Just thinking mechanically, M-Tecs, I would think that with a drilled-out flash hole, the pressure on the primer would be less. Can't address the smokeless/209 issue.
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Just thinking mechanically, M-Tecs, I would think that with a drilled-out flash hole, the pressure on the primer would be less. Can't address the smokeless/209 issue.
Lead Forever!
The 2nd amendment was never intended to allow private citizens to 'keep and bear arms.' If it had, there would have been wording such as 'the right of the People to keep and bear arms shall not be infringed. -Ken Konecki, July 27, 1992
John Galt was here.
"Politics is the art of postponing an answer until it is no longer relevant". (From the movie 'Red Tails')
Same cartridges are 65,000 PSI SAAMI. Priming compound will not produce 65K. With the smokeless muzzloaders some loads are over 50K using a primer designed for a 14.5K max cartridge. The small vent liners restrict the gas pressure enough so it's not an issue until the hole erodes. On cartridges with low pressure it's possible the primer pressure is greater than the chamber pressure.Originally Posted by Bloodman14
I don't ever remember seeing what pressures just a primer would produce in the cup and pocket.
Different relative strengths of primers here:
http://www.castingstuff.com/primer_t..._reference.htm
http://www.jamescalhoon.com/primers_and_pressure.php
Last edited by M-Tecs; 03-21-2019 at 01:24 PM.
2nd Amendment of the U.S. Constitution. - "A well regulated Militia, being necessary to the security of a free State, the right of the people to keep and bear Arms, shall not be infringed."
"Before you argue with someone, ask yourself, is that person even mentally mature enough to grasp the concept of different perspectives? Because if not, there’s absolutely no point."
– Amber Veal
"The Highest form of ignorance is when your reject something you don't know anything about".
- Wayne Dyer
What is a vent liner? Not owning a smokeless muzzle loader, the term is beyond me. Not questioning your wisdom or experience, sir, just looking for some education.
Lead Forever!
The 2nd amendment was never intended to allow private citizens to 'keep and bear arms.' If it had, there would have been wording such as 'the right of the People to keep and bear arms shall not be infringed. -Ken Konecki, July 27, 1992
John Galt was here.
"Politics is the art of postponing an answer until it is no longer relevant". (From the movie 'Red Tails')
"I never was concerned about increased pressure of the powder charge from larger flash holes. I do have a mild concern about increased pressure in the primer itself increasing the chance of a blanked or pierced primer."
That is one of the main concerns that is always expressed. If there was greater pressure in the primer with a drilled out flash hole than with a standard flash hole don't you think it would manifest itself in a greater flattening of the primer? Yet we don't see that at all in either test. The flatness of the fired primers regardless of flash hole size is identical. Thus far I have fired 136 cartridges at 56 t0 57,000 psi (measured) w/o a single indication of any greater primer flattening with drilled flash holes vs "standard" flash holes.
Perhaps there actually isn't any greater increase in pressure inside the primer? Or if there is an increase it is not a sufficient increase to pose any problem or danger.
Attachment 238389
A further argument, if not the main argument, against the use of drilled out flash hole cases for gallery loads is that if you inadvertently use them with a standard load it could be dangerous. Thus if you have a standard load that doesn't pierce or blow the primer and inadvertently use a case with drilled flash holes it appears there really isn't any concern. The point of this test was to determine that. It is not suggested what so ever that full power loads be developed and used with cases having drilled out flash holes.
Such cases should be used with gallery or other low level cast bullet loads. The purpose of drilling out flash holes for use with gallery or other low level loads is to negate the headspace of the case from shortening with repeated firing from the primer pressure in push feed actions. That is all.
Last edited by Larry Gibson; 03-21-2019 at 10:23 AM.
Larry Gibson
“Deficient observation is merely a form of ignorance and responsible for the many morbid notions and foolish ideas prevailing.”
― Nikola Tesla
https://www.badgerridgeind.com/store...VentLiner.html
2nd Amendment of the U.S. Constitution. - "A well regulated Militia, being necessary to the security of a free State, the right of the people to keep and bear Arms, shall not be infringed."
"Before you argue with someone, ask yourself, is that person even mentally mature enough to grasp the concept of different perspectives? Because if not, there’s absolutely no point."
– Amber Veal
"The Highest form of ignorance is when your reject something you don't know anything about".
- Wayne Dyer
"Perhaps there actually isn't any greater increase in pressure inside the primer? Or if there is an increase it is not a sufficient increase to pose any problem or danger."
I don't know the answer but I tend to agree that it's not an issue at SAAMI pressures. Before the high BC bullets were allowed for Palma competition some would push the limits pretty hard. These people claimed the small flashhole small primer pocket 308 case would withstand the high pressures better. The actions for these loads normally didn't have ejectors since the brass would flow into the plugger hole. Barnard, RPA and Gilkes-Ross are the ones that come to mind.
