Tyrantresister
09-09-11, 03:24
LMT Enhanced Bolt
http://i6.tinypic.com/4ife7pi.jpg
http://sgcusa.com/images/supporting_images_large/LMT_Enhanced_Full-Auto_Bolt_Carrier_Group_L7Q3_E.jpg
The bolt itself is of particular interest. The function of the dual spring extractor is frequently misinterpreted as an attempt to add spring force to the extractor claw. Rather it reduces the fatigue that the extractor spring(s) undergo by allowing the use of longer springs with lower K values; the % relative compression during the movement of the extractor is reduced. Remember that additional extractor force is not required now that the carrier is slowing the extraction cycle. The mitigation of stress in the bolt is accomplished in several ways. Material is the least visible change but is important to the design. The traditional Carpenter 158 is abandoned, being replaced by a significantly tougher grade from a different manufacturer. The lugs themselves are generously radiused between lugs and at the rear the diameter is actually reduced to allow a larger transition radius to be machined. The incorrectly identified sand cuts on the lugs are stress relief cuts. These allow any individual lug to elastically deform and give a smoother load over the contact patch. While this type of feature is very difficult to calculate and even more difficult to implement it helps to place the lug in a true shear load rather than amplify the bending moment. As noted the lug opposite the extractor is relieved. This feature prevents the unequal transfer of load to the two opposite lugs but I would argue that the stress relief groove already in place largely accomplishes this purpose. This is a academic quibble so I will bow to LMT in this respect. There is one additional feature that can be found in the bolt, but I am not at liberty to disclose the detail.
Bill Alexander
VS.
Denny's Super Duty Ion Bond Bolt
http://globaltactical.com/_img.upload/upload/ion%20bonded%20bolt%20alone.jpg
http://globaltactical.com/_img.upload/upload/ION%20SD%20BCG%20BOLT%20ASSY.jpg
MPI BOLT ION BONED
SHOT PEENED EXTRACTOR ION BONDED
CHROME SILICON EJECTOR SPRING ION BONDED
CORRECT DUROMETER BLACK BUMPER
EXTRA STRENGTH CHROME SILICON EXTRACTOR SPRING
ION BONDED GAS RINGS
A SHORT ION BOND PRIMER
Ion Bond is a Tribological coating that bonds to the matrix of the base metal and becomes part of it. ION BOND is PVD and PA-CVD technology. It is 90 Rockwell in hardness. Much harder than hard chrome and black in color.
ION BONDING accomplishes several things on the AR BCG:
Reduced coefficent of friction
Increased abrasive wear resistance
Anti-scuffing.antigalling
High fretting resistance
High pitting resistance
High corrosion and carbon resistance(EASY TO CLEAN)
Reduced friction and assisted lubrication
Accomidated higher contact pressures
Ultraclean surface engineering
ISO 9002 certified.
What do you think? Which would be the barnone toughest that there is?
http://i6.tinypic.com/4ife7pi.jpg
http://sgcusa.com/images/supporting_images_large/LMT_Enhanced_Full-Auto_Bolt_Carrier_Group_L7Q3_E.jpg
The bolt itself is of particular interest. The function of the dual spring extractor is frequently misinterpreted as an attempt to add spring force to the extractor claw. Rather it reduces the fatigue that the extractor spring(s) undergo by allowing the use of longer springs with lower K values; the % relative compression during the movement of the extractor is reduced. Remember that additional extractor force is not required now that the carrier is slowing the extraction cycle. The mitigation of stress in the bolt is accomplished in several ways. Material is the least visible change but is important to the design. The traditional Carpenter 158 is abandoned, being replaced by a significantly tougher grade from a different manufacturer. The lugs themselves are generously radiused between lugs and at the rear the diameter is actually reduced to allow a larger transition radius to be machined. The incorrectly identified sand cuts on the lugs are stress relief cuts. These allow any individual lug to elastically deform and give a smoother load over the contact patch. While this type of feature is very difficult to calculate and even more difficult to implement it helps to place the lug in a true shear load rather than amplify the bending moment. As noted the lug opposite the extractor is relieved. This feature prevents the unequal transfer of load to the two opposite lugs but I would argue that the stress relief groove already in place largely accomplishes this purpose. This is a academic quibble so I will bow to LMT in this respect. There is one additional feature that can be found in the bolt, but I am not at liberty to disclose the detail.
Bill Alexander
VS.
Denny's Super Duty Ion Bond Bolt
http://globaltactical.com/_img.upload/upload/ion%20bonded%20bolt%20alone.jpg
http://globaltactical.com/_img.upload/upload/ION%20SD%20BCG%20BOLT%20ASSY.jpg
MPI BOLT ION BONED
SHOT PEENED EXTRACTOR ION BONDED
CHROME SILICON EJECTOR SPRING ION BONDED
CORRECT DUROMETER BLACK BUMPER
EXTRA STRENGTH CHROME SILICON EXTRACTOR SPRING
ION BONDED GAS RINGS
A SHORT ION BOND PRIMER
Ion Bond is a Tribological coating that bonds to the matrix of the base metal and becomes part of it. ION BOND is PVD and PA-CVD technology. It is 90 Rockwell in hardness. Much harder than hard chrome and black in color.
ION BONDING accomplishes several things on the AR BCG:
Reduced coefficent of friction
Increased abrasive wear resistance
Anti-scuffing.antigalling
High fretting resistance
High pitting resistance
High corrosion and carbon resistance(EASY TO CLEAN)
Reduced friction and assisted lubrication
Accomidated higher contact pressures
Ultraclean surface engineering
ISO 9002 certified.
What do you think? Which would be the barnone toughest that there is?