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Old January 25, 2001, 01:17 PM   #1
HKUSP45C
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Hi
I posted this on the semi auto handguns forum with only one reply. I also posted this on the HK-L with no anwser. So I am going to try here.

I notice that my front sight on my USP45c is a little bit off center to the left. (very little, about half a mm but still noticible.) My concern is, does anyone notice the same on yours? Do they come off center out of the box for a reason or is it just mines that is like that? My skills are not good enough to go to the range to see if this slightly off centered sight matters but I am picky. I just want to be zeroed at 25 m though I can't shoot well that far. Can someone please help? I asked this same question on the HK-L three times and no one was able to give me even one response. I hope someone can help me here. Its been bothering me for a few days now.
ST
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Old January 27, 2001, 10:09 AM   #2
gyp_c2
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Have you tried shootin' it yet?
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Old January 27, 2001, 02:36 PM   #3
HKUSP45C
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No, not yet.
I don't think I shoot well enough to tell if a little smidge to the left matters. Its just that I am pickiy about things being the way they should be.

st
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Old January 27, 2001, 02:49 PM   #4
HKUSP45C
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No, not yet.
I don't think I shoot well enough to tell if a little smidge to the left matters. Its just that I am pickiy about things being the way they should be.

st
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Old January 27, 2001, 04:32 PM   #5
CoastieN70
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SHOOT IT! Every weapon is different. Some times it is necessary for the front sight to be adjusted ever so slightly to keep from having to move the back sight radically.

Shoot it and see where YOU hit. If it shoots where YOU aim then you have no problem. If it doesn't, have someone else try it. If you determine it's off, call HK, it's guarenteed.

Bottom line, untill you determine there is something wrong, don't worry.

BTW: A smidge adjustment to the front sight if not necessary is very noticable when shooting so you will determine quickly if it's off.
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Old January 28, 2001, 06:09 PM   #6
Scooter2
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If it shoots straight, don't worry about it. If it still bothers you, take a mallet and a brass or delrin rod and tap the front sight till it's centered. You might have to adjust the rear sights to re-zero that gun. It doesn't really matter where the front sight is, as long as the relationship between the front and the rear are right.

Your simply worrying too much. The front sight of my HK P7M8 is 0.020" off and it's also pinned to the slide. The slide also has a few thousandth of play relative to the barrel/frame. It's not something to lose sleep over. After all, this is a pistol, not a benchrest rifle.

Besides, no pistol is perfect. If you build the perfect pistol with tolereances that NASA would be envious, it would be perfect until you rack the slide and wear down the contact points.

If the sight worries you, I can tell you everything wrong about your gun or any other gun ever built.
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Old January 28, 2001, 09:47 PM   #7
HKUSP45C
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Yup, shot it today. Well, from about 7 - 10 yards, it shoots to the point of aim. Don't know if that would change at 25 yards. Groups didn't seem to go the right. I guess its fine. Thanks all for the comments and advice.
Got a question though. Lets say that my sights are off. How much difference will 1 mm off center to left frnt sight affect groups at say, 10yds? 25yds?
ST
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Old January 29, 2001, 11:08 AM   #8
Scooter2
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HKUSP45C, I don't know what the sight radius is on a compact, but I did the calculation off my fullsize USP45. You have to remember that it is the relationship between the front and rear sights that matters. Let just say that the gun is zeroed at 25 yards with the front sight being offset. If the front sight is 1 mm off, the rear sight would be offset a tad more than 1 mm to keep the zero. So doing some simple trig, with a zero at 25 yards and the front sight being 1 mm offset, at 10 yards, your groups will be 0.024" offset or roughly 0.6 mm.

Now, that's assuming that the gun is zeroed at 25 yards, which it is from the factory. If we take a look at the other situation. The front sight if 1 mm off, but the rear sight is dead centered relative to the barrel. At 10 yards, the POI will be 1.125" off, at 25 yards 17.67" off.

If your gun is the latter case, you shouldn't be able to hit anything at 25 yards unless you're a really, really bad shot.

Since you shot POA at 7-10 yards it's not the second case.
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Old January 30, 2001, 01:26 PM   #9
HKUSP45C
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Cool!
Thanks Scooter. Whoa, 17" off is alot.
I took a little more measuring. My rear sights are dead centered while the front is almost exactly 1 mm to the left. The sight radius on my USPc is 5 3/4".
Scooter, can you help me do some calcualtions with the above info with the new sight radius? I really (x5) suck at Trig.
Actually, I don't even remember anything about Trig. Oh well, I am a marketing major and accounting minor so I am not going to need too much of it. But now I wish I did so I can have fun with ballistics.
ST
But no, I am not going to take Trig again.
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Old January 31, 2001, 02:27 AM   #10
Scooter2
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It appears that I'm not that good either. My numbers for the second set is way off. I've no clue what I did.

Here's the numbers for the 5.75" sight radius. 2.5" at 10 yards and 6.26" at 25 yards. With a fullsize USP45, it is 2.25" and 5.63" respectively.

You still have to take into account that we really don't know where the barrel is pointing relative to the slide.
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Old January 31, 2001, 03:43 AM   #11
HKUSP45C
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Thanks for the math help. What you just did would of taken me about a decade to figure out. 2.5" off @ 10yds is a sigh of relief for me because @ 10yds, I shot to POA. If it was 2.5" off, I would of caught it for sure. Yeah, I was freaking for nothing. I guess I can conclude that my gun is zeroed.
Thanks everybody for your contributions. You all have been a great help.
ST
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