cautery Posted October 1, 2005 Share Posted October 1, 2005 (edited) OK... I just tried to zero my new Dawson (FO front/target rear) sights today on my G35... At 25 yards and the rear sight ALL the way down, POI is still about 5" above POA... and that's with a 6 o'clock hold... Add about 1.5" for center hold... At 15 yards it's only a couple of inches high... Now... I love the sights, though I had to relieve the inside corner after sacrificing two polo shirts this past weekend, and.. I could probably learn to use them as is... Hold low at 25, and 6 oclock at 15... Hell, at 50, they are probably on, who knows... I need to run the ballistics table... BUT, I don't like the idea of having zero rear sight authority left... Frankly, I'd LIKE to have the POI/POA at approximately the same place for center hold when the rear sight is NEAR mechanical zero (middle of click range)... So... if my geometry is correct... I need: 1) A somewhat taller front post... and the Dawson is already pretty stinkin' tall. 2) Somehow get the Dawson rear lower into the slide (melt it in... yikes) 3) Ditch the Dawson rear and get Bomars melted in... 4) Suck it up and drive on... Any suggestions? As an aside... Last night I dropped another $100+ on a spare set of Dawsons for my range box in case of probs at a match... Thanks, Edited October 1, 2005 by cautery Link to comment Share on other sites More sharing options...
ErikW Posted October 1, 2005 Share Posted October 1, 2005 Ditch the Dawson rear and put in the stock rear sight, backwards. But then your front sight will probably be too tall. Maybe try a Heinie rear. Don't rule out calling Dawson for help. Link to comment Share on other sites More sharing options...
cautery Posted October 1, 2005 Author Share Posted October 1, 2005 Thanks Eric... Already ditched the stock sight. Hate 'em. Yep... I just dropped Dawson a message. Wish I would have done so earlier in the day... Now it'll be Monday. If I didn't have to do without my pistol for so long, I'd send it in for the Bomars... I'll wait to see what Dawson says. I should probably slap my stock barrel in the gun and see if it might just happen to be a barrel fitment problem... Link to comment Share on other sites More sharing options...
DougCarden Posted October 1, 2005 Share Posted October 1, 2005 My Dawson sights for my 5in XD and G34 had the same problem..... Link to comment Share on other sites More sharing options...
eric nielsen Posted October 1, 2005 Share Posted October 1, 2005 They sold me a taller front sight too - a G35, hits too high. Maybe the guy who sighted in the original design was a 300-lb gorilla, many of us normal ppl can't get the POI down enough. They should just sell the "extra tall" as standard. Think it was less than $20 with shipping & all - that's if you already own a set. Link to comment Share on other sites More sharing options...
cautery Posted October 1, 2005 Author Share Posted October 1, 2005 So.... this is not an unknown occurrence then. Why... If you KNOW there is a problem like this would you not find a way to tell customers about it... or better yet make sure they get the right parts the first time... So, there is a taller version of the FO blade they sell for Glocks? Sure didn't see it on the website anywhere... I looked too. That's the other thing... It's not a particularly easy site on which to find specific items... Link to comment Share on other sites More sharing options...
eric nielsen Posted October 1, 2005 Share Posted October 1, 2005 You have to call them. It is what it is... Link to comment Share on other sites More sharing options...
cautery Posted October 1, 2005 Author Share Posted October 1, 2005 I will.... Sorry... didn't mean to gripe. Link to comment Share on other sites More sharing options...
atmar Posted October 1, 2005 Share Posted October 1, 2005 i also got dp's optic front target rear, maybe i was lucky cos the thing came with the extra tall FO eric mentioned, didnt have much of a problem zeroing it...this is OT, bear with me, my problem now is it wont fit the ipsc box, the DP rear is too much high profile. Link to comment Share on other sites More sharing options...
Kevin Kline Posted October 1, 2005 Share Posted October 1, 2005 Ive got WTS or Sevigny sights on all my Glocks and couldnt be happier. Link to comment Share on other sites More sharing options...
cautery Posted October 1, 2005 Author Share Posted October 1, 2005 OK, I found the page with the Glock site height options: http://www3.mailordercentral.com/shootings...aitem=4&mitem=5 Here's the new wrinkle... I HAVE the 0.285" front post already... So, I'm taking my pistol apart to clean it... Looking at barrel.... Hmmm... How would you go about lowering POI by modding barrel.... Looks like a simple stone job on the top flat in front of the chamber block... Run finger down barrel to chamber block.... A DEFINITE step there... Measure it... At least 0.006" and more like 0.012" K... do math: assuming minimum 0.006"; a 5.312" barrel; Let "X" be the POI change at 25 yards; and using a little trig. and geometry voodoo: Pivot Angle(P) = arctan(0.006"/5.3125") = 0.06471050 degrees X=900" tan P = 900"(0.00112941) = 1.01647059 = 1.016" So, I can drop the POI a minimum of 1" if I stone the slide contact face. Might get 2". OK, that helps.... Still would have 3" to go and still no additional sight authority. Link to comment Share on other sites More sharing options...
