Plunk test + XDm issues

[DanK3Pos]

Looking for some input on this one. I have a .45acp and a 9mm Springfield XDm and I reload for both. I'm having problems with my loads and the plunk test in those two barrels. My 9mm loads do fine in my CZ SP-01 and my .45acp loads do fine in my Dan Wesson 1911. They plunk in, they spin, and they drop out.

On both XDm's, the rounds plunk in, -will not- spin, but do drop out. I've read that this is an indication that the bullet is into the lands. I've come to think this is not what is happening with these two barrels. I was loading Zero 230gr. FMJs this weekend, OAL was 1.26". I ran them in all the way to 1.20" and the loaded round would still not spin in the barrel. I think the chamber is tight at the mouth of the cartridge, so the case not the bullet is what prevents the loaded round from spinning.

Anyone else have this issue? Any ideas how I can test this theory?

 

[Blue68f100]

You may need to apply a little more taper crimp. I've had to do this on several guns with tight chambers.

 

[Crazy Horse]

Agree with Blue68F100 on applying more taper crimp.

Another issue I had in the past was with a bullet with too wide an OGIVE. As it was too wide, It never passed the plunk test for 2 of my 9mm's. I didn't want to go any lower on the seating, so I just decided not to use that particular bullet on those 9mm's where it failed the plunk test. Still have some, but have never purchased those projectiles again. This has only happened once with a specific bullet from a particular manufacturer.

GL

CH

 

[jmorris]

I don’t spin, drop in and fall out works for me.

 

[garandsrus]

Make sure you are sizing the brass enough. I have a tight 9mm chamber that requires more sizing than my other 9mm.

 

[Laphroaig]

When loading RMR 124 MPR's for a XDm and a Micro 9 I have to go way shorter than for my other pistols. Not all chambers are cut the same.

Like @jmorris suggested, if they drop in they might feed and shoot fine. Give them a try.

 

[ballman6711]

Anyone else have this issue?

I have this issue with a Kimber 1911 45acp.

You may need to apply a little more taper crimp. I've had to do this on several guns with tight chambers.

^^^ This. On this particular Kimber the rounds may plunk, twist, and drop out freely with a .469" taper crimp, or they may not. My solution is to crimp at .468 ~ .4685 and they all pass the plunk test, feed, fire, and eject fine.

chris

 

[higgite]

If you have some ammo that passes the plunk test, measure the case mouth diameter and compare it to the ammo that doesn’t pass the plunk test.
FWIW, I have to load Zero 230gr FMJ to less than1.230” COL or less for a HK45 while some other bullets have room to spare at 1.260”. The Zeros have a “fat” ogive and I’ve heard that some Springfields have short leades.

 

[GeoDudeFlorida]

The Zeros have a “fat” ogive and I’ve heard that some Springfields have short leades.

This ^^^

My wife's older Springfield compact feeds my XTP, Berry's CPRN, Speer FMJ and LRN loads just fine but they all "fail" the plunk test (drop in - drop out, but won't spin). It works with all of the same loads as my Auto Ordnance but it fails the chamber fit test. I've just come to expect it from that pistol. FYI I don't plunk loads for my WW2 Army surplus Remington-Rand. It feeds anything you can fit in the magazine - empty casings, rocks, chicklets, pieces of finger... whatever.

It rattles, and you're lucky to hit an elephant in the tail if it's sitting on you, but it works.

 

[WeekendReloader]

Size a case.
Cut a slit in it length wise to the mouth with a Dremel tool.
Put a bullet in the case.
Press this into the chamber. The lands will push the bullet back into the case until it fits the chamber.
Remove and measure the OAL.

 

[Rule3]

When did "spin" become part of a plunk test??. If they drop in and fall out then go shoot them

 

[rfwobbly]

You may need to apply a little more taper crimp. I've had to do this on several guns with tight chambers.

When he said "a little more" the accent was on the word little. As in VERY little. As in 0.001 to 0.002".

 

[GeoDudeFlorida]

When did "spin" become part of a plunk test??. If they drop in and fall out then go shoot them

I've always given them a little wiggle and spin. The wiggle to make sure they won't - if they do, they're *probably* undersize for that chamber - and the spin to make sure they will - if they don't, they are *probably* into the lands and *probably* will show pressure signs and not extract reliably.

