Jersey Small Arms
Gunsmithing - John Torelli
501 Ireland Ave. Millville NJ 08332
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Caliber .380 ACP
10 + 1 capacity
Non-removable internal magazine
1988 to 1991
Options included detachable grip extender,
Threaded barrel with muzzle break and "Designator" light assembly.
Loader came with five M16 Stripper Clips
172-Firing Pin Spring
174-Firing Pin Pin
|222-Frame Screw Middle
224-Frame Screw Rear
284-Slide Stop Spring
* Check here for Serial Number Information
The Grendel P-10 is a radically new type of semi-automatic pistol. The P-10 is especially suited for selfdefense or home protection by individuals with only limited training in the use of a hand gun. Like a double-action revolver, the P-10 has no external safety. Also like a revolver, the P-10 uses no loose magazines, but has a high capacity magazine integrated in the grip.
The P-10 is designed and manufactured in the United States. Extensive research and development, especially in the fields of composite materials and ignition dynamics, have been incorporated into this firearm. Thanks to the advanced design and modern computerized machinery, the P-10 can be manufactured at a low cost without compromising quality in materials or workmanship.
The P-10 is a semi-automatic pistol chambered for the .380 ACP cartridge and operated by blowback. The firing mechansim is double-action only, with a novel low inertia safety hammer system. The magazine is loaded from top and holds 10 rounds. A speed loader is also available. The bottom of the grip is designed to accept an extension or our "MMH" target illumination system.
The P-10 has five main component groups: barrel, slide, frame, grip and firing mechansim. The barrel is turned and milled from SAE 4140 ordnance steel with a tensile strength of over 140,000 pounds per square inch. The bore is of standard SAAMI dimensions. The slide is milled from solid stock of La Salle Stressproof™ steel, and contains the firing pin and extractor. The frame is an all steel construction which holds the barrel, firing mechanism, and also forms the magazine lips, slide rails, and ejector. The frame is stamped with the serial number. The grip is made of a polymer metal composite, creating a unique combination of rigidity and impact strength. The grip also forms the magazine and triggerguard. It attaches to the frame with screws. The metal inserts in the grip also facilitate X-ray detection. The trigger with a lever connects via a bar/disconnector to the hammer. The hammer is driven by a novel powerspring. Virtually the whole mass of the hammer is centered around it's axis. The light weight firing pin transmits the energy of the hammer to ignite the primer.
To achieve highest operator safety, combined with ease of handling, the P-10 has no manual safety and the hammer is never cocked. Very much like a hammerless revolver. The hammer is of a novel design. Compared to a conventional hammer, the P-10's is extremely light and consequently, operates at very high velocities. It is driven directly by a special powerspring on the same axis. Furthermore, the hammer's mass is concentrated around its axis giving an inertia in the critical direction of the firing pin close to zero. The velocities necessary to fire a cartridge with the low mass hammer/firing system are so high that they cannot even be approached by the slide's action or an accidental fall. A direct blow to the hammer is impossible, as it is enclosed by the slide and grip. The hammer's energy is transmitted to the primer through a proportionally light weight firing pin.
Clear the P-10 of ammunition. Pull the Slide back until the Barrel Retaining Pin is aligned with the hole in the Slide. Push the Barrel Pin out either side. Restrain the slide and ease it off the front of the receiver. The Recoil Spring, Recoil Spring Guide and Barrel are easily removed from the slide. The P-10 is now field stripped for cleaning. It is not recommended that you proceed any further with disassembly. However, should you need to replace a broken part refer to the following directions.
Slide Group: Use a small tool to push
the Extractor Plunger into the Slide and remove the Extractor from it's
recess in the Slide. Remove the Extractor Plunger and its Spring from the
Slide. Drive out the Roll Pin that retains the Firing Pin and it's Return
Spring and remove the Firing Pin and Spring out the back of the Slide.
Cut a slave
pin of .1 inch diameter to a length of .71 inch.
It will be useful in removing and assembling the Receiver Group.
Receiver Group: Remove the small Hex
Screw at the front right of the Grip Frame which secures the Trigger Pin.
Pull the Trigger about half way. The
Trigger Bar (Part #260) and the Trigger Lever (Part #258) should pop up out of the Grip Frame. Remove the Trigger Lever. Do not try to remove the
Trigger Bar at this time. Remove the Right small Hex Screw at the back of the grip frame and insert the Slave Pin you made. As you remove the Left
small Hex Screw push the Slave Pin into the hole. This will help keep the hammer spring in place as you remove the Receiver. Remove the large Hex Screw
in the middle of the receiver assembly. Remove the Receiver Assembly upwards and out of the Grip Frame keeping a hand over the front part to catch the
Trigger Bar/Slide Stop Lever Spring (Part #284). (This spring can launch itself quite a distance. Don't try this over a carpeted area, or you could loose
the spring.) The Slide Stop Lever is easily removed. Take note of the relationship of the Coiled Hammer Spring and Hammer in the Receiver.
