Late 580-series and newer w/ thick,
tapered 5/8" barrel
Average of five 5-shot groups.
Ammo: Federal 50 grain BTHP (jacketed hollow-point).
Average group size: 2.4" (std dev
Comments: New barrel
does show an improvement over the older skinnier barrel.
Average group size: 1.6" (std dev
Comments: The Accu-strut
has reduced group size by about 33%. Less dramatic change than with the
old barrel, but still significant improvement.
This is about the maximum
improvement generally seen, in some cases change is much less. We're hearing of
results anywhere in the range of 0-33% with the new thicker barrel.