trodrig Posted October 1, 2007 Share Posted October 1, 2007 When filling in the spreadsheet to calibrate my micrometer for SR7625 I got up to a setting of "4.00" and the case was overflowing with powder (>10.4grains) and therefore I didn't go any higher. Do y'all modify the equations for slope, y-intercept, etc. in the spreadsheet to only work with the range of cells you've filled in? If I don't do this, I get really bogus readings under the "Micrometer Setting Calculator". Thanks! Trodrig Link to comment Share on other sites More sharing options...
Bronson7 Posted October 3, 2007 Share Posted October 3, 2007 When filling in the spreadsheet to calibrate my micrometer for SR7625 I got up to a setting of "4.00" and the case was overflowing with powder (>10.4grains) and therefore I didn't go any higher. Do y'all modify the equations for slope, y-intercept, etc. in the spreadsheet to only work with the range of cells you've filled in? If I don't do this, I get really bogus readings under the "Micrometer Setting Calculator". Thanks! Trodrig Trodrig, maybe I'm not understanding your problem. Why would you want to get to the point, and beyond, of overflowing powder. I didn't modify anything for mine. I just followed the directions. I did use more weigh points. I went over max charges for each powder I was using, but nothing close to flowing over. If you're using the same powder for several calibers, just pick the largest case. I used the spread sheet as instructed (had to convert it to Open Office as I don't have Excel). You might want to give UniqueTec a call. I think you're doing something incorrectly. Good luck. Bronson7 Link to comment Share on other sites More sharing options...
trodrig Posted October 3, 2007 Author Share Posted October 3, 2007 Thanks Bronson7! Sorry, let me give a few more details. The spreadsheet has space for micrometer settings all the way up to 7.50 which is max on the micrometer. However, I can't go above about 10 grains of SR7625 and my super comp brass is overflowing. So, I only weighed powder charges up to a micrometer setting of 4.00 in 0.25 increments on the micrometer. This got me a max weight that was far greater than where I think I'll need to operate in so I thought this would be fine. However, if I enter this data into the sheet and do not delete the cells greater than a micrometer setting of 4.00 from the equations, the calculator box on the right does not give reasonable micrometer settings for powder charge weights within my range. For example, let's say I want 5 grains. From measured data, a micrometer setting of 1.25 gave me 4.8grains and 1.50 gave me 5.3grains. However, with all the data entered (up to a max setting of 4.00), the calculator says I need a micrometer setting of 2.86 which is way higher than 5 grains. I'm assuming this is due to a lot of 0's being taken into the equations but I haven't gone through the math yet to prove this to myself. Am I doing something really boneheaded here?? Thanks! Trodrig Link to comment Share on other sites More sharing options...
XRe Posted October 3, 2007 Share Posted October 3, 2007 (edited) You can do a couple of things, actually. A Super-ish case isn't going to hold more than you get on a setting of 3.something. I used a .40 case, set on top of the shell plate to activate the powder drop and catch the charge. I could go all the way to 5.00.... The past two times I've changed lots of powder, I just threw charges at 0.00, 1.00, 2.00, and 3.00, and then figure the slope by hand - typically I end up at .1gr per .05 movement for 7625 - that gets me close enough to dial in close to the charge, and then tweak until I find the right weight. ETA - even w/ the spreadsheet, you've got to double check the charge on a scale, so... I think the spreadsheet expects you to have data for 5.00 to work properly, so.... without that, it isn't going to work correctly. Interestingly, it looks like you have the same delta per tenth that I do... .05 on the micrometer equals roughly .1gr.... So, dial in 1.35 and weigh that Edited October 3, 2007 by XRe Link to comment Share on other sites More sharing options...
trodrig Posted October 3, 2007 Author Share Posted October 3, 2007 Thanks for the reply Dave! The spreadsheet is off even on charges that I do have data for which is what has me stumped. From my measured data 5 grains should be a setting of around 1.3. However, the calculator says 2.86 unless I remove 4.25 through 7.50 from the equations. After removing 4.25 through 7.5 I get a much closer 1.36 from the calculator. Like you said though, the charges have to be verified with a scale anyway when changing so I guess I'm not going to worry too much about it. I'll have a good starting point and can dial in from there! Spreadsheet or no this is MUCH better than the stock adjustment screw!! Thanks! Trodrig Link to comment Share on other sites More sharing options...
Ming the Merciless Posted October 3, 2007 Share Posted October 3, 2007 (edited) I've always just done like Xre and measured at 0.0, 1.00, 2.00, & 3.00, then entered the values in a blanked copy of the spreadsheet, then saved that spreadsheet with the name of the powder. If I want to load 8.5 grains of SR7625 I enter that in the calc space and Bingo it comes out as 2.60 Edited to correct for faulty memory Edited to correct for VERY faulty memory Edited October 4, 2007 by Ming the Merciless Link to comment Share on other sites More sharing options...
XRe Posted October 4, 2007 Share Posted October 4, 2007 Thomas, if you want, drop your spreadsheet that you're working with to me via email - maybe I can figure out what's going on??? I haven't had any problems like what you mention, but I stopped using the spreadsheet, since it just became too bulky for me - I can figure the slope out pretty easily by hand while I'm sitting at the press Link to comment Share on other sites More sharing options...
trodrig Posted October 4, 2007 Author Share Posted October 4, 2007 Thanks Dave! I'll send a couple of versions (with and without my edits) this evening. T Link to comment Share on other sites More sharing options...
XRe Posted October 4, 2007 Share Posted October 4, 2007 Edited to correct for VERY faulty memory 2.60 does sound more correct The nature of these bars, though, is that we can't share measurment numbers accurately. For instance, to get 8.2gr, my mic is set at 3.00... Link to comment Share on other sites More sharing options...
askomiko Posted January 5, 2008 Share Posted January 5, 2008 (edited) Thanks for the reply Dave! The spreadsheet is off even on charges that I do have data for which is what has me stumped. From my measured data 5 grains should be a setting of around 1.3. However, the calculator says 2.86 unless I remove 4.25 through 7.50 from the equations. After removing 4.25 through 7.5 I get a much closer 1.36 from the calculator.Like you said though, the charges have to be verified with a scale anyway when changing so I guess I'm not going to worry too much about it. I'll have a good starting point and can dial in from there! Spreadsheet or no this is MUCH better than the stock adjustment screw!! Thanks! Trodrig I tried to change the area that the equation reads in excel, so that it wouldn't care for the blank areas (which I cant measure since I use 9mm brass only.) Well, it didn't work either, which seems really weird for me! Well, then I just deleted the numbers on the left until the equation gave correct looking numbers, and now it seems to work... Brute force mathematics for dummies - hit it with a sledgehammer until it gives the number you want Edited January 5, 2008 by askomiko Link to comment Share on other sites More sharing options...
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