Anschutz 9015 Regulator adjustment
String 1: Avg=785, ES=32, SD=9.3
String 2: Avg=780.4, ES=48.1, SD=12.2
adjusted velocity up a little (increased striker spring tension) before string 3
String 3: Avg=813.1, ES=47.1, SD=13.8
single string of 15
Avg=802.6, ES=15.2, SD=4.1
This extreme velocity variation seemed unacceptable although it didn't result in really huge groups at 55 yards (see attached target scans for Steyr and Anschutz). These targets were shot separately after chronographed groups.
On the subsequent days I sought to adjust the regulator to get optimum balance between regulator pressure and striker force yielding a velocity of about 800 fps at 70 degrees and altitude of about 750 feet.
I took apart the gun, turned the regulator about 1.25 turns counterclockwise, reassembled and tested the gun. No air pressure -- just like dry firing. I turned the regulator a half turn clockwise and screwed the gun cylinder in -- it proceeded to dump the cylinder. I turned the regulator another 1/4 turn tighter (clockwise). The pressure held but when I fired the tank would start to dump until the gun was recocked. I turned the striker spring (not the regulator) tension 1/2 turn counter clockwise (looser) and this leaking stopped. I chronographed the gun --- 190 fps. Ughh. I turned the regulator another 1/4 turn clockwise and rechecked the speed -- 560 fps. I turned the regulator another 1/4 or 1/8 turn (not sure which) and the velocity went to 781 fps. I did a 10 shot test -- Avg 781, SD=2.3, ES=8.1. I increased the striker force by tightening the adjustment screw 1/4 turn -- 10 shot average = 785, SD=3.0, ES=10.0. I turned another 1/4 turn and got about the same speed with 3 shots. I took the gun apart and turned the regulator 1/4 turn, turned the striker back 1/2 turn and retested: 810, 811, 810 fps -- too fast. I turned the regulator back a little bit counter clockwise and retested: Average 802.4, SD=2.3, ES=7.2. Now I should have just stopped then, shot myself and died a happy man -- but nooooo!!! I had to fool around. I backed off the striker force 1/4 turn: avg=805.4, SD=3.6, ES=11.6. Then I backed off another 1/4 turn: average=781 for 3 shots. Stopped and turned the striker tension back 1/2 turn to what I hoped would get me to the 802.4 fps. But... the light was failing and the chronograph wouldn't read. Temp 64.2 F, Air Density 1.166 kg/mx3
Rained all day yesterday -- no testing.
Today May 28th.
Rechronographed the gun -- chronograph likes solid, even, cloudy skies. The temperature was 65 and air density was 1.165 kg/mx3.
String 1 (all 10 shots unless noted): 800.0, SD=2.6, ES=7.7
increased striker tension/force (turned clockwise) 1/8th turn
String 2: Avg=799.4, SD=5.9, ES=21.8
Striker force -1/8 turn
String 3: Avg=800.9, SD=3.2, ES=11.9
Striker force -1/8 turn
String 4: Avg 801.6, SD=3.8, ES=11.8
Refill and turn striker -1/16 turn
String 5: Avg=794.6, SD=3.6 ES=11.7
Turned striker force up 1/8 turn
String #6: Avg=797.3, SD=3.4, ES=13.1
Turned striker spring -1/16 turn counter clockwise
String #7: Avg=800.2, SD=2.6, ES=8.0
String #8: Avg=800.1, SD=2.4, ES=8.5 Now I am happy -- hope it stays that consistent.
A couple of notes: The regulator is in a block with the barrel and air cylinder screwed to the rest of the receiver with the trigger and striker (two separate pieces). This is good and bad. It makes it relatively easy to adjust the regulator (with large Torx driver) but it is not as solid as the one piece Steyr and other guns. My gun has a large aluminum scope rail that bridges and rigidly holds the front and rear halves of the gun. After tightening on the block with the regulator tightening the scope rail screws raises the point of impact about 10 clicks at 30 yards -- surprising.
Photos: 9015 May 24 This is a scan of a 55 yard target shot with the Anschutz 9015 when the velocity variation was the greatest. You can compare this to the Steyr target shot at the same time. The Steyr has much less velocity variation but the group size is fairly similar. For comparison there is another target from May 26th when the Anschutz was shooting at 802.6 with a SD of less than 3 fps. The group sizes at 55 yards are hardly any different. Its the pellets, idiot!? Next study... individual pellet BCs and weights vs target impact at 55 yards -- maybe we can prove if it is pellet variaion or weight that gives rise to large group size? Hard to find no wind conditions here.