Please note the word *probably* - don't skip over it or underestimate it. YMMV, ask your doctor before wiggling or spinning. Don't wiggle or spin bullets in your chamber if you are allergic to wiggling or spinning. If you have trouble wiggling or spinning in your chamber, discontinue and advise your doctor immediately.

 

[Trent]

Looking for some input on this one. I have a .45acp and a 9mm Springfield XDm and I reload for both. I'm having problems with my loads and the plunk test in those two barrels. My 9mm loads do fine in my CZ SP-01 and my .45acp loads do fine in my Dan Wesson 1911. They plunk in, they spin, and they drop out.

On both XDm's, the rounds plunk in, -will not- spin, but do drop out. I've read that this is an indication that the bullet is into the lands. I've come to think this is not what is happening with these two barrels. I was loading Zero 230gr. FMJs this weekend, OAL was 1.26". I ran them in all the way to 1.20" and the loaded round would still not spin in the barrel. I think the chamber is tight at the mouth of the cartridge, so the case not the bullet is what prevents the loaded round from spinning.

Anyone else have this issue? Any ideas how I can test this theory?

I had a rotten time getting 45ACP flat nose to feed reliably in all of my guns. The feed angle on XDm is on the abrupt side. After a *ton* of experimenting with OAL I finally found a +/- 0.001 tolerance band on those flat nose bullets that'd let me cycle them in all of the guns. It was ridiculously time consuming though, to get a flat nose to work in them, and the XDm was by far the most picky of all!

The plunk test is useful but the more useful answer will be at the range, when you shoot them, and see if there's any problems cycling. You can only do so much sitting at a bench at home messing around with dummy rounds.

 

[mdi]

I learned the plunk test maybe 25 years ago, but just recently heard "twist" added to the process. If any cartridge is questionable (won't drop out when barrel inverted) I'd jmake sure the chamber is clean as oil sometimes will slow the drop out, then just color the bullet to see if it's hitting anything, and if the bullet hits just seat it .008"-.010" deeper...

 

[Thomasss]

An easy way to determine the issue is to take a magic marker (in a nice color) and color the entire cartridge from top to bottom. Then do a plunk test, and a drop out and look for any missing coloring. If there is, put it on the side and color another one, plunk that one and then rotate and drop it out and look for missing color. Now you can compare the two and see where there is rubbing. You have to remember, you not just looking at the bullet, but at seating and at the cartridge and how the bullet affects the cartridge. Good luck and let us know what you find. And while your are at it, some 9mm info might also help us trouble shoot. I by the way also shoot a 9mm XDM with no problems.

 

[dcloco]

Cleaned the chamber? Serious......carb cleaner, Hoppe's #9 and a GOOD nylon brush (chucked in a low/slow speed variable drill).

 

[Klaatu Barada Nikto]

I had a similar problem with 200g 45 Auto bullets from eXtreme.
About one in ten would fail on a Shooters Box 45 Auto case gauge, but would drop in fine on a Hornady case gauge.
I used a Springfield XD Tactical 5" barrel for the plunk test.
The rounds that wouldn't go in the tight CG would drop in and pass the Plunk Test and rotate easily enough.
Same seat and same crimp but 10% of the completed rounds didn't like my tight gauge.
Got out my trusty 0-1" mic and started checking some of the remaining plated bullets.
Measured a couple hundred, they would measure .4516" and then rotate 90 degrees and they would measure as much as .4530"
As I suspected it was the plating that was making the projectiles slightly oval shaped.
I switched back to Berry's and the tight gauge only had issues with one in fifty.
Not surprised at the plating variance. In Aerospace we always finish machined the plated part just because of the plated material variance.
I think to ask a manufacturer to have zero to .0005 tolerance would be cost prohibitive.
The powder trickling competition shooters could probably go much further into this.
BTW, buy some Blue Dykem. Comes in a plastic can with a brush. When in doubt mock up a round, no powder or primer and press it into the chamber. Put a little thumb pressure on it and then gently remove it with a Delrin or similar non marring rod. That's always been a good indicator if the rifling leads are the issue.

