its roots from the Finnish KP31, it was a natural t to use original Finnish and Swedish parts in the Stemple 76/45 system.
Weight: 12 lb Magazine: Suomi KP31 25 rd, 36 rd, 60 rd magazines, and 40 rd & 70 rd drums Rear Sight: Finnish KP31 500M Tangent Tangent or Picatinny Rail Barrel Length: 12.5 in., 7.5 in. Cycle Rate: 750 rpm Finish: Black Bipod: Detachable STG, Page 2
Stemple Takedown Gun (STG) Manual The STG is a blow-black submachinegun that requires knowledgeable operators. Full and complete adherence to the following instructions is an absolute necessity for safe and responsible use of the STG. This system is NOT meant for anyone other than individuals knowledgeable in the safe operation of machineguns and who have a thorough understanding of automatic rearms. If you are not such an individual you pose a danger to yourself and those around you by using this system. The following Suomi parts and accessories will work with the STG: • Magazines and Drums • Slings • Extractors • Firing Pins • Barrels (collar may have to be modied) • Internal Trigger Housing Components • Mainspirngs
The Differences Between the Original Suomi and the STG The STG res from the open-bolt position just as the original Suomi. The major components of the STG are mostly Suomi 31. A newly manufactured magazine sleeve and barrel shroud assembly is designed to sleeve over the STG lock nut and give the appearance of a Suomi barrel shroud. The Suomi bolt has been reduced in diameter to t the Stemple 76/45 receiver and hole pattern drilled for a new cocking handle compatible with the cocking handle slot of the Stemple 76/45 receiver. The Suomi trigger housing has been modied to t the 76/45 sear opening. The internal components are the same, however the sear is newly manufactured. The trigger housing system has a 3-position setup: safe, semi, full.
The Essentials of Running The STG: Following these steps will help you use this system reliably and prevent malfunctions, dangerous operation, and damage.
1) Following Loading Protocol: Do not retract the bolt until you intend to re. 2) Correct Ammo: Use full metal jacketed ammo only to ensure proper feeding. 3) Correct Mags & Drums: Drums and mags are not dimensionally consistent; contact BRP CORP for tting if necessary. Make sure that each Magazine or Drum locks on the Magazine Latch and does not rock back and forth in the Magazine Housing. 4) Lubrication: Use lubricant sparingly on the outside edges of the Bolt. 5) Cleaning: When cleaning the STG, pay special attention to cleaning the bolt face, barrel, and feed ramp. 6) Inspection: After cleaning, fully inspect and reassemble the STG.
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Safety – Your Responsibility SAFETY MUST BE THE FIRST AND CONSTANT CONSIDERATION OF EVERY PERSON WHO HANDLES FIREARMS AND AMMUNITION. This manual is designed to assist you in learning how to use and care for this system properly. Only when you are certain you fully understand the manual and can properly carry out its instructions should you practice loading, unloading, etc. with live ammunition. If you have doubts about your ability to handle or use this particular system safely, then you should seek super vised instruction. Such personalized instruction is often available from gun dealers, gun clubs or police departments. If none of these sources can help you contact the National Rie Association. You are also encouraged to contact BRP CORP for assistance. The person with a gun in his possession has a full-time job. He cannot guess; he cannot forget. He must know how to use his rearm safely. Do not use any rearm without having a complete understanding of its particular characteristics and safe use. Remember: There is NO such thing as a foolproof gun.
Basic Safety List • A loaded rearm has the potential to kill. Intelligently handled it is safe. • An accident is always the result of basic safety rules neglect. • Accident prevention is user responsibility. • Never point a rearm at anything you don’t want to shoot. • Before handling a rearm be sure to use correct and undamaged ammunition. • Be sure your rearm is clean – before loading inspect the barrel to insure it is perfectly clean and free of foreign objects. Shooting with an obstruction in the barrel such as dirt, mud, grease, lodged bullet or jacket, residues, etc, can cause barrel bulging and/or rupture. • Never assume that the chamber is empty, visually inspect it every time you handle the gun. • Avoid alcoholic beverages or drugs before and during shooting. • Avoid hard hitting or dropping of a loaded rearm. • Store rearms and ammunition separately, beyond the reach of children. Be sure cartridge chamber is empty. • Thoroughly clean the rearm to prevent corrosion. • Wear eye and ear protection. • Firearms Safety Course is recommended. • Handle it with respect not fear.
