The Creedmoor Forum

Creedmoor Technical Info => Reloading => Topic started by: gman47564 on January 02, 2022, 07:50:02 AM

Title: Primer pocket uniformity?
Post by: gman47564 on January 02, 2022, 07:50:02 AM
My first question is do you uniform primer pockets ?

I been watching alot of videos on this subject.. some say its a must and some say not so much.. what are you guys finding on this matter?

My next question is about primer seating depth.. how critical is it?  If one primer is .005 below flush will it shoot differently than one seated .008 below flush.. some say it will.. some say not so much..

I know to really answer these questions is to try it for myself.. and i will. But i would appreciate you guy's thoughts on the matter.. thanks..
Title: Re: Primer pocket uniformity?
Post by: Rob01 on January 02, 2022, 08:00:22 AM
I run a primer pocket uniformer on a drill through the pocket every time I prep brass but more so for the cleaning of residue than for uniforming as after the first time it doesn't seem to change much.

Never measured primer depth. A rabbit hole I won't hop into.
Title: Re: Primer pocket uniformity?
Post by: HufD63 on January 02, 2022, 09:04:05 AM
It depends on the brass IMO

If you are uniforming pockets to get uniform seating depth the critical dimensions are extractor rim thickness pocket depth and primer cup and anvil thickness. The extractor rim is what the priming tool "works" off, the rim. So if a person were trying to develop a process to achieve a consistent below flush measurement the rim is hurdle #1

Primers all have varying amounts of anvil protruding from the cup. The goal is to touch bottom of the pocket and put a uniform crush on the anvil. Measuring below flush would be a very inconsistent way to achieve this. Because of varying pocket depth, varying rim thickness and varying anvil protrusion measuring below flush would accomplish nothing in the way of uniform seating.

The only way below flush is a meaningful measurement is if you measure pocket depth and measure the primer including protrusion then do the math to see how much below flush gets the desired crush. In other words measuring every pocket, every primer and checking the below flush. There are inconsistencies in cup and and anvil in lot to lot as well as within lots.

.002" crush seem to be the minimum crush to insure good consistent ignition. This should be very similar to seating the primer until it firmly bottoms out in the pocket by feel. This explains why many of us have shot very well using any number of tools.

Getting to the point where a ladder test with primers seated .002 crush, .003 crush, .004 crush etc to find the optimum crush is a quantum leap from bottoming the primer out and calling it good.

With all that being said it's ironic you posted this because it's something I feel has been the "uncontrolled variable" in my reloading and I'm gearing up to get to the point where I can ladder what crush is optimal and be able to reliably repeat it.

As @Rob01 said it is a rabbit hole and a deep dark one at that LOL

Title: Re: Primer pocket uniformity?
Post by: gman47564 on January 02, 2022, 09:12:05 AM
Thanks for that write up dave.. well said. And i agree with everything you had to say..

Heres a video i found on it.. i like this guy.. he has alot of good videos on you tube called winning in the wind..

It may or may not shed some light on this subject..

https://youtu.be/Ep4KOhCWsV0
Title: Re: Primer pocket uniformity?
Post by: HufD63 on January 02, 2022, 09:41:21 AM
I like that he staggered his crush, I think .001" would be hard to accomplish and .002" should show a difference.

His results however were impossible for me "The viewer" to see.  Unless I missed it there was no mention of distance. The groups should have been shot on paper with either colored colored bullets or at seperate aiming points. I realize you could pull the individual shots off the shot marker but i would rather have a piece of paper i could look at and instantly see how they printed.

The groups or how they printed were quickly dismissed and he went straight to chrono info and I've never seen an award for ES or SD at any match I've shot. They've all been scored by group size and where they landed on the paper LOL

I completely understand the thought process and don't need any light shed on that,  I also don't believe the crush amount is a one size fits every situation but needs tested to a specific gun.

What I'm really interested in is how different people measure, sort, prime etc to arrive an exact repeatable crush. This guy skipped all that and for all I know he may have been seating to below flush with no regard for primer thickness and anvil protrusion making his test unmeaningful in regards to his goal. Probably not but you and I will have to just take his word for it that he actually got the crush he claimed.
Title: Re: Primer pocket uniformity?
Post by: Rob01 on January 02, 2022, 09:47:20 AM
And a real accuracy shooter weighs each primer separately to make sure there is the exact same amount of priming compound in each. Lol
Title: Re: Primer pocket uniformity?
Post by: jvw2008 on January 02, 2022, 10:16:35 AM
To me, this reloading subject is like the cherry on top of the sundae. It's the last step in making the best final product you can.