When the 80 grain Sierra Bullet was the only option for 5.56 long range loads the AMU used a load called the V8. They used virgin primed LC brass with crimped GI primers. The primer pocket was shot after one firing. If I remember correctly the claim was it was about a 77,000 PSI load. Never fired any but I did pick up some of the brass from V8 loads and even with the hard LC brass and crimp GI primer the case pockets loosened to the point they were unusable after the first firing.
Would enlarged flasholes make a difference in this loads? I don't have a clue and the need for these type of loads has long since past due to rule changes and higher BC bullets.
Back to reality. The only cases that I have enlarged the holes on are 38 Spec and 45 Colt for wax bullets and 45/70 rifle for Blackpowder loads. These were mostly for other people. I did try a limited amount of 45/70 with enlarged holes for BPCR but I found no improvement in accuracy. My testing was limited and far from the end word on the subject. I didn't see any advantage and since I segregate my 45/70 into the 3 pressure levels and a fourth for Blackpowder only cases I didn't want to mess with a fifth group for enlarged flash holes unless I saw a real benefit.
All of my ultra low pressure loads have been on rimmed cases shoulder so setback is something I have never had to deal with.
Personally I always believed that the pressure inside the primer cup would be the same based on gas flow dynamics regardless of flashhole size in the case until I started with the smokeless muzzleloaders with 209 primers. In this case the .032 vent liner allows the 209 primer to be used with 50K+ loads. I an not sure why this works since a restriction of this type should not reduce pressure just volume of flow. It may be a simple as the volume of flow is reduced enough that it allows the 209 primer to leak enough that pressure limits are not exceeded. Not sure if I will build anymore but if I do I will switch to the newer designs that use large rifle primers like this: http://arrowheadsporting.com/arrowheadplug_lrmp.html
Last edited by M-Tecs; 03-21-2019 at 03:33 PM.
2nd Amendment of the U.S. Constitution. - "A well regulated Militia, being necessary to the security of a free State, the right of the people to keep and bear Arms, shall not be infringed."
"Before you argue with someone, ask yourself, is that person even mentally mature enough to grasp the concept of different perspectives? Because if not, there’s absolutely no point."
– Amber Veal
"The Highest form of ignorance is when your reject something you don't know anything about".
- Wayne Dyer
WOW, This is why I hang out here and read more than I post. Lots of brain power here making me a bit more enlightened about this new hobby. Thanks Larry!!
So, does that thing thread into the front of the breech plug, with the 209 in the back? Does it act like a flash hole extension?
Lead Forever!
The 2nd amendment was never intended to allow private citizens to 'keep and bear arms.' If it had, there would have been wording such as 'the right of the People to keep and bear arms shall not be infringed. -Ken Konecki, July 27, 1992
John Galt was here.
"Politics is the art of postponing an answer until it is no longer relevant". (From the movie 'Red Tails')
Yes it threads into the front of the breech plug. Other versions use carbide bushings. http://arrowheadsporting.com/breechplugs.html
Not sure what a flash hole extension is but these systems do reduce and extend the flash hole. Once they erode accuracy goes south fast. If you continue primers get sticky. The question is why? I am starting to believe the sticky primers are from increased volume of gasses exceeding the leakage. Not sure why the accuracy goes south so fast.
Last edited by M-Tecs; 03-21-2019 at 05:52 PM.
2nd Amendment of the U.S. Constitution. - "A well regulated Militia, being necessary to the security of a free State, the right of the people to keep and bear Arms, shall not be infringed."
"Before you argue with someone, ask yourself, is that person even mentally mature enough to grasp the concept of different perspectives? Because if not, there’s absolutely no point."
– Amber Veal
"The Highest form of ignorance is when your reject something you don't know anything about".
- Wayne Dyer
Keepers those are expensive. I think you can buy the Savage ones cheaper.
Even though I don’t shoot my rifle very much every year (two sighters, two deer max) I bought a bag of stainless coned head screws and some .030 bits. I am planning to make my own if I ever use up the factory ones I have.
NRA Endowment Member
Armed people don't march into gas chambers.
Is drilling-out, enlarging, flash holes "dangerous"?
I dunno... but since I have owned the RCBS broach tool for about 25yrs; I use it.
Seems like a lot of trouble to drill flash holes larger; and it changes one very large variable; namely, the volume of flame entering the case and igniting the powder charge.
To what real purpose? Does it invalidate all the loading manual data? Probably. Loading manual data all works off pressure readings. The flash hole uniform diameter is a very valid pressure constant. Anyway.... what kind of jig would you use to maintain the centering? Sure, there are taper drills and two-step drills; but very spendy and wouldn't you still need your brass mounted in a die or something like a Wilson Trimmer case-holder?
