FSB & GB DIY removal and installation guide.

[thuban 0]

FSB & GB DIY removal and installation guide.

 

This is for the 7.62 X 39 but you can adapt it for others.

If you have cut the shroud off your muzzle and have threads or you cut your own threads, continue.

If you have threads but haven't cut the shroud back even with the FSB....do it now. Half round jewelers file works.

 

Jig Material:

10 inches of 5/8 square key stock

2 ea 1/4 X 1 1/2 bolts and nuts. (1/4 X20 threads)

 

Tools:

Drill Index up to 1/2 inch plus a 9/16 bit and a 5/8 bit.

Dial Micrometer and/or Feeler gage

Scribe

Jewelers file, 100 sand paper, 220 sand paper

Chop saw or hack saw

Drill Press and drill press vise ( or bench vise and 1/2 chuck gear reduction hand drill)

Shop press (or some means of protecting the muzzle and a BIG hammer)

 

Cut key stock in half approx 5 inches long each. Dress ends.

 

On one piece of key , measure back 1 1/4 inch from each end and mark a line.

 

Find the center of the stock on each line and center punch.

 

Sandwitch the two pieces of stock together making sure one end is flush.

 

Place sandwitch in drill press vise punch marks up. Can use vise grips to lock top piece to lower while first hole is being drilled.

 

Start with 3/16 bit and drill thru both pieces of stock at once. Use oil. Take your time. Step drill up to 1/4 inch hole.

 

Remove from vise keeping the stock matched and punch match-marks onto one end. Use a bigger bit to debur the holes to make it look like someone else did it.

 

Use the match marks to match up the peices. Stick a 1/4 X 1 1/2 bolt thru the hole, add nut and snug your sandwitch back up.

 

Return the piece to the drill press and drill this end as you did the last. (You can do this in a vise with a 1/2 inch chuck rate reduction drill. Just keep the blocks matched and clamped till you get the first 1/4 hole drilled thru and bolted together. Then do the other end. The holes may wander or be off but they will match. The jig will be flush on one end and lie flat when in the press.)

 

Now to the 5/8 center hole:

 

With the 1/4 inch bolts tight and material laying with the bolts horizontal, measure back from the

stocks even end 2 1/2 inches and scribe a line across both clamped pieces.

 

Now you have a clear center boundry mark for your 5/8 hole. Center punch the middle.

Try to make this hole straight as possible. Step drilling will help ( For the cost of the 9/16 and 5/8 drill bit, a machine shop can drill this hole cheaper. If you take this route, read on down and mark the gas block removal hole so they can drill them both at once. This is why you flushed one end of the stock. The Gas Block removal hole will need to be close to this end.)

 

Ok, you have your 5/8 hole for the FSB removal drilled. Debur the hole before you separate the pieces and check your match marks so you can get the jig back same, same. Separate the Jig stock and de-bur everything with 100 sand paper.

 

Drill out the FSB dimples:

 

Support the barrel/FSB and use a 9/64 th bit to drill down into the dimples .072 of an inch. I used a dial mic to check my progress but you can use a .023 +.024 +.025 feeler gage to get an idea of how far to drill. Do one side and then the other. Use a little oil; the metal isn't hard.

 

Pressing the FSB forward:

 

Put two wraps of electrical tape around the muzzle threads to protect them. Sand the smooth area in front of the FSB with 220 sand paper.

 

Bolt the jig around the barrel below the FSB and mount in the press. Put a soft copper on top to protect the muzzle crown and put a bit of oil around the front of the FSB.

 

Start to press...It will take a bit and when it starts to move a couple pumps, STOP! ( If your using a BFH to inflect movement, god help you.)

See below how the thing looks in the press. I'm about to continue to pressing. Don't forget the copper on the crown end...I almost did.

 

 

Now your gona do something to make you proud.

