Posted: 12/29/2016 8:46:01 AM EDT
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I have an FNH SPR rifle with an SWFA 5-20x SS scope mounted in Nightforce steel rings. I have noticed that when dry firing, the reticle will move downward on the target roughly .5 MOA upon breaking the trigger. Live fire results are vertical stringing usually all rounds touching.
What could cause this? |
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not loading the bipod enough and the minimal force of the firing pin is causing the rifle to push forward. (with every action there is a equal or opposed reaction) the firing pin being the action or force and when it stops abruptly that force wants to continue in the same direction.
The only other thing I think that could cause that is if your trigger has a lot of overtravel after the shot breaks which would also cause a slight jolt as your finger would accelerate to the rear when the sear breaks engaugement until it stops abruptly after the overtravel. Dry firing is very beneficial. your doing good catching this. you just have to figure out the mechanic's behind the fault and work them out. here's my flowchart of the firing sequence, Verify parallax, verify natural point of aim, bipod loading, pulling trigger directly to the rear, follow through after the shot break's. |
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It's exactly the same thing. Happens when shooting off a bag or off a bipod. I have the same scope on my REPR. Rock solid. Hammer drops, perfect follow thru. No reticle movement.
Amazed me. Perfect shift. Everytime the trigger breaks. Reticle drops .5 MOA on the target. As though something is loose. Everything is torqued. Action bolts are 65 inch pounds, ring nuts are 65 inch pounds, ring cap screws are 15 inch pounds. I plan to work on it today. |
| well in that case try playing the swap diagnostic's game. put the optic from your REPR on this rig, if the dip repeats then you know it's the rifle, if it doesn't try the optic on the REPR if it dips on it then no brainer, send it back for a replacement. does the trigger stop after the break or does it have a lot of overtravel? |
| Get a laser cartridge bore sighting tool. Aim it at a wall a decent distance away. Video the dot on the wall as you dry fire. Watch your video. Does the dot move? |