M
moreguns
Guest
I have a bench mounted RCBS priming tool . Is there something better ? I have trouble seating them to the same depth in depth uniformed pockets.
I always use my primer pocket uniformer after depriming my cases and it seems to always take a bit of brass out of the bottom of the pockets; this is after having made them uniform during the case prep process. I use an RCBS Universal Hand priming tool now-a-day after having blown my left thumb up whilst using a Lee hand primer some years ago.
One notices while using the RCBS or the lee, because of the lack of much leverage, that some primers seat to the bottom of the pockets easily and some are seated with a lot of the ram travel left to go. Seating them to the end of the ram's travel requires the use of one's second hand.
This brings up the question: How are we getting consistent seating if we have to crush the heck out of some of our primers? I think this situation is masked when using a number of the other seaters that have more mechanical advntage.
Perhaps it makes no difference if some primers are crushed more then others but it runs counter to my logic. It makes me wonder if perhaps we should be measuring the length of our primer cups. Perhaps this condition lends itself to variations in crono numbers? If this situation does cause crono numbers to differ, what is the point of exactly measuring the depth primers are seated?
Primer crush does affect velocity. It can change 'boomyow' to 'click' in the extremes.
The K&M seater(with an indicator) is the only seater I'm aware of that leaves primers at the same CRUSH(whatever you choose for it).
It makes no difference if you uniform the pockets or not(I don't) with this seater, as it's zero'd for each primer height to the pocket it will come to rest in. I've tried it, and checked, you cannot do this by feel. Impossible..
It doesn't leave primers at the same height, and this doesn't matter at all.
Crush is what matters.
During load development(after seating adjustments), I've adjusted primer crush and firing pin strike for lowest ES. Then I test this again when it's cold out.
For CCIs I've settled at 5thou crush, and Feds at 2thou. This has been reliable, hot or cold, in various guns.
This also accounts for the ~thou of creep that occurs within a week of seating in normal tightness pockets. If your pocket's are loose, it's probably a waste of time to set crush consistantly. It'll never hold.
So why doesn't it make a difference in BR?
Alot of things make no difference in BR.
They are compensated for with sighters or distance.
Pete, over the years I have noticed that a difference in primer diameter, just 0.0005" makes a big difference in seating pressure. A Wolf is about 0.0005" larger than a Fed 205GM. The WSR (Winchester) is about 0.00075" larger. But, the seating pressure, while harder in one of the larger primers, and using the Lapua 220 Russian example, all seat with the same pressure within like primers and the same lot of cases.
If you are getting noticeable variation in pressure within the same brass and within the same primers you may have other problems. They should all seat within the same pressure feel.