Friday, February 10, 2012

Multi-Caliber AR15

AR15 LW Project set up for .22 LR
 Hi folks!!

Quick little write up on the project.  This build is for my son.  It is designed so he can grow into the platform.

I started with a Delaware Machine AR-15 lower and went from there.  The lower was put together using a CMMG parts kit, a RADDLOCK 2 bullet button (I'm a California resident and want to stay legal), and Fulton Armory 4 position stock.  The grip is an excellent slim line Ar15 grip from Stryke Industries  I have large hands but this AR is set up for my little guy so the grip is PERFECT for him.  I have a large Stryke Industries AR15 grip on my rifle and I'm truly happy with the product.  (NOTE:  They make a really nice IPhone 4 case).

A Cerro A3 upper receiver was used with an FN bolt carrier and bolt, Double Star Ind. charging handle and a CMMG upper parts kit completed the upper.  A CMMG .22LR drop in conversion fills in the .22 LR role.  Flip up sights were purchased at a gunshow and I'm unnsure of the brand.

The barrel is from E.R. Shaw and was originally a 1:9 twist non-chrome lined 14.5" M-4 profile.  I had the barrel turned down to .606" except at the front sight/gas block area which I kept at .750" (standard) profile.  A Phantom Flash Hider was pinned and welded in place to make it over the 16" legal length.  A picatinny gas block finished up the upper.  Standard CAR slimline carbine foregrip in green to match the stock and grip finished off the basic build.

AR15 LW Project set up for 5.56x45/.223 Remington
NOTE:  This is a blocked 30 round mag holding only 10 rounds.
A Bushnell TRS-25 red dot optic mounted on top of a 1/2" riser was mounted on the A3 upper. 

Bushnell Red Dor 1x Sight
Black Dog Machine magazines were used in the .22 LR kit and CProducts 10/30 mags were tested at the range.


I tested the build over a two weekend range trip.  Both times 250 rounds of .22 LR (mixed manufactures) and  90 rounds 5.56/.223 ammo (also mixed manufacturers and reloads) were tested.  The weapons was NOT cleaned at all.  I had several malfunctions (about 10) using the .22 LR converstion.  This was due to a faulty Black Dog Machine magazine and not anything else.  The rifle ran flawlessly with the exception of the magazine issue.  I lubbed the CMMG .22  LR unit after every 250 rounds and the 5.56/.223 bolt/carrier after the initial testing cycle.  Just a note, the 5.56/.223 rounds were fired after the .22 LR rounds.


I set up the Bushnell TRS-25 to shoot 5.56mm/223 at 25m.  At this range the point of aim and point of impact from this roound will be the same at 100m (roughly).  With the .22Lr converstion at 25m it was dead on as well.  I saw a change at about 50m where not only where the groups opening up (because of the twist rate in the barrel) but also in bullet drop.  At 50m the .22LR was still "soup can" MOA.  I did not shoot the .22 LR at 100m but I would say you'd get pie plate accuracy at this range with the .22 LR unit.


For what I spent on the build (Less than $1000.00 including optic/riser and .22 LR magazines) I could not be happier.  I have a rifle my son can grow into and keep forever (or until the make me turn them it in).