I like the RCBS Flash Hole uniforming tool because the broach uniforms the brass that's extruded into the case from the flash hole drill. Not every case needs uniforming; Lapua is about 100% ready to go, but for uniform ignition in making match quality ammunition, you do it anyway; at least I do.
Certainly drilling out flash holes would be a danger in an over-pressure situation, pierced primer, blown primer. Greater volume of gas venting through your bolt body, about 4" from your eyes???
Uniforming with a broaching tool delivers consistency within the spec used by all companies that publish data. There are, after all, different load data sets for large and small primed case cartridges. Doesn't seem worth the risk to me.
edward hogan
Is drilling-out, enlarging, flash holes "dangerous"?
I dunno... but since I have owned the RCBS broach tool for about 25yrs; I use it.
To what real purpose?
That is the subject of the question asked in the opening post. The test has shown that it is not, at lest with a 55 - 56,000 psi load using hacketed bullets of 147 - 168 gr. I use a Lyman flash hole uniformer but it does not alleviate the problem that drilling flash holes alleviates; that of case headspace problems associated with reduced loads (squib, cat's sneeze, mouse fart, etc). It is a known. provable fact that drilling the flash holes out larger in cases used with such loads negates the primer from pushing the shoulder back on rimless cases, especially in push feed actions. when inadvertently using such a case with a drilled flash hole presented any problems was the question.
Seems like a lot of trouble to drill flash holes larger; and it changes one very large variable; namely, the volume of flame entering the case and igniting the powder charge.
It's not really a "lot of trouble" as it is easily done with a hand drill or with a drill press. Takes no more time than uniforming the flash holes with a RCBS or Lyman tool. Yes, it does change that one variable that the flame does get into the case quicker filling the case volume better. This has proven beneficial with improved ignition when small charges giving very low load density are use. Internal ballistics are often improved with those loads and powder position sensitivity is also lessoned.
Does it invalidate all the loading manual data? Probably. Loading manual data all works off pressure readings. The flash hole uniform diameter is a very valid pressure constant.
How so would it invalidate loading manual data? Probably not as the test pretty conclusively demonstrates there is little difference between standard flasholes and those drilled out as large as practical. I measured the peak pressure, the time/pressure curves, the rise, the area under the curve etc. and found no evidence of any change between the standard size flash holes and the drilled out flash holes or of any size in between.
Anyway.... what kind of jig would you use to maintain the centering? Sure, there are taper drills and two-step drills; but very spendy and wouldn't you still need your brass mounted in a die or something like a Wilson Trimmer case-holder?
None is needed at all, the cases used above were held in my left hand while I used a small hand drill in my right hand. The existing flash hole is the guide for the drill bit.........was very easy to do.
I like the RCBS Flash Hole uniforming tool because the broach uniforms the brass that's extruded into the case from the flash hole drill. Not every case needs uniforming; Lapua is about 100% ready to go, but for uniform ignition in making match quality ammunition, you do it anyway; at least I do.
Again you miss the point of using cases with the flash holes drilled out. Were not talking "making match quality ammunition" we're talking making squib, cat's sneeze, mouse fart loads.......
Certainly drilling out flash holes would be a danger in an over-pressure situation, pierced primer, blown primer. Greater volume of gas venting through your bolt body, about 4" from your eyes???
Ah yes, one of the usual "fears" expressed.......except the evidence doesn't demonstrate that. By the time you get to a blown primer the size of the usually is eroded out also. You have blown enough primers with various size flash holes with "over pressure loads" in an actual test to have definitive proof? Or is it just conjecture?
Uniforming with a broaching tool delivers consistency within the spec used by all companies that publish data. There are, after all, different load data sets for large and small primed case cartridges.
Again you miss the point. Obviously you don't use squib, cat's sneeze or mouse fart loads because I don't see any in the major loading manuals. Certainly is your choice. If you should change your mind and try some (BTW; drilling the flash holes is only recommended in cases taking LR primers........a closer reading of post #1 would reveal that), especially in rimless cases in a push feed action you may find to your dismay the headspace of your uniformed cases that the headspace has shortened in only a few firings of such a load. When you get misfires and/or failure to extract you'll then, perhaps, understand.
Doesn't seem worth the risk to me.
The reason for the test was to determine if there was a "risk". The test demonstrated there is no "risk". But again, you are entitled to your own opinion.
Larry Gibson
“Deficient observation is merely a form of ignorance and responsible for the many morbid notions and foolish ideas prevailing.”
― Nikola Tesla
On the issue of does a drilled out flashhole increase the pressure in the primer? I don't see anyway this could be possible since the duration of maximum pressure in the case and barrel far exceeds the time it would take to equalize pressure in the primer pocket. What could change is the rate of flow but again I don't see how this would have a meaningful effect at SAAMI and under pressures. The other theory is the larger flashhole changes the rate of the powder burn. Larry's test results show this is not a significant factor.
