Plugged flasholes--does it hurt anything?

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snuffy

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There seems to be a controversy about whether a piece of tumbler media left in a flash hole , then having a primer seated will have a bad effect on performance of a handload.

So I purposely tumbled de-capped, sized brass in corn cob media to get some with one chunk of it in the flash hole. From the same batch, some came out without the flash hole blocked. Leaving the FL die OUT of the first hole in my dillon 650, I proceeded to load 50 rounds.

The load is one that I have loaded thousands of, R-P brass, WC-844 powder at 24.0 grains, WW-sr primers, trimmed and FL sized,(but not in that order), Hornady 60 gr. V-max bullets.

The top two bullseyes are the two test groups. The two hits to the left of the right group were sighters. I was shooting 600 yds last Sunday, had to bring her back down. The group to the right of the center bull is where I was trying to get the chrono to register the bullets!:mad: Rifle is a bushy 20" HB, Nikon Monarch 5.5 X 14.5 AO

plugged%20.223-2.jpg

Now the chrono readings
Plugged
AV 2940
Hi 2953
LO 2929
ES 26.6
SD 11.6
AD 9.0

Unplugged
AV 2927
HI 2948
LO 2904
ES 44.7
SD 18.3
AD 14.9

To my way of thinking, the chrono said it didn't make any difference. Actually the plugged ones had a better ES and therefore SD But the target was double in size. I have some of each left, I'll run another test next time I go to the range. Right now, I think it does make a difference, in this particular load, rifle, and ammo combination on this day.
 
I had ONE 38 special cartridge that squibbed with 3.5 of Titegroup and a WIN small pistol primer, 158 lead SWC.
It was a weird squib, not even the pop of a primed, empty case. Kind of a snap and fizzle.

When I broke it down I found a clump of corncob stuck in the flash hole had blocked the primer flame from entering the flash hole. The powder was unburnt. The primer had popped.

A contributing factor I am sure was Titegroup is a very reduced volume powder and the .38 special is a large case. I use a small amount of powder in target loads. It's almost a pinch and nothing more.

Small amount of powder in a great big case, with a very weak primer flash= squib.

I decap AFTER tumbling, so how did this get in there?

My thoughts were it fell out of the bucket o'brass as I was topping off the Lee Pro-1K case feeder funnel, and landed in the primer trough, and got mushed in the case head when the primer seated.

I've had leftover media get left in cases and wind up in the case bucket before. I've had it jam up cases in the case feeder.

A freak occurance I am sure, but I always decap after tumbling.
 
I also wonder if the walnut would be worse than the corncob as far affecting shooting.
 
I tumble in corncob before depriming, then tumble again in walnut media after depriming, then inspect each case before hand priming.
 
Sure, a plugged flash hole will affect the firing. Just how much and in what way the change will be seen is dependant on how completely the plug covers the hole, how large the media particle is and the briesance of the primer. In other words, it will be totally unpredictiable so we should clean the media out before priming.

On average, doubt you will find any significant difference between cob and nut.
 
if I read your description correctly. You got .83" and 1.70" groups at 600 yards??!! Is that correct?
Click to expand...

Yikes, if that was so, I'd be looking into getting in the record books for that group!:what: Nope, I was shooting 600 yds, the week before yesterday, so I had to bring the elevation back down to 100 yd zero. I had it up 50 ¼ clicks to hit on at 600. Just forgot the 100 yd numbers on the turret.

Well, it's clear I have to shoot some more groups, plugged and unplugged to convince myself and others that it DOES cause problems. Yes the primer is perfectly capable of pushing the chunk of corn cob through the flash hole. BUT it apparently disrupts the shape of the flame to cause turbulence in the gas generated.
 
IMHO: I simply can't believe a piece of corncob, or even walnut tumbler media would stand a chance in heck of staying in a flash hole when the primer went off.

There is intense pressure generated in the primer cup just by the primer charge itself.

Enough to back out primers, and enough power to operate some early machinegun designs with backed-out primers alone.

A speck of tumbler media, and a fart in a tornado would stand about the same chance of staying together and causing any noticeable effect.

