New project: building an AR15 for cast

[Stoats]

After my relative success with 223 cast in a bolt gun, I got onto thinking about cast in the AR 15. Of course, I will load up some 223 and see how they go, but I got onto thinking about how one would optimally shoot cast in one.

1st step: what do you feed it on?

I did a bit of thinking and a bit of research and I came up with a relatively unoriginal conclusion, which has already been experimented with by people on this board: 300-221/300 Whisper is already specified to shoot cast-weight bullets (150-200 + grains) at cast-type velocities (1000-2200 fps) using cast-type powders (N 110, H 110, number 9, etc) in cast-type quantities (12-20 grains).

Seems like a perfect vehicle to me! Particularly as I can use my standard magazines (getting 7.62 x 39 or 6.5 Grendel magazines is an expensive thing to be doing over here).

2nd step: what configuration?

I will probably go for an ipsc-type setup, since I reckon that as a secondary use the cartridge should be able to launch 150 grain flat base J-words (probably moly- coated to squeeze a little more velocity for a little less pressure) at just past the 2150 FPS mark to make ipsc major (although the idea of a 160 grain cast bullet doing just over 2000 FPS and making major is rather exciting!)

So that would probably be an 18-inch setup with a carbine-length adjustable gas system then.

Since I'm not in the US and getting upper receivers out of the US is a complete pain (not impossible, but too much hassle) I'll be getting it made up as a custom item over here (for about twice as much as it would cost me in the US, unfortunately...)

This will start coming together at the trailing end of the summer, so I will keep you posted with accuracy information and hopefully a torture test (how many cast rounds can you fire before you start to gum up the gas system).

[burr7870]

I have been playing with a model 1 sales 300 whisper upper. It is a blast to shoot. I use 200 gr lee cast & 110 grain j-word bullets. AA 1680 in subs for cycling & h110 for supersonics. I find the subsonics a riot and usually shoot them. Remember small case capacity not a magnum!!! Don't try to turn it into one!!

[GabbyM]

I'm still waiting to see someone try the 6.8 SPC with cast.

[AviatorTroy]

This is just me, but if I were to build an AR for cast, I would go with a .45 ACP which you can get bolts and barrels for from Olympic.

Or, even easier, build a .50 Beowulf, I bet that would shoot cast extremely well.

[StarMetal]

The 50 Beowulf is a fine round but getting brass is kind of hard, not to mention getting the pricey barrel and bolt.

[Stoats]

I have been playing with a model 1 sales 300 whisper upper. It is a blast to shoot. I use 200 gr lee cast & 110 grain j-word bullets. AA 1680 in subs for cycling & h110 for supersonics. I find the subsonics a riot and usually shoot them. Remember small case capacity not a magnum!!! Don't try to turn it into one!!

what length barrel and what length gas system do you have?

[burr7870]

I have the standard 16" barrel with the carbine gas port. AA1680 for subsonic loads cycles fine. H110 cycles fine with supersonic loads.

BTW I do not know about the olympic arms 45acp AR-15 but I can tell you their 9mm is a blast with boolits:-P.

[Patrick L]

How do the 7.62x39 ARs shoot?

I know the round doesn't have a reputation for stellar accuracy, but I always figured it was the AK/SKS platform, plus the fact that most guys shoot cheap surplus ammo through them. In a good gun with quality reloads it seems it should shoot well.

I must confess I would love to play with cast in my AR, but I don't feel like casting .22 boolits. A well built 7.62x39 upper would be a pretty easy way to get into it.

[mike in co]

How do the 7.62x39 ARs shoot?

I know the round doesn't have a reputation for stellar accuracy, but I always figured it was the AK/SKS platform, plus the fact that most guys shoot cheap surplus ammo through them. In a good gun with quality reloads it seems it should shoot well.

I must confess I would love to play with cast in my AR, but I don't feel like casting .22 boolits. A well built 7.62x39 upper would be a pretty easy way to get into it.


me thinks the clue is in your last line: A well built 7.62x39 upper

you dont want an ak chamber on an ar, ar clearances would be fine.
a short throat
correct twist
and quality ammo
r-p has boxer brass ammo comming from three plants, but i have never shot any of it.
i do have some lapua 7.62x39....which shot well from a bolt gun.

me thinks it would be a great gun..and have plans to build one when..."i get a round tuit"

mike in co

[mike in co]

This is just me, but if I were to build an AR for cast, I would go with a .45 ACP which you can get bolts and barrels for from Olympic.

Or, even easier, build a .50 Beowulf, I bet that would shoot cast extremely well.


lets just say that that company is not someone i woul fbuy ar parts from , much less a bbl.

[StarMetal]

How do the 7.62x39 ARs shoot?

I know the round doesn't have a reputation for stellar accuracy, but I always figured it was the AK/SKS platform, plus the fact that most guys shoot cheap surplus ammo through them. In a good gun with quality reloads it seems it should shoot well.

I must confess I would love to play with cast in my AR, but I don't feel like casting .22 boolits. A well built 7.62x39 upper would be a pretty easy way to get into it.


20 inch heavy barrel in 7.62x39 on my AR15 that I built. .3095 groove with a 10 twist. The LEE 155 grain loaded over 26.5 grains of 4895 any flavor and she shoots into 3/8 inch at 100 yards. Can't ask for more then that. If I remember somewhere in the neighborhood of mid 1800 fps.

[Stoats]

I'm at the point now of choosing a chamber reamer.

Should I go for a .3085, .3090 or other throat for shooting cast?

[gds]

I have a barrel for a .300 whisper AR 15 scheduled to be finished this weekend. I have cast a lot of those Lee 200 gr in anticipation of having some fun.

[johnly]

me thinks the clue is in your last line: A well built 7.62x39 upper

you dont want an ak chamber on an ar, ar clearances would be fine.
a short throat
correct twist
and quality ammo
r-p has boxer brass ammo comming from three plants, but i have never shot any of it.
i do have some lapua 7.62x39....which shot well from a bolt gun.

me thinks it would be a great gun..and have plans to build one when..."i get a round tuit"

mike in co

Let me give you a point in confirmaton.

I have a Colt 7.62x39mm flat top upper with a red dot sight and it shoots cast into 2" at 100 yards. I use a 155 gr. NEI GC bullet sized to .313" pushed downrange by 2400 powder.

John

[Lloyd Smale]

Ive played with cast with good luck in my 50 beowulf and my bushmaster 762x39. to be honest i havent done alot with the 762x39. I have two group buy molds for it. A 130 and a 140 and both shot about 2 inches with the loads i tried and ran the action. Jacketed bullets have shot one inch 100 yard groups out of that gun. Your whisper idea might be better if you want to run lower velocitys and still run the action though. the beo shoots cast even better. Ive got loads close to an inch out of it with cast but recoil is much higher and you use more powder and lead for each shot. Nice thing about going with a 762x39 is brass is easy to find. I bought mine when the ammo shortages started. I had a chance to buy 5 cases of wolf ammo cheap and figured if the shortage got to bad i could allways shoot that. I also liked the idea of a ar i could take to camp and shoot a few hundred rounds and not have to worry about picking up brass. I really like this gun and its become probably my favorite ar. Recoil is mild and it definately hits things harder then a .223 and has proven to be very accurate. Ive yet to kill anything with it but its set up with a trijicon accupoint 1x4 on it and i think it will make a great whitetail rig.