AR 15 plunk test ?
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Just get a “chamber checker”. Mine is a 50 holer from EGW.
I'm hooked...
2 chamber checkers available both 5.56 and 223.
I would be tempted to get the 223 one then rounds would surely fit in 5.56 but (not always) the reverse. Any comment. Swear I'm not trolling or whatever, I have read myself cross eyed and this is the first time I have seen "plunk test"
Wilson case gauge is my guide. I know its size and chambers are not same nor is anything absolute. Guide being the key word.
Thanks All!
2 chamber checkers available both 5.56 and 223.
I would be tempted to get the 223 one then rounds would surely fit in 5.56 but (not always) the reverse. Any comment. Swear I'm not trolling or whatever, I have read myself cross eyed and this is the first time I have seen "plunk test"
Wilson case gauge is my guide. I know its size and chambers are not same nor is anything absolute. Guide being the key word.
Thanks All!
Not all case gauges check case body and neck diameter, meaning many gauges are at max SAAMI diameter.
I use a JP Enterprise gauge because it is smaller in diameter. And check the resized case and check the loaded ammo. If it passes a plunk test it will chamber in any rifle.
Below a Wilson, Dillon and JP Enterprise gauges with the cases put in base first to show the gauge diameter.
Below a Dillon .308 case gauge with a "FIRED" Lake City case in the gauge.
Below the same "FIRED" case in a JP Enterprise .308 gauge. As you can see the JP Enterprise gauge is smaller in diameter.
In a semi-auto the resized case should be .003 to .005 smaller in diameter than its fired diameter. This allows the case to spring back from the chamber walls and extract reliably.
NOTE, The new JP Enterprise gauges are now made of stainless steel.
And I use the Hornady cartridge case headspace gauge to check fired cases and then set the die up for proper shoulder bump. I have chronology gifted eyesight and the digital display on my vernier calipers is easy to see vs the other type gauges.
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Link
Silver $$ Contributor
The first time I heard about ''plunk test'' is on a 1911 forum. If the round doesn't drop or plunk into the barrel / chamber it's not sized enough. Now this was from a member and he didn't get corrected so I ''ass u me'' it's correct?
Thanks all.
Get a couple different factory loads and compare insertion depth or stick out.
I do same to see what case gauge says about factory loads compare to my sizing.
I do same to see what case gauge says about factory loads compare to my sizing.
memilanuk
Gold $$ Contributor
Years ago I had some "once fired, 100% processed"
LC brass that did the same thing.Come to find out, whatever they'd 'once fired' that stuff thru had done a number on the case rims. Some were so beat up that they wouldn't fit into a LE Wilson or Dillon case gauge, despite being properly sized everywhere else.
So I started gauging every round I used in matches (shooting Service & Match Rifle at the time) because I didn't care to have things hanging up going into the chamber, however slight.
Cemetery21
NRA Life since 1975
Plunk test works great when you can take the barrel out and see that the round drops in level with the hood on a 1911 barrel. Then turn the barrel upside down and the round drops out.
I do use a rifle barrel for the final gauge after using the Hornady gauge, but not as a Plunk, since I also use the bolt.
I do use a rifle barrel for the final gauge after using the Hornady gauge, but not as a Plunk, since I also use the bolt.
Dusty Stevens
Shiner
The wilson/dillon case gages always seem to work for me. Seeing our uncle’s pictures of a JP gage id probably have to get new dies to use it. Its probably sized to their match chamber. If you have a custom barrel on the AR it wouldnt be tough to get a case gage made from your reamer and a stub that way you know its right
Coyotefurharvester
Silver $$ Contributor
I have Wilson gages for several cartridges, I find that my Lyman small rifle ammo checker is my to go after setting dies for hunting rifles. Especially since I load 204,223,22-250 more than anything else.
My point being the Wilson and Dillon gauges just check shoulder location and case length. And the JP and some other gauges also check case diameter that is important for semi-autos.
If you watched the video I posted even fired cases would drop all the way into a Dillon case gauge. Meaning case body diameter was not being checked.
I’m wondering how do you plan on plunking it ? I do a plunk test with my pistols all the time with new bullets and it always requires me pulling the barrel . Is that your plan with your AR pulling your barrel every time you try new brass ?
