As noted in Does Not Follow, I did a bunch of chrony testing yesterday. I am not going to post all the chrony data since it mostly pertains to my rifles alone, but I have at least one observation that might be of interest. Rifles were a 16" AR that I recently finished that is made with an AAC pistol gas barrel, .081" gas port, the second was my 10" SBR using an Aero upper with (of course) pistol gas an an .098" gas port (very slightly enlarged over how Aero supplies it), and lastly my 16" bolt action, also built on an AAC barrel and Remington action. Similar in configuration to the factory Model 7 that Remington built with the same barrel, but I put it together myself. Both 16" guns were the result of having found those barrels deeply discounted and then building rifles around them.
I loaded 2 different bullets; the first was the standard Sierra 220 grain Matchking that everyone uses (though these are silver colored, came in a 500 piece bulk pack from American Reloading on sale), and the second is the Lapua 220 grain Scenar-L. The Lapuas are normally a VERY expensive bullet that you would ordinarally never lob into the dirt at 1000fps, but I found them HEAVILY discounted at Graf's and ended up buying 1000 of them. I loaded up 20 round batches of each at 3 different charge weights of A1680 powder, beginning at the 11.2 grain starting load that I believe originated with AAC when they created the cartridge, and then some at 10.8 and 10.4 grains each, for a total of 120 rounds. 5 of each combination for chrono testing with each rifle, and 5 of each for groups at 100.
Maybe the most interesting thing from the data to me is that the action type had a much greater effect on velocity than the barrel length did. I expect the results would be different for supersonic ammo, but between the 16" bolt action and the 16" AR, there was usually around a 50fps difference, while between the 16" AR and the 10" AR it was generally 15fps or less.
I only loaded up one supersonic test load. A couple years ago I bought 5 boxes of the same 110gr black tip bullets that Barnes loads in their factory ammo, again because they were on sale. I loaded 25 of them up in 5 round batches increasing in .5 grain increments of W296 powder, using the H110 data for that bullet from Barnes (it is well documented that they are the same exact powder in different packaging, Google it if you wish). I also fired 5 rounds of factory Black Tip as a control so I would have velocity data under the same conditions, even though I had chronoed that round from the same rifle previously. They were loaded to the exact same OAL as the factory rounds (which was also the OAL listed in the data used) in once fired Barnes brass, using a CCI small rifle magnum primer (which I also used for the sub loads).
Tested them using the bolt action. The factory rounds averaged 2394fps with a standard deviation of 23, and extreme spread of 56. The max load of 20.2 grains of W296 averaged 2437fps, with an SD of 6 and ES of 16. Since my goal is to replicate the factory load rather than exceed it, I will be loading the rest at the next step down of 19.7 grains, which averaged 2407fps with an SD of 7 and ES of 17. The step down after that averaged 2378 and had much worse SD and ES, same for the two lowest charges I used. This is consistent with what I have read about H110/W296, that it is happiest when loaded at or near max levels.
I did have a couple of primers in the supersonic loads that required multiple strikes, and I suspect these are the same ones I had difficulty seating in the brass (I think I have that issue resolved now). I didn't have that problem with any of the sub loads using any of the rifles and the same primers, so I am not going to worry about it for now.
All charges were individually weighed using an RCBS Chargemaster electronic scale and powder dispenser, and loaded on a Forster Co-Ax single stage press. My plan is to eventually acquire a Dillon XL650 which will be used for loading the subs (and lots of other things of course), but I will probably stick with the current equipment for at least the black tip hunting ammo due to the high precision that can be obtained that way.