DaveT Posted August 20, 2014 Report Share Posted August 20, 2014 Busy prepping my Wylde chambered AR for October and starting to reload both sets of brass to see what it performs well with. I always measure virgin brass / unfired headspace with Hornady comparators and then measure again at 1 x fired to give me a start point and expanded point to determine shoulder setback for resizing. On my bolt guns I set back by .001" but I know for the AR that I need to setback by .003" or .004" to ensure clean cycling. My comparator measures indicate that unfired Lapua Match starts life .002" shorter than unfired GGG (1.4500" vs 1.4520") and the 1 x fired measures are correspondingly different (Lap Match at 1.4550 vs GGG at 1.4570). I therefore conclude that my chamber produces a maximum fired headspace size of 1.4570 (or a little greater if I allow for springback on the brass) and that I could actually let my Lapua brass 'grow' a little more in respect of headspace on subsequent firings to match the GGG ...IE rather than setting back from 1.4550 to 1.4510 I could setback to about 1.4530 and help extend brass life a tad. If future batches do not show the same variances I would need to think again. Anyone care to confirm my conclusions or rubbish them? Does the military brass always assume a larger chamber than LAPUA 223 which , I guess, assumes a standard 223 Rem chamber size? Link to comment Share on other sites More sharing options...
John MH Posted August 20, 2014 Report Share Posted August 20, 2014 Not sure why you have differences but it could be different amounts of spring back due to slightly different alloys. You don't need to bump the shoulder back 0.003 to 0.004 just 0.0015 to 0.002 will be more than enough but it is recommended you FL resize. I use a Forster Bump die that allows precise control of shoulder set back and neck sizing. Link to comment Share on other sites More sharing options...
bradders Posted August 20, 2014 Report Share Posted August 20, 2014 Load the cases and go shooting and stop being so anal Link to comment Share on other sites More sharing options...
DaveT Posted August 20, 2014 Author Report Share Posted August 20, 2014 Load the cases and go shooting and stop being so anal Anal always works for me.....and I shoot a lot. Link to comment Share on other sites More sharing options...
brown dog Posted August 20, 2014 Report Share Posted August 20, 2014 Anal always works for me.....and I shoot a lot. Ummmm, I think that doesn't read quite as you intended.......! Link to comment Share on other sites More sharing options...
DaveT Posted August 20, 2014 Author Report Share Posted August 20, 2014 Ummmm, I think that doesn't read quite as you intended.......! See what you mean...Doooh!!!!! Well spotted. Link to comment Share on other sites More sharing options...
Offroad Gary Posted August 20, 2014 Report Share Posted August 20, 2014 Anal always works for me.....and I shoot a lot. Link to comment Share on other sites More sharing options...
DaveT Posted August 20, 2014 Author Report Share Posted August 20, 2014 Must get the T shirt! Link to comment Share on other sites More sharing options...
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