That picture is from a couple years ago.
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It has had more soot and lead on the bell now than you would believe, finish is screwed, but the glass is perfect - all I care about. Like GB said, moving back would cause big problems. I have seen guys move them back and put on sun shades to deal with the gas problem, but this has been working fine for me.
Oh, I just got the 1/4" part... Lone star, it's ported, if you see the cutouts in the barrel. I would have to move it back 2" to miss the blast on the bell, and then my glass would be completely screwed in a cylinder full or less.
I would have to do the sunshade thing, or put a cantilever mount on (which would look rediculous because I would have to mount it like 5" back to save it), or a red dot if I didnt have it set as I do.
Hey krooz, was wondering, after your 9 shot group... where did the last three of the two cylinders full go, don't tell me you stopped before you were empty... I know I can't.
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3.5" at 50 is plenty good for killin stuff. In my .454 I am loading some 300grn LFNGC over XX of IMR4227 (xx think WAY over max, but worked up safely for MY gun) and am happy to be getting just over 4" at best one cylinder groups at 50 with it.