How Much Primer Crush?

[Kyle Schultz]

Just acquired the 21st Century priming tool that has 0.00125" travel per click. Very pleased with my purchase. I'm priming 6.5x47 Lapua cases with CCI 450 primers.

I found that generally the primers "bottomed" at 27 clicks back from the tool head being fully "closed". From there, I screwed the head in 3 clicks or a theoretical 0.00375". With the head in this position, when the primer bottoms, there is about a 1/4" of space between the tool body and the handle. And when I complete the cycle, I get what I would describe as a medium soft crush.

I fired 90 of these cases with no problems but just because the rounds fire that doesn't mean what I'm doing is optimum. Does this degree of crush sound about right depth? TIA!

 

[spclark]

Hmm... not on first-hand terms with that particular device. I use a Sinclair tool, like it a lot since the RCBS I started with 14 years ago self-destructed around 2005. With that I squeeze just a little bit more until I feel a firm resistance once I have the cups seated. This click-notch thing sounds intriguing, kinda like a torque wrench? But vertical rather than rotational?

 

[Damon555]

Push it in until the primer bottoms out......Is there another way to do it? Maybe I've been missing out on a little secret.

 

[BoydAllen]

The shooters that I know that shoot short range benchrest, including world record holders seat primers by feel. I do the same thing. It is hard to know what someone else is feeling as he uses a tool. I use the adjustment on my 21st century tool to put the lever where I want it when the primer is seated. As long as the handle does not finish too near the tool's body, I am good to go. I prefer not to use handle contact as a stop. I seat till I feel the primer bottom and then apply a little more pressure to preload the priming pellet a bit. Yes it is subjective. The only exception would possibly be the Russian primers that have been said to require more pressure after bottoming, because their compound is of an entirely different material that others, more like an extruded plastic pellet.

 

[Kyle Schultz]

... I seat till I feel the primer bottom and then apply a little more pressure to preload the priming pellet a bit...

"a little more pressure" is the phrase I'm trying to better appreciate. It's easy to feel the cup touch bottom but the additional seating beyond that; do you feel like you're firmly seating or are you just lightly loading? My suspicion is that I'm crushing a bit too much.

 

[BartsBullets]

Primer Preload Test

This was a post of mine over on benchrest central. I tested various primer depths with the PMA priming tool shooting a dasher.


Findings:

1. Nothing good happens until the primer touches the bottom of the primer pocket! I started with primers seated as far out as possible and worked my way in using a priming tool that I bought from PMA tool. The tool has tactile clicks so it's very easy to adjust and incrementally change the primers seating depths .002 per click

2 Primers with a slight amount of crush shot just as well as primers that were seated just touching! Slight amount being .002 to .004, after that groups started getting erratic and opening up!

Addendum - I was told that it moved .002 per click which very well could be wrong. So anything 2 tactile clicks from just touching the groups started to open up.

The primers that I used were small rifle CCI 450 Magumums.

Conclusion: I really like my 21 Century priming tool from PMA!

Bart

 

[msinc]

I have to ask this question: How do you know when you...A. Seated a primer correctly {as opposed to not getting it right, what happens when you fire the round. Do you see it on target, chronograph, fired case, what???} B. Have what is termed "reliable ignition"???
I understand now {didn't a week or so ago} why you want a good firing pin and spring and if we are talking benchrest not necessarily a lightweight {like a Tubb} firing pin. I get that it is supposed to give you "reliable, consistent ignition"...but, how do you know when you fire the rifle that is what you have or have not??? What specifically are you looking for??? How much smaller of a group do you expect "having it" and/or and more importantly, how much larger of a group would you expect if you believe {or even better, can prove} that you don't??? How do you positively prove you have or do not have "reliable ignition"???? Thanks in advance for any info!!!!
This may sound stupid but, I have been reloading since 1979 and can count on one hand the number of my reloads that failed to fire. Sounds reliable to me...what am I doing wrong anyway????
Edit: I ask this because I see a lot of posts and hear a lot of talk regarding this subject, but invariably no one ever backs it up with facts or really defines reliable ignition...i.e. groups opened up .XXX" or chrono showed XXX. Even Tony Boyer in his book about rifle accuracy has an entire chapter devoted to firing pins and "reliable ignition", but no one ever defines it. Obviously, the gun going "BANG" every time is not "it." So what is "it"???? If it is just a matter of groups opening up, how do you know they opened up due solely to unreliable ignition????

 

[JohnKielly]

I've an excuse because I can't feel the primer seating over my screams from the arthritis in my thumb, so I went over to thes unit ( http://kmshooting.com/primer-tools/primer-seater/primer-gauge.html ). It's admittedly slow, because the first step is to measure the depth of each primer pocket relative to the thickness of the primer, adjust the dial to zero, then seat with .003" crush for LR primers, .002" for SR recommended by K & M. Seems to work, because immediately I changed over to it, my Palma loads went from high teens or low twenties to below 10 velocity spread.