OK let’s say a plunk test is possible with a rifle , any rifle for that matter . How do you plan on measuring if its plunked correctly or not . The plunk test does more than just sees if the brass freely falls into the chamber , it also tells you if your cases are cut too short or long . How do you plan on measuring oh I don’t know your headspace considering you only have .004 variance from GO to NOGO ??
No a plunk test is not a reasonable way to test anything in a rifle cartridge that doesn’t headspace off the mouth .
OK let’s say a plunk test is possible with a rifle , any rifle for that matter . How do you plan on measuring if its plunked correctly or not . The plunk test does more than just sees if the brass freely falls into the chamber , it also tells you if your cases are cut too short or long . How do you plan on measuring oh I don’t know your headspace considering you only have .004 variance from GO to NOGO ??
No a plunk test is not a reasonable way to test anything in a rifle cartridge that doesn’t headspace off the mouth .
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Not all case gauges check case body and neck diameter, meaning many gauges are at max SAAMI diameter.
I use a JP Enterprise gauge because it is smaller in diameter. And check the resized case and check the loaded ammo. If it passes a plunk test it will chamber in any rifle.
Below a Wilson, Dillon and JP Enterprise gauges with the cases put in base first to show the gauge diameter.
Below a Dillon .308 case gauge with a "FIRED" Lake City case in the gauge.
Below the same "FIRED" case in a JP Enterprise .308 gauge. As you can see the JP Enterprise gauge is smaller in diameter.
In a semi-auto the resized case should be .003 to .005 smaller in diameter than its fired diameter. This allows the case to spring back from the chamber walls and extract reliably.
NOTE, The new JP Enterprise gauges are now made of stainless steel.
And I use the Hornady cartridge case headspace gauge to check fired cases and then set the die up for proper shoulder bump. I have chronology gifted eyesight and the digital display on my vernier calipers is easy to see vs the other type gauges.
Uncle Eds vid and post mirror my experience exactly. I started with a Dillon case gage to set up the Dillon press for 223. Didn't take me long to see what was happening.
J P Enterprise
SEMI-AUTO CASE GAUGE
Oversized ammunition is the biggest cause of failures in self-loading rifles such as the AR-15, so verifying that your ammunition is properly sized is imperative. While oversized cases can be forced into a bolt gun thanks to the tremendous leverage potential of the bolt in the action, a cartridge must fit freely into the chamber of a self-loader for safe, reliable function. Specifically, the ammunition must be sized well enough to allow extraction of an unfired round. If your ammunition is just slightly out of spec, it may go into battery with the forward kinetic energy of the bolt and carrier, but once wedged in the chamber, may not allow for extraction of the unfired cartridge when unloading. Most case gauges indicate SAAMI maximum and minimum case head space, which still allows for a possible interference between a max. cartridge and a minimum allowable chamber. This would not be an issue in a bolt gun but will bring everything to a stop in a self-loader. Taking this into account, our gauge ensures that the maximum cartridge as indicated by the gage is still within the minimum SAAMI allowable chamber. In other words, if your ammunition passes our gauge, it absolutely will fit the chamber.
SEMI-AUTO CASE GAUGE
Oversized ammunition is the biggest cause of failures in self-loading rifles such as the AR-15, so verifying that your ammunition is properly sized is imperative. While oversized cases can be forced into a bolt gun thanks to the tremendous leverage potential of the bolt in the action, a cartridge must fit freely into the chamber of a self-loader for safe, reliable function. Specifically, the ammunition must be sized well enough to allow extraction of an unfired round. If your ammunition is just slightly out of spec, it may go into battery with the forward kinetic energy of the bolt and carrier, but once wedged in the chamber, may not allow for extraction of the unfired cartridge when unloading. Most case gauges indicate SAAMI maximum and minimum case head space, which still allows for a possible interference between a max. cartridge and a minimum allowable chamber. This would not be an issue in a bolt gun but will bring everything to a stop in a self-loader. Taking this into account, our gauge ensures that the maximum cartridge as indicated by the gage is still within the minimum SAAMI allowable chamber. In other words, if your ammunition passes our gauge, it absolutely will fit the chamber.
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dellet
Gold $$ Contributor
A “plunk” test is easy with an AR, just pull the upper. You should be able to drop or push a round I. And have it fall out freely.
As for gauges there are three types, headspace, case and cartridge. The headspace like the Wilson will take a fired case, A few just the sized case, then the cartridge like the one below.
