01-13-2014, 07:45 PM
Tedward Wrote:Well like I just read from LRRPF52, every manufacture does things different.
JP Rifles uses .650 under the hand guard on there Grendel between the upper receiver and the gas block so who really knows. They do use there thermal dissipation to stiffen the barrel as they note on the link below.
http://www.jprifles.com/buy.php?item=JPSM6.5G-22M8
http://www.jprifles.com/1.4.5_hs.php
As far as contouring, I talked to my machinist and he has blanks that are 1.5" from one end of the blank to 1.25 at the other end. All contouring and cambering is done after rifling and he doesn't do any stress relief. According to him its not needed and he has done lots of barrels in all kinds of lengths. He makes Silencers and all kinds of custom SBR rifles so a 5lb barrel blank turns into a 1.5lb or less barrels sometimes.
Tedward:
I take NRA Gunsmith courses at Montgomery Community College in Troy, NC. I turned this blank in the Alternate Caliber AR-15 course last March. There were 7 other guys taking the course and we all had problems finding enough parts to build our AR 15. If it was not for the instructor I would have never found a bolt for my barrel. Some built 300 Blackouts and the rest 6.5 Grendel. The course lasted 5 days.
I wish I knew then what I know now. I would have made some changes then. But, it was a good experience and I enjoyed it very much. They offer these courses at various community colleges across the nation. All that is required is a little knowledge in how to read blueprints, use a micrometer, and follow instructions. I am fortunate in that I have been doing this kind of work since high school. I have a lathe, milling machine, and TIG welder in my shop that allows me to work on most of my projects.
I would recommend these courses to anyone who has the time to do them as some of them are offered on the weekends as well. I wish I lived close enough to a range that offered marksmanship courses. That would be a big plus I am sure.