Now I can get both thumbs on the lever in the most comfortable way & hardly ever cry when I'm priming.

 

[waldo1979]

It's my understanding that the 21st century tool was 0.002" per click? I generally crush about 0.001" which is 1 click more than where i start to feel the slightest pressure from bottoming.

 

[BartsBullets]

I have to ask this question: How do you know when you...A. Seated a primer correctly {as opposed to not getting it right, what happens when you fire the round. Do you see it on target, chronograph, fired case, what???} B. Have what is termed "reliable ignition"???
I understand now {didn't a week or so ago} why you want a good firing pin and spring and if we are talking benchrest not necessarily a lightweight {like a Tubb} firing pin. I get that it is supposed to give you "reliable, consistent ignition"...but, how do you know when you fire the rifle that is what you have or have not??? What specifically are you looking for??? How much smaller of a group do you expect "having it" and/or and more importantly, how much larger of a group would you expect if you believe {or even better, can prove} that you don't??? How do you positively prove you have or do not have "reliable ignition"???? Thanks in advance for any info!!!!
This may sound stupid but, I have been reloading since 1979 and can count on one hand the number of my reloads that failed to fire. Sounds reliable to me...what am I doing wrong anyway????
Edit: I ask this because I see a lot of posts and hear a lot of talk regarding this subject, but invariably no one ever backs it up with facts or really defines reliable ignition...i.e. groups opened up .XXX" or chrono showed XXX. Even Tony Boyer in his book about rifle accuracy has an entire chapter devoted to firing pins and "reliable ignition", but no one ever defines it. Obviously, the gun going "BANG" every time is not "it." So what is "it"???? If it is just a matter of groups opening up, how do you know they opened up due solely to unreliable ignition????

MSINC,

I suggest you try and test some of this stuff for yourself.

But as far Seating a primer goes "push until it hits bottom." You can even push on it and crush it a little and it still won't screw things up.



Ignition overall is a lot bigger picture. Probably the easiest way to determine if your ignition is good is with a chronograph. If you meticulously reload your rounds and can get your ES to 15 fps or better, I say you're good to go.

Yesterday, I was chronographing a friend shooting his rifle. He was getting ESs in the 40 plus range. I think he has an issue.

Bart

 

[Kyle Schultz]

It's my understanding that the 21st century tool was 0.002" per click? I generally crush about 0.001" which is 1 click more than where i start to feel the slightest pressure from bottoming.

The new 21st Century tool is 0.00125" per click.

 

[Kyle Schultz]

Thanks to everyone for your input. I think I'm going to lighten up 1 or 2 clicks.

 

[waldo1979]

The new 21st Century tool is 0.00125" per click.

Do you have a link to the new tool? The one I have is 0.0025" per click.

 

[ireload2]

I have an old McDonnell-Douglas white paper on the use of small arms primers in aircraft applications.
What we call crush they called reconsolidation .
Their recommendations came from the small arms primer manufacturers Olin and Remington.
The recommended reconsolidation was .002" to .006".

 

[BartsBullets]

I have an old McDonnell-Douglas white paper on the use of small arms primers in aircraft applications.
What we call crush they called reconsolidation .
Their recommendations came from the small arms primer manufacturers Olin and Remington.
The recommended reconsolidation was .002" to .006".

Ireload2,
Good info, however I'm very familiar with military specs. The "reconsolidation" or "crush" of .002 to .006 is to make sure it goes bang everytime. Military specs are all about reliability not accuracy.

LTC(r) Bart Sauter
U.S. Army, Aviation

 

[ireload2]

You must also have reliability for accuracy. I am way more than a little familiar with military specifications having worked in the defense industry and with their specifications for over 40 years. Many military specifications also address accuracy if you want to explore them a little more. The data that I mentioned was not originally from McDonnell Douglas. It was from Olin and Remington, people who know more about small arms primers than the US military. It does provide a basic range for a shooter begin his study of what works and what doesn't.

