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Does the POI move as you use pressure?

June 3 2013 at 2:51 AM
Jay  (Login Kill_Zone)
YF


Response to Cure for mrod that did not group well.

I machined a bushing with a groove on the OD that uses the o-ring in the barrel band to retain the bushing. I rapped one layer of Teflon tape around the shroud tube to protect it from the bushing and to allow the shroud to slide axially to allow for changes of pressure in the tube and temperature changes.

Then I shot 5 string groups at 20 yds stating at 3000psi on different targets down to 2000psi. The idea was to see if the groups would move as the pressure in the reservoir dropped. As suspected, the groups moved as the pressure dropped. The groups moved about 3/4 of an inch vertically and 1/2 inch horizontally. I dont know how much of the drop is from changes in reservoir pressure and how much from change in velocity.

Has anyone else experienced this?


    
This message has been edited by Kill_Zone on Jun 3, 2013 2:59 AM


 
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