There is a lot of time and effort that goes into uniforming pockets and sorting primers by weight and/or height. More effort, is then expended getting the same amount of crush on each seated primer. I've been looking at this for about two years and have come to some conclusions that work for me.

It is too much work and there isn't enough benefit for me to chase this rabbit for plinking or steel shooting, even out to 1000 yards.

If you are going to strive for consistent pocket depth and crush, it's a lot easier if you use a high quality brass to start with. Pocket depth in Hornady brass is all over the place. In Alpha brass, it is extremely consistent. I just proved this to myself last night with 400 virgin Alpha cases, using a new tool from Primal Rights.

I have not yet done a controlled primer seating ladder with either my Dasher or BRA competitive rounds. However, random testing last year convinced me that long distance group size is affected by both primer depth and the consistency of primer crush.

The video that Grant referenced is interesting, but it's important to realize that there is not an optimum seating depth for every primer, case, and reload formula. Every rifle and every cartridge reload formula is different. I shoot two different 6mm cartridges in two different rifles. However, the primer, cup depth, powder, bullet, and bullet seating depth are the same in each of those two rifles.  One likes a 5 thousandths primer seating depth and the other prefers 3 thousandths. So just like bullet seating, there is a benefit to tuning your load via the amount of primer crush you use. If I had to guess, I would say there is a potential of improving group size by approximately 10% with this method.  To me, the effort is worth it for competitive BR shooting, but little else.
Title: Re: Primer pocket uniformity?
Post by: HufD63 on January 02, 2022, 10:23:23 AM
Quote from: Rob01 on January 02, 2022, 09:47:20 AMAnd a real accuracy shooter weighs each primer separately to make sure there is the exact same amount of priming compound in each. Lol

I'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
Title: Re: Primer pocket uniformity?
Post by: gman47564 on January 02, 2022, 10:27:37 AM
Thank you jerry.. well said as well.. i was thinking of getting a 21'st century primer pocket uniformer but after checking the depth on 20 lapua cases and found only a .0015 difference in them.. i think i will hold off getting one.. no desire to weigh primers and probably cant seat them any better than what the pockets are.. will stick to feeling them bottom out in the cup and calling it good.. thanks for all you guys insight on this..
Title: Re: Primer pocket uniformity?
Post by: Rob01 on January 02, 2022, 10:30:52 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

Was a joke but see the crew in here now so going to bow out. Never had a low power round ever so must just be lucky with my primers. You guys have fun weighing and measuring. ????
Title: Re: Primer pocket uniformity?
Post by: jvw2008 on January 02, 2022, 10:35:29 AM
Dave, you and I were posting at the same time so I didn't see your question regarding techniques to assure reliable results.

As you know, Greg Dykstra (Primal Rights) believes there are typically primer seating nodes, just as we see with bullet seating depth or a narrow range of powder charge. So hitting the mark in crush to the exact thousandth may not be necessary.

I think the real key is using a tool that measures pocket and primer depth very accurately and very rapidly. The old caliper method just doesn't get it done. There are some new tools which have come out over the last few years that do that job nicely. I can tell you I am extremely pleased with the new PR tool.

If anyone is interested in this PR tool, you will have to call to order it. It's not listed on the website yet.
Title: Re: Primer pocket uniformity?
Post by: HufD63 on January 02, 2022, 10:45:08 AM
Quote from: Rob01 on January 02, 2022, 10:30:52 AMWas a joke but see the crew in here now so going to bow out. Never had a low power round ever so must just be lucky with my primers. You guys have fun weighing and measuring. ????

I'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.
Title: Re: Primer pocket uniformity?
Post by: LeadHammer on January 02, 2022, 02:52:56 PM
I have often wondered about primer depth. Maybe next time I will group like depths together, and take note. The problem I have is we get lots of wind, may not be able to see the difference with my setup.
Title: Re: Primer pocket uniformity?
Post by: bikemutt on January 02, 2022, 04:04:12 PM
If the primer seating depth is more about the distance from the primer to the flash hole rather than from the case base to the primer, I wonder if single-use, or reusable shim washers would eliminate the need to measure depth, or use sophisticated primer seating tools.

