Rainier Arms mountain series

[Steel head]

I have the 18" in my thread here:

https://www.m4carbine.net/showthread...l-Review/page2

Waiting on a Precision Armament AFAB before I shoot it (it's arriving tomorrow). I'M EXCITE!

lookin forward to see how it shoots!

[Obscenejesster]

lookin forward to see how it shoots!

Same here....Hopefully he's a good shooter...LOL J/K.

I'm more interested in seeing how it cycles lower powered ammo. I think I'd prefer a mid or intermediate gas system over a rifle for an 18" barrel even though the rifle is softer shooting, I was thinking about doing an 18" build for a SHTF main and I'd rather have the ability to shoot a wide variety of ammo over a softer shooting rifle.

[BufordTJustice]

Same here....Hopefully he's a good shooter...LOL J/K.

I'm more interested in seeing how it cycles lower powered ammo. I think I'd prefer a mid or intermediate gas system over a rifle for an 18" barrel even though the rifle is softer shooting, I was thinking about doing an 18" build for a SHTF main and I'd rather have the ability to shoot a wide variety of ammo over a softer shooting rifle.

Hehe. Depends on the day.

I'm sure this will be fine. I will be running it with an LMT E-carrier and std LMT mil-spec bolt. The Lower uses the Vltor A5 system and I'm going to start with an A5H4 (6.8oz) buffer and a Wolff RP rifle spring. I'll test first with Federal XM193 since that is my agency issued training round. I'll see if I have any weak stuff laying around. I might just strip all the lube off after the initial function test and evaluate it that way.

[DreadPirateMoyer]

Necroposting this to avoid starting a new thread on the same topic.

Now that these have been out for a few years, does anyone have any further feedback on the Rainier Mountain series of barrels? Accuracy with quality ammo/10-round groups at range? Undergassed or overgassed? Overall barrel quality and impressions?

I ask because I'm in the market for a rifle-length chrome-lined barrel with a medium or lightweight (read: not HBAR or stupid government) profile, and the only two I can find that appear to be reputable are these (likely from FNH) and the Fulton Armory 20" pencil barrel (Criterion), the latter of which I can't use since it has a rifle barrel extension and I'll be matching it with a VLTOR MUR upper.

That said, I always get the heebiejeebies buying any parts not from Colt, BCM, DD, or LMT, so even though these are likely made by FN, I still need confirmation.

[pointblank4445]

Necroposting this to avoid starting a new thread on the same topic.

Now that these have been out for a few years, does anyone have any further feedback on the Rainier Mountain series of barrels? Accuracy with quality ammo/10-round groups at range? Undergassed or overgassed? Overall barrel quality and impressions?

I aks because I'm in the market for a rifle-length chrome-lined barrel with a medium or lightweight (read: not HBAR or stupid government) profile, and the only two I can find that appear to be reputable are these (likely from FNH) and the Fulton Armory 20" pencil barrel (Criterion), the latter of which I can't use since it has a rifle barrel extension and I'll be matching it with a VLTOR MUR upper.

That said, I always get the heebiejeebies buying any parts not from Colt, BCM, DD, or LMT, so even though these are likely made by FN, I still need confirmation.

I have a 16" middy that I used for a build that I started a little over 2.5 years ago. I wanted an FN-made 16" middy barrel, but didn't want to pay for a Noveske. I also wanted to use a certain gas block, so I wanted it to come plain so I took a chance with the Mountain barrel offering.

I came to like the upper/gun so much that I carried it for duty/SWAT for nearly two years (6 months of that was as a secondary to my issued 308 bolt gun). At this point I have 4000 rounds through the gun and it is probably one of my favorite rifles. With Black Hills ammo, I can consistently string together groups that are about 1.5 MOA...and this is with no biopd. No fancy bolts, receivers, or triggers...the gun has had an ALG ACT most of its life, but it has an SSA now.

Here is the gun yesterday (3/25/16); I was taking a bunch of short dot reticle pictures:
http://i.imgur.com/eua3LiH.jpg

Just yesterday afternoon, I was out with a buddy shooting some steel at distance. I was having some bad luck with the 308 bolt gun that I had brought. Between the heavy mirage and the rifle's distaste of the load that I brought, I packed up the 308 and got this AR out of the truck. I wanted to get my confidence back up, so I dropped into prone (probably still grumbling about my misses with the 308), held 2 mils high, and went 5/5 on the 2/3 scale IDPA target 402 yards away. While this isn't a difficult feat for some, this little Rainier-barreled AR did more in 5 rounds than my GA Precision did all day with 5x more ammo.

It hasn't slipped my mind that I may have gotten lucky, but I would say from my sample-of-1 experience, the Mountain barrel has far surpassed my requirements and expectations. Dare I say, the performance has been on par with some of those that you name, and surpassed the others.

Hope that helps.

[DreadPirateMoyer]

That helps a lot. Thank you! That performance looks to be similar to my BCM BFH barrels, which I use as a benchmark for chrome barrels. Good stuff! And that rifle is beautiful, by the way. Worn in all the right ways.

I also just spoke with Rainier and they confirmed these are exactly the same as FN barrels, made by FN to FN specs with no deviation other than the midweight profile. Sounds like a quality barrel in that case, as my fear with components like these is always what the distributor might have changed from the manufacturer's normal spec, which in this case is nothing other than the profile in front of the gas block.

Does anyone know the gas port size on these or 18" FN barrels? That's the only thing the guy at Rainier didn't know.

And, of course, any further experiences or insights appreciated.

[556BlackRifle]

I'm glad you resurrected this thread. I've been eyeing the mountain barrel as well and look forward to hearing how it shoots.

[jstalford]

I do not know the gas port size, but rainier has always been forthcoming about it when I've asked them. Not "its a secret."


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[JG007]

I wanted a chf carbine barrel for a custom build and got a FN barrel from rainier as opposed to noveske, bcm, etc. Price was right, they were very helpful on the phone and even went to go measure the gas port while I waited

[DreadPirateMoyer]

Nice. I'll give them a call on Monday and see if I can get the gas port size. Hoping it's under Crane spec (.0995) as I run suppressed a lot.