Embarking on an AR-40 "tractor gun" build

[darkminstrel]

I've a nice bit of land and am often out on a tractor mowing or plowing, etc. I all too often see coyote standing out in one of my fields or parked just inside the tree line and want something smallish I can use to pop them. "Why a .40 S&W?" you ask? Because I don't want to have to load another caliber. Ranges would rarely exceed 100m.

Basically I want to build a beater that I can shove into a scabbard for those rare shots I'd need to take. I'm leaning towards picking up used furniture and going with an 80% from New Frontier. I have also never held an AR so this is gonna be fun.

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[rick benjamin]

Good luck!
I couldn't find a .40 barrel but there are a lot of 9mm uppers.
I bought
Davidson Defense Assembled 9mm Rifle Upper - 100% Made in America $159.99
Tactical Shxt Billet 9mm 80% Lower (C-9) -for Glock Style Mags, $109

Found a 9mm BCG on sale, $130

 

[IronMonster]

I can understand not wanting to add another ammo category to stock but the reality is it will be quite a bit cheaper to build and far cheaper to shoot a 9mm AR. Sounds to me like a good excuse to add a 9mm Glock to your pile and then have a pair that share magazines

 

[osprey]

Excellent application for a 300 blackout. Either buy ammo or buck up and load for it. It is easy to handload and you could probably pay for the dies and components with the savings you get by not paying for a rare caliber upper. Ballistics will be much better with 300 blk as well.

 

[osprey]

If you are dead set on a 40 sw, it does look like Rock river arms offers a complete 40 sw upper for $640 with 20% off that right now.

 

[jordanka16]

I am with the others on building a 9mm, it will be far easier to get good parts and they will be cheaper to boot. Since it sounds like it would be rarely used anyway you shouldn't need to load ammo for it, and 9mm is cheap.

 

[SportingArms]

16" Quarter 10 Circle Barrel
Karri's Guns .40 BCG
ATI Omni Hybrid Upper
New Frontier Glock 80% lower
KAW Valley Compensator
Rifle buffer/tube

I am loading up test rounds for accuracy and fps.

I have 180 gr Berry's and 165 gr CMGs

I already loaded the 180s for my pistol and can't remember th recipe after so long but I will be trying 46gr Titegroup and maybe 48gr.

Any suggestions on loading are greatly appreciated. I am trying to stay with Titegroup since I am also trying subsonic .223 recipes with lightened buffers/springs and Adams Arms gas piston setup on my 10.5" pistol.

 

[darkminstrel]

That is pretty much a similar build to what I would like. Planning on going carbine length due to size considerations.

 

[Deavis]

This is cheaper and no paperwork:

80% Glock lower from polymer 80 and a Mechtech CCU.

180 moly over 4.6 BE gives me subsonic velocity and 1" 50 yard groups.

I chopped the barrel and put a pistol brace on it.

Optic could use some upgrading but it is fun and cheap.

Pictured with my .45 suppressor.

I call it The Abomination.

 

[SportingArms]

The Mech Tech was my first choice since I could use my glock frame but not in CA. Not unless I build one from the 80% frame lower on it's now from Midway. Although I'm not sure I can have the Mech tech shipped here. No suppression here either.

At least I can still use my Glock mags from my pistol.

I am planning on folding stocking and possibly a Pantheon quick change barrel system.

 

[Republican]

The Mech Tech was my first choice since I could use my glock frame but not in CA. Not unless I build one from the 80% frame lower on it's now from Midway. Although I'm not sure I can have the Mech tech shipped here. No suppression here either.

At least I can still use my Glock mags from my pistol.

I am planning on folding stocking and possibly a Pantheon quick change barrel system.

So you guys can still build traditional standard capacity AR type weapons on 80% lowers in CA ?

 

[Kruel J]

So the OP has never held an AR and yet wants to start with an AR in .40 cal? I know I'm a bit late to this party since the OP was in June but geez why not just run a standard AR-15 and load some 74-78 grain projectiles? With a 1:7 twist rate you'll have plenty of accuracy and knockdown power for dogs. Make it a pistol with say a 10" barrel. Compact, accurate and will deliver a lot more power than a .40.

 

[Velzey]

I've seen it time and time again, truck gun, camping gun, tractor gun, boat gun... but it turns out nice and you don't wanna mess it up.
Sooo it's easier to just Glock it!

 

[darkminstrel]

why not just run a standard AR-15 and load some 74-78 grain projectiles?

I own guns in 4 calibers. I do not want to introduce another one because then I'd have to buy in brass, proper powders, projectiles, etc. I have .40 in my daily and tens of thousands of cases and projectiles of various weights and the same for 2 other calibers and only the .22s don't get reloaded.
It's the same reason I don't want this in 9mm; I have a strong belief in being able to load every caliber I shoot. I'm also on a critically tight budget and just don't see the need for .223 in my life when I have rifles in 30cal weights for the deer and elk I hunt. This AR build is going to only ever be broken out when I'm out in the fields working. It's not going to clear rooms or engage hostiles at 600m; it's gonna hang off my tractor's fender and fire off half a dozen rounds per year.

Now you might ask "Why not get a purpose built rifle in carbine length that does what you want?". Well, because I think it would be fun to build this and i've been wanting to finally get familiar with the AR platform.

That's why.

 

[Twodogs]

I would just buy a Ruger american in .22 mag and call it good.

 

[Republican]

Crossbow

 

[SportingArms]

CA allows ARs IF they are featureless. No more pistols or AWs.

AWs can never be transferred or sold and die with you.

All firearms have to be serialized end of June next year and all AWs have to be registered by end of this year. BUT you can't reg an AW without a serial number and the form is a dead link on the CA DOJ website.

But any one can say they bought an 80% and say they made it before Jan 1 2017.

Still loopholes and I'm sure they are being made. I see tons being sold at the gunshows.

 

[darkminstrel]

Fortunately I live in a free state so that's not much of an issue.

 

[djharteloo]

I just finished a 9mm ar build and am fairly in love with it, but it woulnd't be my first choice for your application. whenI think "Farm gun" usually what comes to mind to me is a shotgun or bolt action rifle. If I was in your position I would be looking for a 22 magnum of some kind or an old Savage model 340 in 22 Hornet. Thats just my opinion. Although after I finished my 9mm ar build, it makes me think that now I want a 10mm ar........

 

[Deavis]

CA allows ARs IF they are featureless. No more pistols or AWs.

AWs can never be transferred or sold and die with you.

All firearms have to be serialized end of June next year and all AWs have to be registered by end of this year. BUT you can't reg an AW without a serial number and the form is a dead link on the CA DOJ website.

But any one can say they bought an 80% and say they made it before Jan 1 2017.

Still loopholes and I'm sure they are being made. I see tons being sold at the gunshows.

Wow, those Californians sacrificed liberty for safety. Must be a super safe place now. In a few years people will probably just destroy their own guns as they won't have any need for them.