.257 POI Shifts while shooting
Hi all, Asked on the GTA forum too. Have 2 .257 rifles. Randy built first in Feb with Ultima stock. I built with my gunsmith doing machining on one pictured here…..This one has TJ bbl 34″, carbon sleeved, HATSAN airstripper, 105 gram brass hammer, dyotat valve and one piece stem, also have his spring but used a tad heavier one on there now. Maddog BENCHREST STOCK, 4′ aluminum machined one piece barrel bushing. Can shoot 1/2 moa and then throw shots high, low and right left, Have to use another mil dot for awhile and then it goes back to same mil dot for same POI??? I didn’t chrono these but records shot with PW 0 and 3200 psi, shooting 72 gr fp at 1000-1010 fps..All screws blue locktite and are not loose. have tried 3 scopes and same thing….Try hard hold and free recoil and in between…………i have 4 molds. these were the 257420 . Have tried Porters bullets, and now mikes from Randy and all will shoot a good group or 2 then spread out 2-4 inches at 100 yds? Have hit rock size of mop bucket at lasered 460 yds…….If it shifts like that indicates to me something moving or loose but all seems tight to me? Bottom 2 groups were yesterday at 220 yds.. Help any IDEAS?
Thanks…………Carl
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That tiny allen hex head screw is so tight i am afraid to strip out the hex??? Lay the heat gun on it and that thing is held by some epoxy or something???? I have thought of it but didn’t do it yet as didn’t want to ruin the stripper or ruin the hex head ……as it CAN be moved in and out somewhat…I doubt that is the cause of the erratic grouping but anything is possible.May take to my gunsmith to loosen that screw??…………Thanks for your input……….Carl
Does the stripper allow you to fiddle with the cone distance from the muzzle? i.e. can you move the cone closer/further away from the muzzle. Maybe you can try that?
I shot it for 3 weeks with stripper on…………..Took it off Sunday for a string and notiecably larger groups…Like 6 inches? Thanks for replying…Carl
Thanks……..It CAN shoot fantastic but why it then moves all over the place …..my first Randy built gun in FEB all the screws came loose..Dyotat explained i HAD to locktite them……….BEST groups are better but still wanders….? Thanks for the reply and reading..I with my gunsmith will get it? Maybe have to have another bushing at end of the frame…As is free floating from front of 4″ bushing to end of 34″ bbl???
How does it do without the air stripper ❓
impressive gun brother, Doug at MD talked about this gun to me, sorry i have no suggestions, still awesome groups at 220yds, maybe wind??
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You’d be surprised… I’ve seen (posts online) strippers of that design affect accuracy on Theobens, and on bench guns- Mac1 sells a stripper similar, and uses the same idea (moving cone) for Mrods. No reason it wouldnt work on a .257. I hope you get to see!! I’m wary of small allen screws as well. I’ll be having a muzzle brake similarly made down the road.
Not my design (It’s a 220swift creation, for a Rapid), but I’ll have one similar to it… Adjustable cone:
