Possible fix for my ES woes

Gregg C

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Nov 15, 2017
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Tucson AZ
Broke my RCBS primer seater last nite. It's on a Rock Chucker Supreme, so was unable to find a replacement today. Instead I bought a Lyman EZee Prime. This is the third loading on new brass, so I knew that the primers would seat at least flush. Well, they didn't. Some were ok, others stuck out. Scratching my head I re-read the destructions, and it says that the plunger will NOT bottom out, yet I could not squeeze the handle hard enough to get any more travel in order to push the primer up into the case, to at least flush. I found an old feeler gauge spark plug gapper in my tool box that is narrow enough to lay in that recess in the middle of the RCBS shell holder. Stuck a shell on there, pushed the .013 feeler gauge in, pointed the **** thing away from my face, squeezed the handle....and pushed the primer home . Not just flush, either. It has the "right" feel to it, slightly below the case head. Did them all again, got that same recessed depth to all of these cases. I have been fighting protruding primers in this cartridge for the entire time I've been loading for it. Sometimes the durn things would not even chamber. And my new chronograph has been telling me that my velocities are all over the map. ES this last time out was 72fps.
As to the cause of this, I have no idea. At a WAG, I think the shell holder is minimal in some dimension or other, or wore out, or ...yeah, I dunno. But, if primer seating depth affects velocity, then could be I found at least PART of my problem. Questions, comments, concerns are welcome, encouraged, even. What say you all ? Hope this was not to long, tried to keep it short. Thanks.
Gregg
 
Can't help on this one, I use my press for priming. But I would think that inconsistent primer seating would definitely lead to inconsistent ES .I'm interested in the outcome of this issue, always something new to learn .
 
Have not yet uniformed pockets. That is next acquisition. My scale is a 5 0 5 RCBS beam scale. Probably not top notch, but I am slow and patient with it. The bullets , till they are gone, are 265 Barnes 338 Lapua LRX BT. Moving to 300gr SMK next batch. RCBS dies. Nobody that I can find is making a competition type seater die for the big WBY case, and I need a comparator, also, but I'm getting there.
Gregg
 
Seating depth on the primers need to be even, I set them all .004 into the pocket. Having inconsistent depths changes ignition a little and everything after that suffers.
Do you use a bench mounted primer seater? I'm kinda liking the look of that one from RCBS. I think I want to get away from the one on my press, but I'm not sure I like the hand held, either. Thanks
Gregg
 
Been thinking on this some more. Way back when I first got my rifle back from the Smith, I had problems getting the bolt to close. I even went so far as to file the tops of the belt away, some. After some in depth memory searching, I realized I saw some circular marks on the primers on the cases that the bolt WOULD close on. I think I can attribute probably 90 percent of the problems I THOUGHT I was having to primer depth. I knew that some of the primers weren't seated deep enough to my satisfaction, but they wouldn't go deep enough on the press, so I just chalked it up to cup and brass variation. He'll, I eventually bent the little arm that the primer cup is attached to. Actually broke it last nite, trying to seat primers. Any way, I blamed everything from the alignment of the planet's to my wife's pms rather than studying the problem, and figuring it out MECHANICALLY. I still don't know what really caused this anomaly, but I'm excited to know that it is not related to a brass issue. Now that I know a tiny bit more about what I'm doing, I realize that this primer seating depth has been a real issue from day one. There is , that I can see, NO reason a primer should not seat below the base if every thing is copesetic and proper. If anyone has ever had this type of problem, I'd sure like to know. And if anyone ever reads this WITH a similar problem, use a micrometer, and be sure. I did not, and gave myself headaches.
Gregg
 
I think you have answered your own questions.
Consistent ignition is key to low ES, although I take a bigger concern over ES than SD in the game I do, which is 1000yrd work. Both low ES & SD go hand in hand, but ES rules for long range.
I have seen tremendous 1/4 MoA groups @ 100yrds with terrible ES, above 100fps deviation. This all boils down to barrel vibration and where the barrel is pointing at time of bullet exit. At 1000yrds the ES would destroy ANY good things regarding the previous accuracy with that load.
Just as a side note, I have never seen a difference on target with uniformed pockets, but have shrunk groups by employing a technique of swirling the powder into the case and having very consistent packing of the powder, this is very important to extreme accuracy.
'As dumped' & 'swirled' charges sit at very different heights in the case, differing heights in the powder also influenece ignition and burn time, getting it all consistent is key.

Hope this makes sense.

Cheers.
;)
 
I think you have answered your own questions.
Consistent ignition is key to low ES, although I take a bigger concern over ES than SD in the game I do, which is 1000yrd work. Both low ES & SD go hand in hand, but ES rules for long range.
I have seen tremendous 1/4 MoA groups @ 100yrds with terrible ES, above 100fps deviation. This all boils down to barrel vibration and where the barrel is pointing at time of bullet exit. At 1000yrds the ES would destroy ANY good things regarding the previous accuracy with that load.
Just as a side note, I have never seen a difference on target with uniformed pockets, but have shrunk groups by employing a technique of swirling the powder into the case and having very consistent packing of the powder, this is very important to extreme accuracy.
'As dumped' & 'swirled' charges sit at very different heights in the case, differing heights in the powder also influenece ignition and burn time, getting it all consistent is key.

Hope this makes sense.

Cheers.
;)
I am sure your rite. Thanks all, will post results soon.
Gregg
 
I've done priming several different ways and don't see a difference when seated correctly. I uniform the primer pockets on win brass but it was not needed on Norma brass.

Magmaniac, how do swirrled case perform in a hunting setting where they are packed around and could go a few years without being shot? Are you using compressed loads with this method?
 
I had the same thing happen with my EZ prime. The rod was just too short to seat the primers all the way. I took it out and went to my anvil and hammered on the rod a little stretching it another .010 and now I can feel the primer seat all the way.
Broke my RCBS primer seater last nite. It's on a Rock Chucker Supreme, so was unable to find a replacement today. Instead I bought a Lyman EZee Prime. This is the third loading on new brass, so I knew that the primers would seat at least flush. Well, they didn't. Some were ok, others stuck out. Scratching my head I re-read the destructions, and it says that the plunger will NOT bottom out, yet I could not squeeze the handle hard enough to get any more travel in order to push the primer up into the case, to at least flush. I found an old feeler gauge spark plug gapper in my tool box that is narrow enough to lay in that recess in the middle of the RCBS shell holder. Stuck a shell on there, pushed the .013 feeler gauge in, pointed the **** thing away from my face, squeezed the handle....and pushed the primer home . Not just flush, either. It has the "right" feel to it, slightly below the case head. Did them all again, got that same recessed depth to all of these cases. I have been fighting protruding primers in this cartridge for the entire time I've been loading for it. Sometimes the durn things would not even chamber. And my new chronograph has been telling me that my velocities are all over the map. ES this last time out was 72fps.
As to the cause of this, I have no idea. At a WAG, I think the shell holder is minimal in some dimension or other, or wore out, or ...yeah, I dunno. But, if primer seating depth affects velocity, then could be I found at least PART of my problem. Questions, comments, concerns are welcome, encouraged, even. What say you all ? Hope this was not to long, tried to keep it short. Thanks.
Gregg
when it seats.
 
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