Build Thread 6.5 Grendel or 6.8 Rem SPC?

[P7M13]

Awesome!

 

[CamoDeafie]

Slight update. I swapped out the unshielded skinny 6-hole carbine handguards for a set of shielded 6-hole carbine handguards that I picked up yesterday from Gunrunner Arms. They are not Colt originals, but of a similar age (1990s-2000s, before M4s).. not sure who made them, Bushmaster? DPMS, RRA, others? No inside pics, but the heat shield isn't tabbed. And just pressed into slots. Shown with PSA Fat M4 single shield set, and the unknown 6-hole unshielded set that I took off.

 

[CamoDeafie]

Good news. Its not overgassed. Might be undergassed.

Bad news, heres the symptoms

1. Feeds 1st round only if I pull bolt way back and let fly,

2. Fires fine, ejects between 4-5 o clock (borderline ideal/undergassed?)

3. Won't feed next round, bolt carrier goes over next round, have to pull back with CH

4. Noticed a brass line going from round to m4 feed ramp on the rifle upper.

Works OK with 100gr Wolf FMJ. Won't pick up 123gr Hornady Frontier FMJ, in a different magazine.

Looks like I'll have to either send or go visit @Velzey for the ramp cutting?

May need either lighter buffer or lighter bolt carrier ? Have full mass M16 carrier in and standard carbine buffer, H2 I think? Will take it out and look for markings

 

[monkeybutler]

M4 ramps are needed for 6.5 Grendel in an AR.

Wish I had seen this thread two years ago, woulda mentioned this then...

 

[CamoDeafie]

M4 ramps are needed for 6.5 Grendel in an AR.

Wish I had seen this thread two years ago, woulda mentioned this then...

Yeah, If I had known about this earlier, I would have looked for the M4 ramp fixed carry handle upper from Luth-AR or Nodak... or built the C7 I have to a different retro configuration. Oh well. Just waiting to hear from @Velzey .