BAR­REL SWAP?

Airgun World - - Points Of You -

Ques­tion for Jim: If an air­gun de­liv­er­ing 11.5 ft.lbs. in .22 has the bar­rel changed to .177, does this al­ter the ft.lbs. out­put? A sim­ple ques­tion, but I bet not a sim­ple an­swer. Al­ready look­ing for­ward to the next is­sue of Air­gun World. GRA­HAM WIL­LIS

Jim’s re­ply: Com­par­ing like for like – test­ing with sim­i­lar pel­lets – chang­ing the cal­i­bre from .22 to .177 most cer­tainly will have an ef­fect on muz­zle en­ergy. It will re­duce it, be­cause the .22 is in­her­ently more en­ergy ef­fi­cient. The ex­act amount by which the en­ergy will re­duce de­pends on the type of ri­fle (PCP or spring) and, in the lat­ter case, on the spec­i­fi­ca­tions of the ri­fle; pis­ton stroke, cylin­der di­am­e­ter, spring en­ergy and preload, seal type, trans­fer port di­men­sions and lost vol­ume. In the case of the 11.5 ft. lbs. .22, the muz­zle en­ergy drop might be in the gen­eral or­der of a foot pound or two. The only way to be cer­tain is try it and see. - Jim Tyler

Jim says swap­ping bar­rels from .22 to .177 will drop the air­gun’s muz­zle en­ergy.

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