02-10-2016, 05:48 PM
There's an excellent thread on ARFCOM right now where a gun rental place in Vegas reports the long-term durability of various guns that they abuse on extreme full auto firing schedules.
They run 25 mags average per day through M4's of various types. Daniel Defense, J&T Distributing, Palmetto State Armory, HK, etc.
They recently added a bunch of Colt's to the mix, and they are seeing excellent bolt longevity with the Colt's.
They usually replace barrels/bolts after 20,000-28,000 rounds in the M4's, or when they start to see key-holing in the targets at 10 yards.
All the piston guns they tried broke, except the HK416, although the HK's barrel started key-holing at 10,000rds.
Headspace stretches over time in a firearm, so bolts and barrels are expendable items when you shoot in high volume. Colt has forgotten more about what makes the AR15/M16/Mr FOW work than most companies combined.
The only company that I know of that took a very close look at Colt's work on the 7.62x39 Sporter was Alexander Arms, when Bill was doing research for the bolt for the 50 Beowulf. What I've seen with the rest of the industry with 7.62x39 was the assumption that you can just use a .125" bolt face, but wider for the fatter case, and that has been a failure time and again.
On top of that, very few companies are QC'ing their bolts to find the weaknesses in each batch, and culling those bolts, so customers end up with failure-prone bolts. They can sell more volume that way because the price is so low, as they didn't take the time and resources to MPI or do any destructive test and analysis of grain structure.
The result is the customer gets to do the final QC, which results in a much higher failure rate and unacceptable bell curves on Total Quality Management. This is happening with 5.56 bolts as well, although MPI has become much more prevalent with people becoming more aware of what makes the reliable bolts work, compared to imitation bolts.
I think Sharps had a good strategy to differentiate themselves from the rest, but their choice of S7 tool steel and failure to QC their initial production lots really didn't help them, and word of failures spread quickly.
![[Image: hqdefault.jpg]](https://i.ytimg.com/vi/tE0Jw0O2Mfo/hqdefault.jpg)
They run 25 mags average per day through M4's of various types. Daniel Defense, J&T Distributing, Palmetto State Armory, HK, etc.
They recently added a bunch of Colt's to the mix, and they are seeing excellent bolt longevity with the Colt's.
They usually replace barrels/bolts after 20,000-28,000 rounds in the M4's, or when they start to see key-holing in the targets at 10 yards.
All the piston guns they tried broke, except the HK416, although the HK's barrel started key-holing at 10,000rds.
Headspace stretches over time in a firearm, so bolts and barrels are expendable items when you shoot in high volume. Colt has forgotten more about what makes the AR15/M16/Mr FOW work than most companies combined.
The only company that I know of that took a very close look at Colt's work on the 7.62x39 Sporter was Alexander Arms, when Bill was doing research for the bolt for the 50 Beowulf. What I've seen with the rest of the industry with 7.62x39 was the assumption that you can just use a .125" bolt face, but wider for the fatter case, and that has been a failure time and again.
On top of that, very few companies are QC'ing their bolts to find the weaknesses in each batch, and culling those bolts, so customers end up with failure-prone bolts. They can sell more volume that way because the price is so low, as they didn't take the time and resources to MPI or do any destructive test and analysis of grain structure.
The result is the customer gets to do the final QC, which results in a much higher failure rate and unacceptable bell curves on Total Quality Management. This is happening with 5.56 bolts as well, although MPI has become much more prevalent with people becoming more aware of what makes the reliable bolts work, compared to imitation bolts.
I think Sharps had a good strategy to differentiate themselves from the rest, but their choice of S7 tool steel and failure to QC their initial production lots really didn't help them, and word of failures spread quickly.
NRA Basic, Pistol, Rifle, Shotgun, RSO
CCW, CQM, DM, Long Range Rifle Instructor
6.5 Grendel Reloading Handbooks & chamber brushes can be found here:
www.AR15buildbox.com
CCW, CQM, DM, Long Range Rifle Instructor
6.5 Grendel Reloading Handbooks & chamber brushes can be found here:
www.AR15buildbox.com