EdgeReady

I will retest again and attempt to remove some variables. At this point I don't trust the chronograph readings. I did some research and apparently there's some sorcery regarding chronograph setup and lighting conditions. I probably had it too close to the muzzle and the sunlight conditions were extremely bright. Also, I'm going to ground the rifle next test. I've been shooting from a carpeted platform installed on a Polaris Ranger for that purpose. It permits me to keep my kit mobile and quickly change shooting locations. I'm standing when I shoot, but can base out, lean over the platform, and get onto and into the rifle. While it's pretty stable, especially with a bag and GI socks, it's not like being grounded. I will also shoot from 100yds. If this next test brings results consistent with those to date, I'm going to move on a different barrel. My build goal was portable, accurate, suppressor host. 3 or so MOA is thus far failing in the accuracy category. I had a POF308 with 20" bbl for years, and it consistently shot sub-MOA with FGMM from the same shooting platform.

Are you aware of any reason that a particular system would run lower than expected velocities? The short barrel length is the only factor I'm aware of if you rule out the ammo. The ammo I'm using is well established. The performance of that 14.1 Hanson barrel is also established by others who have used it. I did drill out the gas port, but the gas pressure is controlled with an adjustable block and there appears to be plenty of gas available in the system. The block is only 1 turn from off, which is 75% closure. What other system factors could cause this ammo to be low velocity?

No doubt on the velocities. The highest velocity measured was measured after this test at 2330fps. It was measured at the muzzle. This barrel is consistently printing those groups with three types of 140gr ammo. Unless I become aware of some new sorcery, I'm headed for a different barrel. BA won't honor this one because I've modified it. It's looking like I've got a very short Tomato stake.

I just hit the range to run more tests on the 6.5 CM BA Rifle w/14.1 Hanson bbl. Here's what I did since we last messaged... Thoroughly cleaned chamber/bore and lubed BCG Checked scope & mount torques Re-torqued flash hider using formula to compensate for wrench extension Shot comparison test groups using American Gunner 140gr and FGMM 140gr 200yds Rifle bagged fore & aft 85 degree F Light variable breezes, tree cover either side of range I also chrono-graphed and the velocities seemed low to me Here's a pic of the American Gunner 140gr group, my control group... Here's a pic of the Federal Gold Medal Match 140gr group, my test group... My conclusion remains the same at this point...something is up with this barrel. Thoughts?

I run the FGMM 168/175 in my .308 precision guns and they do run just like you said. This build is a 6.5CM, so Federal offers a 140 Sierra and a 130 Berger in FGMM. I'll try the 140 BTHP.

After boring out gas port, I got everything running, gas tuned, and function tested. I picked up some better ammo (American Gunner) to see what kind of accuracy I get achieve. The American Gunner shot better than the FMJ was using for function testing, but I was underwhelmed with the accuracy to say the least. At 200yds I could only squeeze 2MOA groups from it. The rifle was bagged front and rear, using a Nightforce 3-15NXS for testing. I did have some gusty tailwinds, but I honestly think I could have shot better groups with any AR from my fleet. I'm prepared to just ditch this Hanson barrel and invest in a Criterion, but I think I owe it a bit more effort before going to the nuclear option. After all I've been through with this build, I just don't have confidence in this barrel. Any thoughts?

Gents, Clint's Armalite spring was shipped most rikitik. I installed the spring with the 5.6oz buffer and I achieved functionality. However, after drilling the gas port out to 0.094, it was highly gassed at max gas setting. I had ripped case rims, base marking, and stovepipes until I dialed the gas down. I had to go about 1 full turn from CLOSED to achieve reliable function, bolt lock, with strong 4pm ejection. After single round function testing, I performed multi-round reliability testing. Slow fire or mag dumps, the gun is running well. I retested everything suppressed and the gas block setting end up being only 1 click down for best suppressed function. I'm happy with the way the gun is running now, but I'm concerned that the functional "window" of gas block settings is very small. 1 click more gas brings overgassing with a 1pm ejection or and 1 click less gas brings failure to lock back. There are settings on the gas block that are in-between the detents and provide even more optimal function, but I'm not comfortable adjusting between a detent as it probably won't stay there. I learned long ago never to underestimate the ability of gun fire vibrations to screw stuff up. Question: I filed and polished ramps to eliminate the scarring I was seeing on the casings. Now it does not scar when I load and eject a round, but the scarring is still there when I fire and eject an empty casing. The scarring is two lines on the case neck about 1/4" apart. I thought I would ask before I do anything else with ramps. Thank you all kindly for your assistance with this project. Had I not invested the time in joining this group, I would not be where I'm at with this. I hope that I'll be able to repay the favor in some way. Edge

