Working on my first AR build. I'm going for a varmint type set up primarily for p-dogs and coyotes. I've got my eye on a WOA 18" varmint barrel as a coworker has a midlength rock river varmint that I really like. However I have some concerns about the twist rate and chambering. They only offer them in 1:7 or 1:12 twist. I would really prefer a 1:8 or 1:9. Will the 1:7 be too fast for 50gr pills? Also, they claim they use a WOA chamber reamer suited for varmint bullets. Will this limit me from using some heavier match bullets, particularly 69gr SMKs. Does anyone know who makes their barrel blanks by chance. Any help is appreciated.

I have the same upper you are looking at. I have only used the 69 grain SMK's so far. I have zero complaints about the accuracy. I haven't tried the 55 grain bullets in mine yet. Until I use up the 1,000 plus left over 69 SMK's I don't think I will dip into my stock of 52 grain WATSON's. Mine has a Kriger barrel, and sure shoots.

White oak uses a wiley chamber - I had them make me two uppers - I think you'll be fine with the 1:7..

And it stabolizes 70-80 grains nicely.

I was looking for semi-custom a while back myself. I shoot 50-55 grn bullets just about exclusively. My intentions for this upper was dogtown, target, & maybe some predator hunting. The builder offered 1/8 & 1/12. After talking with him about it I went 1/12 & a 'wylde' chamber, or version thereof. He said I would be fine up to 60grns/62? in the 1-12. I really can't see myself going above 55 though. I also went 22", .75" fluted barrel. I have other 1/9 ARs in various configurations for other stuff. If I planned to carry it a lot I would of went shorter & lighter.

White Oak just built me an 18" upper using their SPR barrel at 1:7.

Talk to John there about your concerns. I surely did. He only shoots 50,000K rounds or so a year with his 1:7.

I have shot as low as 50's with my 1:7 and all have been very, very accurate...

I shoot 60 Vmax's from mine...

I too ordered a WOA barrel the other day, though I am headed in a different direction. I will be building a dedicated predator (coyote)hunting upper. I ordered a 16" lightweight barrel with a mid length gas system. I have humped enough miles with heavy rifles that I can really appreciate a light one.

WOA uses Wilson blanks. I have heard very good reports about WOAs quality so I decided to give them a try.

Mackay,

Jeff Rost told me to get a WOA and I'm glad I listened.
My 18" is a dedicated predator guna s well. It is fitted with a carbon fiber handguard and is mighty light...

The bottom one is the WOA...

Wylde Chamber is normally what John uses, though he has a few others and may use them depending... I believe the 12 twists is a still different chamber, but don't recall what it is.

The Wylde is about as good as it gets as a generic chamber.

Barrels on guns unless mentioned are Wilson tubes but not finished and chambered by them which is where a big difference comes into play.

7 twist. I shot it for years. Liked it more than the 7.7s.... but never shot lighther than 52s. I currently run 6.5 twist barrels so they'll stabilize 90s, but can easily shoot 52s, though it will torch 60 sierra flat base HPs... thin jackets and all and would torch 64 bergers till they put tougher jackets on.

As long as you arent ever going to shoot over 55s the 12 is fine. But that limits you on wind drift a lot. 7 twist will work just fine down to the 52bthps... and still allow you to shoot without a doubt, the 69s and 73/75s if needed for longer shots in the winds.... About all I shoot coyotes with is 75bthps... works just fine. At least out to a couple hundred yards, never shot one past that so far. Although there was the time we shot at one around a mile away and got so close... but that was with a 300.....

Jeff

I have a couple of 1/7 twist guns, had a 1/8 and have a 1/9. I shoot 50 grain American Eagle hollow points in all, my favorite 1/7 Colt light weight chrome lined barrel shoots them into an inch at 100. Not match grade accuracy but it works for coyotes and everything else I've tried.

The 1/8 was a Kreiger and it shot the WW white box 45 grain ammo around 1/2" so I wouldn't worry about twist rate. Get a good barrel in 1/7 and go kill stuff.

I can also reccomend the 77 gr SMK's for coyotes but only if you ain't saving fur...

I ordered a WOA upper last month, 18" spr barrel. One option that you might be interested in is the Squad Designated Marksman, 20" fluted match barrel available in 1-7 or 1-8.

I plan on shooting up to 75's so went with the 1-7 twist. I don't think it'll handicap me shooting 50 v-max from what folks have said, and the faster the bullet is spinning, the faster it'll come unglued.

I'll probably get another WOA barrel in 20" to build a slightly different upper. This first upper was an attempt at a compromise "tactical" upper that would also offer great accuracy and reasonable weight. The 16" tubes are just too loud, but I figured an 18" mid length wouldn't give up much in the handling department.