Headspace

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daboone
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Re: Headspace

Post by daboone »

Horseman wrote:.... "Bumping" the shoulder a couple thou using a standard size die (brass from my rifles) to me is just to make sure the round will chamber easily and not "over work" the brass. Am I missing something here? My limited knowledge has me thinking that using a body die in conjunction with a neck die like the Lee collet die would really be the ticket for the utmost in accuracy, providing "proper" brass prep is done. :?:
I'm no expert here. Things I've found that do improve my old bolt shooters are neck sizing. Either by using a Lee collet or if one is not available then using a full length sizing die backed out so only the shoulder is being "bumped" slightly while the actual aim is sizing the neck for bullet fit. I've never heard of using the Collet and sizing die/body die together.
As mentioned in the video the reason neck sizing works is because the fireformed case (especially the shoulder) fits precisely in the chamber and can't "flop" around.

So you see I don't know enough to a answer you question. Hopefully someone way smarter than me can give you some actual advice.
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Re: Headspace

Post by horseman »

Thanks Dan. A discussion on body dies, bump dies, neck bushing dies, etc; would only muddy the content of your excellent OP and can be a topic for another day. +of
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Re: Headspace

Post by cj8281 »

I recently read that some rimmed straight walled cases need to be checked for head separation. Apparently it has more to do with the firearm than the cartridge. I read this in conjunction with the 357 mag in the Marlin with max loads. The issue is the bolt flexing backwards while the brass is expanded in the chamber. I will have to see if I can find that.
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Re: Headspace

Post by Ranch Dog »

cj8281 wrote:I recently read that some rimmed straight walled cases need to be checked for head separation. Apparently it has more to do with the firearm than the cartridge. I read this in conjunction with the 357 mag in the Marlin with max loads. The issue is the bolt flexing backwards while the brass is expanded in the chamber. I will have to see if I can find that.
Rossi R92 454 Casull with Starline brass, 2nd firing.

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All of the brass has the ring so one shot! These were running about 56K PSI. Chamber is tight as confirmed with a chamber case but it is experiencing quite a thump at the shot.
Michael
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Re: Headspace

Post by cj8281 »

I found it in the #13 Speer reloading manual in the forward of the 357 mag rifle.
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Re: Headspace

Post by daboone »

WOW RD, I bet that was an exciting(?) experience. Was it difficult to extract the both or either haft of the case? Any problem for you or the rifle?
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Re: Headspace

Post by Ranch Dog »

daboone wrote:WOW RD, I bet that was an exciting(?) experience. Was it difficult to extract the both or either haft of the case? Any problem for you or the rifle?
The Rossi 92 is a strong action, I knew something different had happened at the shot but not what. The action extracted the case head without issue. I pondered the remaining portion of the case for a bit and then sent the largest pin gauge down the barrel that would drop free, about .001" under bore. It dropped right out. There is no evidence that anything happened in the chamber.

I had quite a few reloads on my Winchester cases but I was shooting all of them at around 42.0K. My plan is to pull the remaining ammo and reload a few of them to see if the ring or failure occurs. I will probably just use five of these cases and cycle them until something happens. That will tell me what to do with this lot of brass.

This happened while I was prepping the rifle for a January mule deer hunt and it is sitting on the project shelf and the rifle in the project rack, it line with others. I want to glue a strain gauge on the barrel as well before I do any shooting but it needs to get to the front of the line before that happens.
Michael
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