Building a precision AR-15: Questions about barrel, bolt, twist, etc...

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Originally Posted by SWThomas

Again, huge thank you for taking the time to be so exponentially helpful!!! You're a gentleman and a scholar.

Being a military man, my cammies weren't tailored with deep pockets. So going super-huge on a barrel is pretty much off the table. I've been scouring the interwebs looking for AR barrels from WOA, Shilen, Ranier, Bartlein, Kreiger, and a few others. I'm not coming up with a whole lot. WOA and Raniers seems to have some options but they're all backordered.

I did find a Shilen barrel/bolt set that looks promising, but it has a 1/8 twist. If it had a 1/7 twist I would be posting this reply to tell you I had bought it.

http://www.midwayusa.com/product/156...tainless-steel

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Retired Army here - 28yrs. Thanks for your service.
Try Frank White at Compass Lake Engineering (CLE) - look for one of his stainless Douglas premiums with a bolt. I think he gets right around 400 for the bbl & bolt fully finished.
If it's back ordered - order one - it appears you are getting into high power rifle (NRA/CMP) (I may have missread that from another post - if so disregard) and this is a great initial bbl. They shoot well, they last and Frank stands behind his work. There are three things make all the difference on a NM AR - barrel, sights & trigger - THAT is where you need to spend you hard earned dough. Don't chase the snake oil BS. Sights are relatively inexpensive - get them pinned and get a 1/2 x 1/2. Triggers - buy what you can afford - Giessle is creme del la creme - older 1st Gen Armalites are good (adjustable) Krieger Milazzo 2 stage triggers were the best until the Giessles. Unfortunately I think Charlie Milazzo doesn't make them anymore - all he does is sue everyone that copies his design KAC - great but way over priced. All the rest of your cash - put it in a good bbl. You'll never regret it.

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Originally Posted by opsoff1

Retired Army here - 28yrs. Thanks for your service.
Try Frank White at Compass Lake Engineering (CLE) - look for one of his stainless Douglas premiums with a bolt. I think he gets right around 400 for the bbl & bolt fully finished.
If it's back ordered - order one - it appears you are getting into high power rifle (NRA/CMP) (I may have missread that from another post - if so disregard) and this is a great initial bbl. They shoot well, they last and Frank stands behind his work. There are three things make all the difference on a NM AR - barrel, sights & trigger - THAT is where you need to spend you hard earned dough. Don't chase the snake oil BS. Sights are relatively inexpensive - get them pinned and get a 1/2 x 1/2. Triggers - buy what you can afford - Giessle is creme del la creme - older 1st Gen Armalites are good (adjustable) Krieger Milazzo 2 stage triggers were the best until the Giessles. Unfortunately I think Charlie Milazzo doesn't make them anymore - all he does is sue everyone that copies his design KAC - great but way over priced. All the rest of your cash - put it in a good bbl. You'll never regret it.

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U.S. Marine for 15 years now. LOVE IT!

I'll look into the CLE combo you mentioned. That price range sounds good to me, as I'm willing to go up to about $600. I'm not getting into any competitions. I'm just an expensive hobby kind of guy. I'm going to scope this rifle with some good glass. I have a Geissele in my other AR-15 and this one will most definitely receive the Geissele treatment as well. To me they're the only game in town when it comes to AR triggers.

Good stuff - try your hand at the HP stuff - it's intoxicating. If you use a flat top, you can get (and it's legal in competition) a carry handle w/ a competition tuned rear sight - it'll get you out to 600yds. Pop the handle off and you can scope it pretty quick.
I used to shoot at the Interservice Championships at Quantico every summer - that was some seriously riflery - off for 3 days then to the Nationals for 3 weeks - at the end of it all I didn't want to look at a rifle, never mind shoot one...LOL
If you're at Quantico - look up the Quantico Shooting Club (http://www.quanticoshootingclub.com/) GREAT bunch of folks and you get a ton of assistance / help.
Also - forgot to add from before - Free float tube or forend - a CMP legal under the hand guard version or a tactical version is imperitive - nothing touching the bbl.

1/7 is geared more for 16"barrels. I would go 1/9 with a 20" inch personally.

