I read an old post where the POI shift in the Impact cold be because the loose tolerance between the liner an the tension sleeve at the end of the barrel allowing it to move around because of barrel whip. Hum.... made sense to me. In fact I was surprised after checking mine and found that there was considerable difference between OD of barrel liner and ID of tension sleeve , approximately .005" The fix that was recommended was to wrap the end of the liner with Teflon tape or box tape to take up the difference. So I tried both methods and for a few shots it worked well then The POI shifts started to return. Pellets started to move all around again. This result was the same for all projectiles. Fresh tape, good groups then things went to hell again. I have owned my M3, 25cal since January 2022. I have owned the 1st, 2nd and 3 generation (M3) Impact. I have struggled with POI shift in all 3. The worst being the M3. I have shot approximately 15 tins of FX 34 grains.10 tins of 25.39 grains and 8 boxes of NSA slugs using both superior and superior heavy liners with CF sleeves. I ran speeds for 800 FPS to 1005 FPS and different reg pressures to valve combination. I was able to achieve ES 5, SD 1.7 within the various projectiles. The POI shift was as much 1.5 to 2 inches at 100 yards and 1 inch at 50yds. I believed the material used began to compress after a 100 or so shots allowing the barrel to shift around again. So i decided to cut a piece of .002 feeler gauge to the proper length, curl it around a pencil and insert it into the sleeve at the farthest point. I lightly sanded the edge to remove any lip created by the scissors. I installed the sleeve with just a slight amount of pressure against the liner. I went to one of my previous tunes for the 34 gr MK11 @ 930 fps, SD 2.5, ES 5,1st reg @ 130, 2nd reg @105, mic @ 11, mic wheel was recalibrated to 3 and 8 respectively then turned to 11, valve wide open. Now 50 yard groups are one slightly ragged hole and 100 yard groups are one ragged hole to 3/4" in calm conditions (Texas). This has remained consistent for a week now. I shoot about 3 mags a day. The NSA 29.5 @ 970fps and the 26.8 @ 1005fps showed the best results before POI shift started again. I will be ordering more and try again If my luck holds with the 34's. the only aftermarket part I have is the Saber Tactical TRS rail and a home made bag rider. I was already starting to look at Daystate for my next gun, LOL https://www.airgunnation.com/topic/point-of-impact-shift-fix-for-fx-impact-and-crown-and-others/
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