AustinMike Posted October 1, 2005 Share Posted October 1, 2005 This must be a problem with the longer slide Glocks? I just put Dawson front and rear sights on my Glock 22 and had no trouble getting dialed in. I've got my rear sight raised a touch, but then again I like to aim at a 6 o'clock position, at least at targets 10 yards out or more. Link to comment Share on other sites More sharing options...
cautery Posted October 1, 2005 Author Share Posted October 1, 2005 It would appear so... I have only found G34 and G35 instances for the most part... Can't imagine why frankly... I'm going to keep at it though... Too bad Dawson is closed on the weekends... Link to comment Share on other sites More sharing options...
AustinMike Posted October 1, 2005 Share Posted October 1, 2005 Heh, I'm too mathematically challenged to even venture a guess as to why a little extra barrel/slide length would make such a big difference. I'm sure there's a good scientific explanation, but somebody else will have to do it. Link to comment Share on other sites More sharing options...
Nik Habicht Posted October 2, 2005 Share Posted October 2, 2005 Clay, got a stock barrel? Might give that a try. The cool thing about glocks is they run in virtually any configuration, because the tolerances appear to be pretty loose. The bad thing about Glocks is, every once in a while you get a combination of loose tolerance parts that combined does something funky...... You're sure the slide isn't cracked, right? (Just drawing on stuff I've seen over the years...) Link to comment Share on other sites More sharing options...
cautery Posted October 2, 2005 Author Share Posted October 2, 2005 AustinMike - Couple of things going on here actually... First, let me address the barrel fitment deal I briefly touched on above. The first time I reasoned out the Tangent formula was back when I was playing with my G22 and first started playing around with barrel chamber design. I was trying to find a way to make sure the barrel was laterally stable at lockup and found that in a G22 a mere 0.006" of lateral pivot can make a significant difference in POI from round to round. Without going into that in any depth, suffice to say that the same trig/geo. formula works in the vertical plane too... BUT, in a G35, the magnitude of the POI change is LESS per given change in vertical pivot due to the nature of the Tangent function (opposite over adjacent). The opposite measurement in this case is the vertical displacement/variance. The adjacent measurement is the barrel length, thus a LONGER barrel reduces the tangent value of the displacement angle, thus reducing the resulting angle... Smaller angle equals smaller POI delta downrange... On this specific barrel, the top flat face that locates the barrel vertically in the slide at lockup (in battery) is slightly above the plane of the top of the barrel tube proper. By examining the metal wear pattern on this face and the barrel hood face, it APPEARS that the barrelis slightly tilted up when in battery, thus moving the POI up for a given POA. Milling this face down should make the lie closer to the same plane as the slide, thus bringing the POI/POA closer together. NOW... as to why longer slide Glocks manifest this behavior in the first place, I am not completely sure... The only difference is the sight radius. I suspect that REALLY all that is happening is that the longer sight radius is magnifying a condition that exists already in the sight pairing to begin with... I'd have to draw/graph it out to know for sure. Link to comment Share on other sites More sharing options...
cautery Posted October 2, 2005 Author Share Posted October 2, 2005 (edited) Yep... still have the stock barrel... Plan to compare them on the next trip to the range. Yep, the wrong combination of "loose' tolerances can make a huge difference... I'm still toying around with various ideas to mitigate/fix the tolerance issue on the external barrel dimensions and the the barrel to slide fitment. I'm pretty stinckin' sure the slide is OK... The weapon only has about 1000 rounds through it, and I've examined it very closely... I'm gonna "play" with it some more this afternoon. Maybe I'll have time to jig it up and check various dimensions for consistency et al. Clay,got a stock barrel? Might give that a try. The cool thing about glocks is they run in virtually any configuration, because the tolerances appear to be pretty loose. The bad thing about Glocks is, every once in a while you get a combination of loose tolerance parts that combined does something funky...... You're sure the slide isn't cracked, right? (Just drawing on stuff I've seen over the years...) <{POST_SNAPBACK}> Edited October 2, 2005 by cautery Link to comment Share on other sites More sharing options...
