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Rear Sight Adjustment for Sig Sauer P938 Question

10K views 5 replies 4 participants last post by  Ibmikey 
#1 ·
My P938 is sighted a bit off, though it's otherwise quite an amazing gun. I'd like to move the rear sight to the left about 1/2 mm to zero it horizontally, but I'm not about to pay what the stores are asking for such a trivial tool. I stopped by Tractor Supply today and picked up a length of brass rod stock, with the intention of making a punch of it. This is what I'd normally use when driving steel components, since the brass cannot mar the steel.

But I'm not sure abut the finish on the sight or the gun. Both are a black matte finish, and I'm not certain of the hardness of the coatings Sig uses compared to brass. Can anyone enlighten me about this?
 
#2 ·
I guess no one here knew from experience the answer to my query, so I cautiously clamped the slide in a plastic-padded vise, cut about a 4" piece of rod from the brass stock I bought, polished the end of the rod smooth, and gave the rear sight a couple of light whacks powered by a 24 oz ball peen hammer.

No damage at all, the finish must be harder than brass. And best of all, my sight picture is now nicely aligned with the laser dot from the boresighting tool. There's a tiny elevation difference, but I'd have to get used to that anyway. I'm off to the range after work tonight to check my handiwork, but I don't think I can blame any misses on the gun anymore.
 
#4 ·
Take the hammer and punch with you to the range. You may need to touch up your adjustment. In my experience the bore sighting laser is not necessarily where the bullet will strike. But as a first try it is better than nothing.

What I find better is to do it at the range with the punch and hammer.

Sometimes I do it at home with the target that shows the misalignment. I measure the target error and with some math move the sight the required distance. The formula is:

(Bullet strike error on the target in inches) times (the gun sight radius in inches) divided by (the range in inches) equals (the correction to the rear sighting inches).

But nothing is better than actually shooting and correcting at the range.

LDBennett
 
#5 ·
Well, I managed to get bullets on target this time, so the sight adjustment is much better. But maintaining any kind of grouping at 10 yds isn't working out. I need to get a lot more practice in using this short barrel, and possibly stiffen up my grip. The nearly maximum load I'm using works great in a full size 9mm, but may be the wrong match for this little one, so I'll play with that some, as well. Thanks for the formula, LD; you saved me a bit of math with that.:D
 
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