03-23-2012, 02:10 PM
Ok Guys,
I am back from Vegas. Saw some interesting things while in the metro Vegas area with a 2 mil population, seems like they have a bit of everything you could want or not want, rolled into a ball. :o For us, I saw a new Polymer AR lower and bought one for $100 complete. Also found a new AR 5.56 upper with 1-9 twist, 16 inch, flat top with low gas block and a four rail free float for $298. So I got myself can gun #2 for $400. My Glock nuts buddy calls it a Glock AR.:p
The two powders I did get to work my action were AA #9 and 2015 BR. Now when I say work, I mean the entire show, sub sonic, lock back, strip 5 rounds, etc. #9 had the widest variances so I turned to 2015. But remember, I am using .267 bullets seated all the way down in the case as I must get clear of the throat which is .264 So my pressures have to be up, at least for a very short span of time, as I am swaging the bullets to .264 and with the 16 inch barrel it may well be all that is needed. I note in reading J. D. Jones notes on the Whisper that he was working a lot with short barrels, to make up for the can's length. One thing I found quickly is that the function is a matter of timing not just pressure period. The powder must reach a peak pressure point just prior to the gas port or that is what appears to be the case.
In silhouette shooting from a single shot, the barrel length for the Unlimited class is restricted to 14 inches so to obtain peak velocity you must burn the powder in under 14 inches. 2015 and #9 will burn in 14 inches and apparently delivers some push left over for the gas system at least in the 16. If the gas port position is relative then a 20 gas port should be aprox 4 inches further out the barrel towards the muzzle. If what I think is happening, is correct, then the next slower burning powder on the scale might be the place to look with a 20, if 2015 is just a tad fast. R #7 is the next powder on my scale with 3031 after that. But #9 and 2015 are not even real close on the scale, so.....
I will try to get up to the farm this weekend while getting ready to go tripping again, this time to Tulsa. We go to the big show every year at least once.
Ed
I am back from Vegas. Saw some interesting things while in the metro Vegas area with a 2 mil population, seems like they have a bit of everything you could want or not want, rolled into a ball. :o For us, I saw a new Polymer AR lower and bought one for $100 complete. Also found a new AR 5.56 upper with 1-9 twist, 16 inch, flat top with low gas block and a four rail free float for $298. So I got myself can gun #2 for $400. My Glock nuts buddy calls it a Glock AR.:p
The two powders I did get to work my action were AA #9 and 2015 BR. Now when I say work, I mean the entire show, sub sonic, lock back, strip 5 rounds, etc. #9 had the widest variances so I turned to 2015. But remember, I am using .267 bullets seated all the way down in the case as I must get clear of the throat which is .264 So my pressures have to be up, at least for a very short span of time, as I am swaging the bullets to .264 and with the 16 inch barrel it may well be all that is needed. I note in reading J. D. Jones notes on the Whisper that he was working a lot with short barrels, to make up for the can's length. One thing I found quickly is that the function is a matter of timing not just pressure period. The powder must reach a peak pressure point just prior to the gas port or that is what appears to be the case.
In silhouette shooting from a single shot, the barrel length for the Unlimited class is restricted to 14 inches so to obtain peak velocity you must burn the powder in under 14 inches. 2015 and #9 will burn in 14 inches and apparently delivers some push left over for the gas system at least in the 16. If the gas port position is relative then a 20 gas port should be aprox 4 inches further out the barrel towards the muzzle. If what I think is happening, is correct, then the next slower burning powder on the scale might be the place to look with a 20, if 2015 is just a tad fast. R #7 is the next powder on my scale with 3031 after that. But #9 and 2015 are not even real close on the scale, so.....
I will try to get up to the farm this weekend while getting ready to go tripping again, this time to Tulsa. We go to the big show every year at least once.
Ed