Varmint AR?

[Huntnful]

Great info! Thank you guys!

 

[RegionRat]

Once you mount a scope on a flat top, think about adding the Magpul BAD lever to allow you to release the bolt without reaching all the way over the scope. It makes running the AR from a prone or bench position much smoother.

 

[Capt RB]

If you are running the 50 grn pills why a 7.7tw? I can see if you plan on running 75's and up but for 50's a 9 or 10 would be way more than you need. I've shot about 2k of the 50's and have seen them splash on a shoulder hit 2 times in a 7tw set up for 77 to 90 grain pills. Most of the 2k were range shooting maybe 20% were on song dogs, crows rats or barn cats.

 

[alnpar]

BCG
Gas Block & Tube
Buffer & Spring
Stripped lower
Trigger guard
Pins
Lower Kit - trigger assembly.

And Move out of Cali

I agree, Calif is NOT THE PLACE TO BE

 

[Deviant]

So I just got off the phone with Paul at Compass Lake Engineering. Seemed like a great dude. I have PILE of 50gr. 223 Vmax bullets..... and no 223 rifle haha. So I figured I do an AR style instead of a bolt action. I know literally absolutely nothing about AR's, which is why I did some research and ended up just calling compass lake. After about 20 minutes on the phone, and my main desires being an accurate, varmint style AR, I ended up with:

20" Heavy Varmint Bartein 1-7.7 twist, with a round aluminum upper and bipod pic rail at the front.
Trigger Tech Diamond single stage 1.5lbs
PRS Gen3 butt stock. (I wanted something adjustable with a bag shelf for target shooting)

I live in CA, so he also has to do some random stuff to make it CA legal.

But am I missing anything?

Extremely light, CA legal and shoots .75 MOA with factory ammo. I had exactly what you are thinking but got tired of carrying a 10 lb rifle to go call coyotes. The only thing I would do differently if I built this again would be to replace the Christiensen barrel with a Proof Research.

 

[jrock]

I have a 10 lbs 204 AR with a bull 24" barrel. The recoil hardly moves the cross hairs. Flat would spring or silent capture buffer is the only way to go. While an adjustable gas block is not required, its a nice little feature to have and there are low cost options. +1 for light weight trigger and bag riding butt stock.

 

[Huntnful]

Extremely light, CA legal and shoots .75 MOA with factory ammo. I had exactly what you are thinking but got tired of carrying a 10 lb rifle to go call coyotes. The only thing I would do differently if I built this again would be to replace the Christiensen barrel with a Proof Research.

Dang, that looks nice! Especially, the stock, because I only ever shoot bolt guns. Thanks for pointing out some options!

 

[Huntnful]

If you are running the 50 grn pills why a 7.7tw? I can see if you plan on running 75's and up but for 50's a 9 or 10 would be way more than you need. I've shot about 2k of the 50's and have seen them splash on a shoulder hit 2 times in a 7tw set up for 77 to 90 grain pills. Most of the 2k were range shooting maybe 20% were on song dogs, crows rats or barn cats.

That was just what he rattled off when he was running down the list. Nothing set in stone, but after more research I think a 1-9 would be ideal. I really have no intention to reload for it. They don't excite me that much. Just have a pile of ammo and want to be able to use it if needed.

 

[DSheetz]

My 1:9 likes a little heaver bullet then 55 grains and you have 50 grain bullets that you want to shoot. If you go to say Bartlein barrels web site and look at twist rates vers bullet weights, they will give you a suggested rate of twist for different bullet weights. The old M-16 was designed for a 55-grain bullet with a specific powder burn rate and they started with a 1:14 twist rate then went to a 1:12 to stabilize the 55 grain bullets later models then had some that had 1:10. now they want to use a heaver bullet 62 grain and even up to 75 grains thus they are running the 1:7 and 1:8 twist rates. Twist rates are an important part of a build and there is a lot of information out there so a person can match it to their intended bullet weights.

 

[longtubeman]

Love a 1 in 8 twist for 75 gr Amax at 3000 fps with 26 gr of 760. Gives you good range, good splits at further ranges. 1/4 groups

 

[DSheetz]

There is a site that has a twist rate chart on it called AMMOMAN school of guns. That has a good explanation of the importance of matching twist rates to bullet weights. Lighter bullet weights slower twist rates 50 gr. bullets 1:12 and 1:10 rates are suggested. bullets of 62 gr. 1:9 and 1:8 it's an interesting subject.

 

[RegionRat]

https://www.ammoman.com/blog/5-56-twist-rate-chart/
https://www.everydaymarksman.co/equipment/rifling-twist-rate/
https://bergerbullets.com/twist-rate-calculator/

Opinions on the high and low ends of twist for any given bullets vary.

But since the OP asked for experienced opinions....

I have burned up my share of personal AR barrels on colony rodents.
On many occasions, just for kicks, I have put 40 gr V-Max through the heavy bolt guns with 1:7 twist and some of the bullets blow up. A 50 gr should make it in a 1:7 without blowing up, but that isn't the main point.

A 1:7 is optimal for 77 and 80 gr match bullets. It can run 55 gr at short ranges no problem, but it really isn't meant for this.
The OP wants a barrel specifically for burning up a pile of 50 gr V-Max ammo.

If I have a pile of (40 to) 50 gr V-Max ammo to burn in an AR Varmint upper, I'm probably reaching for the 24" 1:12 to 1:10, not the 1:7

YMMV

 

[Huntnful]

https://www.ammoman.com/blog/5-56-twist-rate-chart/
https://www.everydaymarksman.co/equipment/rifling-twist-rate/
https://bergerbullets.com/twist-rate-calculator/

Opinions on the high and low ends of twist for any given bullets vary.

But since the OP asked for experienced opinions....

I have burned up my share of personal AR barrels on colony rodents.
On many occasions, just for kicks, I have put 40 gr V-Max through the heavy bolt guns with 1:7 twist and some of the bullets blow up. A 50 gr should make it in a 1:7 without blowing up, but that isn't the main point.

A 1:7 is optimal for 77 and 80 gr match bullets. It can run 55 gr at short ranges no problem, but it really isn't meant for this.
The OP wants a barrel specifically for burning up a pile of 50 gr V-Max ammo.

If I have a pile of (40 to) 50 gr V-Max ammo to burn in an AR Varmint upper, I'm probably reaching for the 24" 1:12 to 1:10, not the 1:7

YMMV

appreciate the insight man!

 

[alf]

Since the OP asked for experienced opinions....
If I have a pile of (40 to) 50 gr V-Max ammo to burn in an AR Varmint upper, I'm probably reaching for the 24" 1:12 to 1:10, not the 1:7

Exactly.......

My last AR barrel I ordered a 20" 12 twist for the sole reason of shooting 52 Bergers & 53 Vmax.

I also had it chambered in 223 Remington, not Wilde, for the same reason.