 

[GeoDudeFlorida]

I had a similar problem with 200g 45 Auto bullets from eXtreme.
About one in ten would fail on a Shooters Box 45 Auto case gauge, but would drop in fine on a Hornady case gauge.
I used a Springfield XD Tactical 5" barrel for the plunk test.
The rounds that wouldn't go in the tight CG would drop in and pass the Plunk Test and rotate easily enough.
Same seat and same crimp but 10% of the completed rounds didn't like my tight gauge.
Got out my trusty 0-1" mic and started checking some of the remaining plated bullets.
Measured a couple hundred, they would measure .4516" and then rotate 90 degrees and they would measure as much as .4530"
As I suspected it was the plating that was making the projectiles slightly oval shaped.
I switched back to Berry's and the tight gauge only had issues with one in fifty.
Not surprised at the plating variance. In Aerospace we always finish machined the plated part just because of the plated material variance.
I think to ask a manufacturer to have zero to .0005 tolerance would be cost prohibitive.
The powder trickling competition shooters could probably go much further into this.
BTW, buy some Blue Dykem. Comes in a plastic can with a brush. When in doubt mock up a round, no powder or primer and press it into the chamber. Put a little thumb pressure on it and then gently remove it with a Delrin or similar non marring rod. That's always been a good indicator if the rifling leads are the issue.

Hmmm. I wonder if a .452 Lee sizing die would correct the concentricity without peeling the plating? I also have to wonder if the Lee factory crimping die helps? I use one for all of my ACP loads.

 

[243winxb]

the chamber is tight at the mouth of the cartridge

Is an issue with some XDm
Small in diameter right in front of the case mouth. Mostly a problem using over size cast bullet or a COL that a little to long.

FREE BORE
A portion of the chamber, usually cylindrical, forward of the casemouth of a diameter larger than the projectile in which rifling is not present

As said, a hair more taper crimp may help? If above is not the issue.

 

[sparkyv]

This:

Size a case.
Cut a slit in it length wise to the mouth with a Dremel tool.
Put a bullet in the case.
Press this into the chamber. The lands will push the bullet back into the case until it fits the chamber.
Remove and measure the OAL.

 

[NMexJim]

I had a rotten time getting 45ACP flat nose to feed reliably in all of my guns. The feed angle on XDm is on the abrupt side. After a *ton* of experimenting with OAL I finally found a +/- 0.001 tolerance band on those flat nose bullets that'd let me cycle them in all of the guns. It was ridiculously time consuming though, to get a flat nose to work in them, and the XDm was by far the most picky of all!

The plunk test is useful but the more useful answer will be at the range, when you shoot them, and see if there's any problems cycling. You can only do so much sitting at a bench at home messing around with dummy rounds.

I’m not to hot on flat nose either.

 

[Trent]

I’m not to hot on flat nose either.

Usually I'm not either, but I got a hell of a deal on 10,000 of them, so.. you make do!

I wanted to at least try to get them to run in as many guns as I could, since I don't like having ammo around that "only" works in four or five handguns, and not all of them.

It took a while but I got there. Nice thing about those flat nose, is they were semiwadcutter, so they make really pretty holes on paper targets

 

[Jim Watson]

Although SAAMI and CIP include the throat in chamber specifications, there are a lot of short ones and a lot of what you might call "full figured bullets." Some USPSA shooters match the gun to the load and have their CZs rethroated to take the bullet and length they want.

I prefer 200 grain .45s but not all my guns will feed the usual semiwadcutter and coated cast 200 gr roundnose are not common items, less so in the panicdemic. Plated bullets are more expensive, apparently marked up more than cast.

So I bought a sample pack of 200 gr roundnose flatpoint, with crimp groove for revolver and lever action use. After I got the OAL adjusted to suit (shorter than recommended by the vendor) they fed in my automatics; so I ordered more.
This batch feeds as well, but takes a lot of help in the loading. OAL is more variable and a lot of them tight in the gauge, some total rejects. The Lee CFC straightens them out but it is either an extra step or, if installed on the progressive, more effort on the handle.

So I splurged on some plated bullets and will get some of the 230 coated bullets I had found satisfactory before even though not the original John Browning choice.

 

[DanK3Pos]

When loading RMR 124 MPR's for a XDm and a Micro 9 I have to go way shorter than for my other pistols. Not all chambers are cut the same.

Like @jmorris suggested, if they drop in they might feed and shoot fine. Give them a try.

They do shoot fine. At least, they cycle fine and I don't see any pressure signs. I had loaded some ACME 230gr a while back and used the 1911 barrel, assuming that it would have tighter specs (I know, I know). After noticing the problem with my 9mm XDm I went back and checked those loads in the .45 XDm. They didn't spin, either. By then I had already run several hundred rounds through that pistol, though.