I made it to the range today to shoot the Accuracy Systems 300 SAUM upper I had built. Here is what I had them build: Complete new flat top upper, stainless barrel 1X12 twist 24" plus brake. I had the barrel fluted, a 3 port Maxi Brake, and a quad forend . Cost was $2099 (expensive I know) and it was delivered within the 8 week estimated time frame. This is a nice piece of work and it shoots well under their guarantee of 1 MOA! Today was 101 degrees when I headed to the range. All targets were shot at 200 yards.. Proir to going to the range I had thoughly cleaned the barrel using solvent and gray JB compound recommended by Accuracy Systems. I used the JB compound in three different applications. I also mounted a Leupold LR 8.5x25 scope on the rifle and attached my DPMS 300 SAUM lower with the JP trigger to the upper. Once I arrived at the range I bore sighted the rifle and fired 3 fouling shots to get sighted in. First up was 180 gr Accubonds with 65 grains of Reloder 22 powder and a 215M primer. All fired rounds were seated magazine length. The wind was not strong, but the mirage was running strong. I ingnored it as for as compensating for it on any of the shooting. I fired 2 shots and could not see where they impacted the target until the mirage slowed down and changed directions. Once this happened, I could see the two shots and later determined that they were 1.887" vertically and 1/2" wide. I put this rifle aside to let it cool and shot something else while I waited. Once the barrel cooled, I fired two shots (all I had of this load) with same load except for the bullet was a 180 Hornady IL. These two shots were .835 inches tall by 1/2" wide. I then fired 3 shots using 64 grains of Reloader 22 with 165 Hornady IL and 215M primers. These three were 1.124 wide by .893 tall. The brake made the rifle easy to shoot. I would compare it to a 243 with an 80 gr bullet. I did not take the chrony with me today, but I expect these loads should be around 2900 Fps for the 180's and 3000+ for the 165's. Not hot loads. All were shot in Norma brass. I will get some pictures of the rifle and provide the weight in a later post. A copy of the upper can be seen on Accuracy Systems website as a 325 WSM upper, but with the Maxi brake Needless to say I am pleased with the outcome on this project. I will repeat this test with the same loads in the next couple of weeks.