Don't you just love harebrained ideas, lol :)
Title: Re: Primer pocket uniformity?
Post by: jvw2008 on January 02, 2022, 05:57:36 PM
Yo lost me with the washers Chris! ????

Can you explain more?
Title: Re: Primer pocket uniformity?
Post by: bikemutt on January 02, 2022, 06:50:12 PM
Good 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  :D   
Title: Re: Primer pocket uniformity?
Post by: Rob01 on January 02, 2022, 07:08:54 PM
Lol that's one of the funniest things I have heard in a while but the funniest part is if you made it then there are people that would actually buy it! Lol
Title: Re: Primer pocket uniformity?
Post by: jvw2008 on January 02, 2022, 07:35:54 PM
Chris regardless of whether that idea would work or not, your post is an excellent example of thinking outside the box. ???????? Keep those ideas coming!
Title: Re: Primer pocket uniformity?
Post by: BCz on January 02, 2022, 09:41:37 PM
Grant, as Rob01 stated I use a Lyman uniformer to clean my pockets, I'm finding it trims some pockets more than others. I feel that even though it may only touch the corners of some pockets it is giving me a uniform depth for the primer to bottom out on.
Keep in mind your brass blows out in all directions including the case head.

FWIW  It'll be a cold day in hell with lil devils wearing ice skates before I weigh primers.
Title: Re: Primer pocket uniformity?
Post by: jvw2008 on January 03, 2022, 10:09:26 AM
????????

"FWIW  It'll be a cold day in hell with lil devils wearing ice skates before I weigh primers."

I made a similar statement several years back. I still feel the same way for most of my reloading. Right up until I'm trying to put together a 1000 yard sub 3" group.
Title: Re: Primer pocket uniformity?
Post by: mnbogboy on January 03, 2022, 03:13:40 PM
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.
Title: Re: Primer pocket uniformity?
Post by: mnbogboy on January 04, 2022, 06:38:29 PM
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.
I weighed a couple of flats once and visually inspected the culls.
The 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.
Title: Re: Primer pocket uniformity?
Post by: mnbogboy on January 05, 2022, 10:26:04 PM
Quote from: mnbogboy on January 04, 2022, 06:38:29 PMI weighed a couple of flats once and visually inspe
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  :D   
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! Lol
The 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.
Title: Re: Primer pocket uniformity?
Post by: PaLuke on January 06, 2022, 05:57:37 AM
Eric 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.
Title: Re: Primer pocket uniformity?
Post by: BCz on January 06, 2022, 06:43:16 AM
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.
I can tell you with absolute certainty that on new Lapua and Peterson I've had some pockets trim and some not.  This tells me the brass isn't perfect to begin with.
Our job is to get it as similar as possible, uniforming pockets is a absolute necessity in my book.
Let's look at pin fall and force...
If primers are set at various depths pin fall and striking force will vary causing a inconsistency in ignition and precision of rifles ability.
I wish I could upload pictures to show you how much variation there actually is to new and fired brass just by using a uniformer with a set depth.
Title: Re: Primer pocket uniformity?
Post by: gman47564 on January 06, 2022, 07:03:32 AM
Let's look at pin fall and force...
If primers are set at various depths pin fall and striking force will vary causing a inconsistency in ignition and precision of rifles ability

