Post by youngearl on Mar 28, 2013 13:20:25 GMT -8
I built a 6x45 BHW18" rifle length gas tube, experienced the common problems associated with this combo
Clue #1
When compared to my RRA Predator Pursuit 16" the charging handle was much harder to pull back.
On the first two trips to the range I experienced similar FTF/ short stroking,FTE and bolt not staying open on last round,most all of the problems commonly associated with this barrel/gas tube configuration. I flatten, punched holes in primers @27.0grs and blew out primers at 28.0grs with SMP-842/ CFE223. Hornady 75gr Soft Points are the test bullets
Going on the assumption that BHW would have drilled a gas port to a diameter that would be adequate gas for a functioning I started to look at my other variables.
The rifle is a LKB stripped lower and upper, painted with Aluma Hyde II, the BCG was a WMD M16 length, Geissle SSA-E Trigger, Windam Weaponary Buffer Spring. BCM/Vltor large Charging handle.
Polishing the inside of the upper helped to reduce the effort to pull back the charging handle but not much. I tried different gun oils and super lube grease and spray oil not much difference.
The Windam Weaponary Carbine Buffer spring was about 3/4 to 1" longer that the RRA cabine buffer spring so I installed the a new RRA buffer spring from Brownells # 739-000-005WB. SLAP YO MOMMA!! Big difference when operating the charge handle.
Went to the range with RRA buffer , SMP-842, IMR3031 and RL15. 5 shot groups, some oil on BCG
SMP: 27.0grs rounds fed but bolt closed on round 5
3031: 23.0gr Short stroked rounds 2,4, bolt closed on round 5
23.5 to 24.0 functioned fine, bolt closed on round 5
24.5 Short stroked round 3&4 bolt closed on round 5
Reoiled BCG with Hoppe Elite gun oil got it really wet
RL15 26.0 to 27.5 grs The rilfe functioned Flawlessly. Bolt stayed open!!
So based on the Small Sample of 60 to 70 rounds shot on 3 occasions my initial conclusions:
1. Gas port in Barrel is adequate
2. Standard Carbine buffer spring is too strong for 6x45 bbl with rifle length gas tube. Try 739-000-005WB Rock River Carbine Length Recoil Spring $4.00 from Brownells or the Wolfe reduced power RP Spring $14.99
3. Run your gun wet, based on reoiling BCG for the last 20 rounds; if I had more oil initially on the BCG; the bolt may have stayed open on the last round during the smp842 and IMR 3031 powder tests.
4. More rounds need to be shot through the gun to confirm my conclusions and I better post pictures.
Clue #1
When compared to my RRA Predator Pursuit 16" the charging handle was much harder to pull back.
On the first two trips to the range I experienced similar FTF/ short stroking,FTE and bolt not staying open on last round,most all of the problems commonly associated with this barrel/gas tube configuration. I flatten, punched holes in primers @27.0grs and blew out primers at 28.0grs with SMP-842/ CFE223. Hornady 75gr Soft Points are the test bullets
Going on the assumption that BHW would have drilled a gas port to a diameter that would be adequate gas for a functioning I started to look at my other variables.
The rifle is a LKB stripped lower and upper, painted with Aluma Hyde II, the BCG was a WMD M16 length, Geissle SSA-E Trigger, Windam Weaponary Buffer Spring. BCM/Vltor large Charging handle.
Polishing the inside of the upper helped to reduce the effort to pull back the charging handle but not much. I tried different gun oils and super lube grease and spray oil not much difference.
The Windam Weaponary Carbine Buffer spring was about 3/4 to 1" longer that the RRA cabine buffer spring so I installed the a new RRA buffer spring from Brownells # 739-000-005WB. SLAP YO MOMMA!! Big difference when operating the charge handle.
Went to the range with RRA buffer , SMP-842, IMR3031 and RL15. 5 shot groups, some oil on BCG
SMP: 27.0grs rounds fed but bolt closed on round 5
3031: 23.0gr Short stroked rounds 2,4, bolt closed on round 5
23.5 to 24.0 functioned fine, bolt closed on round 5
24.5 Short stroked round 3&4 bolt closed on round 5
Reoiled BCG with Hoppe Elite gun oil got it really wet
RL15 26.0 to 27.5 grs The rilfe functioned Flawlessly. Bolt stayed open!!
So based on the Small Sample of 60 to 70 rounds shot on 3 occasions my initial conclusions:
1. Gas port in Barrel is adequate
2. Standard Carbine buffer spring is too strong for 6x45 bbl with rifle length gas tube. Try 739-000-005WB Rock River Carbine Length Recoil Spring $4.00 from Brownells or the Wolfe reduced power RP Spring $14.99
3. Run your gun wet, based on reoiling BCG for the last 20 rounds; if I had more oil initially on the BCG; the bolt may have stayed open on the last round during the smp842 and IMR 3031 powder tests.
4. More rounds need to be shot through the gun to confirm my conclusions and I better post pictures.