Sheesh. Stupid gas blocks.

So, replaced a Samson handguard on my 300 Blackout with a BCM KMR 10" this evening. Love the handguard. Looks good, super light weight, lines up perfect. But...

Then I noticed the pinned gas block on my AAC barrel is a little askew. Not enough to cause gas port alignment or function issues but just enough that it is damn near touching the inside of the handguard on one side. Kind of frustrates me. I suppose I could leave the pin out of it and just use the set screws to line it up right. Or I might just pull the barrel and swap it out for a 5.56 and set the Blackout barrel to the side for a project at a later date.

Decisions, decisions.

http://i102.photobucket.com/albums/m...pscdc14179.jpg

Or just not worry about it.
If somebody asks about it tell them it was done in conjunction with the twist of the rifling to optimize the gas expansion velocity impulse for increased trajectory curvature and stability of depleted uranium rounds when fired akimbo.

It helps ya know...

I just ordered a new gas block. Might just run it without the pin. Heck, with my luck the block is on straight. It might be the barrel extension pin that isn't centered.
[facepalm]

Quote:

---

Originally Posted by ray1970

So, replaced a Samson handguard on my 300 Blackout with a BCM KMR 10" this evening. Love the handguard. Looks good, super light weight, lines up perfect. But...

Then I noticed the pinned gas block on my AAC barrel is a little askew. Not enough to cause gas port alignment or function issues but just enough that it is damn near touching the inside of the handguard on one side. Kind of frustrates me. I suppose I could leave the pin out of it and just use the set screws to line it up right. Or I might just pull the barrel and swap it out for a 5.56 and set the Blackout barrel to the side for a project at a later date.

Decisions, decisions.

http://i102.photobucket.com/albums/m...pscdc14179.jpg

---

What did you change besides the Handguard? Sounds interesting, that Gas block was set by AAC and also didn't you take it out and run all the ammo you have though it without a hitch? What changed since upgrading to the KMR?

No change other than the handguard. I'm sure the gas block is back where it always was. It has to be since it has the roll pin. It ran like a top last time out so I'm fairly certain the misalignment isn't bad enough to cause gas issues at the port. It might have even been close to the inside of the handguard on the Samson as well and I just didn't notice. It is really close on the KMR. Like almost touching. Close enough I would worry about it contacting when fired and screwing with my accuracy. I'm going to pull the handguard and install a new gas block and make sure it is centered up properly.

I'm kind of OCD with my parts fit and alignment like you are with colors matching.

[Coffee]

Quote:

---

Originally Posted by BPTactical

Or just not worry about it.
If somebody asks about it tell them it was done in conjunction with the twist of the rifling to optimize the gas expansion velocity impulse for increased trajectory curvature and stability of depleted uranium rounds when fired akimbo.

It helps ya know...

---

Oh my God, my brain just melted...

Quote:

---

Originally Posted by ray1970

No change other than the handguard. I'm sure the gas block is back where it always was. It has to be since it has the roll pin. It ran like a top last time out so I'm fairly certain the misalignment isn't bad enough to cause gas issues at the port. It might have even been close to the inside of the handguard on the Samson as well and I just didn't notice. It is really close on the KMR. Like almost touching. Close enough I would worry about it contacting when fired and screwing with my accuracy. I'm going to pull the handguard and install a new gas block and make sure it is centered up properly.

I'm kind of OCD with my parts fit and alignment like you are with colors matching.

[Coffee]

---

The only thing I can add there is I am picky as well with things being symmetrical and perfectly aligned.

I had that barrel and gas block in the original AAC upper with a Parallax Tactical rail which is just as small as the KMR for inside diameter. The Gas block did not touch the hand-guard and was perfectly aligned, centered, matching the receiver and all. The other difference is it is in a different upper, maybe the AAC upper was off with the key for the barrel extension pin or your upper is off?

Any case there may be something going on............

Quote:

---

Originally Posted by Skully

Any case there may be something going on............

---

Most definitely. I'll get it squared away. I'm not scared.

If I suspect the upper receiver is at fault I happen to have a spare laying around. [Awesom]

Quote:

---

Originally Posted by ray1970

Most definitely. I'll get it squared away. I'm not scared.

If I suspect the upper receiver is at fault I happen to have a spare laying around. [Awesom]

---

Is that the one you had Cerakoted or the Aero Precision pre-coated?

It's the upper I had coated. It also happens to be an Aero Precision upper.

Quote:

---

Originally Posted by ray1970

It's the upper I had coated. It also happens to be an Aero Precision upper.

---

So both were off?

Interesting. Wonder if the AAC was off?

Is the gas block perfect to the hole?

I'll get you some more info this weekend when I get a chance to pull it apart.

Seems the majority of the issue was the gas block was a bit off center when it was pinned from the factory. Removed that gas block and centered and installed a new one and it is much more in the center of the handguard. Still slightly off to that same side but not so close I would worry about any contact in that area.

Crisis averted. Lol.

What brand of block did you go with? I've never had any issues with YHM or Troy

Quote:

---

Originally Posted by firefighter238

What brand of block did you go with? I've never had any issues with YHM or Troy

---

As long as they are made of steel, I'm not real picky about the brand. The one I just put on was from Odinworks. The one that was installed a little crooked was a factory install from AAC. It was pinned so every time you put the pin in it would line it right back to it's slightly askew position.

You should see if AAC will remedy that for ya with a new barrel.