Remove the Magazine Follower downwards. Push the Hammer Pin out towards the left and remove the Hammer, Spring and Magazine Guide Assembly down and out
of the Receiver. These parts are now easily separated. Remove the Trigger Stop Pin and push out the Trigger Pin to the left and remove the Trigger down
and its Return Spring up.
William Wood has a YouTube video up about
disassembling the P12 that's well worth watching.
Here's the link:
Grendel P12 Broken Hammer Spring
Remember, you were warned about taking the P-10 completely apart.
01) First, if you removed it, reinstall the Trigger and its Return Spring.
02) Next, replace the large Magazine Spring back into the Grip Frame onto its stud.
03) Put the Trigger Bar (Part #260) into position in the Grip Frame. Do not secure it to the Trigger yet.
04) Put the Hammer Spring (Part #275) against the Hammer with the small hook in the center bearing on the pin of the Hammer. Slide the assembly into the Receiver.
Push the Hammer Retaining Pin (Part #276) into place. The open end of the hook on the Hammer Spring fits on top of the Frame Bar (Part #226).
05) Insert the Frame Bar being certain that the Hammer is underneath of it. If installed correctly the Frame Bar will be in-between the top hook of the Hammer Spring
and the front side of the Hammer. It is necessary to rotate the Hammer to put the proper tension on the Hammer Spring. Use the Slave Pin to secure the Frame Bar
and clamp the Receiver into a vise.
06) Rotate the Hammer and slip the Magazine Guide (Part #317) down from the top and over the Hammer. Make sure the hook grabs the Frame Bar.
07) Push the Magazine Follower (Part #315) up from the bottom into place in the Receiver. This will help keep everything in place.
08) Remove the assembly from your vice keeping pressure on the sides of the Receiver with your fingers.
09) Put the Slide Stop Lever (Part #280) into the Receiver with it's small tab protruding through the opening and resting on top of the Magazine Follower.
10) Carefully align the assembly with the Grip Frame and insert it into position.
11) Thread in either one of the small Hex Screws that hold the receiver at the rear. As you turn in the Hex Screw it will force your Slave Pin out the other side.
Remove the slave pin and thread in the other Hex Screw. Do not tighten them fully yet.
12) Screw in the large Frame Screw (Part #222) about a third of the way. Do not tighten it down yet.
13) The Slide Stop Lever/Trigger Bar Spring (Part #284) fits into a rectangular opening in the front of the Receiver.
The left extension of the spring bears down on the top of the Slide Stop Lever while the right pushes up on the Trigger Bar.
Keep the Trigger Bar up and out of the way and shove the Spring into the opening with the left side bearing down on the Slide Stop Lever.
Make sure it's in place as you push the Receiver assembly the rest of the way into the Grip Frame. Tighten the Frame Screw the rest of the way.
14) Place the Trigger Bar Plate (Part #258) onto the Right Side of the Trigger Bar with its bearing studs facing in. Pull the Trigger about half way
and the studs will align with notches on the Trigger Pin. Make sure the Trigger Bar is on top of its spring. Secure with the smallest of the Hex Screws.
Tighten, but don't overtighten, the two small Hex Screws at the rear of the Grip Frame. To check your assembly, push the Hammer back slightly and
partially pull the Trigger. It should begin to cock the Hammer.
Insert the Firing Pin and its Spring into the back of the Slide and secure with the Retaining Pin.
Slip the Extractor Spring and Plunger into place and push the Extractor backwards and into its slot until it snaps into position.
Replace the Barrel, Recoil Spring and Guide back into the Slide.
Make certain the Barrel and Recoil Spring Guide are exactly centered or they will not seat properly.
Line up the holes and replace the Barrel Pin.
An evolution of the P-10 was the P-12 with an 11 round detachable magazine
which was made from 1991 to 1995. Most of the parts will interchange and
assembly and dissasembly are identical with the exception of the Extractor.
model of the Grendel is the P-30 in
caliber .22 Magnum, also manufactured from
1991 to 1995. The P-30 held 30 rounds in a
detachable magazine and was available with
a five or eight inch barrel. Sorry, but I have
no parts or sources for parts for this pistol.
Serial Number Location on P10 / P12 Pistols
The serial number can be found in the area
P.O Box 908
Rockledge FL 32955
(Do not write to this