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Recently I swapped from a 20 to a 22 barrel. My zero ended up 10 low at 100 yards. I know all barrels are different but I wouldnt think it would have been so low. I pulled the scope and mount when I did the swap. I zeroed it again day of break in but I went ahead and pulled it and re-torqued the mount and scope anyway when I got home. Any thoughts on this? I have not shot since but will this coming week. Is it barrel harmonics being different? I could see it being high but not so low. I have 22 moa of adjustment left in the scope (Vortex Diamondback Tactical 4-12 and Aero Precision Mount). Barrel is a JP 22 and I bedded it for the first time Ive ever tried it. Shoots tight groups.
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I will add that I was shooting with a bird cage on and now in just using a thread protector. Could that have changed anything?
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Just swapping the barrel could account for that. Diffrent barrel with a diffrent degree of forces acting on the bullet.
The muzzle device change can effect point of impact as well.
I wouldn't worrie about it. Just shoot it and enjoy it and wait to clean the barrel till you have 200 to 300 rounds down pipe, then clean it real good and go do a nice slow firw, cold bore sight in.
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JTB,
That is a big change on the target. Lots of things can account for a change between barrels but for such a large change it's probably down to the direction of the barrel relative to the shoulder on the barrel extension. Unfortunately you can't spin that barrel 180degrees and fire some more groups to see how big, if any, an angle exists between the barrel and line of sight.
I say "if any" because it may not be a fault of the new barrel. Your previous barrel might have the angle, and printing 10" low is where it should be.
I agree with A5, I wouldn't worry about it unless things go wrong down range.
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Thanks for the replies A5 and Klem you guys are great. I was thinking this would in the advice given. She shoots fine and I had been trying not to let it bother me but I finally had to ask. Klem your right it may have been in that last barrel. Receiver is lapped and I bedded with 620. Its solid and all my groups were acceptable with the best being .68 with my hand loads and the worst 1.25. Thats prone cause I dont have a bench yet. I will let it ride. A5 I will take your advice on cleaning cause I know you have experience with JP. I hear they dont like being cleaned often. I love this rifle. Shoots a lot better than me. Thanks again guys.
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That 1.25 was with factory hornady black ammo but that ammo was 3/4 for most 5 shot groups.
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Every time I swap out a barrel, I have to rezero the scope.Not sure if its 10 inches. Sometimes its just a a few clicks. Other times I have to turn the turret quite a bit. As the other guys stated.I wouldnt worry unless I have problems down range.
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My point of impact dropped 5" on the same barrel (a 5.56 upper) just by swapping from a brake to a thread protector. I could certainly understand a change when swapping barrels. Different harmonics.
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SDW Wrote:My point of impact dropped 5" on the same barrel (a 5.56 upper) just by swapping from a brake to a thread protector. I could certainly understand a change when swapping barrels. Different harmonics.
That has to be what it is. It struck me as odd. I had to walk down to my target to make what I was seeing was right. Im going to let it ride. Thanks for the response. I have wondered about effects from different brakes.
