SmallCaliberCentral

I have a Cooper MTV in .204R. I have Forster Bench Rest Dies, and am using Winchester brass.
All the brass has been sized, trimmed and prepped the same.
Some of the loaded rounds are a tight bolt close and others the bolt is smooth. After firing a tight case, that case now
is a smooth bolt close when the case is empty.
Should I look into neck turning to clean up the brass.?

Thanks.

If your chamber is cut to SAMMI specks, I don't really think turning the necks will make any difference, or is necessary.

It sounds like you may need to bump your shoulders to allow that slight bolt closing resistance we're all after. A bump as small as .002 usually does the trick.

Your Cooper MTV was cut like mine with a SAAMI spec reamer, so the neck is most likely .234", so no need to turn necks unless you just want to take off the high spots. I had Cooper send me a chamber cast of my chamber, and it is spot-on at .234". Mic a loaded case and you'll most likely see there's plenty of clearance in the neck; the culprit is the shoulder.

So a Bushing bump neck die is what I need ? I'm using a FL sizer die adjusted to cam over on the shell holder.

That F/L die will work your brass too much IMO. You can use a Body Die which won't work your necks, and if you need more shoulder bump, the Redding Competition Shell Holder Kit will give you six shellholders in .002" thickness increments to properly set your case headspace for every rifle you own with that case head size (223/204 etc.).

Thank You for your help.

Rick in Oregon wrote:That F/L die will work your brass too much IMO. You can use a Body Die which won't work your necks, and if you need more shoulder bump, the Redding Competition Shell Holder Kit will give you six shellholders in .002" thickness increments to properly set your case headspace for every rifle you own with that case head size (223/204 etc.).

Rick, what gauge do you use to measure headspace? I have Redding Shell Holder Kit & ordered a Innovative Technology Head Space gauge set to help me set my dies properly. At the shoulder I usually like .002-.003. Is that about right? JD Texas

JD: Yep, that sounds about right. I shoot for .002" myself and use the old Stoney Point set of headspace gauges, now Hornaday that fits onto a dial or digital caliper. It's very similar to their bullet-to-lands measuring tool and works very well indeed.