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Old January 11, 2019, 09:44 AM   #1
cdoc42
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primer pocket question

It took 40 years of reloading for this question to pop into my mind; I've never read nor heard any discussion on it. So I pose it here:

We clean the primer pockets with tools that vary from hand to electric devices.

The base of the pocket, where the hole is, is exposed to extremely high temperatures and eventually the pocket enlarges, rendering the case useless.

Doesn't the base of the pocket ever get thin enough to disintegrate? Doesn't the hole ever get larger? Or, is it such that the pocket enlarges before these things can happen?
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Old January 11, 2019, 11:26 AM   #2
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I don't have a good theoretical explanation (I'm sure someone can come up with a time/temperature/melting point explanation), but I have reloaded some handgun brass 20+ times with fast powder, nearing max pressures and there is no erosion I see in that area of a case...
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Old January 11, 2019, 11:43 AM   #3
Don Fischer
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I can't answer the question but I shoot rather hot loads an normaly by about 5 rounds, the pocket's are loose. Got a tool to tighten them back up and it actually works. Don't recall what it's called but got it from Hart Gunsmith's in Penn. You stick a rod it the pocket, give it a couple raps with a hammer and presto, fixed problem. Be interesting to her what some of these guy's claiming extreme case life have to say about it. I'm pretty sure low pressure is easier on them. Started shooting some cast bullet's in 30-06 and 308 a few years ago and so fr no primer pocket problems. I keep pressure low using faster shot gun powder's.
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Old January 11, 2019, 11:46 AM   #4
hounddawg
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I have often wondered about flash hole erosion or lack thereof. I do know that a leaky primer pocket can do a number on a bolt face. Savages have replaceable bolt faces and I have replaced a couple due to pitting caused by leakage

I would love to hear some theories on why flash holes don't get eroded by the hot gasses
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Old January 11, 2019, 12:31 PM   #5
oley55
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Quote:
Savages have replaceable bolt faces and I have replaced a couple due to pitting caused by leakage
does this replacement involve the fine tuning skills of a gunsmith?
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Old January 11, 2019, 01:45 PM   #6
hounddawg
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Quote:
does this replacement involve the fine tuning skills of a gunsmith?
if you have some mechanical ability no. Watch the first 5 min of the link. BTW Bighorn actions copied the floating bolt face from Savage.


https://www.bing.com/videos/search?q...8&&FORM=VRDGAR

You can swap to a variety of bolt heads to suit whatever barrel you are running

http://pacifictoolandgauge.com/savag...olt-heads.html

I do check the headspace for safety purposes afterward but never needed to adjust so far after changing one but it is a still a good habit to get into
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Old January 11, 2019, 03:03 PM   #7
cdoc42
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I do notice when I clean the primer pockets with my RCBS Case Prep tool, the soot is usually mixed with brass filings and I assume they are from the sides, not the bottom, of the primer. I assume that only because the bottom never gives out, nor does the hole get any bigger.
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Old January 11, 2019, 03:05 PM   #8
cdoc42
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hounddawg, isn't it interesting that gas escaping around the primer pits the bolt face but does not erode the base of the pocket????
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Old January 11, 2019, 05:18 PM   #9
oley55
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Thanks Dawg for the links. you da man!
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Old January 11, 2019, 06:55 PM   #10
hounddawg
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Quote:
isn't it interesting that gas escaping around the primer pits the bolt face but does not erode the base of the pocket????
yeah I can't figure it out, darn things should look like a crater on the moon or something. The buildup of carbon must insulate the brass somehow. I would think the flash hole edges would look like a alley cats ear
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Old January 11, 2019, 07:04 PM   #11
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The only time i've changed the bolt head on one of my Savages, it was due to a broken ejector pin being wedged tight into it.

As for flash hole errosion, it will take someone wiser than i to answer that with any scientific explanation, and not just a WAG.
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Old January 11, 2019, 07:13 PM   #12
hounddawg
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I had some sleeves of Winchester large rifle primers awhile back that ate two boltheads before I trashed them and switched to CCI. For a month or two there I ran some pretty warm loads too, I quit that. No need to give a good barrel a early death
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Old January 11, 2019, 09:08 PM   #13
oley55
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Quote:
I had some sleeves of Winchester large rifle primers awhile back that ate two boltheads before I trashed them and switched to CCI.
Exactly the same thing happened to me with Winchester LR primers. Even at low to mid-range loads I had primer failures in my Savage 10 and son's Rem 700. I had read about them having had some bad lots a while back so I contacted Winchester. They were very responsive and based on the load data I provided they wanted the remaining 400 of 1K back. I also supplied the LC (11) brass used in the failures.

Although they said they had not had previous issues with my lot#, they paid all the shipping and offered to fix/replace damaged bolts in both rifles. At the time I was more interested in shooting than shipping my weapon away for who knows how long so I told them I was ok.

I did have an additional 7K of Win LR primers on hand of different lot # (all had been purchased in 2014), but they didn't want them back. I was/am so uncertain of their primers, that I swapped n traded them for next to nothing just so I wouldn't be tempted to try them again. I am now using CCI #34s, but plan to try out some Federal primers soon.
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