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Operation 1. Loading the Magazines and Drums a. Magazines • There are numerous magazines manufactured for the Suomi 31&37. Make sure that the magazine ts properly and test its ability to feed using dummy rounds. • When lling the magazines, make sure that the rounds are rmly pressed against the rear of the magazine. b. Drum • You may ll the drum to capacity or only load small amount of ammo. The drum operates on a constant force spring otherwise know as a clockwork spring located in a spring cage in the center of the drum. The spring causes the cage, pusher arm, and base plate to rotate clockwise. • Open the drum by pressing the ratchet release pin and rotating the locking arm away from the retaining shoulder. • Charge the drum by winding the cage counterclockwise. The ratcheting mechanism will ‘click’ as you wind the cage. Each ‘click’ is approximately 10 rounds and represents a locking point for the ratcheting mechanism. Only charge the drum to the point you want to load it. At a certain point, approximately 5 ‘clicks,’ the base plate will start rotating with the cage and pusher arm. • Once the cage and base plate cannot rotate any further, start loading the drum bullet tip up. You will need to do this on a at surface so the rounds do not tip over. Be very careful not to press the ratchet release button, it will release the full force of the spring and possibly crack the feed lip. • Once full, press the ratchet release button and make sure that there is sufcient force pushing the rounds toward the feed lip to feed the gun during cycle. Place the cover plate over the drum body, press the ratchet release pin and rotate the locking arm toward the retaining shoulder.
2. Loading the Gun •
With the bolt forward insert the drum or magazine into the magazine housing and smack into place making sure that the magazine catch lever engages the magazine. Pull down on the magazine to make sure that the magazine or drum is properly engaged. Be careful to not press the magazine catch lever when holding the gun.
3. Firing the Gun a. Retract Bolt to the end of the cocking track b. Pull Trigger
4. Unloading the Gun a. With rounds still in magazine. The bolt is the ‘open’ position. Set the selector is set to the rear (SAFE). Push the magazine release lever forward and remove the magazine. b. With empty magazine. The bolt is the ‘closed’ position. Push the magazine release lever forward and remove the magazine.
Fire Control Selector (Shown in Full Position) Fully Forward: Full Auto 1 Click Rearward: Semi Auto Fully Rearward: Safe
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Disassembly Procedure Step 1: Remove the Takdown Screw • Use the STG Multi-Tool or appropriate screwdriver to unscrew the Takedown Screw (approx. 6 rotations)
Fitted Takedown Screw Tip Takedown Screw
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Step 2: Remove the Buffer Takedown Screw
• Once the screw stops rising from the receiver, hold the Buffer and pull the screw upward from the receiver.
• Remove the Buffer.
Mainspring Buffer Buffer Pad
Step 3: Remove the Bolt and Cocking Handle • Retract the Bolt and Cocking Handle to the end of the Cocking Handle Track, pull the Cocking Handle out of the right side of the Receiver, and dump the bolt out of the rear end of the Receiver. Bolt
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Step 4: Separate the Upper & Lower Assemblies • Use the multi-tool takedown pin pusher to remove the HK-style takedown pin from the rear of the magazine housing area. Lift the upper assembly from the lower assembly.
Takedown Pin Hole
Takedown Pin Pusher
Step 5: Separate the 76/45 Receiver from the Barrel Jacket / Magazine Housing Assembly • Remove the barrel shroud takedown pin by unscrewing the takedown pin retainer, then pushing the takedown pin out with the multi-tool. At this point the barrel shroud can be removed from the magazine housing. • Remove the magazine housing by pulling it forward and away from the receiver. Do not twist to remove since it will scratch the metal nish.
At this point, no further disassembly is required for regular cleaning.
Parts to Thoroughly Clean After Any Shooting All parts listed should be soaked, brused and/or wiped with CLP until free of residue.
