.243 ar build


February 4, 2007, 05:56 PM
I am new to this rifle I don't know anything about the parts and how to build one but I want to give it a go. I have read all weekend all over the internet and have come to the conclusion that I might be able to pull this off. The only way to learn is to do it. I have choose the .243 wssm because it is the smallest cal. Iowa allows to shoot deer yet not to big either. I will be using it mainly on yotes, maybe a fox, or other smaller vermin and maybe some day on a deer not very often though. These are the parts that I found an olympic arms upper in the .243 wssm and I really like the rra lower with the nm 2 stage trigger. My question is will these 2 go together? Is there anything I might be leaving out? Like I said I am new to these rifles so I am open to suggestions. I'd like to keep the rifle under $1500 so that I can still afford to put some nice optics on her. One other question I have is when the receiver says 223 or 5.56 on it will it still fit the 243 upper? Any other Info a newbie might need to know would be great like tools and things to watch out for stuff like that. Thanks guys

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February 4, 2007, 06:18 PM
If the Olympic upper is a true mil-spec upper and the Rock River a true mil-spec lower (I beleive they both are) then, yes, you can put them together.

I don't know if the .243 cartridge length will fit the mag well length of a .223 If it does, then you should have no troubles.

I guess you have found a .243 upper, .243 bolt, and .243 mags to make all of this work?

February 4, 2007, 09:20 PM
You would need a .308/7.62 upper and lower to do this, then you would need to find a Barrel chambered for .243, the .243 was originally a wildcatted .308 round.

February 4, 2007, 10:01 PM
You would need a .308/7.62 upper and lower to do this, then you would need to find a Barrel chambered for .243, the .242 was originally a wildcatted .308 round.

This is the .243 WSSM, not the .243 Win. And it looks like the WSSMs will feed from a standard AR magazine (http://booksbikesboomsticks.blogspot.com/2006/02/boomsticks-i-have-confessi_113901394007508347.html).

Thin Black Line
February 4, 2007, 10:11 PM
Why not run it in the "old" 243 Win and use an established rifle?


Uses same mags, bolt, etc as the 308, just the barrel is different. Never shot
it, but the recoil must be nice (I have a 243 bolt action).

February 5, 2007, 12:08 AM
Nate what source do you have for that information?
I ask because I am not Tech Savy but even a cook like me can use a computer to do research to verify the accuracy of my information.
.243 Winchester
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.243 cartridge
.243 cartridge

The .243 Winchester is a popular rifle round. It is very effective for long range vermin and deer hunting. It is basically a .308 cartridge necked-down, and is known for its accuracy and relatively low recoil compared to other deer cartridges. The .243 Winchester obtains a velocity of 2960 feet (902.21 meters) per second with a 100 grain (6.8 gram) projectile, in a 24-inch barrel.

This cartridge was first introduced in 1955 for Winchester's Model 70 bolt-action rifle and it quickly gained popularity worldwide. Even Winchester's chief competitor, Remington, chambered rifles for the .243 round.

The .243 has gained substantial popularity in the hunting world and ammunition is easy to find. Along with the .270, .308, and 30-06, it is amongst the most popular and available cartridges. The .243 is a common choice for deer, pronghorn antelope, hog, and varmint hunting

Wikipedia is my freind

February 5, 2007, 12:55 AM
As is the Goggle Search engine...
From Gunnersden
243 Winchester History and General Information.
The popular 243 winchester originated as a wildcat based on the 308 winchester brass necked down to 243 caliber, Warren Page developed the first prototype of this cartridge, it was then made available as a factory cartridge to the public by winchester in 1955.

The 243 winchester is the first true dual purpose class of cartridges, loaded with lighter bullets it is an extremely effective varmint round, sending a 70 grain bullet out the barrel at 3,500 fps. this is enough for any varmint sized game at the 400 yard mark, however load it with 100 grain bullets at 3,000 fps. and you have an excellent deer and antelope round good for 300 yards. My own favorite bullet weight is 87 grains which serves the dual purpose of varmint and deer cartridge.

