LorinB

Thank you all for the info. Now there us a proper size gas port.

I am going to enlarge the .076 gas port in my Shilen stainless barrel to .096. Would it be advisable to use inexpensive Harbor Freight numbered drill bits or would more expensive high speed steel bits or even a carbide bit be safer in regard to leaving a burr on the riffling or breaking in the hole? Also, I had the idea of driving a lead slug into the barrel so that it obturates in the lands and grooves to serve as a backer to advoid making a bur on the riffling when the bit penetrates the bore. Then I would blow all of the shavings out through the gas port with compressed air before driving the slug out the muzzel so no steel shavings would be drug along the riffling. Is this a good or bad idea? Has anyone ever made a burr or taken any measure to avoid making one? Thanks! Lorin

Kitchen scale says buffer is 5.6 oz (but could be off) and 5.291" long. Buffer tube is actually 9-11/16". Spring, buffer and tube are some Joe Bob's fifle length set. Before finding this sight I ordered a Tubb flat wire spring that has not delivered. Should I give it a go or just go straight to Sprinco Red? I also ordered a Kak LR 308 buffer body and an assortment of aluminum, steel and tungsten weights that I'm guessing I should probably return, correct? I'm a wood worker by profession with a well appointed wood shop but little to no metal machining experience or machines. I plan to jig up a wooden barrel clap on a table top drill press and drill out the gas port to .093 or .096. Will an inexpensive high speed steel, Harbor Freight set of numbered drill bits do a fine job or would it be safer get a higher quality high speed steel or carbide bit?

Already posted on the build forum and got almost immediate feedback. Thanks Lorin

Real name is actually Lorin and I am brand new here. I just completed a new build that is not cycling and google introduced me to this great place. I am already a little less confused and very optimistic that my grand creation will be more than a single shot soon...

I found this sight through an internet search while trying to determine the cause of a new builds failure to cycle.

New build is short stroking. It ejects about 1' @ 3 o'clock and will not lock bolt back on empty mag or strip off next round. .308, 20" Shilen barrel, rifle length gas system, .75 gas mandrel, JP adjustable gas block (wide open) 5.6 oz rifle buffer. I suspect the gas port is too small at .076 (caliper measurement). I am planning on buying numbered bits tomorrow to confirm size and possibly open it incrimentally until it runs. Where should it be .093 - .096? Also, I have only shot 50 rounds through it and I suspect the problem could be contributed to the fact that I am loading 130 grain Barns TTSX, which is very light for caliber but they are near max load at 3250 fps. That gives a power factor of 422 vs 175 gr bullets @ 2600 fps (PF 455) which is the Federal load that Shilen uses as a proof load. I know the easy answer to this question is to try heavier factory ammo, but is it likely that the 130 gr bullet is the cause of the cycle failure? If so is it reasonable to attempt to tune for this load? I really want to use a fast monolithic bullet for hog hunting at night wich is the primary reason for this build. First post.... and thank you for any feed back!

New build is short stroking. It ejects about 1' @ 3 o'clock and will not lock bolt back on empty mag or strip off next round. .308, 20" Shilen barrel, rifle length gas system, .75 gas mandrel, JP adjustable gas block (wide open) 5.6 oz rifle buffer. I suspect the gas port is too small at .076 (caliper measurement). I am planning on buying numbered bits tomorrow to confirm size and possibly open it incrimentally until it runs. Where should it be .093 - .096? Also, I have only shot 50 rounds through it and I suspect the problem could be contributed to the fact that I am loading 130 grain Barns TTSX, which is very light for caliber but they are near max load at 3250 fps. That gives a power factor of 422 vs 175 gr bullets @ 2600 fps (PF 455) which is the Federal load that Shilen uses as a proof load. I know the easy answer to this question is to try heavier factory ammo, but is it likely that the 130 gr bullet is the cause of the cycle failure? If so is it reasonable to attempt to tune for this load? I really want to use a fast monolithic bullet for hog hunting at night wich is the primary reason for this build. First post.... and thank you for any feed back!