Advice on a new build please!

[Epeeist]

So I am working on my first Grendel build. This will primarily be a paper puncher and secondarily a home defense and tactical match or class type gun. I am hoping to get pro and con thoughts and advice on each of the following three things:

1. AA 16" lightweight barrel Vs. Brownells 18" Vs. Spinta's 20"

I am leaning towards the AA, but I hate the fact that they drill the muzzle for an oddball muzzle device just to extract money from end users. It makes me wonder if they cut corners to maximize money in other ways.

I have heard that the Brownells are good barrels, but it does make me a little nervous that they don't list the maker. It seems they are Liberty/Satern but between oddness about their chamber depth and not knowing for sure if they are Brownell's sole source supplier of barrels I am a little nervous..

Spinta has a great price, but they are only cut to .125 so I worry about bolt breakage and that I have not found anyone that has done a review for it. I also have no idea about the weight. I contacted them asking about weight and if there were any reviews but have not heard anything back yet.

2. Bolt's

It seems that the current thought is that a .136 bolt is the way to go. Are bolts more or less like uppers and lowers in that there are only a few folks making them and everyone just sticks their name on it, or is there an actual difference? Also what is the difference between the AA standard and heavy use bolt? Is there one or is it just a way to charge more for the same thing, kinda like their barrel threading? Also what are some bolts that people recommend?

3. Uppers

I am going back and forth between a lightweight upper like Battle Arms Development or San Tan, or a side charger like Matrix. Does the 6.5 need a stiffer upper for barrel support or chamber pressure?

Thanks so much for reading all this and I appreciate any advice!

[VASCAR2]

Personally for the use you described I'd seriously consider the 16" barrel from AA. The recoil is so light I really don't think you need a muzzle brake. My 16" 6.5 Grendel came with a Phantom Flash Hider with the same thread pitch as the AA barrel. My 20" 6.5 Grendel barrel is unthreaded. AA sells an A-2 Flash Hider with the correct twist and J&T distributing sells the Phantom Flash Hider on my 16" barrel.

A Friend just recently bought an 18" Brownell's barrel so I'll get to see how it shoots. Brownell's now states the source of their barrels is Saturn. I would prefer a SAMMI Grendel chamber over the Saturn Grendel II. The Brownell's 18" barrels ship with a large gas port. You really need an adjustable gas block with the Brownell's 18" barrel.

I have had no experience with the Spinta barrel so I can't help you there.

If I were buying a 6.5 Grendel bolt I'd prefer an AA, J&T Distributing who sells AA bolts, Precision firearms, JP or maybe a Maxim or Underground Tactical but they would least preferred. But if you buy SAMMI 6.5 Grendel it should take a .136 bolt face depth. Many barrels come with a headspaced bolt.

If you go with a 16"-18" barrel I think a forged upper is fine just make sure the the face where the barrel slides into the receiver is square (Brownell's and others sell a lapping tool for this purpose).

[LRRPF52]

1. AA didn't make the 6.5 Grendel with 9/16x24 just to extract money from end users.

That thread pattern was decided on when there was no common thread, because the law forbade you from having threaded muzzle on AR15's, and it provided the best shoulder support for thinner barrel profiles on the light guns that would get permanently attached muzzle devices at the time to meet legality requirements of the Clinton Assault Weapons Ban.

Knights Armament, the first company to re-introduce a production 7.62x51 AR rifle, used and uses a totally different thread pattern on the SR25, namely 3/4x24 muzzles.

ArmaLite Inc. decided to use 5/8x24.

When the ban expired, DPMS started making guns with 5/8x24 threads. This was after AA had already introduced the 6.5 Grendel, done the testing, and was producing guns.

There is no standard for the .308 guns, and 6.5 Grendel is its own cartridge, so no big deal. A2 flash hiders from AA are $16.50. http://www.shopalexanderarms.com/Muzzle_...16-24.html

2. There are a few machine shops that make bolts to vendor specific requests. The 6.5 Grendel bolt has key differences that are specific to the cartridge. The AA hard Use bolt is made from a certain alloy, and has an Ion Bond process done to it to make the surface very smooth, which helps reduce the chances of microscopic fractures from developing for shooters who want to run a gun hard with high volume.

I personally have been using different standard AA bolts for years now, with a lot of load development where I will see pressure spikes in a pressure ladder, finding where my parameters are with a certain load range so I know where to look for the lower pressures that I would feel comfortable with mass-producing. I have yet to experience any failures of any kind. AA has stated that even the bolts they use in a pressure test breech for proof loads have not broken after years of constant testing.

The .136" bolt face depth is so a reliable extractor can be used that will have the groove size that is correct for the 6.5 Grendel's thicker rim, compared to a tiny 5.56 rim. Extractors are what fail regularly with .125" bolt face depths with 7.62x39 in the AR15.

If you get the metallurgy right on a correctly-spec'd bolt, and have a thorough quality control process, you will make reliable bolts that hold up, in any caliber, used within their design limitations. I've been shooting the AR15 since the late 1980's, and the only bolts I have broken are 5.56 bolts, that were run hard, like over 10,000 rounds.

3. Any AR15 upper is fine. I personally prefer a heavy billet receiver if the barrel will be heavy, but for the barrels you are talking about, a lightweight receiver is perfect. I have built several guns with both the AA 16" Lite Fluted, as well as the 18" Brownell's barrels, and a standard M4 or upper of your choice is the norm. The upper receiver is not a factor in containing hoop stress.

Biggest challenge with the Brownell's 18" MLGS barrel is that the gas port is cut way too big, so it needs to be choked with an adjustable gas block right off the bat, and a heavier buffer, like an H3.

The 16" AA MLGS fluted barrel works right out of the gate with no need for adjustable gas, and recoil is pleasant. For what you are doing, I would consider the lighter, shorter option, especially for HD.

My first Grendel barrel was a 16" AA, and I have really enjoyed it over the years. Supersonic reach for me at my altitudes has been well past 1000yds with factory 123gr ammo.

[Epeeist]

Vascar2 and Lrrpf52 thank you so much for the great info. My first post and I am already learning a lot more about the cartridge and system compared to what I "thought" I knew! I am looking forward to being part of the community and exploring this very cool platform.

I think I will go with the AA barrel and bolt. It seems I have been maligning them a bit in my mind based on some faulty assumptions so I should give them a real world test. And fluted barrels are spiffy. Now I just need to decide on rather to go with San Tan, BAD or F1 for the upper and lower.

Once I get it put together I will be sure to post pics and a range report!

[jim_bob]

I highly recommend Mega lowers and uppers, although I'm being tempted by balios light sets.

[2_speed]

How about some love for the Faxon Group Buy? I'm thinking that the velocities will be somewhat better than the standard cut or button rifled barrels of the same length....Just sayin'....
Tom

[Clays23]

"Spinta has a great price, but they are only cut to .125 so I worry about bolt breakage and that I have not found anyone that has done a review for it. I also have no idea about the weight. I contacted them asking about weight and if there were any reviews but have not heard anything back yet."

I went with the Spinta 20" barrel for a hunting/budget build and am very satisfied with it so far. It shoots factory Amax and SST hornady loads very well and I'm 2 for 2 with the SST on deer. Also, it's not listed on there sight but they also sold me a complete BCG for $100 as well, there customer service was also very good to me. Good luck!