andremajic
03-13-2011, 10:35 AM
http://castboolits.gunloads.com/imagehosting/44874d7cd233b6af2.jpg
Started with a .308 diameter "gunsmith special" 1/10 twist cutoff from numrichs. http://www.gunpartscorp.com/catalog/Detail.aspx?pid=593060&catid=6886
17.25 for the barrel extension at del-ton inc. http://www.del-ton.com/AR_15_Barrel_Extension_p/bp1033.htm
125.00 for the reamer, with another 25 for the "go" gauge. http://www.pacifictoolandgauge.com/reamers2.htm
Duke nukem gave me a good deal on the gas block and gas tube which were also used. (Thanks Duke!)
I'm thinking of sandblasting the barrel and using some ceramakote bake on epoxy to give it a durable, non glare finish.
Because of the barrel twist, this is going to be for supersonic velocities.
http://castboolits.gunloads.com/imagehosting/44874d7cd2340f70e.jpg
The barrel is still "in the white", so I have a light layer of oil on it to prevent rust. I cut a stepped target crown and polished it with 600 grit to remove any tool marks that might affect the escaping gases. The chamber was surprisingly easy to cut because of the small amount of material actually removed during the reaming process. I did the reaming by hand, using a 4 jaw chuck to center the bore, with a spider on the other end.
The metal removal when profiling the barrel wasn't much fun. I wasn't getting a good finish with the carbide or HSS tool bits, so after messing around with various speeds/feed rates I gave up and rough profiled it, and finished the last couple thousands of outside diameter with some fine cut files and sandpaper.
http://castboolits.gunloads.com/imagehosting/44874d7cd23450247.jpg
For now, I will be using j-words because of the feeding preference but might start playing with cast when I figure out a good load. Started with the load data for 300 whisper, but because I was using resized LC brass with reduced capacity I reduced the starting load by 2 grains.
I went as low as 10 grains of reloder 7 with the action cycling just fine, but anything under that would half-eject or "stovepipe" the rounds.
Recoil is the same or less than a .223
Drawbacks are that forming your own brass is about an 8 step process which gets monotonous. I was able to speed up production of trimming by using a hand drill attached to my case trimmer.
It's really cool that I can load up a 30 round magazine with 30 caliber ammo. Here's a pic of what I got at 100 meters. I'm sure the accuracy could really be tested once I get something solid to rest it on, tune the trigger, and use a scope that allows me to see the target a little better. With the results I got last trip to the range, I'm SURE the rifle can shoot better than I can.
I'd like to thank 82nd Airborne for bringing this cartrige to the attention of the forum, performance is awesome!
Andy.
Started with a .308 diameter "gunsmith special" 1/10 twist cutoff from numrichs. http://www.gunpartscorp.com/catalog/Detail.aspx?pid=593060&catid=6886
17.25 for the barrel extension at del-ton inc. http://www.del-ton.com/AR_15_Barrel_Extension_p/bp1033.htm
125.00 for the reamer, with another 25 for the "go" gauge. http://www.pacifictoolandgauge.com/reamers2.htm
Duke nukem gave me a good deal on the gas block and gas tube which were also used. (Thanks Duke!)
I'm thinking of sandblasting the barrel and using some ceramakote bake on epoxy to give it a durable, non glare finish.
Because of the barrel twist, this is going to be for supersonic velocities.
http://castboolits.gunloads.com/imagehosting/44874d7cd2340f70e.jpg
The barrel is still "in the white", so I have a light layer of oil on it to prevent rust. I cut a stepped target crown and polished it with 600 grit to remove any tool marks that might affect the escaping gases. The chamber was surprisingly easy to cut because of the small amount of material actually removed during the reaming process. I did the reaming by hand, using a 4 jaw chuck to center the bore, with a spider on the other end.
The metal removal when profiling the barrel wasn't much fun. I wasn't getting a good finish with the carbide or HSS tool bits, so after messing around with various speeds/feed rates I gave up and rough profiled it, and finished the last couple thousands of outside diameter with some fine cut files and sandpaper.
http://castboolits.gunloads.com/imagehosting/44874d7cd23450247.jpg
For now, I will be using j-words because of the feeding preference but might start playing with cast when I figure out a good load. Started with the load data for 300 whisper, but because I was using resized LC brass with reduced capacity I reduced the starting load by 2 grains.
I went as low as 10 grains of reloder 7 with the action cycling just fine, but anything under that would half-eject or "stovepipe" the rounds.
Recoil is the same or less than a .223
Drawbacks are that forming your own brass is about an 8 step process which gets monotonous. I was able to speed up production of trimming by using a hand drill attached to my case trimmer.
It's really cool that I can load up a 30 round magazine with 30 caliber ammo. Here's a pic of what I got at 100 meters. I'm sure the accuracy could really be tested once I get something solid to rest it on, tune the trigger, and use a scope that allows me to see the target a little better. With the results I got last trip to the range, I'm SURE the rifle can shoot better than I can.
I'd like to thank 82nd Airborne for bringing this cartrige to the attention of the forum, performance is awesome!
Andy.