g3 .22 hk51 conversion
don't have any pics yet but here is a detailed written which should give you the picture in written form ; 1) there are 2 basic ways to determine how much your carrier tube needs to be cut down to work in the 51 ; 1st you may place the 2 carriers side by side , your 51 carrier and the .22 g3 carrier. line up the front of both carriers where the carrier tubes attach to the carrier. you should see a weld here on both. 2nd now look at the carrier tubes extending from this position. on mine the unmodified .22 unit was about 2 inches longer than my 51 unit. this is how much need to be cut off. you will notice on both carrier tube ends that there is a steel end that is a greater diameter than the rest of the tube . this is about 5/8 of an inch long. you do not have to cut this off and reweld it to the .22 carrier. it serves no real purpose in the .22 unit. just make sure that the .22 carrier tube is cut to the same length as the 51 unit. if it is cut too long tha .22 bolt will not close flush on the chamber. if it is cut slightly too short it will not hurt a thing as this piece is only used to cock the gun and does not move as the gun is firing. you can cut the carrier on a lathe, with a cutting wheel, or a hack saw. the hack saw works as well as anything just make your cut strait.
the 2nd way to measure is to place the barrel/chamber unit in the gun . the 2 slots go horizontal and the small dot in the chamber face goes down. it is held in place by a spring clip and just snaps in. you should notice that you have 6-10 inches of barrel sticking out the end depending on how short your barrel is. you now detrermine how long to cut your barrel. some want it flush with the 308 barrel, i marked mine at the end of the flash hider and cut it a 1/4 inch shorter than that . your choice. the barrel assembly pops back out with only slight pressure on the end of the barrel . agin you can cut your barrel in the same way as the carrier. i do not recommend the cutting wheel or tubing cutter for the barrel. a lathe is preferred but again you can cut it with a fine hack saw with very slow cuts. check for burrs after the cut. you can recrown your barrel by screwing a round head brass screw into a piece of wood and holding the wood put some valve grinding compound on the head and gently rub the head of the brass screw around the muzzle and it will do the job. a ball bearing will do the same or you can take it to a gunsmith and have him cut and or crown the barrel. unless you are wanting match accuracy a gunsmith is not needed on the .22 barrel.
now slip the cut to length barrel back in the the gun and make sure it is positioned and fastened into place . slide you uncut .22 carrier into the gun. you will notice that it is 1 to 2 inches from the chamber face. measure the distance from the bolt face to the chamber face. this is the amount that needs to be cut off the carrier tube end. you can measure both ways and the should be the same. cut the carrier as in number one.
if your 51 spring is the same length as a g3 spring no other spring is needed. if is not then you will need a stock g3 spring assembly to function. i had one in an old green fixed stock so i just slipped the fixed stock on.
warning ; the firing pin assembly is under enoug pressure to launch parts across the room. you really don't need to disamble the firing pin asembly which is done by simpliy pulling out the wire u-clip at the back top of the bolt.
while holding the outside of the boltand carrier in your hand , push the bolt face rearward. you should see the bolt slide backward around that spring that is protruding out the rear of the bolt. you can now put some lube on these moving parts. put the modified unit back into the gun ; it shold fit flush against the chamber. if not see if the 2 slots are lining up with the 2 extractors sticking out of the front face of the bolt . if there is a misalignment , readjust the barrel unit slightly. this is designed so that this should not be a problem. if the extractors ar fitting into the slots but there is a gap between the bolt face and the chamberface you either have not cut enough off of the carrier, you have not pushed the barrel assembly in far enough, there is an obstruction in your cocking handle tube or something like this.
if you were like me you need to have a 308 or 223 hammer spring in you gun. don't expect it to function at all without this. i have an sef f/a pack. put all together and was ready for the range . i recommend cci minimags solids until teh gun begins to get broken in. yes, i know it is a used unit but it still took 200-250 rounds to get functioning in my gun. load 5-10 rounds into one of the mags and make sure the mag locks into place . pull the cocking handle back ; it will not lock into position ;let go forward; a cartridge should feed into the chamber.
get it running on semi 1st , then f/a. mine didn't want to function well even with the cci at 1st. although mine eats alot of different brands of ammo it still doesn't like federal value pack asit kicks it hard enough to ejest a round but not pick a new one up. this should help--dave