I'm going to chime in here with a few questions. While a sling attached to the bbl can, in theory cause a shift of shots depending on the pressure exerted use of a sling definately improves accruacy.
So my question is what will the weapon be used for and how will it be used?
Are we talking competition here where you are all tucked in, with jacket, competition sling slung on you arm? Or are we talking about a hasty sling used in field work to take game?
I've got a Ching Sling on my AR. While it is a competition model I don't shot competition. Mostly I just paper punch for pleasure and use it as a expediant varmint slayer. It has all the accuracy I need for this work even using the Ching Sling.
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Schmit, GySgt, USMC(Ret)
NRA Life, Lodge 1201-UOSSS
"Si vis Pacem Para Bellum"