Barrel: You can run the cleaning rod through the rear of the Receiver
Feed Ramp, Rear Barrel Face, & Ejector
Step 6: Remove the Barrel • Unscrew the barrel lock nut and pull the barrel from the receiver. You should use the BRP lock nut wrench, rubber strap wrench, or adjustable wrench to unscrew the locknut. Be very careful not to mar the lock nut. • You should add a drop of Lock-Tite (blue/non-permanent) to the threads of the trunion to prevent the lock nut from vibrating loose during use Barrel Lock Nut
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Be careful not to pull the trigger with the selector in the middle position when disassembled. The sear will disconnect from the trigger and you may loose the sear spring & plunger When separated from the 76/45 receiver, the middle/semi position is only for disassembly of the trigger pack. Typically, there is no need to disassemble the lower assembly as pictured.
Optional Bipod Setup
To remove the bipod simply unscrew the socket head cap screw at the top of the bipod and detach from the base. STG, Page 10
Assembly Procedure • Reverse operations 6, 5, and 4 until you have the STG-W as pictured.
• To install the Mainspring and Buffer Assembly: Be careful to follow these instructions, otherwise, you may bend the mainspring - Pull the bolt back to the sear catch area. - With the Mainspring and Buffer Assembled; install the Mainspring into the rear of the Bolt making sure that it guides into the opening in the rear of the Bolt. - While pulling back on the Mainspring against the Buffer Block and Buffer Rod, push the BuffeAssembly forward making sure that the Mainspring continues to guide on the Buffer Rod and rear of the Bolt, and the Buffer Block guides into the rear of the receiver. - Once the Buffer Base is at the rear of the Receiver, guide the Bolt forward. - Grasp the Lower Trigger Housing Assembly and squeeze it to the Receiver. - Push the Buffer Assembly forward until the holes in the Buffer, Receiver, and Lower Trigger Housing Assembly line up - Push the Takedown screw through the Receiver until it stops on the Buffer Base. - Use the STG Muli-Tool or appropriate Screwdriver to tighten the Takedown Screw. (there is no need for excessive torque)
The stainless steel Rear Post is semi-permanently xed to the lower housing. It is thread ed and counter-bored to t the Takedown Keeper Screw. * Screws and pins with red in-ll should not be removed. STG, Page 16
Top view of full-auto-only sear system and Rear Post
Step 1: Insert the Bolt and Cocking Handle Assembly
Step 2: Insert the Mainspring & Buffer Assembly
To ensure that the Mainspring and Buffer Rod are properly guided into the rear of the Bolt, retract the Bolt and grasp the Upper Receiver assembly as pictured as you push the Buffer & Mainspring assembly forward.
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Step 3: Insert the Alignment and Guide Tool
Make sure that the groove on the Buffer Cap is facing down. Insert the Alignment and Guide Tool through the top of the Receiver. This will retain the Buffer and Mainspring assembly and maintain rear Buffer and Receiver alignment with the Rear Post.
Step 3: Attach the Upper Assembly to the Rear Post
Takedown Keeper Screw
Alignment & Guide Tool (stainless steel)
Rear Post (stainless steel)
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Firmly seat the Guide Pin part of the Alignment and Guide tool into the top of the Rear Post.
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Push down on the Upper Assembly so the Rear Post Guides into the bottom of the Receiver and Buffer.
Once fully pushed down, the Alignment and Guide Tool will fall from the top of the Receiver.
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Step 4: Attach the Rear Keeper Screw (loosely)
Loosely attach the Rear Keeper Screw so the Mag Housing and Shroud Assembly can slide easily into position.
Step 5: Attach the Mag Housing and Shroud Assembly
Carfully guide the Mag Housing and Shroud Assembly into the slot at the front of the Trigger Housing assembly. Make sure that it is rmly seated at the back for Trigger Housing assembly to ensure proper hole alignment.
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With one hand, grasp and squeeze the Upper and Lower assemblies. With you other hand, insert the HK takedown pin from the right side of the rearm.
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Step 6: Tighten the Rear Keeper Screw
Use the tted multi-tool to tighten the Rear Keeper Screw. Excessive torque is not required.