Not yet. I'd like it to be fairly in depth, and I simply haven't had much for right testing conditions this year.
Primer crush…does it matter?
- Thread starter Justice1327
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you could have given that info in about 2 minutes. I almost fell asleep with this LONG presentation.
QuietTexan
Well-Known Member
Looking forward to it!
Do we have an understood definition of "primer crush"? Is it just moving the anvil legs closer to the primer cup mouth during seating, or does it include seating the primer so deep enough as to deform the primer cup itself?
You need to do some reading, to bring yourself up to speed. I done even want to be around if you are deforming the primer. It's seating the primer to about just below the back of the case. Seating the primer uniformly. Need to uniform the primer pocket depth. The primers work a little different depending on how much pressure is placed on the primer being set. You don't have to that exacting. Watch the video above. Everything helps.
Mikecr
Well-Known Member
In our context, crush is preloading, or pre-sensitizing seated primers.
2thou of crush used to be recommended as standard from primer makers. As far as I'm aware, there has never been another suggestion about this, one way or another. I have tested it with every primer brand/type I use, and found that it actually does seem best, with exception of CCIs (which for me, prefer 4thou crush).
You can resolve a common misconception with an understanding that crush is not directly tied to seating depth, or the case head, or force/feeling. Extrapolating crush from any of these doesn't work at all.
The only way to know crush for each primer seated is to actually measure it's crush.
The ONLY seater that does this is the indicated K&M.
It's a quality seater. The process is a bit slower in that there is a pre-seating/measure step added to use, but it's built in, you get good at it.
Anyway, why pre-sensitize (you may ask)?
It is to reduce the affect of striking variances, and then ES/SD from our loads. It can remove flyers from cutting edge tunes,
By reducing the force needed to set off the primer pill, any pin force beyond that need no longer matters. The primer has already gone off before the pin even stops traveling.
I don't know how, but consistent primer initiation actually affects results.
I have witnessed inconsistent striking directly causing significant flyers, that are very difficult to troubleshoot & prove..
Think about it, how are you going to prove it and fix it? Well, you can eliminate one contributor by setting primers to a standard.
The rest resides in your striking system. That would be another thread.
rsbhunter
Well-Known Member
I watched an older YouTube video with F Class John using a now unavailable Bald Eagle primer seater similar to the CPS. he was seating at .010 "depth". Sounds like ALOT to me, but its never disclosed how deep his primer pockets are. I'm still on the fence about how critical I want to be on primer seating, I use a Frankford Arsenal hand tool which is adjustable for depth, and I can still get .001 varience. But it intrigues me to do more research.... rsbhunter
marchboom
Well-Known Member
Has anyone called the primer companies and spoken with the engineers about proper primer seating? I'm sure they have done extensive testing on this "crush" issue. I would definitely go by their recommendation. How about talking with benchrest shooters to see what they do? If "crush" is beneficial then they will be doing it.
IMO, seat the primer until it firmly seats in the pocket and be done with it. With this method I have NEVER had a misfire in 50 yrs of handloading.
IMO, seat the primer until it firmly seats in the pocket and be done with it. With this method I have NEVER had a misfire in 50 yrs of handloading.
rsbhunter
Well-Known Member
marxchbloom ,THAT is an excellent idea!!!!! I agree that the companies have probably invested a lot of man hours ($$$$) into testing the results of primer depth and "crush" results.....see, there's always a gold nugget if you look through enough mud....rsb
I find it beneficial to define a term, especially a technical one, when involved in a conversation. My intent was to help everyone reading this thread know what is being referenced. I started with a broad range of possibilities in order to focus the perspective. This in no way infers I have performed at these extremes. However, some posts in this thread mentioned they have, see number 36 for example.
Your assertion that I am unread is ill founded. I have 17 reloading manuals dating back to 1978 as well as handloading books from authors ranging from Brennan to Zediker, and many in between.
I did view the above videos, and several others as well. Here is another one you may not have seen:
It provides an example how professionals discuss the definition of primer crush. Even they recognize this is a misnomer.
And speaking of reading, you would benefit from proofreading your replies before posting.
Excellent discussion. Thank you.
Justice1327
Well-Known Member
I have…2-4thou is what I was told. But being consistent is more important… providing your striking system is functional and consistent too.
I have reloading manual from the early 60's. Started reloading in 1962.
QuietTexan
Well-Known Member
We should have that thread. I'm putting a Tubbs pin and springs into a rifle to replace factory parts, but have had Gre-Tan recommended enough times that I'll probably try one of theirs.
I don't know of any methodology for comparisons here other than no mis-fires, no excessive spring grab on the pin, and no primer piercing.
