Gentlemen,
Please see the below linked thread if you would like to see my testing leading up to these final charts. I have over 1,000 pellets through the gun now so I feel after today's tests, this is as good as it's going g to get.
https://www.airgunnation.com/topic/aa-s510-xs-first-40-shots-over-chrono/#post-360223
That thread has a full shot string I just did on the FX Streamline 22. Even starting from what I have determined to be the Optimal Fill pressure for the US (180bar) based upon this latest shot string, the ES still isn't as low as the FX factory reg of the Streamline.
This lower ES, which I would be satisfied with, comes only by sacrificing 29 shots. Instead of 60 shots that AA claims this rifle will get, I can only get 31 if I want to get the ES down to an "acceptable" value of 30.
Moving forward from here, my testing has shown me that the reg in the FX Streamline is set to 115bar, where the Ultimate Sporter 22 has it set at 125 bar. Now the Streamline makes a distinct "ping" the moment it falls off the reg. The velocity of my Ultimate Sporter will drop rapidly at 125 bar but will only ping slightly when it reaches 115 bar.
SUMMARY:
My Ultimate Sporter, if filled to 250 bar and shot down to 115 bar when it makes a slight ping, will get 101 shots with an ES of over 100. Being Air Arms makes a claim of 60 shots, there's no way the fill pressure is meant to be 250 bar.
If filled to 220 bar and shooting down to 125 bar, my US gets the claimed 60 shots with an ES of about 40.
In order to come close to the performance of my FX Streamline 22, I have to start at a fill pressure of 180 bar and end at around 125 bar.....this gets the ES down to 30 but reduces shot count to only 31.....nearly half of the AA-spec'd 60-shot claim.
FINAL THOUGHTS:
1. If the reg pressure on the Ultimate Sporter is in fact 125bar, determined by me only from a velocity drop, then it could stand to be lowered by 5 bar and do further testing. Note that the AA manual for this rifle states to refill the air cylinder between 110 and 115 bar.
2. If the reg pressure must stay where it's at - what ever that pressure may be - then the hammer spring could stand to be adjusted for more tension. As far as I'm aware, adjustments to the hammer spring tension are not easily made.
One last thing to note.....my Ultimate Sporter reaches the AA-claimed 950fps using JSB 15.89gr pellets, though only at peak and not by average.
Please see the below linked thread if you would like to see my testing leading up to these final charts. I have over 1,000 pellets through the gun now so I feel after today's tests, this is as good as it's going g to get.
https://www.airgunnation.com/topic/aa-s510-xs-first-40-shots-over-chrono/#post-360223
That thread has a full shot string I just did on the FX Streamline 22. Even starting from what I have determined to be the Optimal Fill pressure for the US (180bar) based upon this latest shot string, the ES still isn't as low as the FX factory reg of the Streamline.
This lower ES, which I would be satisfied with, comes only by sacrificing 29 shots. Instead of 60 shots that AA claims this rifle will get, I can only get 31 if I want to get the ES down to an "acceptable" value of 30.
Moving forward from here, my testing has shown me that the reg in the FX Streamline is set to 115bar, where the Ultimate Sporter 22 has it set at 125 bar. Now the Streamline makes a distinct "ping" the moment it falls off the reg. The velocity of my Ultimate Sporter will drop rapidly at 125 bar but will only ping slightly when it reaches 115 bar.
SUMMARY:
My Ultimate Sporter, if filled to 250 bar and shot down to 115 bar when it makes a slight ping, will get 101 shots with an ES of over 100. Being Air Arms makes a claim of 60 shots, there's no way the fill pressure is meant to be 250 bar.
If filled to 220 bar and shooting down to 125 bar, my US gets the claimed 60 shots with an ES of about 40.
In order to come close to the performance of my FX Streamline 22, I have to start at a fill pressure of 180 bar and end at around 125 bar.....this gets the ES down to 30 but reduces shot count to only 31.....nearly half of the AA-spec'd 60-shot claim.
FINAL THOUGHTS:
1. If the reg pressure on the Ultimate Sporter is in fact 125bar, determined by me only from a velocity drop, then it could stand to be lowered by 5 bar and do further testing. Note that the AA manual for this rifle states to refill the air cylinder between 110 and 115 bar.
2. If the reg pressure must stay where it's at - what ever that pressure may be - then the hammer spring could stand to be adjusted for more tension. As far as I'm aware, adjustments to the hammer spring tension are not easily made.
One last thing to note.....my Ultimate Sporter reaches the AA-claimed 950fps using JSB 15.89gr pellets, though only at peak and not by average.