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Started by gman47564, January 02, 2022, 07:50:02 AM
Quote from: HufD63 on January 02, 2022, 10:23:23 AMI've been weighing them over 2 years now. I'm looking for the low end and the high end not neccessarily the exact same weight. I had a round that sounded and felt weak and hit low on the forward pit berm not making the target out at DC a couple years ago. Had to be powder or primer and since I was weighing powder on the A & D I had to believe it was a primer.DQ'd for the match after about $900 spent in travel and hotels alone. I haven't DQ'd from a weak round since LOL In my dog saga I came upon an interesting result.As it turned out my press priming bit me compared to hand priming. After studying my whole process the priming pin apparently was bent and it would force the primers in at an angle enough to tip the case to one side and jam the primer in the pocket. The cup would in turn distort to the point that the anvil would dislodge from the primer itself.I pulled down all dogs and noticed loose anvils as i deprived those vases and caught the primer for reuse. Even all fired cases for some time had loose anvils upon depriming. The interesting part was the salt & pepper appearance of the salvaged powder from the dog cases. ( I had noticed this in the past.) Also had several ftfs with the bullet jammed in the lands! Several of this bullets had a definite carbon burn stain on their base. This told me the primer had indeed ignited and would account for the partially burned salt & pepper powder. The primers from those also clearly indicated a burn had taken place. The autopsies of all these ftfs give me some idea that primer strike indeed will affect every and all aspects of shooting. The anvil "vrush" on a flat bottomed pocket places it for proper operation. A poorly installed primer is a recipe for failure. Clean bottom pocket is the only way to fly.Another problem encountered was it was super difficult to start the primers crooked in the pockets. For a time I actually chambered the pockets slightly to help start and seat any primer.For a time I blamed my repurposing of "pull down" primers as the cause and climate control in my reloading room was trying the primers.I guess we a learn from our mistakes.
Quote from: HufD63 on January 02, 2022, 10:45:08 AMI've had only that one low power round and after weighing 6000+ primers over the last couple years I've not found one I was scared to shoot in a match. However like i said with the money invested in getting to a match from where I'm at im not going to leave it to chance. There is no fun in weighing and measuring primers but to know i dont have an outlier in the box is worth it to me.
Quote from: mnbogboy on January 04, 2022, 06:38:29 PMI weighed a couple of flats once and visually inspeQuote from: bikemutt on January 02, 2022, 06:50:12 PMGood question Jerry, let me try to elaborate.Imagine a flat washer with an OD the same as a primer pocket, and a center hole at least is wide as the flash hole.If said shim washer happened to be 0.002 thick, and was set in the pocket, a pressed-in primer would be 0.002 off the flash hole.It'd be a bit like herding cats but, who knows a paer punch may be just the tool to punch some out the righttype of paper or sheet plastic may just fit the material bill.cted the culls. Prepunched perforated material with oversize flash hole size holes might be a good start or a window screen type of material. The plastic stuff! LolThe priming compound when it dries in the cup has a tendency to crack the light [email protected] had some cracks. Evaporation during drying must be pulling the weight out. In this past years shortages I saved hundreds of cups and anvils. I could weigh some samples of each and determine if weight differences could be tied to the metal parts. Obviously the thinner cups may indeed be less apt to cause missed or delayed ignition.
Quote from: bikemutt on January 02, 2022, 06:50:12 PMGood question Jerry, let me try to elaborate.Imagine a flat washer with an OD the same as a primer pocket, and a center hole at least is wide as the flash hole.If said shim washer happened to be 0.002 thick, and was set in the pocket, a pressed-in primer would be 0.002 off the flash hole.It'd be a bit like herding cats but, who knows
Quote from: PaLuke on January 06, 2022, 05:57:37 AMEric Cortina has a video on YouTube about primer pocket uniforming tools. Apparently they believe with top quality brass anything except cleaning the pocket is a mistake. The brass is so uniform that measuring from the top of the rim to the bottom of the primer pocket is almost perfect in distance. This distance is the only measurement that matters. I never really thought about it. I just clean my pockets and shoot. Probably not the way to do it but with my luck I'd trash new brass. Take care.
Quote from: HufD63 on January 06, 2022, 09:01:56 AM@gman47564 I don't pretend to completely understand it either Grant.I do however believe ignition can be tuned and optimized. The farther a pin falls the less the strike force as the spring extends it should weaken. Probably difficult to measure yet testing by some of the top shooters from many disciplines show it matters.A primer not fully seated that moves under the pin pressure is going to use up some of the pin fall energy. Again probably tough to measure.I've had FTF rounds that when pulled down the priming compound was burnt and the powder was discolored but the bullet never left the case. I've had FTF rounds when fire forming from parent to improved cases that the headspace was a little loose and the whole round was moved forward and the primer was dimpled. This is clear proof if the primer or the whole case moves under the pin a weak strike will prevent ignition. Many times a second hit will light these off. Too much grease on the pin on a cold day will slow the pin enough to affect ignition as well.So while I don't completely understand it ignition has to be just so to fire and with that I can believe irregularities in ignition will produce irregularities in accuracy. At that point it comes back to what is the acceptable amount of accuracy a shooter is looking for and is it being measured with a caliper or ruler?