Cartridge gauges are cut with a chamber reamer at minimum spec so if it fits, it loads, as long as the chamber is within spec.
Then you can get a cutaway version that helps with diagnosing problems. Sheridan Engineering makes a nice one. But cartridges are limited. Sometimes it’s nice to see how it lays in the chamber. It does not replace being able to measure if there is a problem, but if it fits, it ships is all you need, it’s pretty fast.
https://sheridanengineering.com/product-category/ammunition-gauges/
As for gauges there are three types, headspace, case and cartridge. The headspace like the Wilson will take a fired case, A few just the sized case, then the cartridge like the one below.
Cartridge gauges are cut with a chamber reamer at minimum spec so if it fits, it loads, as long as the chamber is within spec.
Then you can get a cutaway version that helps with diagnosing problems. Sheridan Engineering makes a nice one. But cartridges are limited. Sometimes it’s nice to see how it lays in the chamber. It does not replace being able to measure if there is a problem, but if it fits, it ships is all you need, it’s pretty fast.
https://sheridanengineering.com/product-category/ammunition-gauges/
dellet , what does having the case fall in and out tell you ? . I say it tells you zero of anything important. I can only think that it would tell you the case is of a small enough diameter and that's not all that important IMHO . If the case was sized to allow for .015 of excessive headspace it could be potentially dangerous when fired . That case would fall in and out no problem .
This is what you get wit excessive head clearance .
I just don’t see what a rifle plunk test would accomplish that has any real relevance like it does when done in a pistol .
Here's a passing pistol plunk , The fact pistol headspacing is quite generous you can actually tell if you're gtg at a glance . We can't see that when plunking a bottle neck rifle round . Maybe a rimmed cartridge you could and I'm not sure about belted .
Here's that same round being plunked in a PX4 Storm barrel which would likely be similar to a rifle barrel . What does this photo say ? Does it pass ?
This is what you get wit excessive head clearance .
I just don’t see what a rifle plunk test would accomplish that has any real relevance like it does when done in a pistol .
Here's a passing pistol plunk , The fact pistol headspacing is quite generous you can actually tell if you're gtg at a glance . We can't see that when plunking a bottle neck rifle round . Maybe a rimmed cartridge you could and I'm not sure about belted .
Here's that same round being plunked in a PX4 Storm barrel which would likely be similar to a rifle barrel . What does this photo say ? Does it pass ?
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dellet
Gold $$ Contributor
In general, A plunk test will tell you everything that a non-slotted cartridge gauge will tell you. That you need the proper tools to find the answer to why it does not fit. With a slotted gauge you can see inside the chamber and have a better idea.
A plunk test with a properly sized piece of brass, is called finding the lands. So there is the exact same value as using the cartridge on a stick type tool, or closing a bolt by feel.
Same as a round that has failed a gauge due to diameter, which is common in an auto loader. Why use a small base die so your round fits a gauge, when it already fits your chamber?
So with a plunk test I can make sure that a bullet is not jamming the lands, even tho it is .100” shorter than spec or magazine length. I can tell if the base will hang up in the chamber, even tho it has been full length sized and has the proper base to datum/headspace.
Both of those have value to me.
The original question was not the value, only if it can be done.
A plunk test with a properly sized piece of brass, is called finding the lands. So there is the exact same value as using the cartridge on a stick type tool, or closing a bolt by feel.
Same as a round that has failed a gauge due to diameter, which is common in an auto loader. Why use a small base die so your round fits a gauge, when it already fits your chamber?
So with a plunk test I can make sure that a bullet is not jamming the lands, even tho it is .100” shorter than spec or magazine length. I can tell if the base will hang up in the chamber, even tho it has been full length sized and has the proper base to datum/headspace.
Both of those have value to me.
The original question was not the value, only if it can be done.
The chamber checker is for completed cartridges. The main difference between 556 and 223 is the throat. So a bullet that fits in a 556 might not fit in a 223, but 90% of the time a round that fits 223 will fit a 556.
a case gauge like Wilson CAN be used to check the case area, but their main use is to set your die for proper resizing. While this may seem heresy, when I load for a semi-auto like an M14 or AR-15, I size so it fits the Wilson gauge “zero” (flush with lower groove) +.002. This is to provide clearance for the case to the chamber. I got in this habit after a semi-out of battery discharge in an M14,,,,
as always, YMMV.
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