*CLICK*.....
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I think I know the answer and solution to this, but I just want run it by the crowd to confirm.
I'm working with the 7 LRM Travis built for me, (Its a wet dream, but more on that later) and have been having some issues with some of my handloads going CLICK rather than bang.
I'm working with virgin hornady brass, 180 Berger VLD's, 70 Grains of H1000 and CCI 250's.
Using a 284 expander mandrel, I punched out the necks of the brass to round them out, primed, charged and seated a bullet.
What I'm thinking is the virgin brass is sized too short from the factory, so when the primer gets struck by the firing pin the whole cartridge slides forward in the chamber, causing a light strike. CLICK
The fireformed cartridge is abut 6 thousands longer than the virgin brass at the headspace datum line. (I don't have the right headspace insert, which I think is .4650 so I can't actually measure the real datum line)
My solution is going to be to load the bullets to jam, in order to prevent the cartridges from sliding forward in the chamber. BANG
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I want to add this because I'm hoping someone can clarify my understanding of headspace in this instance.
Looking at the brass drawing halfway down the below article, I believe it shows a datum line at a length of 2.005+/- and a width of .4650. I also note the shoulder angle of 30*.
http://site-media.net/gunwerks/7LRMarticle(1).pdfWhile looking for a bump gauge insert. I found the Sinclair set, that says it will work for any 30* shouldered cartridge ultramag and up.
Am I correct in my understanding that this is the one I need, or do I have to find one specific to a .4650 headspace?
In that same vein does headspace diameter matter for the purposes of bumping the shoulder, or will any gauge that fits the shoulder consistently work?
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Headspace is the measurement from the bolt face/base of case to the shoulder at its angle.
I'm not sure why you need a headspace gauge however. I don't have one. @tscustoms has them and uses them when chambering... but I don't need one.
Six thousandths short typically isn't enough to cause light strikes on its own. Remember that the case is not just floating in there. It's being pushed forward by the ejector plunger. It's certainly possible though. Are you sure the primers are being seated to the bottom of the pocket? You are correct in your proposed solution to seat the bullets long and jam them. As long as they are jammed correctly, it will compress the ejector and push the case back against the bolt face. If seating pressure is too low, this may be difficult.
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@orkan said:
Headspace is the measurement from the bolt face/base of case to the shoulder at its angle.
I'm not sure why you need a headspace gauge however. I don't have one. @tscustoms has them and uses them when chambering... but I don't need one.
I suppose I have my terminology wrong. When we resize a case and push its shoulder back that 1-1.5 thousandths isn't that it's headspace which we then measure with these?
http://ads.midwayusa.com/product/479835/hornady-lock-n-load-headspace-gauge-5-bushing-set?cm_mmc=pf_ci_google--Reloading+-+Metallic+Reloading+Equipment+(Not+Presses)--Hornady-_-479835&gclid=CMG5mbn8g9UCFYlgfgodyWID8gDo I need a special one to set up my dies on the 7lrm or will any one for a 30'degree shoulder work?
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It sounds like your understanding of headspace is correct. Product definitions can be confusing sometimes.
Headspace gauge
Hornady Headspace gauge
So you're right! I thought you were talking about the OTHER headspace gauges. lol :)
Just get the right diameter. You don't have to concern yourself with shoulder angle. That's why you had me confused.
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Alright! Got something right for a change!
Understood. I got confused and brought in the angles because Sinclair lists their bump gauges in degrees rather than specific cartridge diameter. If I had read the description it would have made sense why that's the case. http://www.sinclairintl.com/reloading-equipment/measuring-tools/bullet-comparators/sinclair-bump-gage-insert-prod35265.aspx
So for the 7 LRM I need a .4650, correct? Because it's not standard from hornady any recommendations where to find one?.
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