As promised.......
PLEASE NOTE: This was a testing session. I am learning the gun and sharing that experience through the documentation that I do here on the forum. Poor strings like these often happen when messing with the adjustments and settings of a gun. Going through this process teaches the user what the gun does, and doesn't like. The information collected today will be used to arrive at a more optimal tune.
First chronograph string, 9 full magazines for 108 shots. Bottle pressure reached the current regulator pressure of 160bar at shot #72.
Each magazine was shot at the same aim point at 53 yards. Once that group started, scope was left alone, but between each group I was clicking here and there to shift groups closer to aim point. I'll attach that pic at the end. So there will be a pic of 108 consecutive shots on paper, 12 shots/group. Good test of a gun, although hard for the shooter to make that many good shots in a row (especially when trying to keep the gun over the top of the eyes of the chrono without shooting it)
Starting pressure was 260 bar.
240 bar after shot #12
225 bar after shot #24
210 bar after shot #36
190 bar after shot #48
175 bar after shot #60
160 bar after shot #72
145 bar after shot #84
130 bar after shot #96
115 bar after shot #108
The first shot of the day was low fps. I've seen this with lots of regulated guns, even high priced ones. The gun had been sitting for about 24hrs at this point.
I'm also going to show ALL the data plotted out, in various ways.
This is many more shots than we can realistically expect to get at this power level, at least if the goal is consistency. I intentionally shot past the reg pressure, hoping to see how the valving, hammer tension, and regulator pressure all work in this particular gun.
This is a long string and it looks bad. (I will put more effort into a tighter spread, I'm pretty sure it will be possible, especially with AOA's owner adding the valuable information from RTI about how to tune for the 25.4 MRDs.) Furthermore, I was using a tin of pellets where most of them looked like this:
yep, pretty mangled skirts. I was hoping to use up these rough pellets for tuning purposes, vs accuracy testing. BUT I suspect some of the large ES issues can be attributed to really shady pellets.
First off, data for shots 1-100 Shots 2-72 Shots 2-60 Analysis Generally we can see that the fps rises after shot 72, which happens to be when it came off the reg. There are also some outliers really wreaking havoc with the consistency, for example shots #1, #13, #49, and #61 were low fps.
I'm betting that first shot being low won't go away, even with a better tin of pellets and a better tune. Some regulated guns just do that. I do think that I can get it more consistent though. From RTI (per Robert), I should be looking at a reg pressure of more like 170-180 to be rocking these Monster RDs in the >1000fps range to make the gun happy. It should be easy to get there, and I'm guessing it's going to take more hammer tension in addition to the bump in the reg pressure (that's how it behaved when I bumped the reg up from 130 to 150 and then again from 150-160.....it needs more hammer tension for each new reg pressure).
I also think a less $hi77y tin of pellets should improve the spread.
So, goal for the next time I have a chance to work with the gun: tighter ES through increased reg pressure, increased hammer tension, and non-mangled pellets.
I'll share it all and post a full string demonstrating the results of my plan (you know what they say about a plan though, "The best-laid schemes of mice and men.........."
Oh yeah, here are the shots above, on paper, @ 53 yards, WITH those junky pellets. (the last 5 or 6 shots were hitting so low that they were below the paper so technically there are only about 102 or so shots on here). Dime target/aim points are true to size (about 0.7inches). Shots were taken just holding center of dime, best I could.
). With the tension backed off of the hammer cocking effort is negligible, (less than pushing the pellet into the breach). To get power without cocking effort you'd have to run the reg above 180 with less tension, (provided that the hammer has enough energy to open the valve); i haven't tried that. 
