# Diet & Makeover (AR)



## Frisco Pete (Sep 22, 2007)

You see TV shows where people go on a diet and get a makeover - but for that can happen to some of our guns too!

I've had my Rock River CAR A4 for a decade now. In fact it was an AWB era rifle as well as my first AR15. It is so old that it was made in the original RRA facility in Cleveland IL before they moved down the road to Colona. 
It also is my most-used AR and has seen a lot of action hunting jackrabbits in the desert. As a hunting tool it has evolved somewhat to fit my needs better. 
Over the years it has seen several upgrades; changing from a Burris 1 3/4-5x to a FFII 3-9x, different mounts to get things right; the barrel threaded for a flash hider post-AWB; a change in furniture from OD A2 stock (AWB) to a Coyote/FDE Vltor Carbine stock and Coyote/FDE-color carbine handguards and pistol grip - which has gone from a Hogue to a TangoDown. It also now has a mil-spec FA M16 BCG.

The stating point:









But it has come time to do a more major component make-over. While the stock RRA/Wilson full-profile 16" barrel has been extremely accurate (_down to 1/2 MOA_), its main problem is not the lack of chrome-lining, but WEIGHT.
The heavy barrel 10.5+ pound AR just plain becomes a burden to carry for a couple of hours or more at a stretch in the desert when by necessity it has to be carried at the ready position in order to make the very rapid sight acquisition necessary in hunting jackrabbits. Most of this front-heavy weight burden is carried mainly by my left arm, unfortunately. The Spectre Gear SOP sling helps, but isn't a cure.

In addition, as a possible SHTF rifle, the burden of carrying it for miles and many hours as easily would be the probable scenario would be a real negative. If mainly range and bench rest work, or PD shooting was the main use, things would be fine. I swear it was lighter a decade ago...

It was time to put the old CAR on a diet.

Of course AR15 parts have been difficult to find, but things are coming back. After looking around for a lighter profile, preferably stainless barrel, I ordered a 16" M4-profile stainless steel Black Hole Weaponry barrel.

It is a 1-8" twist with the obligatory M4 feed ramps - that has been MPI inspected. The gas port on this carbine-length system is basically correct Colt-spec at 0.0625" which is slightly smaller than the RRA that measured between 0.066" and 0.069" (still decent spec).
Total weight savings on just the barrel is 8 ounces.

Originally I was just going to install the barrel with no other changes to the carbine handguards, but soon realized that I really wanted a free-float rail instead that wouldn't affect the barrel vibrations when the barrel heated up - especially seeing as how the M4 profile has a lot less meat as a heat sink than the full profile barrel .
Therefore I ordered a Midwest Industries 7-inch Carbine Gen2 SS-Series One Piece Free Float (#MI-SS7G2) quad rail. This is a new generation quad rail that allows you to add rail pieces where needed, and thus is much thinner in cross section and lighter. In fact it is 4+ ozs. lighter than the MI FF T-series Gen 1 quad rail on my last build as well, and more comfortable in the hand for me. Weight is only slightly more than the plastic carbine handguard setup. I like the anodized FDE color a lot!

If I had this to do over again, I would have ordered the longer 9" or 10" MI SS quad rails. The carbine version is plenty short with the sling attachment installed. I wasn't planning on changing the gas block when I ordered this, and then I changed my mind.

Other miscellaneous items need for the upper change were a Vltor clamp-on low-profile gas block and a MI sling swivel attachment for the rail. I also got a new WMD Nitromet gas tube. The low-profile gas block is a couple of ounces lighter than the original Weaver-mount gas block/sling mount setup, though the rail sling attachment takes half of that back.










The original full-profile barrel and gas block:









Actual disassembly of the old upper and assembly of the new upper went smoothly. This time I got help in advance for pinning the gas tube in the block which was the main problem with my first upper build. Not really a 1-man operation with the equipment I have!










The sling mount was moved to a rail section mounted on the left side from the bottom trial position and the cumbersome strap attachment system of the Spectre Gear SOP sling that adapted the side mount to a bottom gas block mount was eliminated for a slicker straight side attachment. 
For additional comfort a supplied MI plastic panel was attached to the bottom and a rubber rail ladder cover will be attached to the top rail to eliminate the sharp edges for my thumb curled over it.

The old scope setup was reinstalled. It consists of a RRA extended Scout rail and heavy duty steel Warne Tactical rings. After some initial rounds downrange for function testing and to see how far off zero I was - I decided to replace that old setup with a RRA Hi-Rise Cantilever 1-piece ring/mount setup I had around for a future build. The extended rail over the monolithic quad rail looked odd (_though it was a good setup with the carbine handguards_). This also afforded a chance to lose some more weight due to those heavy rings. What surprised me was just _how much weight_. As much weight as the barrel change! 1/2 pound.
The scope setup was changed out and the aesthetics of the whole rig were improved by the swap.
The biggest thing was the reduction of the weight of the AR15 by a full pound+ with the barrel and mount changes - most of that towards the front end of the balance point. My goal had been achieved.
*FINAL WEIGHT* with sling and a fully loaded 30-rd P-Mag = *9 lbs. 6 oz.*

To put that in perspective, my bolt-action Winchester Model 70 Featherweight .223 weighs 8 lb 12 oz ready to go with 6 rounds. The difference between a fully loaded P-Mag (30) and an empty one is about 1 pound. So the AR is really quite comparable to the light bolt action in weight now.

The original Scout Rail and ring setup:









The Hi-Rise Cantilever setup and MI Gen 2 SS 1-piece FF rail:









The barrel was thoroughly cleaned, and JB Paste was liberally worked thru the barrel in order to polish the bore further for break-in.
Ammo used for sight-in was my standard handload of Hornady 55-gr SPs ahead of a max load of H-335 fired by a Rem 7 1/2BR primer in LC brass.

Things went well on the newly-lightened rifle, though POI was noticeably off of the original setup and again noticeably off when the switch was made to the Hi-Rise Cantilever mount system - particularly in elevation. Nevertheless I finally got it to where I wanted.

The BHW barrel is advertised as a match-grade barrel, and though I really didn't expect it to out-group the old barrel (_nor did it need to for intended use_), it seems to really want to shoot with sight-in groups ranging from 1/2" to 1" as a rule. Considering it is new unbroken-in fairly light barrel that had more than a box of ammo fouling it, and only one 55-gr flat base load was tried in the 1-8" twist - I am very happy with the results. It appears that it should give solid MOA or less performance. The wind started picking up alarmingly as the sight in session concluded, so I was unable to shoot for group size without sight-in distractions and constraints.
69 and 77 grain match bullets might be tested in the future.










Certainly one of the great things about the AR15 platform is the ability to change and upgrade components from minor to major as needed or as improvements come along. And these are reasonably easy to install with only a few needed tools by a person with only moderate mechanical ability. 
So while this particular Rock River CAR A4 was as good as I could afford and as good as was, unfortunately, legal over a decade ago, it can now benefit from current upgrades and evolve to present-day needs.
And lose more than a pound of weight _and_ get better looking in the process 8)


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## sawsman (Sep 13, 2007)

Good lookin' rig Frisco!


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