You should never measure headspace with primers in. Get a universal decapping die and punch them out before you use your sizing die. That being said I believe your not sizing the base enough is the issue. Your having to move the die down further which is bumping the shoulder more. A small base die if they make one will fix the issue.
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.008 Bump Required to Smoothly Chamber Round??
- Thread starter General RE LEE
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His fired brass, prior to resizing of any kind, are hard to chamber when put back into the rifle. That should NEVER be the situation. The problem isn't the sizing, it is the brass or the chamber.
Ahh I have seen difficult to chamber fired brass before and don't find it uncommon. I have some barrel nut rifles where I set the headspace fairly tight to limit case growth. Once fired brass is hard to chamber but it only takes .002 to make it chamber. I have seen this exact issue and a small base die fix the problem.
xsn10s
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I'd start off by using a universal depriming die. It doesn't resize at all so then you'll be able to get an accurate baseline. Then check the shoulder bump on some of your already resized, bumped shoulder brass. And like I said earlier check your casehead diameter. I've seen this before and my bet is that area is larger and what is causing the hard bolt close.
If you have case head, the area just ahead of the web, expansion that is large enough to cause hard chambering after firing and need small base dies to get it back into spec in a bolt gun, you are running too much pressure for that brass. That is a classic over pressure sign and along with rim expansion, the very best way of gauging load pressure. Back down the load if you are going to keep using that brass, or try Lapua, ADG etc.
I haven't read all the replies, so I apologize if it has been covered.
I'm assuming multiple firings on this brass with 1500 rounds down the pipe. Brass flows forward and start to "build up" in the neck/shoulder area. You are having to push the shoulder back to make this area clear most likely. Seen it before with a 284w.
I'm assuming multiple firings on this brass with 1500 rounds down the pipe. Brass flows forward and start to "build up" in the neck/shoulder area. You are having to push the shoulder back to make this area clear most likely. Seen it before with a 284w.
TRG65
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This happened to me when I started loading 6ARC. The Hornady dies I got did not resize the base sufficiently. I was bumping 0.010 to get smooth loading and chambering. I got an RCBS small base die. When I started using that for sizing, I only needed to bump 0.002 for smooth operation. I still use the Hornady seating die, but I only use the RCBS for sizing.
I have several 6ARC (2 BA & 2AR), a 22ARC, and 2 Grendels. I see it in my ARs but I can't remember ever having a problem in any of my bolt guns. I can recall screwing the sizing die down further and further trying to get the base sized. Hornady brass was the worst. A small base 6.5 Grendel die will get the base without touching the shoulder. This will allow you to get at least 2 to 3 firings to find your chamber length before setting the 2 thou bump. BTW Starline 6 ARC brass is excellent and readily available.
I've relegated all my hornady brass to my ARs for varmint and hog hunting and I don't care if I lose it in the field.
I've relegated all my hornady brass to my ARs for varmint and hog hunting and I don't care if I lose it in the field.
I could really use that Grendel brass.... I'll send a pm in a minute...
General RE LEE
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Yes with an AMP
xsn10s
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No I'm speaking about after he bumped the shoulder. If you bump the shoulder and the die doesn't touch the casehead area the brass is naturally going to go to the area of least resistance. So if this is what is happening then the OP needs to adjust his die down to size more. Since the OP is measuring the bump with the primer still in the "shoulder bump" is probably not accurate to begin with.
xsn10s
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The other possibility is the OP is actually causing his case to lengthen during sizing. So say his primer has backed out .005". So it will be measure .005" longer than the brass actually is. He then bumps his brass and comes to a measurement that appears as a .002 bump, when it reality if the primer is gone his bump is actually .003" longer. This can happen if the body gets sized when the shoulder isn't being touched at all by the resizing die. A rough expander ball can also cause a case shoulder to get elongated. In any case I'm done here. Good luck to the OP.
Tootallsteve
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I'm interested in the 6.5 Grendel. Let me know how much you want for it . Thanks Steve
randy86314
Well-Known Member
Interesting problem. Are you sizing brass that was fired once in your rifle?
Do you expand the necks on the upstroke of the press? Does the upstroke require more than usual force to complete?
When I sized some 257Roberts brass 8 years ago, the resistance of the expander button stretched the shoulder upward several thou. I moved to neck bushings. As
Off-center chamber might be possible.
edit: I didn't see it: are the primers backing out, too??
Do you expand the necks on the upstroke of the press? Does the upstroke require more than usual force to complete?
When I sized some 257Roberts brass 8 years ago, the resistance of the expander button stretched the shoulder upward several thou. I moved to neck bushings. As
xsn10s
stated above.Off-center chamber might be possible.
edit: I didn't see it: are the primers backing out, too??
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