As a side note, I once fired a 5.56 GI round in an M-16 that did not have a flash hole drilled in the case.

It had enough power to expand the case head, leak smoke out of the action, and the crimped primer fell out when the round was ejected manually!

rcmodel
 
I've seen a couple of factory rounds with no flash hole at all. Both of them had very minimal reports, both backed the primers out, and both locked up the actions. One was in a Kel-Tec P32 around 2002 or so at my local range. The other was in a Glock 19 at the 2003 GAS match.
 
Since the differences appear to be small, you need more groups to tell.

Shooting the groups "blind" would be good science: You should not know, when you are firing them, whether you are firing the clogged-flash-hole cartridges or not. It will require some cunning on your part to be able to know when you are loading them and doing the analysis which were clogged, but not to know when you are firing them. You may need the help of another person to help encrypt the records after reloading (and decrypt them after shooting).
 
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I'm thinking that to test a worst case, you would need to press a piece of media into the flash hole. If those cases showed no difference then you would know plugged flash holes is a non-issue.

Do I understand correctly that you are applying Std Dev to 5 shot groups? That is a little silly unless you suppose you are seeing the vast majority of likely variation in just 5 shots. Since the difference in highest velocity between the two groups is less than 0.17% and the difference in low vel for the two is less than 0.86% I would be skeptical that you have seen all the statistically significant variation in your first 10 shots. The same principle applies to a target i.e., if a 10 (or 50) shot group (of a given sample) prints a larger group than a 5 shot group (of the same sample), the 5 shot group didn't show all of the variation. On the other hand, if your 5 shot group is just as large as your 50 shot group, those 5 shots are all you needed to determine the accuracy of that group.
 
I'd just like to thank snuffy for sharing the results of his testing with us.

Nice to see some facts rather than just conjecture. Or even facts followed by a bunch of other people offering conjecture. :cool:
 
I would shudder to think 1/2 of the rounds in my little 25 round load box had corncob in the flash holes and 1/2 did not when I went to the line, but for general plinking we would certainly never see the difference.

It may not make a difference period, but it would be in my head, causing doubt. :uhoh:
 
My take

first of all i believe it was Remington that had a problem with some .223s where the flash hole was missing and jammed up some guns. This happened a lot in California. There were a ton of threads on it last year on calguns


2nd as for the media in the flash hole. i think its more of a safety issue more than its a fireing problem. I dont think it should have made it to the firing process. Think about what your doing a piece of media is stuck in the flash hole. either sticking out in the primer pocket or the case. However lets just say its stuck in the flash hole. So now your about to take out your primer hand tool installer and install a live primer. Hoping the anvil does not engage the fulcrom and detonate the primer. Now i dont know about you guys. but its not worth the test. If i have media stuck in the flash hole im picking it out. So there will never be a test for me on how well it shoots with the flash hole partially covered.
 
I went to the range with a friend from work a few weeks ago. He had a box of Monarch ammo (45acp) Several of them had no flash hole at all! The primers blowing out the back left pieces of copper in the headspace and we had to beat it apart to get them out.
 
Bench rest shooters use a tool to remove the 'dingus' from the inside of the case. (That's the brass chunk that was punched out when the flash hole was formed.) It seldom falls free, and I have seen many rounds where this dingus was practically put back in place by a GI crimp removing tool. I check every flash hole before priming. Just my .02
 
Dingus may not be, Doofus is maybe. They sound like that they would be related. "That Doofus didn't remove the Dingus." I'm not sure on pluralization though.

I think Snuffy was sharing his info on "what if" one got by you. Personally I tumble then size/decap to avoid having to laboriously pick the media out the hole. I haven't found the walnut to clean the primer pocket enough to be worth it on .223 something with a large primer might work better. I have a universal decapper so it's not a problem just adds more steps. I think if I were cleaning in a liquid solution I would decap first. They would also drain better, I think.

Deburring the flash holes is not that bad and is only a one time thing.

Snuffy, keep up the good work.

Thanks,
RDO
 
Plurals...

