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Rear Sight Height Checker

Posted: Tue Feb 03, 2015 3:29 am
by jmoore
Measuring the sight settings on S&W revolvers has always been a pain for me, so started to cobble up this business out of a bit of plastic block and an old depth micrometer:

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Hope to try it out soon. Weather hasn't been cooperating lately! Rain, wind or both every time a range opportunity has come along lately. Not worried about wind deflection on bullets, more on the shooter.

Re: Rear Sight Height Checker

Posted: Tue Feb 03, 2015 7:25 am
by borregos
Good idea, I struggled at the weekend trying to figure out the rear sight on my T/C 7mmTCU (T/C silhouette type) but you have given me an idea now :)

Re: Rear Sight Height Checker

Posted: Tue Feb 03, 2015 2:13 pm
by 260 Striker
Great idea. I think you may be surprised when you check the variance between clicks. Some screws have stamped indentations that are of unequal length. Some sight screws have notches on the edges and tend to be more accurate since the up/down is then controlled by the pitch of the threads and not the notches. Another suggestion would be to mount a dial indicator on the block to rest against the sight blade. If you have a hole in your block you could then use a screwdriver to move the sight while watching the dial indicator. You may have come up with a good tool.

Re: Rear Sight Height Checker

Posted: Wed Feb 04, 2015 2:59 am
by jmoore
Was pondering the possibility of an adjusting hole earlier with a friend. Could burn a hole through the depth gage base, but I think it'll be an option left for the Mk2 version. First need to find out how useful at the range and or match it's going to be. Given that it'll be a new revolver, new ammo, and the new tool all at the same time, I reckon things will be messy for a bit!

BTW, it will be interesting to see how much elevation is changed with corrections to windage. S&Ws seem particularly prone to "wobbly" adjustment screws.

Re: Rear Sight Height Checker

Posted: Thu Feb 12, 2015 12:47 am
by jmoore
Some quick photos of the Mk. I* version. Added a sliding screwdriver guide for "on the gun" adjustments. Hence the offset plate on the indicator stem.:

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Seems to repeat well as far as removing and replacing the unit.

Re: Rear Sight Height Checker

Posted: Thu Feb 12, 2015 1:12 pm
by Richard Pickering
Necessity begets Invention. also; Being satisfied with the present never advanced any cause. Good for you Jonathan. RP

Re: Rear Sight Height Checker

Posted: Thu Feb 12, 2015 3:43 pm
by 260 Striker
Looks like you could get very accurate readings with that setup. Let us know what variances you get between clicks. That might be of some help to other S&W shooters. I always wondered if adjustments are the same when the sight is just moving off bottom versus say 10 or 12 clicks off bottom. I'm sure you will probably figure out a way to adapt that setup to other iron sighted guns. Good job.

Re: Rear Sight Height Checker

Posted: Fri Feb 13, 2015 3:00 am
by jmoore
Thanks for the support, y'all!
260 Striker wrote:Looks like you could get very accurate readings with that setup. Let us know what variances you get between clicks. That might be of some help to other S&W shooters. I always wondered if adjustments are the same when the sight is just moving off bottom versus say 10 or 12 clicks off bottom. I'm sure you will probably figure out a way to adapt that setup to other iron sighted guns. Good job.
One "fun" thing about S&W revolver sights is they also have a tendency to change elevation slightly with windage changes. Often the windage screw will either be bent or just not be concentric to it's axis of rotation. Won't matter much to those shooting 25yds or closer, but can be a big bother further out! Never mind the occasional blade cant induced by turning the W screw...

Was going to range test it today, but 18 degree weather makes for lousy testing conditions, a least for me.

Thinking o-ring retention for the elevation screw gizzy will work. Had thought a single ring internal, but there may be room to do a top and bottom ring. The bottom being the question at this point. Allowing a bit of play will make using the unit a bit easier. Less need for perfect fore-aft alignment on various revolvers. Also easily upgraded if it doesn't work out as expected...Have only tried this on the one revolver so far.