 

First notice how the drill bottoms are being pushed back up into the dimples. When you press the sight the distance across the dimple it will get easier to move. ( Not that easy)

 

Is your FSB canted? Look at the factory witness marks on the front of the FSB. IF your marks are centered and your windage barrel is centered and your front sight post is centered between the ears, your FSB is not canted and you can skip on down a ways. However....

 

If your witness marks are true and your front sight post is off, usually to the right as looking down the barrel, now is the time to straighten it.

 

Get your front sight tool and center the front sight post between the ears. There will be the same amount of windage barrel sticking out from both sides of the sight. Eyeball is close enough.

 

Your gun should be stripped so you can sight down the tang thru the rear sight block. You can see

into the shiny bore...the gas block outlet is centered in the "window" of the rear sight block but now you can clearly see the FSB is canted to one side - usually leaning left. ( That is why your sight post was drifted right)

 

 

Scribe a fine line on the FSB to sanded barrel area. This is your index mark so you can see how much you have twisted the sight on the barrel. ( Your gona twist the barrel/receiver not the sight but...)

 

Ok, Back in the press with the mark where you can see it. Apply pressure (don't forget the copper) and if your sight was canted to the left while looking down the tang, reach under and gently turn the receiver clockwise while still applying pressure...as the pressure builds the SB will quit turning.

You just felt a little twist as the barrel started down again. Stop. Take it out and sight down the tang again. I got lucky on the first try. If it's off a hair the MoJo will take care of it. Don't use any more movement downward of the barrel than necessary to get the sight picture straight. You will have no doubt when it's straight. Forget the string...it's sight picture. This is a pix of mine now straight. Strip your gun and take a look!

 

 

 

Go too far? Need to back up? Cut a small tab of beer can and wrap around the barrel. Apply the jig...it will clamp tightly and you can use it to drive back against. Use a deep socket, careful not to form a crimp!

 

Ok, an 1/8 or so inch to go. Screw on your brake all the way. Back it up whatever it takes to get the index on the top where the retainer pin would catch it. Measure the distance with feeler gage. Remove the brake. put the feeler against the FSB and chalk the threads by the gage. Now you can see on the threads how much the sight has left to come forward, have the brake index and use the max amount of threads. You will notice just a little less than half the rear dimple in the barrel peeking out from beneath the FSB in the pix below. This is what it looks like when done. (Retaining pin not installed yet) It will take any 14mm X 1 LH attachments.

 

 

I think you can take a sharp punch and do a tap reset in the dimples to hold the sight...then fill them with bondo in case you want replace the sight later and need to get in the dimples. Or drill and use pins and bondo in the dimples to hide them.

 

 

Now...Install the brake retaining pin. ( I haven't gotten mine yet but....)

 

Get a strip of beer can and this time use the end hole in the jig to clamp down on the barrel. It is 90 degrees to the barrel if your hole is straight. Clamp the free end of the jig to the drill press table and rotate the table around and under the chuck to drill the hole for the brake retaining pin. Step drill and it should be straight. Or bite down on the free end of the Jig with your vise and you will have a stable platform to drill your retaining pin passage with your hand drill.

 

I won't be able to give a blow by blow of this till I get my pin and dig up some small roll pins. Roll pins are hardened and will not come out of their proper size hole without being driven. Small nails you'll have to peen over.

 

To make and fit the bayo mount and/or cleaning rod mount on the Saiga is easy but you have to have a wire welder. Just two quick hits on the trigger is all it will take and you'll never see the welds.

 

If you do not have a press, and you don't want to beat on the muzzle, (god bless you) you can do this but you will need a 5/8 hole drilled in the other end of the Jig and a sister jig to boot and at least 1/2 all-thread, nuts and washers.

 

This is not the end-all fix-all. It's a cheep and easy? way to DIY, save bucks and still have a great looking, solid business end!

 

Make the tool!

 

Thu

 

[brickvader 3]

Or you can use the proper sized wrench I think a 14 or 15 mm fits perfect

Edited March 26, 2010 by brickvader