Range Report - Chupacabra, an AR style carbine I assembled an AR pattern carbine, using parts from various manufacturers. I named it Chupacabra. I took it to the range. Here is my story. I began with 5.56 upper and lower receivers from J D Machine Tech for two reasons. I have used JD receivers before. They fit tightly with no play or rattles, and the finish is smooth and uniform. I was painfully unemployed and underemployed during the mid- to late ‘70’s, and I wanted to buy from a local business. I selected a Bravo Company “recce” style barrel, machined from 410 stainless steel, with a 1-in-8” twist, medium profile, and mid-length gas port. I completed the upper with a BCM bolt carrier group, Samson Evolution hand guard, Benny Hill Rolling Thunder compensator, Badger Ordnance ambidextrous charging handle, and a J P Enterprises low profile adjustable gas block. The lower receiver assembly sports a Timney 4 lb. trigger, Magpul ACS stock, enhanced butt pad, and enhanced trigger guard, B.A.D. ambidextrous safety with a hybrid lever on the off side, DoubleStar lower parts kit, Brownell’s carbine stock completion kit, Assault Planet bullet button, Falcon Industries Ergo Suregrip, and a superfluous set of KNS non-rotating pins. Chupacabra weighs 7 pounds 8 ounces with no sights, optics, or magazine. Overall length is 39”, and the length of pull is 14 ¾” with the stock fully extended, which is how I leave it. On December 21, I took the carbine to a local range with three objectives: function testing, adjustment of the gas block, and preliminary accuracy testing. I wanted to keep the round count low until I saw how it shot and cleaned up, so I could assess the need for break-in or fire-lapping procedures. I mounted a Burris Fullfield II 3-9x40 scope with a Leupold mount for the test. On the 25 yard range I fired ten handloads consisting of Winchester 64 grain Power Points over 24.3 grains of Winchester 748 and Small Rifle Primers in Remington brass to adjust the gas block, zero the scope, and qualify the carbine for the 100 yard range. On the 100 yard range these handloads yielded an 8 shot group and a 5 shot group, both of which measured 1.90”! I wasn’t too concerned about the size of these groups because I haven’t gotten much better accuracy from these bullets in other firearms, because my eyesight is not good, and because I am just getting used to the idiosyncrasies of shooting the AR platform. Ten handloads consisting of Sierra 69 grain MatchKing Hollow Point Boat Tails over 24.9 grains of Reloder 15 and Winchester Small Rifle Primers in Remington cases yielded five-shot groups measuring 0.95” and 1.50”. The barrel cleaned up pretty easily, with no indication of copper fouling to speak of. I then mounted a huge Nikon Monarch 5-20x44 scope with a Nikon M-223XR mount for the next test. On January 11 I returned to the range. A total of 34 rounds were fired at 100 yards during this session. Four handloads consisting of Winchester 64 grain Power Points over 24.3 grains of Winchester 748 and Winchester Small Rifle Primers in Remington cases were fired to zero the scope. Five more rounds yielded a group measuring 1.10” (four rounds into 0.85”). Fifteen handloads consisting of Sierra 69 grain MatchKings over 23.3 grains of IMR 4895 and Winchester Small Rifle Primers in Remington cases (range pickup) at about 2,550 fps yielded three groups measuring 1.10”, 1.00”, and 0.75”, for an average of 0.95”. Ten handloads consisting of Hornady 75 grain Match BTHP’s over 21.7 grains of Reloder 15 and Winchester Small Rifle Primers in Remington cases (range pickup) at about 2,400 fps yielded groups measuring 0.85” (0.50”) and 1.00” (0.60”), for an average of 0.93”, or 0.55” without two fliers. The average for the day (six groups) was 0.97”. Discounting the 64 grain Power Point group the average was 0.94”. Discounting the 64 grain Power Point group and two fliers the average was 0.79”. I will call the gun a 0.95” shooter without feeling like too much of a liar. I will do further testing with the Sierra 69 grain MatchKings, Hornady 75 grain Match BTHP’s, and some Sierra 65 grain GameKings. I think with a little practice and load development I can get Chupacabra knocking down 0.70” 5 shot groups at 100 yards, consistently. If not, I spent an awful lot of money to build a plinker!