Tuning Tuning and modding my mk2 impact

So I had a compact mk2 22 bought a 700 barrel 25 cal the barrel kit had the dual hole so I installed it with the slug hole facing down and installed a 25 Huma probe that come with the daul flow v2 transfer port just stole it out of my 500 25 kit I have and since the transfer port on the 700 kit looks like the Huma transfer port I just left them the Huma on my 500 and the 700 with what came on it my reg was set about 110 bar on the gauge I added the Huma bottle reg awhile back about the time the Maverick came out it's set to 150 my 22 was pushing 18 gr at 930 installed the 700 and tried the 34 gr mk2 730 fps the valve adjuster was on line one and about 1/2 I opened it up to 4 and fps went to about 820 fps I added more spring pressure till it hit 926 fps with 34 mk2 25 cal with a mrshosted power wheel on max then I adjusted the valve down to about 905 I turned the power and found I can adjust from 750 fps to about 915 ish so I tried max and one spot before max and settled on that spot the sound changed from max to the next step down it is running about 900 to 908 fps so I had a app on my phone to check db level for sound found it was running 70 to 71 with a koi on it I took the shroud off ported it in the back so it would be under the rail found piece of copper pipe that just slid over the outer part of the barrel I removed the shroud ends and milled 2 more holes in the air stripper end and took out the other end of the shroud found a 5/8 bit was just large enough for copper pipe to slide into the rear end cap I opened the hole on the inside just past the inner oring slid in the copper pipe into the rear end cap and measured from the rear of the shroud to the air stripper starts cut the pipe to that length plus what slid into the back shroud cap I wrapped copper pipe with felt used rubber bands in a few spots to keep it tighter wrapped slid in the copper pipe wrapped in felt using the shrouds rear end cap to insert it into the shroud and tightened it down the copper pipes was in the middle of the shroud I then put the air stripper end in place and tightened it down I made a spacer also to tension the barrel slid that on and installed the shroud tight and installed the koi sound level according to the app change to 66to 68 db running same speed it sounds quieter to I should have taken pictures I vented the shroud so the air would use the whole shroud and not just part of it because it was sealed with orings In the rear I don't know how accurate the app is but it sounds quieter the smack of the target is definitely louder than the shot