Starting from scratch. Will be working with a very experienced gunsmith to be sure everything matches and works smoothly.

For use in mixed opportunity environments: rabbit, squirrel turkey, pig, deer.

Another take on survival firearms:

http://www.usrsog.org/surfire.htm

Think that the forum that has more information that you ever wanted to know is ar15.com. Don't know which one of the conversions works the best, would recommend doing a little research. There are are also different vendors and not all are honorable places to deal with.

It is good to know that you are going to have a gunsmith "tune" the conversion they are supposed to work with most but slight manufacturing differences in the bolt assemblies and the many AR variants can make the conversions problematic at times. Accuracy is not real good, don't know if it would be good enough to hunt with or not. You can also buy a new upper with a 22 barrel that seems to offer a much higher degree of accuracy but also adds quite a bit to the cost. Think a built 10-22 might be cheaper and be very accurate.

Should mention that a couple of years ago i worked at a machine shop that fabricated the conversions for one of the AR-15 specialty shops. Did like our quality control testing for the conversions that we made. The owner of the AR-15 shop is a class 3 dealer and he would bring in his personal silenced M-16 and we would go out behind the shop and run a few magazines through it just to make sure everything worked as it was supposed to. And most of the time the conversions would run full auto without any problems.

The hope is a one rifle, two calibre solution for hunting. Not a target rifle; probably never try any 22 shots further than 30 yards.

.22lr conversions in .223/5.56mm barrels is not accurate enough for hunting, in most cases. I assume that you mean small game like rabbits and squirrels. The .22lr bullet is a true .22 inch diameter. AR bullets are .224 in diameter. barrels for the AR are wider than for .22lr, thus .22lr bullets do not "grip" very well in the larger barrel. Rifling twist rates are also much faster in the AR barrels and the .22lr bullets don't stabilize well. Results are lost velocity, erratic accuracy (12" groups at 50 yards in some cases), heavier leading in your barrel, etc. That being said, inside 30 to 20 yards, you may be close enough that the above doesn't matter that much and you can still get your squirrel. This is where your stalking and other hunting skill come in.

The .22lr kits really shine for cheaper training options. If you want to hunt, but maintain your AR system, I recommend a dedicated .22lr upper that aleviates most of the above problems.

Friend suggests that .223 tumbles on impact by design making them meat destroyers and unsuited to hunting. Others claim that only happens with old military surplus stuff and is banned by the Geneva Convention so no such tumbling occurs.

Maybe a different AR calibre, like 7.56? More research!

Wonder what a 22LR upper and receiver for AR-15 cost? Could still share optic and perhaps other accessory costs. More research.

You could purchase a decent O/U Savage Mod.24,though they are single shot,& quite heavy,but in various combo calibers,including .223/.22 L.R. The mod.24's are not made anymore,& haven't been for more than 30yrs.New England Arms are the Newest choice here,they make O/U singles in just about every caliber out there,much lighter due to synthetic stocks/furniture,modern mfg. technique.The Ruger 10-22 is what I've used for squirrel hunting most of the time,& A Sears-Roebucks single shot in .22 gallery shorts in my post-toddler yrs. The .223 conversion to .22 LR is NOT practical,at the very least,The Ar-15 bore is designed for the .223 round which is 2 times longer in length than a .22 LR round,& are usually bored with a 1-9"twist,thats 1 complete revolution per 9" which will put a very tight spin on the much longer .223 giving it a Very flat Trajectory,well past 100yds.with Ball ammo.Don't waste your Money on the conversion!

This is becoming a complex discussion. Apparently AR-15's vary in barrel twist [1 in 7, 1 in 9, 1 in 12, and 1 in 16 at least], performance with different grades of .223 or 22LR ammunitiion [more expensive genreally more accurate], and on and on.

Various internet sources and forum contributors differ on whether .223 shot from AR-15s tumble and so damage larger parts of what the slug hits. Ditto with the effectiveness of the AR-15 .223 as a one shot, one kill deer rifle.

At the moment in my researches, it seems all concur that the accuracy of 22LR fired through and AR-15 .223 barrel is not great and probably not appropriate for hunting at any distance.

More research!

Turns out my little brother, the police chief, has been sand bagging during my talks with him about .223 AR-15s. You guessed it, that is the department issue long gun. According to the ex-marine officer I spoke to this morning the round is a penetrator and does not by design tumble in flight or on impact. My brother the chief added that if it did the suits against the department would make national news.

So the research continues.

From looking at several thousand targets shot by M16s, the vast majority of holes in them are round. A tumbling round leaves a larger oval hole. It's really obvious when an M16 round has hit something to cause it to tumble before striking a target.

Once the round strikes something it may tend to tumble, as do most hot small caliber rifle rounds, but not always.

Personally, I own a .223 and a .22. I use the .22 for plinking, general tuning up my marksmanship, and general usage, as it's freaking cheap to shoot a .22.

dweste...I paid about $180 for the drop in conversion and magazine and another $25 for an additional magazine...I don't know your background with shooting sports, but I compete in a sport called 3 gun.. go to YouTube... Ft Benning 3 gun 2009 stage VII, and look at the video with Mike Darby, Kurt Miller et al...then go to Viking Tactics by Kyle Lamb and look at the video called "Highsmith Rifle Drill" and "9 hole rifle drill" and "three little kittens" the practice to accomplish and maintain these skills can be pricey at $.25 a shot... hence the .22lr conversion

you can purchase a second hand Ruger 10/22 for less than what the conversion will cost you and end up with a much more accurate rifle

If you want to continue your research on the .223/5.56 look at the recent ballistic gel tests (FBI) used to approximate animal tissue... when the velocity of the bullet is above about 2700feet per second, (depending on bullet weight) at 200m or less, the bullet will yaw 90 degrees and break apart the the cannelure (the groove on the bullet the case is crimped into ),and the resulting fragments will shred the temporary stretch cavity caused by the hydrostatic shock of the projectile impact producing a devastating wound....at velocities less than this the projectile will rotate 180 degrees, and leave base first (naturally depending on thickness of tissue and whether it strikes any bone... larger diameter bullets shot in non magnum .308 guns typically don't reach this velocity to yaw, drilling a caliber diameter hole, so hunting projectiles typically have a "hollow cavity" which allows them to mushroom to increase the the permanent stretch cavity producing a more humane kill. AS far a bullet yaw, a 3000fps bullet fired from a 1/9inch twist rate rifle is going 240,000rpm..(if my math is correct) and anything can cause it to deflect... regards Les