This i don't understand.. by no means am i saying its not true.. i just dont understand how it has a effect on ignition.. does a primer burn hotter if its hit harder vs a lighter strike? In my mind the primer either ignites or it doesn't.. but there is probably more to it than that .. i just dont understand it.. can anyone shed light on how a difference in pin fall effects primer burn rate..
Title: Re: Primer pocket uniformity?
Post by: PaLuke on January 06, 2022, 07:07:13 AM
Hello, according to the video the pocket uniforming tool uses the bottom of the case as a stop for the depth of the tool. Out tools we use for installing primers use a shell holder and thus the top of the rim. I guess what he's saying in the video is that we can be changing the distance from the top of the rim to the bottom of the pocket with a uniforming tool which will add to inconsistency. I sometimes use my press primer installing tool and sometimes my Frankford Arsenal tool. Which pocket uniforming tool is best?  Thanks.   
Title: Re: Primer pocket uniformity?
Post by: 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?
Title: Re: Primer pocket uniformity?
Post by: BCz on January 06, 2022, 10:35:24 AM
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?
Thanks Dave!! Well put.
Title: Re: Primer pocket uniformity?
Post by: mnbogboy on January 06, 2022, 10:07:39 PM
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.
I did have a complaint about starlings brass, supposed to be high quality but i noticed that pockets were deeper than other brands and my uniformer ( redding) never touched or cleaned the bottoms as other brass. I did notice this on another batch of brass after the fact. It could have been prime (norma) or Hornady in another caliber.
From.my experience initial informing with my cordless drill method takes the majority out of the pocket bottoms and subsequent firings stretch it out enough that the uniformed takes out a little more for the first two firings I also found that as the pockets stretch and loosen that more will show up at the bottom to be removed. My uniformed is the operation that removes primer residue from the pocket.
Also my routine of stabbing the pockets with an alcohol swab cleans up slight residue on the pocket walls an provides for a better primer seal. Dirty pocket walls lead to primer leakage and ultimately loosens the primers. The clean each cycle routine has given me better pocket fit and ultimately longer brass life with less scrap from loose pockets. The primer pocket go-no-go gauge is also a great tool for measuring primer pocket health. Loose fit primers can be pushed out by hand with a depriving pin.
I tried the pocket tightening method that uses a pin and ball bearing. It does work somewhat to snug up the head end (rim end) of a pocket.
Title: Re: Primer pocket uniformity?
Post by: HufD63 on January 07, 2022, 05:56:15 AM
Link to a primer article I found interesting. Towards the end it touches on seating briefly.

 https://www.shootingtimes.com/editorial/ammunition_st_mamotaip_200909/100079
Title: Re: Primer pocket uniformity?
Post by: jvw2008 on January 07, 2022, 09:45:16 AM
I read that article probably 4 years ago. I thought it was great then and still do. I didn't really understand what he meant by "the bridge" but I do now.
Someone on here mentioned primer ignition in terms of burn rate. I didn't have the time to address it then but this article brings out a important point.

Smokeless gunpowder burns, primers explode. When thinking about how a primer performs it should be in the context of brisance not burn rate.

Because ignition of the primer explosive depends on a mechanical impact rather than the presence of a flame, proper and complete ignition requires a very specific impact and an appropriate bridge. Thus, adjustment of different seating depths can result in either very poor or very optimal ignition. So once again, this is an avenue towards tuning a load.
Title: Re: Primer pocket uniformity?
Post by: mnbogboy on January 09, 2022, 12:01:46 AM
Quote from: bikemutt on January 02, 2022, 04:04:12 PMIf the primer seating depth is more about the distance from the primer to the flash hole rather than from the case base to the primer, I wonder if single-use, or reusable shim washers would eliminate the need to measure depth, or use sophisticated primer seating tools.

Don't you just love harebrained ideas, lol :)
Chris in my quest for primers last winter I bought some #11 percussion caps for muzzleloaders. I dismantled a couple for the priming compound and they use a paper washer to hold that priming power in. It appeared to be like at him  tissue paper and when fired it would/could blow right through it but not plug the nipple on thecgun.

Maybe a paper punch on tissue wrapping paper would help you dispell your idea and provide the thickness you require to "lift" your primer. My wife said I shouldn't be shooting in the house when I was solving the ftf problem. I did shoot several primers as a test out in my mancave. My guess is it would blow right through tissue paper with enough fire to ignite powder. I would have to step out the garage for full power loads!
I've shot many times over the magneto speed after dark! She didn't like that either, she said the neighbors will think I'm nuts ( ah ye s but i am).
Title: Re: Primer pocket uniformity?
Post by: gman47564 on January 09, 2022, 05:45:52 AM
Its the "crush" of the anvil here that their trying to control if im understanding this right.. the distance between the tip of the anvil and the inside face of the primer cup.. knowen as the "bridge". I dont think you could control that with a shim..
Title: Re: Primer pocket uniformity?
Post by: NightForce on January 22, 2022, 05:08:14 AM
Quote from: Rob01 on January 02, 2022, 09:47:20 AMAnd a real accuracy shooter weighs each primer separately to make sure there is the exact same amount of priming compound in each. Lol

I didn't think anyone saw me!  ;D