The 243 winchester is a light recoiling round which is comfortable enough for anyone to shoot, and it is inherently accurate which is a bonus to all that own a rifle chambered in this round. For a beginner just getting into the high power rifle sports the 243 winchester round is highly recommended. Also for anyone that is recoil sensitive this is a great cartridge.

243 Winchester Barrel Specifications.
Common Barrel Twist Rate - 1/10 & 1/9 (uncommon) 1/12
Bore Groove Diameter - .243"

243 Winchester Reloading Specifications.
Bullet Diameter - .243"
Maximum Case Length - 2.045"
Trimmed Case Length - 2.035"
Primer Size - Large Rifle

Should I continue?

February 5, 2007, 01:10 AM
If you are going to use a short magnum, the best way I know of is to go with an Armalite. I believe they have a build in .300 RSUM already, just replace the bbl with one chambered in .243 RSUM


February 5, 2007, 12:00 PM
Nate, I read your post as correcting me regarding the .243 and it's origins, not the platform that would shoot .243 WSSM.
My apologies.

BTW DPMS makes a .243 winchester on the AR10 Platform according to my freind who builds ARs

February 5, 2007, 12:38 PM
Most expensive parts would probably be the barrel and bolt assembly.
The magic rule with AR's, is that if it fits in the magazine, it would probably work - depending on how much money you are willing to throw at it.

February 5, 2007, 04:37 PM
This is the .243 WSSM, not the .243 Win. And it looks like the WSSMs will feed from a standard AR magazine

If you click your link and read what it says you'll see it has nothing to do with the current topic of a .243.

Quoted from the link you posted. Bolded what I'm talking about.

Ever since I found that .223 Winchester Super Silly Magnum will feed out of a GI AR magazine (albeit turning it into a single-stack mag due to the chubby case,) I have been dying to get an AR in that chambering. And not a long-barrelled varminter, either, but a stubby 16-inch carbine, just because I think it would make really, really cool fireballs.

Hey, people spend lots of money on fireworks all the time...

The .223 Winchest Super Silly Magnum on the page your link takes me too, goes to another page that expressly says .223, not .243. Please read your information more carefully before posting.

February 5, 2007, 05:28 PM
Skidoorider, since you said you were open to suggestions I think you should look at the 6.8 SPC. It's enough for deer and since it's .270 caliber it would be legal. There are tons of vendors selling upper assemblies and complete rifles, and since there are quite a few people using 6.8 in ARs you won't have to worry so much about whether it's going to work.

February 5, 2007, 06:08 PM

The information posted by NateG is entirely relevant because the .223 WSSM and .243 WSSM catridges are closely related, the only difference being about .5mm worth of neck diameter. They both feed from a standard AR-15 lower into a WSSM upper.

It seems like a good way to go, all the ballistics of the (308 based) 243 Winchester, with a platform that's much cheaper and has a better aftermarket than the AR-10.

February 5, 2007, 07:06 PM
The reason I choose the .243 wssm is because I will mostly be using it on dumb stuff like crows, badgers, coyotes, fox, ext. out in the field 2-300 yards. I thought that round was small enough that it wouldn't do to much damage but I was still open to use it for deer hunting if I wanted to. I did a little research and that round seems to fly pretty flat and accurate. Maybe there is a better choice in caliber also. I'm looking for something fairly cheap to shoot. In the regulation book for Iowa centerfire deer hunting the caliber has to be .24 or larger. Also I have always wanted an ar just because they look neat and so versital.

June 28, 2009, 09:27 PM
The 243 WSSM rifle will be lighter in weight and cheaper than the 243 Win rifle. The ammo for the 243 Win will be easier to find and cheaper. Little bit of a trade off there, cheaper and lighter rifle and more expensive ammo if you can find it against the 243 Win with the higher weight, higher price and cheaper ammo that is really easy to find. 243 Win ammo is still easy to find and price isn't sky high yet. Finding either rifle now could be a real problem.

June 28, 2009, 11:00 PM
Finding either rifle now could be a real problem.But not in Feb. of 2007...check your dates or the necromancer cometh for you. :)

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