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Posted: 12/30/2013 1:57:14 PM EDT
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ok well today i got my hornady headspace gauge kit, and i went to check my 308 to see if i was close with my rcbs 308 mic, i also got my hornady 9th edition out and looked at the 308 brass blue print, i think it said 1.711 shoulder to the back of the brass ( by the primer ) so i checked with my hornady gauge in some brown and sharpe digital mics 1.611 is what i got, so either i did it wrong with my 308 mic or something, can some one please explain if i am good to go or not, i am sure i am good to go but should i try and bring the shoulder up to 1.707 or around their |
| Saami drawings for .308 Win show that at the .400" diameter of the shoulder that the measurement from that point on the shoulder to the case head is 1.634 (-.007) and the chamber drawings say they should be 1.630 minimum to 1.640 maximum. Not a 308 Win reloader myself but with the .400 Hornady insert on the headspace gauge mounted to your calipers and zero'd when closed you should be getting measurements between 1.630-1.640". While the Hornady Headspace gauge is just a comparator it should be close to these dimensions. On a factory new brass the RCBS Precision Mic should read very close to zero when screwed down to lightly touch the shoulder and your fired cases would probably read plus 2 to plus 6 on the mic. Again if you use the 400 insert it corresponds to the saami measurement point on 308 cases. |
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ok well today i got my hornady headspace gauge kit, and i went to check my 308 to see if i was close with my rcbs 308 mic, i also got my hornady 9th edition out and looked at the 308 brass blue print, i think it said 1.711 shoulder to the back of the brass ( by the primer ) so i checked with my hornady gauge in some brown and sharpe digital mics 1.611 is what i got, so either i did it wrong with my 308 mic or something, can some one please explain if i am good to go or not, i am sure i am good to go but should i try and bring the shoulder up to 1.707 or around their Your Hornady kit is a comparator not a gage as the same insert works for different calibers. You would use this to compare a fired case from your gun to a case you are resizing for your gun. |
| http://www.brownells.com/.aspx/lid=12897/GunTechdetail/Gauging_Success___Minimum_Headspace_and_Maximum_COL Measure a fired case from your rifle. When you FL size, the gage should read about .003" less or shorter head to datum. Hope this helps. |
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<a href="http://s250.photobucket.com/user/dryflash3/media/Case%20Gauge/P3030544_zps10acbd9b.jpg.html" target="_blank">http://i250.photobucket.com/albums/gg272/dryflash3/Case%20Gauge/P3030544_zps10acbd9b.jpg</a> With the correct insert, 223 works fine. Different insert for 308. Hint, read the instructions. 
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so this hornady comparator is not going to help me get my 223 brass sized to proper spec With the correct insert, 223 works fine. Different insert for 308. Hint, read the instructions.
i glanced at them lmao just to see what one i needed for the 308 since i have a rcbs mic to compair |
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These "devices" are not to be used to compare to each other or to a SAAMI drawing. They are not that precise.
They are used to compare "Your" fired case to Your sized case using the same device. Not your fired case to a Drawing. 1) Fire the round. 2) Measure the case with the correct comparator. 3) Size the case and adjust the die for desired shoulder bump. If you want .002 bump then set up your die so your sized case measures .002 less then your fired case. Forget SAAMI, it has no place on Your loading bench. |
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so this hornady comparator is not going to help me get my 223 brass sized to proper spec It is preferable to size to the chamber of the actual gun you are loading for rather than going by a SAAMI spec. Then you wont have to come back here with hard to chamber or extract issues after loading 500 rounds to SAAMI spec. |
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I feel compelled to post this somewhat contradictory information.
I have measured the diameters of the holes in my Stoney Point gage inserts and they are all as close to the SAAMI spec as I am able to measure. This included correction for the width of the flats on the caliper. My inserts are stamped with a diameter and a letter. In that respect, I consider mine to be gages which CAN be used to check case dimensions against spec values. I have compared my Stoney Point gage measurements to my Precision Mic measurements. I have measured headspace gages and fired cases. In all cases the Stoney Point was correct (assuming the headspace gage is correctly labeled) and easier to use than the Precision Mic (whose readings on fired case were sensitive to torque used). Yes, you must use the correct insert for the cartridge being checked. Yes, you have top ensure everything is "plumb and level" and the gage is zeroed. There is one way in which the RCBS gage is clearly superior to the Stoney Point and it is an important to note. The RCBS gage has a clearance hole in the base which prevents the primer from interfering with the measurement. If you are using the Stoney Point gage and have cratering or other protrusions of the primer, you will have to punch the primer out before measuring the case. Otherwise, removing the primer will look like you are setting back the shoulder. You can use yours as a comparator but mine is a gage. No matter what, the tool will help eliminate sizing problems associated with sizing. Enjoy! If Hornady has gotten sloppy since buying the rights to these gages from Stoney Point, that would be a significant loss of quality. |
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