AustinMike Posted October 2, 2005 Share Posted October 2, 2005 Interesting stuff, Clay. Keep us posted on your findings. I'm curious to know what the guys at Dawson will have to say. Link to comment Share on other sites More sharing options...
carinab Posted October 2, 2005 Share Posted October 2, 2005 Hey Clay...I ran a set of MMC's on my Glock 24 when I was shooting it. I had a custom FO front (in other words Ashley grooved the top of the front site) and I super glued an archery fiber optic in the groove. I ended up going back to a black silohette though. Here's MMC's website. If you can wait until the NTSC, I can bring some of my old glock rear sights (MMC, Arotek, etc) and you can try them out to see if any of them will fix your problem. Link to comment Share on other sites More sharing options...
cautery Posted October 2, 2005 Author Share Posted October 2, 2005 Carina, That'd be great... I'd love to take a look at whatever you have... Thanks! Link to comment Share on other sites More sharing options...
cautery Posted October 3, 2005 Author Share Posted October 3, 2005 Just got off the phone with Dawson... They esponded that they have literally "thousands" of these sights in the field, but a small number of folks DO have this problem... Not ON the site, but they DO have a 0.300" front blade that they can send out... They are sending me one to replace my first blade along with swapping out to a long blade in the backup set I just ordered Friday... I'm going to try this out and see what I think about it... If it fixes the problem, I don't THINK the exta 0.015" will bother me. But I'm gonna try out whatever carins has in her goody bag as well... I may have to fall back and punt, and send my slide off to have a melted Bomar put in on the rear... I'm not SURE I am completely sold on the front fiber optic yet... So far, I like it, but I might back up to a target front too... Maybe in a 0.090" over length and cut it down to get the rear sight closer to the mechanical middle... In any event... first order of biz, is to get a good zero for the North Txas Sectional. Thanks all... Link to comment Share on other sites More sharing options...
madone Posted October 3, 2005 Share Posted October 3, 2005 cautery, please keep us posted as to what you find out. I just ordered the DP optic front/Target rear for my 34..fingers crossed Link to comment Share on other sites More sharing options...
eric nielsen Posted October 3, 2005 Share Posted October 3, 2005 I was hoping they would swap out the standard-height FS that you hadn't even put in a gun yet, that's good. I also think you're right about the height problem being masked on the shorter guns. I see it often on the stuff I calibrate at work - things that measure very nice at 1/10th scale and even 1/2 scale, then they fall out of tolerance at full scale. I didn't like the Dawson sight at first but now I wish I had them all along. 2 years worth of shooting a modified factory sight spoiled me in one respect, which was that you could only SEE the sights if they were already lined up well enough to make a 15-yard shot. There was almost no daylight on the sides of the FS and very low height above the slide. A lot of the time I spent looking for the factory sights was actually wasted time compared to Dawson's sights that allow you to blaze away more and just call the shots that aren't good enough. Should've made up more shots that I could see were bad, just wasn't used to it yet. I called all the "bad" shots [four] that I missed at Area 6, just hadn't trained myself to make them up. Link to comment Share on other sites More sharing options...
cautery Posted October 3, 2005 Author Share Posted October 3, 2005 (edited) madone... Will do... I'm going to do some testing as soon as the sights get here... Check the stock barrel in the pistol as it is now, and then switch to the .300" front blade if necessary... I'm not going to stone my stainless barrel until I know more... Eric - Dawson folks are good people as far as I can tell... I offered to pay for the replacement blade for the first set of sights, but they said no.... of course. So... I bought 5 new mag springs from them to add to the backup sights... I've only used the Dawsons for about 1000 rounds, but I DO really, really like them... I'd like to hang onto them if I can make it all work out right... But, I still have to run the zero out to 50+ as soon as I fix the problem in close... I'm not going to get caught short on the next long distance standards stage. I've not COMPLETELY nailed down the short slide vs. long slide reasoning/reality as to why the POI thing happens, but I will... And hopefully, I can come up with some additional options. I REALLY need the rest of my tools and instruments form storage... They sure would come in handy about now. Edited October 3, 2005 by cautery Link to comment Share on other sites More sharing options...
cautery Posted October 6, 2005 Author Share Posted October 6, 2005 Got the Dawson sights in today with the 0.300" front blade (optic). I think I am just going to put the 0.300" blade on and re-zero... Then conpare the stock barrel to see the diff in POI... Headed to the range tomorrow... I think. Link to comment Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now