Stripping down loaded rounds

finnbear270

Well-Known Member
I decided to disassemble some loaded rounds this morning, that I considered may be too hot to shoot, The reason for this act was on shooting the starting charge loads, primer flattening was observed, this on its own is no real fright, as the velocities were well inside those expected, but considering these were right at the recommended starting charge, a voice in the head said "Whoah there!" what will the further prospective loadings be giving as we go up the ladder, when you have a further 7.9 grains available according to data?........As these very first loads were very accurate & will be downloaded by 0.02 grains it seemed foolish to continue, so stripping began, these were the first loads I have stripped that have been charged with ball or spherical powder, all the other experience gained has been with long grain stuff, so I was looking quite closely at things as we went on our way,good job too!, as this powder tends to stick in tiny amounts to the case wall, no amount of tapping, running in an empty tumbler, inserting picks, guarantees an EMPTY case! each case has had to emptied by use of a case neck brush (oversized), this powder is not faulty in any way either damp or contaminated, just seems naturally "sticky", so any of you that are thinking of stripping loaded rounds for the first time, ensure that the case is EMPTY, or you could overcharge on reloading, some of the amounts that were finally removed came to around 2.0+ grains!Steve.
 
FB: Sound advice. I pulled some loads that were about 30 years old and found that the "stick" powder had settled into a bit of a wad at the bottom of the case. I was not planning on using the brass but powder wadded into the base of the case sent a chill through me!

I am curious about your flattened primers. What was the cartridge and load? Was the brass FL resized or new? I often see flattened primers with light loads in cases that aren't formed to a particular chamber.~Muir

PS: Happy New Year!
 
Were the cases Fl resized? That 7.9 grain expanse ahead of a flattened primer has me boggled. Not that I haven't seen it happen: I had a 17MachIV that would blow primers with starting loads!~Muir
 
There is a phenomenon whereby in light loads, the primer backs out during primary ignition and the casing, during the powder ignition, slaps back to reseat the primer against the bolt face. It will put an alarming flattening on a primer but it isn't due to pressure.

Common sense tells us that it can only happen with slightly undersized cases or in extereme cases, a rough chamber that the case adheres to for a protracted number of nano seconds before the case releases it's grip on the chamber walls and is slapped rearward, catching up with the primers rearward travel.

You might want to try a fireformed case with the same load... or seat the bullet into the lands to support the case against the boltface. JUst a thought.~Muir
 
We would see it frequently in cast bullet bench rest; especially when the shooter got the seating depth of the bullet too deep with fresh brass. It was commonly refered to as "primer slap". It can show up in a gun with a rough chamber all the time.

It may not be your Gremlin but it's got all the earmarks.~Muir
 
Muir, what are your thoughts on substituting standard large rifle primers for magnum primers, I had a chat with another reloading pal, & he has suggested a possible pressure spike, produced by a magnum primer flash burning straight through the powder column & giving a sort of knock effect, as in fuel without the anti knock ingredient, reckon this could account for flattish primers with starting charge weights? :eek:
 
Potman has just been on the phone, he wants to try Ramshot in his 6.5x55 Swede, his cases are fire formed in his rifle & have been neck sized, so will have look at what gives in his loads :)
 
FB: I use magnum primers when I need to and treat them like match primers; both seem to have a higher brissiance factor. As with any primer change, it requires a rebuilding of the load. I have severl thousand, 20 year old magnum rifle primers in one of my storage cans that I'd like to use up but I have been putting it off out of laziness. I would reduce loads 5% and start again with the magnums. If your'e using slower powers like 4350 or 4831, the magnums are an optional primer anyhow. I don't think the effect you described happens exactly in that manner but it will raise pressures somewhat.

I think you may have a hard time replicating primer slap in that 6,5x55. It is very particular to each chamber and especially cartridge shape as chamber wall adherance has much to so with it. Were I in your moccassins, I'd make up a couple of rounds with the old load and seat the bullet out to gently kiss into the lands. This will support the case head against the bolt face and should eliminate the problem.... if indeed this is the problem. All this theory is predicated on the idea that your cases are trimmed properly, neck clearance is proper (factory rifle shouldnt be an issue) etc, etc, etal. I'm sure you have a handle on all of this but I thought I'd FYI it for the youngsters. Untrimmed cases and neck impingment can jack pressures to catastrophic levels.

Good luck with the Ramshot in the 6.5. Let me know how it works. The stuff is reasonably priced here. Priced some Vit-V powder yesterday at one of the discount houses. Almost all other powders are $20/pound. The Vit-V powders are $34/pound. It's little wonder that relatively few American reloaders have a real working knowlege of the V-V line! Good Luck! ~Muir
 
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