for example for the M-14 Rifle

http://quicksearch.dla.mil/Transient/AABF82492B954C37801B8B2E67733C7B.pdf

MIL-R-45012E
3.3.24.2 Accuracy.
3.3.24.2.1 Process qualification rifles. The accuracy of process
qualification rifles shall be such that when fired 10-shot targets at
a range of 100 yards, the average figure of merit (FM) shall not be
more than 3.2 inches and the standard deviation shall not be more than
0.6 inch when tested as specified in 4.5.7.1 and 4.5.7.4 using selected
lots of ammunition (see 4.4.4.2).
3.3.24.2.2 Individual rifle acceptance. me accuracy of individua
l
rifles shall be such that when fired 10-shot targets at a range of 100
yards, the figure of merit (FM) shall be not more than 3.2 inches when
tested as specified in 4.5.7.2 and 4.5.7.4, using selected lots,of
ammunition (see 4.4.4.2).
When using unselected lots of ammunition
(see 4.4.4.2), the accuracy of individual rifles shall be in accordance
with the acceptance criteria established by firing the ammunition to be
used for testing in the process qualification rifles (see 4.4.3.4, 4.5.7.
2
and 4.5.7.4)

Ireload2,
Good info, however I'm very familiar with military specs. The "reconsolidation" or "crush" of .002 to .006 is to make sure it goes bang everytime. Military specs are all about reliability not accuracy.

LTC(r) Bart Sauter
U.S. Army, Aviation

 

[BartsBullets]

You must also have reliability for accuracy. I am way more than a little familiar with military specifications having worked in the defense industry and with their specifications for over 40 years. Many military specifications also address accuracy if you want to explore them a little more. The data that I mentioned was not originally from McDonnell Douglas. It was from Olin and Remington, people who know more about small arms primers than the US military. It does provide a basic range for a shooter begin his study of what works and what doesn't.

for example for the M-14 Rifle

http://quicksearch.dla.mil/Transient/AABF82492B954C37801B8B2E67733C7B.pdf

MIL-R-45012E
3.3.24.2 Accuracy.
3.3.24.2.1 Process qualification rifles. The accuracy of process
qualification rifles shall be such that when fired 10-shot targets at
a range of 100 yards, the average figure of merit (FM) shall not be
more than 3.2 inches and the standard deviation shall not be more than
0.6 inch when tested as specified in 4.5.7.1 and 4.5.7.4 using selected
lots of ammunition (see 4.4.4.2).
3.3.24.2.2 Individual rifle acceptance. me accuracy of individua
l
rifles shall be such that when fired 10-shot targets at a range of 100
yards, the figure of merit (FM) shall be not more than 3.2 inches when
tested as specified in 4.5.7.2 and 4.5.7.4, using selected lots,of
ammunition (see 4.4.4.2).
When using unselected lots of ammunition
(see 4.4.4.2), the accuracy of individual rifles shall be in accordance
with the acceptance criteria established by firing the ammunition to be
used for testing in the process qualification rifles (see 4.4.3.4, 4.5.7.
2
and 4.5.7.4)

So back to the topic of primers. Are you saying that an aircraft ammunition spec of crushing a primer up to .006 equally applies to tuning for a benchrest competition load?

 

[Frankr]

I have to ask this question: How do you know when you...A. Seated a primer correctly {as opposed to not getting it right, what happens when you fire the round. Do you see it on target, chronograph, fired case, what???} B. Have what is termed "reliable ignition"???
I understand now {didn't a week or so ago} why you want a good firing pin and spring and if we are talking benchrest not necessarily a lightweight {like a Tubb} firing pin. I get that it is supposed to give you "reliable, consistent ignition"...but, how do you know when you fire the rifle that is what you have or have not??? What specifically are you looking for??? How much smaller of a group do you expect "having it" and/or and more importantly, how much larger of a group would you expect if you believe {or even better, can prove} that you don't??? How do you positively prove you have or do not have "reliable ignition"???? Thanks in advance for any info!!!!
This may sound stupid but, I have been reloading since 1979 and can count on one hand the number of my reloads that failed to fire. Sounds reliable to me...what am I doing wrong anyway????
Edit: I ask this because I see a lot of posts and hear a lot of talk regarding this subject, but invariably no one ever backs it up with facts or really defines reliable ignition...i.e. groups opened up .XXX" or chrono showed XXX. Even Tony Boyer in his book about rifle accuracy has an entire chapter devoted to firing pins and "reliable ignition", but no one ever defines it. Obviously, the gun going "BANG" every time is not "it." So what is "it"???? If it is just a matter of groups opening up, how do you know they opened up due solely to unreliable ignition????

My experience with a rifle with erratic ignition(bad firing pin) A rifle that should shoot .100 to .250 moa at 100 yards would shoot .750 no matter what you tried..You will replace a scope and it will shoot the same you will install a new barrel and it will shoot the same.so erratic ignition will show up as a bad group I never chrony'ed any but I am sure you would see a hugh variation in Velocity.

 

[21shooter]

Do you have a link to the new tool? The one I have is 0.0025" per click.

 

[21shooter]

Hi Waldo, Here you go..http://www.xxicsi.com/super-precision-click-head-br-priming-tool.html Thanks, John