Dingus may not be, Doofus is maybe. They sound like that they would be related. "That Doofus didn't remove the Dingus." I'm not sure on pluralization though.
Click to expand...
Dingus; dinguses. Doofus, doofuses.

My Dad, a New England Yankee to the core, used "dingus" approximately as a synonym for "thingamajig."

"Doofus," in the Midwest, IMX, is an incompetent of relatively low intelligence.

I shudder to think of what sort of dinguses a convocation of doofuses might produce.

Bensdad: If someone says it, and someone else understands it, it is a "real word." Now if you mean "officially," then it has to be written and published, and then listed and cited in the next edition of The Oxford English Dictionary. That takes a while. In between these extremes, there is a wide variation in "officialness" of a word, from slang terms and esoteric professional jargon on the one hand, to general, formal, wide usage and acceptance on the other. The English language is wonderful that way--always changing, and quick to embrace new words from almost any source.
 
It appears that "dingus" has been around a long, long time, although I'll admit to never having heard it until now. In my Webster's New World Dictionary dated 1968, it lists dingus as "humorous substitute for a name not known or temporarily forgotten". Man, I feel like a doofus.

Don
 
well, my motivation for this project came a couple of months back during a discussion on tumbling, whether it should be done before, after, FL sizing, or both. Then came the standard comment, "be sure you pick out the chunks of media that get lodged in the flash hole." Some doofus said "hell don't worry about it, it don't make a bit of difference". Well that raised a red flag to me. It don't??¿ Does it? Since it should be easy to find out, I proceeded to do so.

Now as I said, I have no doubt that the chunk of media will be blown on through the flash hole, then the powder will still ignite. BUT does it change anything in doing so? Someone touched on the procedure of uniforming flash holes. There's tools sold to do just that. The burr that forms on the inside of the case bottom by the punching/drilling of the flash hole is removed and replaced by a slight chamfer. If everybody agrees that's important, then how about something as big as a chunk of media?

So what happens when that chunk of media is slammed into the base of the powder charge? Does it make a tunnel for the flame front, where there was a flat wall before, or if there weren't a piece of media?

On the basis of my one test, it appears so. It will take a number of tests to either confirm or deny the first test. I have more shells that are plugged, I will do another test during the next range session.

I consider my self to be open minded enough to not subconsciously affect my groups in a way to influence the out come. I can tell you I tried to shoot as good a group as I could. Since I shoot alone at a club that usually doesn't have anyone else around, I can't do a blind test. I also am single, with no live in maid or anything like that, so that's out as well. My GR doggy is wonderful company but not well trained enough to help me do tests.:uhoh: He loves to ride along to the range, sits by my side while I shoot! If I could just figure out a way to fit ear muffs on him, I'd feel better.

MD, the std deviation was read from my pact chrono after each string. It is what the built in computer comes up with. I agree that a 5 shot group is NOT enough of a spectrum to say with any certainty what the actual mean velocity would be. Also the same to be said for the paper target group. I CAN tell you that I have 8 pound jugs of that WC-844, and I have been shooting the Hornady 60 gr. V-max for a couple years from that rifle. It will average between ¾-1 inch any time I go shooting.
 
I think this test is a bad idea!

What if you find out the plugged flash hole ammo is 29% more accurate across the board?

Then we will all have to set around pounding tumbler media in every flash hole.
Just think how long that is going to take! :eek:

Or wait for Dillon to invent another expensive reloading tool to do it faster.
Just think how much that is going to cost! :what:

I just think it better that we don't know.
:D

rcmodel
 
I guess they/somebody should tie me to a ships anchor to keep me from dreaming up new things to test!:scrutiny:

I just hate not knowing "what if"? So I try to find out, bear with me, more to come!:neener:
 
I didn't realize that you were calculating SD on only five shots. You need more than five data points for standard-deviation to be meaningful. I like twenty or more. Just because your chrono spits it out doesn't make it meaningful.

Welcome to the wiggly squiggly world of statistics. But data in the hand beats speculation in the bush, so keep on collecting!
 
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