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Posted: 7/17/2004 8:25:20 PM EDT
| I have a 2003 series SAR-1. When firing the other day, I noticed that the gas piston was becoming unscrewed from the bolt carrier. I disassembled it, and screwed it back in again, and fired 10 rounds. Afterwards, I noticed that the gas piston was becoming unscrewed again. Is there something wrong with my gun, or is this common? |
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If it's a Century import then the piston was probably welded to the carrier and the weld failed. To pin the piston first tighten by hand untill it is barly seated . Back out the piston 1/8 to 1/4 turn. This will let the piston "wobble" a little. Next drill a 3/32" hole thriugh the carrier and piston. Make a pin out of a piece of 3/32" wire slightly longer than the hole in the carrier. Peen the ends of the pin and file or grind smooth. At this point the piston may not wobble anymore. It will loosen up with use. HTH |
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Sorry I forgot to mention the nesisity for the wobble. This helps to keep the piston/carrier from binding. If you look closly you will probably see where it was welded. Being as the carrier is carbon steel and the piston is stainless and a monkey at Century did the weld is why it failed.  As far as the potential problem goes. If the piston were to back out far enough while firing it can bottom out agenst the gas block and keep the locking lugs of the bolt from rotating to FULL lock up. This will cause an OUT OF BATTERY condition. This condition is real bad news. The result can be anywhere from a case seperation to a destroyed gun and shooter. Fix it right and be safe. HTH |
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read the installation instructions here: www.redstararms.com/index.htm?catalog.htm&1 Follow these steps and install your RSA gas piston like a PRO! GAS PISTON INSTALLATION INSTRUCTIONS 1.INSURE THE RIFLE IS UNLOADED AND REMOVE THE BOLT CARRIER ASSEMBLY FROM THE RIFLE. 2. REMOVE THE BOLT FROM THE CARRIER. 3. LOCATE THE 3MM DIAMETER CROSS-PIN (THE PIN SIZE MAY VARY BY COUNTRY OF ORIGIN) THAT RETAINS THE GAS PISTON TO THE CARRIER. IT MAY BE NECESSARY TO REMOVE THE FINISH FROM THE CARRIER IN ORDER TO LOCATE THE CROSS-PIN ENTRANCE AND EXIT HOLES IN THE CARRIER. 4. USE A NAIL SET OR DRIFTPUNCH TO START THE CROSS PIN MOVING AND A DRIFT PIN PUNCH TO DRIVE THE PIN THRU THE HOLE. IF EXCESSIVE FORCE IS REQUIRED TO DRIVE THE CROSS-PIN OR IF THE CROSS-PIN REFUSES TO MOVE, CENTERPUNCH ONE END OF THE CROSS-PIN AND USE A 3MM DRILL BIT TO DRILL .10" DEEP INTO THE CROSS-PIN. DRIVE THE CROSS-PIN OUT FROM THE SIDE YOU HAVE DRILLED. NOTE: THE CROSS-PINS ARE OFTEN PEINED INTO COUNTERSUNK AREAS ON THE CARRIER. WHEN DRIVING THE CROSS PIN OUT IT IS NECESSARY TO DISPLACE THIS METAL BEFORE THE PIN WILL MOVE. 5. CHUCK A 3MM DRILL BIT INTO A DRILL PRESS AND INSERT THE BIT THRU BOTH HOLES IN THE BOLT CARRIER WITH THE BOLT CARRIER HELD LOOSELY IN A DRILL VISE. USING THE DRILL BIT TO POSITION THE BOLT CARRIER, TIGHTEN THE DRILL PRESS VICE SECURELY AGAINST THE BOLT CARRIER. 6. THREAD THE RED STAR ARMS GAS PISTON INTO THE CARRIER. IT SHOULD SCREW IN USING ONLY THE HAND. A PAIR OF PLIERS, PADDED WITH A THIN RUBBER SHEET, MAY BE REQUIRED. IN CASES IN WHICH THE FEMALE THREAD OF THE CARRIER HAS BEEN DAMAGED BY THE REMOVAL OF THE CROSS-PIN A 12MM X 1.25MM TAP SHOULD BE USED TO CHASE THE THREADS. 7. DRILL THRU THE GAS PISTON USING THE 3MM DRILL BIT ON THE SAME LOCATION AS THE TWO 3MM HOLES IN THE BOLT CARRIER. 8. INSERT A NEW 3MM CROSS-PIN INTO THE HOLE. THE CROSS PIN SHOULD BE LONGER THAN THE HOLE IS DEEP, AND EXCESS STOCK SHOULD BE POSITIONED EQUALLY ON BOTH SIDES OF THE BOLT CARRIER. USE A HAMMER AND PUNCH TO PEIN THE ENDS OF THE CROSS-PIN INTO THE COUNTERSINKS ON BOTH SIDES OF THE BOLT CARRIER HOLE. DRESS THE ENDS OF THE CROSS-PIN FLUSH WITH THE SURFACE OF THE BOLT CARRIER. |
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I checked Global Trades and K-VAR. The cheapest carrier from either one is $49.99. Is it cracked on only one side or both? Can you post a pic? It may be possable to repair it but , without seeing it it's hard to say. You may also find one at a fun show cheaper. Check the EE too. |
| When the bolt carrier was welded, it didn't seem to have any wobble to it at all. So I think it would be safe to locktite it, seeing as how I don't think the wobble is necessary for safe functioning. By the way, the gas piston unscrewed itself almost all the way, and I continued to fire the weapon for 60 rounds, without a malfunction. Perhaps I was just lucky? |
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