FC Posted August 24, 2009 Report Share Posted August 24, 2009 When I was in dental lab we had a mm gauge that measured how thick crowns were. Is there a gauge like this to measure shell cases you are reloading? I've heard enough of the evils of head space separation. Quote Link to comment Share on other sites More sharing options...
AzRednek Posted August 24, 2009 Report Share Posted August 24, 2009 http://www.midwayusa.com/viewproduct/?productnumber=456614 Quote Link to comment Share on other sites More sharing options...
Dr.Hess Posted August 24, 2009 Report Share Posted August 24, 2009 I was just reading an article, I think in one of the NRA mags, on some really big round like in 300 Win Mag class or something, and it said that case life was terrible in that round and the failure was usually from a case head separation. The suggestion was to take a paperclip, straighten it out and bend a L in the end, stick that down the case and drag it on the inside of the case. If you feel it catch or not smooth, that case is getting ready to go. I used to have case head separations with my Contender in 22 Hornet. I was loading them pretty hot with 296. Basically just filling the case to the top and pushing a bullet in. First time it happened, I took it to a gunsmith. He just stuck a tap in, twisted a turn or so and pulled it out. After that, I kept a broken 1/4x20 tap in my box and used it a few times. Quote Link to comment Share on other sites More sharing options...
AzRednek Posted August 24, 2009 Report Share Posted August 24, 2009 I used to have problems with full length sized 303 British separating on me. Using a Lee Loader, just sizing the neck gave me longer case life. The paper clip method works pretty good or at least it did on one occasion for me. After getting a suspicious feel I put the case up to a grinding wheel and sure enough the case had a hair line crack I couldn't see on the outside. Quote Link to comment Share on other sites More sharing options...
FC Posted August 25, 2009 Author Report Share Posted August 25, 2009 Is the first sign of problems the case neck getting thinner? I wonder what that thickness should be in ratio to the rest of the case? I have an excellent idea for a modified dental caliper for this sort of thing. Nobody seems to make what I'm thinking of. Quote Link to comment Share on other sites More sharing options...
FC Posted August 26, 2009 Author Report Share Posted August 26, 2009 Shows what I know- I should have said case head separation. Anyway, I see the RCBS Case Master can do this measurement, but it doesn't have to be that complicated. I know of a much simpler gauge design that would do the job, but it just isn't made yet. Articles about case head separation: http://www.exteriorballistics.com/reloadba...caseinspect.cfm http://gunsandammomag.com/cs/Satellite/IMO...rgs=pagenum%3D2 http://www.recguns.com/Sources/VIIG2.html http://www.exteriorballistics.com/reloadba...caseinspect.cfm Quote Link to comment Share on other sites More sharing options...
AzRednek Posted August 28, 2009 Report Share Posted August 28, 2009 Is the first sign of problems the case neck getting thinner? Usually it is the neck growing in length, signaling the need to trim. Quote Link to comment Share on other sites More sharing options...
pacrat Posted September 2, 2009 Report Share Posted September 2, 2009 As the brass internally flows forward with the plasma from combustion at time of ignition it makes the neck area longer and thicker. As it is flowing forward it makes case thinner from web forward. Just how much per firing depends on how hot load is, shoulder angle, etc, etc. Sharper shoulder angled cases are less prone. Quote Link to comment Share on other sites More sharing options...
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