So I have been wanting to build an AR10 in Creedmoor for some time and I finally bit the bullet and bought an Aero Upper/Lower kit minus the BCG and Barrel. I bought a Ballistic advantage 20" barrel from cheaper than dirt for $206 and an AERO BCG on a sale from somewhere else. The irony of it is that all my components combined are the exact package AERO sells as a complete rifle but I got it for about $500 cheaper. I pulled my PRS stock off of another rifle and I was set to go. I broke in the first 20 rounds with boxed 140 ELD which ran very hot in the gun and my 2 10 shot groups were both right at 1MOA.I then switched to hand loads that I worked up from 40.5 grains to 42.4 grains of H4350 and the 140 ELD. I found a good node between 42.1 and 42.4. That was my first trip to the range.
For my second trip to the range I loaded up 20 rounds of 42.1 and 20 rounds of 42.4 to test further and get some chronograph numbers. Initially the numbers had me a little baffled as my 42.1 grain load averaged 2580 fps which felt a little low and had a huge SD around like 20 fps. Then I chronographed 42.4 and it was lower than the 42.1 gain load at around 2540 fps but the SD was below 10 and the ES was 15. I decided my placement of the chronograph must have been giving it ackward sunshine angles so I moved it to a place I have had good results before and the numbers started to look like what I expected. 42.4 grains ended up being the more accurate load with my lowest group being .611" for 5 shots and highest being .780" for 5 shots. Here are the Chronograph numbers for that load.
1.2665 2.2669 3. 2668 4.2651 5.2658 6.2675 7,2662 8. 2669 9.2664 10.2675.
Based on my calculations that is an Avg of 2666 an ES of 14 and an SD of around 7
Overall Im pretty pleased with this build so far. Next Im going to play with the seating depth of the load to tune it a little and then take it out to 300 and 600 yards to see what she does there.
For my second trip to the range I loaded up 20 rounds of 42.1 and 20 rounds of 42.4 to test further and get some chronograph numbers. Initially the numbers had me a little baffled as my 42.1 grain load averaged 2580 fps which felt a little low and had a huge SD around like 20 fps. Then I chronographed 42.4 and it was lower than the 42.1 gain load at around 2540 fps but the SD was below 10 and the ES was 15. I decided my placement of the chronograph must have been giving it ackward sunshine angles so I moved it to a place I have had good results before and the numbers started to look like what I expected. 42.4 grains ended up being the more accurate load with my lowest group being .611" for 5 shots and highest being .780" for 5 shots. Here are the Chronograph numbers for that load.
1.2665 2.2669 3. 2668 4.2651 5.2658 6.2675 7,2662 8. 2669 9.2664 10.2675.
Based on my calculations that is an Avg of 2666 an ES of 14 and an SD of around 7
Overall Im pretty pleased with this build so far. Next Im going to play with the seating depth of the load to tune it a little and then take it out to 300 and 600 yards to see what she does there.