In the case of the why smokeless muzzleloaders running very high pressures can get by with using 209 primers I am not sure. They do use vent liners with .030" holes. I have ran mine you to about .040" and started getting sticky primers. Sticky primer extraction indicates over pressure for this type of system but why? These types of systems have some leakage and the larger hole MAY allow the rate of flow to exceed the rate of leakage??? Could be something else also?????
I have no clue how much pressure a 209 will withstand but based on Tom Roster tests it's a lot more than I would expect . https://www.shotgunlife.com/shotguns...pressures.html
Last edited by M-Tecs; 03-28-2019 at 10:43 PM.
2nd Amendment of the U.S. Constitution. - "A well regulated Militia, being necessary to the security of a free State, the right of the people to keep and bear Arms, shall not be infringed."
"Before you argue with someone, ask yourself, is that person even mentally mature enough to grasp the concept of different perspectives? Because if not, there’s absolutely no point."
– Amber Veal
"The Highest form of ignorance is when your reject something you don't know anything about".
- Wayne Dyer
I received 100 30-30 cases from a member here in which the primer Pockets had been uniformed and the flash holes drilled out larger. I am glad to hear that I can use them with normal loads not just light loads.
Sent from my SAMSUNG-SM-G930A using Tapatalk
Thank you for sharing all that work. I don't often size cases and this seems to be the root of my intermittent low pressure neck joint donuts in 308 and 358.
Larry, you never replied to my questioning of the data you posted here, did you make a mistake? 43.0 grs of IMR 4350, 147gr fmj from 24 inch barreled 308, 2800 fps and 56k psi, this just does not sound correct?????
I went out today with 5 rounds of 308 ammo to run over the chrony
Temp was 47*F
308 TC Compass 22" barrel
IMI brass FL sized(heaviest brass I have)
150 Horn SP seated to cann seating depth .322"
CCI#250 Primer
43.0 Gr IMR 4350
2234fps 43 fps extreme spread
If I had to make an educated guess as to pressure 40K
550 fps is a big gap for 2 inches of barrel
Last edited by swheeler; 04-15-2019 at 09:51 AM.
Charter Member #148
Larry, interesting work, thanks for publishing your results.
“The results of my test firmly demonstrated to me that it was the force of the primer explosion that drove the case forward and set back the shoulder. The squib load does not have the pressure to expand the case out to fit the chamber. By drilling out the flash hole the force of the explosion mostly went directly into the case as there is little rim left to contain it.”
Is it correct to say that this depends upon the primer backing out? If the primer does not back out then it would exert no net forward pressure on the case, correct? I’m working from 1st year physics that’s several decades old; the question is sincere.
If that’s the case, then would staking (difficult) or sealing (easy) the primers in cases with standard flash holes contribute additional useful data to the analysis? I’d think that such cases would show no increasing headspace, further refuting the firing pin theory and supporting the primer pressure theory.
Jim, I think your question is correct; the primer fires, and sets back against the bolt face, hence driving the case forward (since it cannot expand into the chamber fully), which in turn forces (sets) the shoulder back. Sealing or staking the primers in might work, but with properly sized brass, don't know how worthwhile it would be, unless you are working with new brass that has been FL sized.
Lead Forever!
The 2nd amendment was never intended to allow private citizens to 'keep and bear arms.' If it had, there would have been wording such as 'the right of the People to keep and bear arms shall not be infringed. -Ken Konecki, July 27, 1992
John Galt was here.
"Politics is the art of postponing an answer until it is no longer relevant". (From the movie 'Red Tails')
When the primer fires the pressure in the primer pocket dislodges the primer and it starts moving back and the case moves forward. The product of ignition is also squirting through the flash hole which also tends to push the primer and case rearward.
Where I have a problem with the idea that the primer firing is causing shoulder setback is that it seems counterintuitive for the primer to show no effects of firing even though it has negligible mass relative to the mass of the rest of the cartridge. I understand that the energy is mass x velocity, so the primer is going to be going rearward at high speed while the rest of the cartridge is poking along until the powder charge fires, at which point the bullet pops and the case moves rearward.
I’m rambling, but the physics of the thing interests me.
What happens if you fire a primer in a case with no bullet? If the primer is moving the case forward, removing the powder and bullet shouldn’t materially change the deformation at the shoulder.
What happens if you fire a primer in a case with no bullet? If the primer is moving the case forward, removing the powder and bullet shouldn’t materially change the deformation at the shoulder.
But it does as mentioned in the testing conducted and reported in post #1 I believe.
Larry Gibson
“Deficient observation is merely a form of ignorance and responsible for the many morbid notions and foolish ideas prevailing.”
― Nikola Tesla
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