I lube all my weapon systems with a mixture I learned from the armors at Blackwater which they referred to as "monkey cum". It's a mixture of MIlitec grease thinned by Militec oil to lower it's viscosity. I only place it on mating surfaces or wear points, nowhere else. It stays put even under extreme heat and use, but is thin enough to lubricate well. It lubes well, lasts long, and does not tend to collect debris. I use it in all my rifle and handgun systems, except when in extreme cold conditions when I switch back to a lighter lube. It's always worked well for me, especially once I learned where and how much to use.

Thanks for the compatibility tip, that's just what I needed to scratch my itch to make progress here. I'll gladly purchase a reasonable substitute until the real deal comes in, which will permit me to verify my progress thus far and get some other things sorted out. If you're looking for SpringCo Red, I'll be happy to send it your way. I'm only holding one 308AR system at present so you'll probably need it before I do again.

I have the 5.3oz/3.25" buffer and I ordered the Armalite spring from Clint at HeavyBuffers.com. I'm not 100% sure if he has them in stock. I used all my google-fu and that was the ONLY source I could find with an Armalite EA1095 buffer spring that wasn't out of stock or closed down. I'm shut down on this project until I can get the spring. Is anyone aware of any obscure source for an EA-1095?

Roger that. Will do.

The 0.094" hole is drilled and the spring is ordered. I have one of Clint's CAR-10 heavy buffers that he recommends for 7" tube 308s. It's 5.7oz. Will that work?

Thank you for that guidance. I will shoot for 0.094 and be done with it. Once the gas is flowing as it should, I will redo the recoil system testing at various gas settings. Hopefully I will find the happy & reliable zone. (I will not bother retesting the Yellow spring as I think its way too light). After that, redo the same suppressed. Thanks again.

I performed my recoil system tests this evening. Here are the results. As expected, I'm still thinking low gas due to small gas port. Sorry that results do not format well here. All tests done at max gas pressure using 140gr Sellier&Bellot SMK Locked on bolt L Short- lock on carrier SL No lockback NL Failure to eject FTE Stovepipe SP Carbine Length Springs (in order of comp strength) CAR-10 Buffer 5.7oz Eject O'clock Comments 308 Carbine Buffer 3.7oz Eject O'clock Comments SpringCo Orange, 28 coils NL 3-4ish Casing dribbled out onto arm FTE n/a Failure to eject, strong eject to 6ft SpringCo Orange, 28 coils SP n/a 2nd shot, Stovepiped NL 5:00 2nd shot, casing dribbled out to 2ft Spring 2, 24 coils NL 3:30 Ok ejection, not strong, 6ft NL 3:30 Ok ejection, not strong, 5ft Spring 3, 27 coils NL 4:00 Low order ejection, 3ft NL 3:30 Ok ejection, not strong, 5ft Tactical Spring 4, 35 coils NL 3:00 Ok ejection, not strong, 5ft NL 3:30 Ok ejection, not strong, 5ft Yellow, 38 coils NL 4:00 Failure into battery, spring too weak, ok ejection, not strong, 5ft NL 4:00 Failure into battery, spring too weak, ok ejection, not strong, 5ft Notes: All brass is scarred pretty well going across the feed ramp. Common report for 6.5CM AR. I will address later. Any chance these scars cause the casing to grab in the chamber thus requring more force to extract?

This weekend I will conduct recoil system games and record the data from all the testing. I have arranged my springs from heaviest to lightest. I'll be using two 308 buffers in the series as well, 5.7oz and 3.7oz. I will track the results of each combination on a spreadsheet. All tests will be conducted at single shot, empty mag, and maximum gas port setting. After these recoil system games are complete, I will use bits to gauge the gas port diameter. Question: if we verify that the gas port is to be drilled out, what increments of enlargement should I shoot for? Is there a typical increase used, or should I just go up bit size by bit size? My main concern is that by moving up gradually over several small increments, I will increase wear & tear over the number of re-assemblies and will increase the chances of bit breakage over many subsequent drilling operations. I would prefer to be more targeted about the diameter increase if this is possible.