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Joined: Nov 2017
Posts: 1,188
Campfire Regular
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OP
Campfire Regular
Joined: Nov 2017
Posts: 1,188 |
I've been loading some Hornady brass in 6.5 PRC. The brass is from the 143 ELD-X and ELD_M factory ammunition. It's been fired twice. I loaded up some 130 Accubonds and 130 Sirocco's a couple of weeks ago, setting the shoulder back by .001. I didn't check the case length before loading them. Saturday at the range I had several rounds that would not load meaning I couldn't close the bolt and several where it was damned hard to close the bolt. The load was 58.5 grains of H1000 and either the CCI-Br. 2 primer or the CCI-200. I got some pretty good groups with the BR-2 at 50.0 and 58.5 grains, but closing the bolt was damned hard. I had some light marks on the case head as well, but primers weren't flat or any other sign of pressure.
I finally gave up and came home. Pulled all the bullets, dumped the powder and checked the case length. Case length was 2.025 and the Hornady website indicates trim length should be 2.015.
My question is would the 0.010 length difference cause a difficult bolt close when the website shows max length as 2.030? I also checked the shoulder length and it was identical to the Hornady factory ammo. Unless I used the wrong headspace gauge when I originally sized the cases I can't figure out the issue.
I went back yesterday and loaded some more. I resized the cases, setting the die to set the shoulder back .001, trimmed them to 2.105 and loaded them up with the 130 AB seated to 2.388 length to the ogive and we shall see what happens. They all chambered with very little difficulty.
The lack of planning on your part does not constitute an emergency on my part!
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Joined: Mar 2002
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Campfire Outfitter
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Campfire Outfitter
Joined: Mar 2002
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For a hunting rifle I usually bump shoulders .003!
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Joined: Mar 2002
Posts: 9,130
Campfire Outfitter
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Campfire Outfitter
Joined: Mar 2002
Posts: 9,130 |
Inconsistent trim lengths can cause chambering issues if a carbon ring develops and is not taken care of, a case that is 0.010 to long can be bumping the case mouth against the carbon ring and cause a difficult bolt close and in some cases higher pressure, maintaining a consistent trim length is a must!
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Joined: Mar 2006
Posts: 14,534 Likes: 3
Campfire Outfitter
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Campfire Outfitter
Joined: Mar 2006
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Sounds like you were sizing the case just enough to squeeze the body and elongate the case body a bit. You've gotta adjust the sizing die down just a bit more to hit the shoulder and bump it back 0.003" or so, and feeding should be smooth as silk.
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Joined: Nov 2017
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Campfire Regular
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OP
Campfire Regular
Joined: Nov 2017
Posts: 1,188 |
Sounds like you were sizing the case just enough to squeeze the body and elongate the case body a bit. You've gotta adjust the sizing die down just a bit more to hit the shoulder and bump it back 0.003" or so, and feeding should be smooth as silk. I think you're correct. On my next loading I'm going to bump the shoulders back .003. The .001 bump was obviously not enough and I don't want to have chambering issues when I'm 250 miles from home. I usually chamber every hand load after reloading, but didn't this time. If I had, I would have found the problem sooner.
The lack of planning on your part does not constitute an emergency on my part!
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Joined: Jul 2001
Posts: 60,170 Likes: 17
Campfire Kahuna
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Campfire Kahuna
Joined: Jul 2001
Posts: 60,170 Likes: 17 |
You might also be getting a little bit of the "dreaded donut" at the bottom of the neck. Have encountered that occasionally with Hornady 6.5 PRC brass, even after the first firing with factory ammo.
“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: Sep 2004
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Campfire Outfitter
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Campfire Outfitter
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Remove all doubt as to what's happening - use a Sharpie and blacken the shoulder and neck to see where things are binding. Could be due to a lot of things.
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Joined: Oct 2016
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Campfire Regular
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Campfire Regular
Joined: Oct 2016
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Sounds like you were sizing the case just enough to squeeze the body and elongate the case body a bit. You've gotta adjust the sizing die down just a bit more to hit the shoulder and bump it back 0.003" or so, and feeding should be smooth as silk. This^^^ I would like to add that not paying attention to whether or not the cases need trimmed can result in a catastrophic failure. Imagine the end of your case being jammed into the throat so it won't let loose of the bullet when you pull the trigger. Trystan
Good bullets properly placed always work, but not everyone knows what good bullets are, or can reliably place them in the field
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Joined: Jul 2001
Posts: 60,170 Likes: 17
Campfire Kahuna
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Campfire Kahuna
Joined: Jul 2001
Posts: 60,170 Likes: 17 |
A little too much donut in the base of the neck can also result in very high pressures.
The standard test for that is sliding a bullet into the neck of fired cases. If it slides in easily, no problem, but any resistance ain't good.
“Montana seems to me to be what a small boy would think Texas is like from hearing Texans.” John Steinbeck
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