AR Sponsor
Posted: 1/13/2004 3:06:03 AM EDT
|
Hi guys, maybe this is an old topic, but I need Your help. Is it quite easy to change my barrel? Or it's a work for good gunsmiths? I found 2 or 3 kinds of barrel wrenches on ebay.. 1) http://i17.ebayimg.com/02/i/01/12/b5/1b_1.JPG 2) http://i8.ebayimg.com/02/i/01/27/57/ef_1.JPG What is the best one? Do I need torque wrench too? What about to align the barrel? Plz help me. Thank You very much. Mauri |
|
The hardest part will be to get the old barrel off. Sometimes they seem pretty tight. I have the top wrench..Multi-Wrench... works pretty good for me. Yes you need a torque wrench. Same one used for car motors and such. Sears or auto parts store are good places to get one. On alignment; there is an alignment pin at the top of the barrel extention that fits into the upper, so the barrel only goes on one way. You will also need a good action block. This fits around the upper reciever so you can clamp it down in a vise without dammaging it. I got my Multi-Wrench and action block from Midway. Make sure the barrell wrench is in the nut real good and loosen the old nut and remove the barrel. You might want to check in the Tech Manuel for barrel removal. [url]http://www.ar15.com/content/books/TM9-1005-319-23.pdf[/url] When putting on the new one I use a little "anti-sieze" on the threads then torque it to 30 ft lbs then loosen it then tighten it again to 30 ft lbs. Do this 3 times and on the third time, after reaching 30 ft lbs, just tighten to the next slot that will line up with the gas tube hole. Make sure you don't exceed 80 ft lbs to acomplish this. The butt end of a 1/4 inch drill bit works good for checking the alignment. I don't think I forgot anything. Good Luck. |
|
YES..! you need an AR-15 wrench !! any good one will do... YES...! barrel changes are quick & easy...!! BUT !! i disagree on the torque wrench !!! i have removed barrels from AR-15s simply by removing the gas tube & unscrewing the nut by hand !! when installing a barrel you will find notches on the nut.., when torquing i have found that the proper torque value will leave you half a notch or more off.., if you turn the nut further for alignment you stand a very good chance of stripping the threads. i just replaced a 20" barrel on one of my ARs, i hand tightened the nut, then used the wrench to tighten it to the next notch, installed the gas tube, reassembled & put it on a lower & checked the head space & it is fine, shot 200 rnds thru it & she works fine !! barrel is still solidly tight !! |
|
Quoted: What is the best one? This [url=http://www.bushmaster.com/shopping/gunsmith/223-wrench.asp]one[/url]. [img]http://www.bushmaster.com/shopping/gunsmith/Images/223-wrench.jpg[/img] Avoid the GI wrenches, they have limited utility. Do I need torque wrench too? What about to align the barrel? No, you don't need a torque wrench. Given quality parts the barrel should align well. If you bore sight while tightening the nut you can correct as you tighten. |
|
Quoted: i just replaced a 20" barrel on one of my ARs, i hand tightened the nut, then used the wrench to tighten it to the next notch, installed the gas tube, reassembled & put it on a lower & checked the head space & it is fine, shot 200 rnds thru it & she works fine !! barrel is still solidly tight !! The 3 time 30 ft lb and never more than 80 ft lb to align the hole method is what is described in the tech manuel. Sure the slot won't line up thats why you have to go to the next nearest slot and never more than 80 ft lbs to accomplish this. Hand tight may or may not be ok, but it won't back off cause the gas tube goes thru it to secrue it and keep it from loosening. |
|
Gas tubes are cheap and you may destroy the one you have when taking the barrel off. I would not install a barrel without a torque wrench, a multi-tool (like the DPMS you showed), and a receiver block ([url=http://www.bushmaster.com/shopping/gunsmith/om-003.asp]Action Block[/url])from [url=http://www.bushmaster.com/shopping/gunsmith/om-003.asp]Bushmaster[/url]. Installing a barrel is actually quite easy. The barrel extension will come with the barrel and therefore headspacing should not be an issue. |
|
Quoted: Do I need a new gas tube? weldox, Mic the diameter of the end of gas tube that goes into the carrier key. Compare that diameter with the ID of the carrier key. If they're real close to being the same then you can keep using the gas tube. The nub on the rear end of the gas tube is designed to wear, When it gets too small gas will start to blow by and cause short strokes. You can use the gas tube to align the barrel nut. Get the nut tight with the teeth aligned by eye then insert the gas tube and rotate it into its proper orientation. Slide the tube forward until it touches the back of the FSB. Compare the position of the gas tube to that of the hole in FSB for the gas tube. Rotate barrel nut as necessary. If the teeth are quite a bit off loosen the nut and retighten, repeat if necessary. If you're using Colt parts (esp barrels and bolts) then HS isn't as big an issue. As for torque, tight is tight, loose is loose. Use lots of grease on the mating flanges on the barrel nut and barrel extension. This is the surface that transfers rotation to the barrel thereby disturbing sight alignment. I don't see a hole in the DPMS wrench to attach a torque wrench. Once again, if you're using Colt barrels and Colt uppers, sight alignment isn't as much of a concern. I once swapped the barrels around on 5 uppers, 3 Colt's, 2 off (but same) brands. At the range all the Colt assemblies with their new Colt barrels shot nearly POI/POA at 25m. The other two required extensive adjustment to zero. We got a good laugh out of that. |
|
Quoted: As for torque, tight is tight, loose is loose. Use lots of grease on the mating flanges on the barrel nut and barrel extension. This is the surface that transfers rotation to the barrel thereby disturbing sight alignment. I don't see a hole in the DPMS wrench to attach a torque wrench. Grease is a very good idea in terms of future disasembly. Those square notches in the DPMS wrench are for the torque wrench. I had to use an adapter with mine - IIRC, my torque was 3/8 whereas the DPMS wrench is 1/2, or vise versa. I used an old gas tube to line up the notch, then inserted the new one. |
|
One of the notches is sized to fit a fixed-stock receiver extension, and the other notch fits flash suppressors. There should be a 3/8" square hole for a torque wrench that used to be on the DPMS wrench, but has been omitted on the recent models. That hole is present on the wrench that Tweak posted (which is what I use). -Troy |
AR Sponsor