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Originally Posted by opsoff1

Good stuff - try your hand at the HP stuff - it's intoxicating. If you use a flat top, you can get (and it's legal in competition) a carry handle w/ a competition tuned rear sight - it'll get you out to 600yds. Pop the handle off and you can scope it pretty quick.
I used to shoot at the Interservice Championships at Quantico every summer - that was some seriously riflery - off for 3 days then to the Nationals for 3 weeks - at the end of it all I didn't want to look at a rifle, never mind shoot one...LOL
If you're at Quantico - look up the Quantico Shooting Club (http://www.quanticoshootingclub.com/) GREAT bunch of folks and you get a ton of assistance / help.
Also - forgot to add from before - Free float tube or forend - a CMP legal under the hand guard version or a tactical version is imperitive - nothing touching the bbl.

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Sounds like fun. I'll have to check it out. I've been stationed at Quantico before but I'm currently stationed down in Petersburg at Fort Lee. We teach the Small Arms Repair Course here.

I was planning to go with a 15" Troy VTAC Alpha Rail so it can match my other AR. It mounts to the barrel nut and doesn't touch anything else. I really like that rail.

BTW, I sent you a PM.

Give Black Hole Weaponry a look. Not trying to step on any toes, just making a suggestion. They will make you anything you specify at a reasonable cost. Carl is good people, he just ran into some bad situations before he moved to Oregon. I think he's on to something with the 3 grove poly. All his 5.56/.223 chamberings are in fact 5.56. Give them an honest look.
http://www.google.com/url?q=http://w...pO7iAFZd2jvYKg

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Originally Posted by lowbar

1/7 is geared more for 16"barrels. I would go 1/9 with a 20" inch personally.

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Umm....whaaaat?
A 1/9 will limit you to 69gr stuff - max and a 69grainer at 500 or 600yds will be like throwing wiffleballs in a wind storm. Barrel length has VERY little to do with stabilizing bullets - it does help but in very small and in a different way - longer bbls will give you more velocity which aids stabilization. A bullet that is on the edge of stabilization can be helped "a bit" by velocity.
A 1/7 isn't geared towards any 16 inch bbl in any way shape or form.

I don't mean to be rude but where does this bovine scathology come from??

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A 1/9 will limit you to 69gr stuff

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In general you're right, of course, opsoff1, but there are bullet options above 69 grains that "appear" able to be stabilized in a 1/9 twist barrel.

On a cursory look only, it appears the Miller stability breaks at around less than 1" in length projectile for stability in the 1/9 twist barrel and there are valid options above 69 grains one could use with that twist. Of course, not all are going to work and they are on the fringe of being acceptable, but they do fall within the acceptable range.

For example, a .990" 77gr bullet shows a Miller stability of 1.44 which is deemed stable, although admittedly on the edge.

Am I missing something? I've not shot anything above 69 grains yet as my distance shooting options are limited.

Edit: To be clear, I'm not just talking about "fictional" bullets. The Sierra 77 gr Matchkings are .994 and appear to be judged stable if you believe the Miller formula. I suppose experience might be different from theory. Not trying to argue with you, hoping you have some experience that says different. :)

Opsoff1 posted some very good info, and I don't see a need to rehash it.

My personal inclination for your purposes would be a 20" barrel. Just last week I ready a study on the relationship between velocity, gas pressure, and sound pressure with regards to barrel length. 18" - 20" was the sweet spot, with 20" producing the best velocity (the tests went up to 24").

Here's the study: http://www.dtic.mil/ndia/2010armamen...hilipDater.pdf

I'd go for a 20" 1/8 or 1/7 twist from manufacturer of choice. Mount it in a Vltor MUR or quality billet upper. Get good glass and call it a day.

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Originally Posted by HKGuns

In general you're right, of course, opsoff1, but there are bullet options above 69 grains that "appear" able to be stabilized in a 1/9 twist barrel.

On a cursory look only, it appears the Miller stability breaks at around less than 1" in length projectile for stability in the 1/9 twist barrel and there are valid options above 69 grains one could use with that twist. Of course, not all are going to work and they are on the fringe of being acceptable, but they do fall within the acceptable range.

For example, a .990" 77gr bullet shows a Miller stability of 1.44 which is deemed stable, although admittedly on the edge.

Am I missing something? I've not shot anything above 69 grains yet as my distance shooting options are limited.

Edit: To be clear, I'm not just talking about "fictional" bullets. The Sierra 77 gr Matchkings are .994 and appear to be judged stable if you believe the Miller formula. I suppose experience might be different from theory. Not trying to argue with you, hoping you have some experience that says different. :)

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Sierra's doppler radar would disagree with you