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Joined: Feb 2011
Posts: 10
New Member
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OP
New Member
Joined: Feb 2011
Posts: 10 |
What is considered an acceptable level of case neck runout? I know we would all like to see zeros however, when that is not achievable what is considered acceptable. I remove the decapping pin and expander ball from the FL length die when I resize. I can have 0-.001 runout from the FL sizing die. However, when I expand the neck with a mandrel die and a gauge pin that is 0.002 less than the bullet diameter I get .003-.005" runout on the necks. I have tried allowing the mandrel die to float in the press so it will self align, however, don't see any improvement in the results.
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Joined: Dec 2002
Posts: 15,860
Campfire Ranger
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Campfire Ranger
Joined: Dec 2002
Posts: 15,860 |
0.0"~ .002" goes into the competition ammo box. .003"~ .005" gets straightened to <.002" and is reserved for fouling shots. Anything >.005" (if it happens) is reserved for dicking around on plates. All values are TIR.
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Joined: Jun 2004
Posts: 44,835
Campfire 'Bwana
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Campfire 'Bwana
Joined: Jun 2004
Posts: 44,835 |
How uniform are the case necks?
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Joined: Aug 2015
Posts: 13,235
Campfire Outfitter
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Campfire Outfitter
Joined: Aug 2015
Posts: 13,235 |
This ^^. Easy to have .002"-.004" variance in neck thickness. The full length die uniforms the o/s of the case, pushing any variance to the inside. The mandrel die pushes the variance back to the outside.
Let's Go Brandon! FJB
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Joined: Feb 2011
Posts: 10
New Member
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OP
New Member
Joined: Feb 2011
Posts: 10 |
This ^^. Easy to have .002"-.004" variance in neck thickness. The full length die uniforms the o/s of the case, pushing any variance to the inside. The mandrel die pushes the variance back to the outside. After thinking about what I am seeing this is the next thing to check. With Laupa brass I see .002 after mandrel neck sizing. With RP I am seeing .005. I am thinking neck turning to get uniform neck thickness is in order.
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Joined: Jul 2001
Posts: 60,122
Campfire Kahuna
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Campfire Kahuna
Joined: Jul 2001
Posts: 60,122 |
The problem with neck-turning brass that has .005 inch variation in neck thickness is that variation usually extends into the case body as well--which results in cases that are often slightly curved overall themselves. This makes it more difficult to minimize seated bullet run-out.
All of which is why it's far better to start with more uniform brass in the first place.
“Montana seems to me to be what a small boy would think Texas is like from hearing Texans.” John Steinbeck
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Joined: Jan 2005
Posts: 11,322
Campfire Outfitter
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Campfire Outfitter
Joined: Jan 2005
Posts: 11,322 |
0.0"~ .002" goes into the competition ammo box. .003"~ .005" gets straightened to <.002" and is reserved for fouling shots. Anything >.005" (if it happens) is reserved for dicking around on plates. All values are TIR. ^^^^^ This Check and turn your necks if needed.
I may not be smart but I can lift heavy objects
I have a shotgun so I have no need for a 30-06.....
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Joined: Jul 2015
Posts: 14,694
Campfire Outfitter
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Campfire Outfitter
Joined: Jul 2015
Posts: 14,694 |
What's your game?
Hunting - What runout? Anything goes. Highpower? I don't check, but around .004" or less and I'm happy. Multi-lug actions like in the AR aren't as sensitive to runout as 2 lug bolts. Benchrest? You want to win? How badly?
Politics is War by Other Means
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Joined: Mar 2020
Posts: 139
Campfire Member
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Campfire Member
Joined: Mar 2020
Posts: 139 |
for low run out and consistent neck tension i do the following: A. full length body size and bump shoulder 0.002-0.004 depending on what your chamber needs. B. bushing size neck to enable 0.0005-0.0010 I/D cleanup. This will remove donut brass flow C. Neck turn using oversize pilot hard turned to provide tight fit to reamed neck I/D. D. Bushing size for 0.003" press fit to bullet
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Joined: Dec 2004
Posts: 10,345
Campfire Outfitter
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Campfire Outfitter
Joined: Dec 2004
Posts: 10,345 |
Fellers, I fireform first with a stiff load of pistol powder and a wax plug instead of a bullet. This way you start with a straight case. I used to be in the carbide neck bushing business and neck size only to a slip fit for the mandrel of my Pumpkin neck turner. On my new brass I don't want any expander or sizing die touching it until after I fireform, neck size, and turn.
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Joined: Jul 2015
Posts: 14,694
Campfire Outfitter
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Campfire Outfitter
Joined: Jul 2015
Posts: 14,694 |
What is the game those cases are used for, Butch?
Politics is War by Other Means
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Joined: Dec 2004
Posts: 10,345
Campfire Outfitter
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Campfire Outfitter
Joined: Dec 2004
Posts: 10,345 |
This is for my 30BR and 6ppc cases. I am not a range hound and on my hunting rifles I use a combo that shoots under 1"MOA with a cold, hot, dirty, or clean barrel. My personal hunting limit is 300 yards. As I don't wear out components at the range I buy the best brass that is available. Basically with my hunting brass I fireform and trim to length.
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Joined: Jan 2005
Posts: 38,869
Campfire 'Bwana
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Campfire 'Bwana
Joined: Jan 2005
Posts: 38,869 |
Corollary: how many times in a row must a measurement repeat before it is accepted as the true measure?
Not a real member - just an ordinary guy who appreciates being able to hang around and say something once in awhile.
Happily Trapped In the Past (Thanks, Joe)
Not only a less than minimally educated person, but stupid and out of touch as well.
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Joined: Mar 2006
Posts: 14,497
Campfire Outfitter
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Campfire Outfitter
Joined: Mar 2006
Posts: 14,497 |
Corollary: how many times in a row must a measurement repeat before it is accepted as the true measure? There is no “true measure”, only a true dimension which can never be measured with arbitrary precision. The uncertainty about the measurement agreeing with the true dimension decreases with each additional measurement. It’s a judgement call determining how many measurements are “good enough”, depending on your uncertainty requirements.
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Joined: Jan 2010
Posts: 32,130
Campfire 'Bwana
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Campfire 'Bwana
Joined: Jan 2010
Posts: 32,130 |
There is no “true measure”, only a true dimension which can never be measured with arbitrary precision. The uncertainty about the measurement agreeing with the true dimension decreases with each additional measurement. It’s a judgement call determining how many measurements are “good enough”, depending on your uncertainty requirements,
Fantastic! LOL
If you put Taco Bell sauce in your ramen noodles it tastes just like poverty
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Joined: Dec 2004
Posts: 10,345
Campfire Outfitter
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Campfire Outfitter
Joined: Dec 2004
Posts: 10,345 |
I'm most concerned with a fouled and cold barrel. I do not go hunting with a clean barrel. Probably doesn't matter, but that is my practice.
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