AR 1-8" Rifling - who has it?


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Lovesbeer99
July 16, 2010, 11:54 AM
I'm looking for a new barrel and I see that most people have have a specific purpose and pick 1-7 or 1-12. For those who want a general purpose the 1-9 seams to be the choice.

So why 1-8? What's the advantage?

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Z-Michigan
July 16, 2010, 01:03 PM
1:8 will handle any common .223 bullet that when loaded into a cartridge will fit into a standard magazine. This equates to 77gr SMK and 77gr Nosler, for the most part, as well as anything lighter with the possible exception of the Hornady 75gr A-Max Match (not the 75gr BTHP match).

Really, 1:8 is a very practical twist rate, it's a shame that it isn't more common. It is fairly easy to find in heavy stainless steel "match" type barrels from a number of manufacturers. Look at Bravo Company and CMMG for some starting options.

1:7 was the military choice to get M856 tracer to stabilize under the coldest arctic conditions. It does that, but is excessively fast for any other use including what 99.999% of us civilians are likely to want to do. It will also stabilize the ultraheavy 80gr and heavier match bullets, which won't fit into a standard magazine when loaded in a cartridge.

TonyAngel
July 16, 2010, 01:18 PM
I have a Bravo Company SS 410 1:8 twist barrel. It shoots everything from the Walmart Winchester (I believe) 45gr varmint rounds to 77gr rounds very well. I haven't tried anything lighter than 45gr though, because I have no use for them.

1:9 also does very well with anything up to 69gr projectiles and I've also seen some do well with 77gr projectiles. 1:9 is not a slow twist by any means. Go the Berger's website and take a look at their twist recommendations for their projectiles. I was really surprised by the slow twist rates that they recommend. IIRC, they have a 73gr target projectile and their minimum recommended twist rate is 1:9.

I think the advantage is that 1:8 is a bit more flexible and is fast enough to stabilize any round that will fit into a magazine. I haven't regretted going 1:8.

I might be way off base here, but it's also my understanding that faster twist rates will also exagerate instabilities that can be caused by projectiles that aren't perfectly balanced. Put plainly, a standard M193 cheapo mil spec round may arguably shoot better out of a 1:9 twist barrel than it will out of a 1:7 twist barrel because it won't wobble so much due to being spun more slowly. I just figured that the 1:8 would be more forgiving than a 1:7. Whether or not I'm right, I don't know. I'm still satisfied with my barrel.

strambo
July 16, 2010, 01:26 PM
As posted above, the 1:8 is a popular twist in stainless match barrels and is as fast as needed if your aren't shooting tracer. I wouldn't mind seeing standard barrels in 1:8 twist and would buy them. Given the current choice with most barrels of 1:9 or 1:7, I go 1:7 to handle the 75 and 77 gr without worry.

Lovesbeer99
July 16, 2010, 02:15 PM
So just to make sure, will the 1-8 handle 69 and 77 gr rounds?

Currently I have a 1-9 twist barrel that really likes the 52 and 55 gr rounds. I'd like something heavier but I'm not sure 77 gr is the ultimate solution as most of my shots are at 300 yards. I might shoot 600 yards once or twice per year, but not more.

I was thinking the 1-8 would be great for me in that I could shoot the 55, or 69 gr bullets most of the time, and get a 77 gr when I need to get out to 600 yards.

Any thoughts? And thanks for the feedback so far.

Z-Michigan
July 16, 2010, 02:54 PM
1:8 would work for your purposes and would probably be the best compromise among the options out there.

NY Marksman
July 16, 2010, 08:19 PM
Sabre Defense makes several different 1 in 8 barrels. The make excellent barrels. I have an 18 inch Stainless fluted one on my AR.
http://i64.photobucket.com/albums/h198/HVBowman/finalAR.jpg

JDGray
July 17, 2010, 12:45 AM
All RRA SS barrels, are 1 in 8 twist:)

hub
July 17, 2010, 06:53 AM
So just to make sure, will the 1-8 handle 69 and 77 gr rounds?

My RR NM A2 gets a steady diet of 77gr Matchkings, and 80gr Amax's and it stabilizes them just fine. I've also run some 55gr sp through it with pretty good accuracy.

M&PVolk
July 17, 2010, 10:52 AM
I think 1:8 should replace 1:9 as perhaps the best twist rate out there. Unfortunately, none are chrome lined, which may or may not be an issue for you depending on what you want to use your gun for.

Slvr Surfr
July 17, 2010, 05:33 PM
Les Baer's police spcl also uses 1/8. Both the old version and new.

• LBC forged and machined upper and lower receiver • Removable carry handle with rear sight • Picatinny flattop rail on upper • LBC National Match carrier, chromed • Precision bolt and extractor • 16” precision button rifled steel barrel with 1 X 8 twist • LBC flip-up front sight • 6-position ATI collapsible stock with adjustable cheek piece and ATI grip • Special Picatinny 4-way handguard, free floated • Lockable sling swivel mounted on stud on 4-way handguard • 1” nylon sling • A2 style flash hider • Bead blast blue finish on steel parts • Anodized finish on aluminum parts • Timney Match trigger group • (2) 30-round magazines for 5.56 and 6 X 45; (2) 14-round magazines for .264 LBC-AR™

TonyAngel
July 17, 2010, 09:59 PM
I shot these today out of my 1:8 barrel using 77gr SMKs.

http://i154.photobucket.com/albums/s265/ajangelettejr/Groups/finalgroups.jpg

I'm not a good shot, but you can't say that the 1:8 won't shoot heavy bullets. These were at 100 yards. Please forgive the group on the bottom right. It was the last of the day and I was tired.

Sgt. Stiglitz
July 17, 2010, 11:35 PM
My Rock River Arms 20 Inch Varmint A4 with 1-8 twist.........

http://i454.photobucket.com/albums/qq263/Sapo60/100_4704.jpg


http://i454.photobucket.com/albums/qq263/Sapo60/100_0303.jpg

As it is today..............



http://i454.photobucket.com/albums/qq263/Sapo60/100_5824-1.jpg

BHillman
July 18, 2010, 02:13 AM
I decided to get a Lothar Walther bbl off Gunbroker.
http://www.gunbroker.com/Auction/ViewItem.aspx?Item=179877085
I added the extra $30 for finishing and built it as pictured. Shoots great and for me, the 1 in 8 twist was the correct bbl. They also have 20" and longer and other chamberings.
http://www.fototime.com/0C0C6E1420DD849/standard.jpg"]http://www.fototime.com/0C0C6E1420DD849/standard.jpg
HTH
Bruce

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