Failling plunk test with Precision Delta 9mm 124 gr JHP bullets

[Jeffsbooks]

Hi, I'm new here, and my intentions are good, so if I goof up, please bear with me. 

 

I've been reloading with 124 gr Precison Delta JHP bullets (working up loads right now at 4.7 gr of N330 VihtaVuori. Powder isn't my issue). I'm experiencing two oddities. In this first instance, using fresh Winchester brass, the loaded PD bullet creates a bulge at the neck. The other problem? The loaded bullet fails the plunk test. 

 

I'm using Lee dies and a Lyman case gauge.  

 

Here's more info. The fresh exterior WIN cartridge case measures 0.37" outside and 0.35" inside before the flare. The base of the 124 gr JHP bullet is 0.3550 ", as you might expect.

 

The OAL on the round I just made measures 1.11", but I have experimented with the OAL. The final loaded cartridge case shows a visible bulge at the neck measuring 0.37" caused by the seated bullet. It fails the plunk test.

 

If I taper the case until it screams uncle, it will pass the plunk test.

 

A 115 gr Precision Delta FMJ round nose has no problems. 

 

Sometimes I get the same bulge with Starline brass but not always. Most other varieties of used brass don't bulge.

 

Here's my question. Does Winchester make a weak case? Or does Precision Delta make a bullet too wide for the Winchester brass?

 

Thank you. 

 

 

[Joe4d]

you seating and crimping in one step ? COuld be source of your problem, assuming its not OA and you are sizing the new brass 
case being crimped before bullet being seated can cause a slight bulge... Most loaders give up trying to do both in one step. It can be done but the adjustment is pretty critical.

[Jeffsbooks]

No, Joe4d — I seat the bullet before I crimp it. I chose Winchester shells because I took apart a Herter's round (or maybe it was Eley) and tried to rough out their load for myself. I use Winchester brass, CCI primers, the VihtaVuori, and the crimp, which is from RCBS. I just use the RCBS crimp on the die, not the two seating stems.

Edited October 31, 2023 by Jeffsbooks

[shred]

What OAL are you loading to?  What crimp?  Are you sizing the brass before loading it?  Where is it failing the plunk test (mark a round up all over with a sharpie and see where that ink gets scraped off)?

 

 

[ddc]

Depending upon bullet and case there is a tendency for 9mm reloaded ammo to have a "wasp waist" effect.

That all by itself is common and is typically a cosmetic issue rather than a functional one.

(Some people don't like it and go to lengths to avoid it. Personally I couldn't care less.)

 

The only reason I bring that up is that perhaps the "bulge" you are referring to is simply that wasp waist effect and there is actually something else going on.

 

Edited to add:

How much are you flaring?

What is your crimp?

Edited October 31, 2023 by ddc

[Jeffsbooks]

Shred, OAL is 1.14. Yes, I size and flare. Crimp is RCBS screwed to case mouth plus 1.8 turn. I will try the sharpie test and let you know.

[Jeffsbooks]

ddc, I didn't know about the wasp waist effect. I thought I had a shell with the Glock bulge. If it's just wasp waisted,  I couldn't care less. 

 

I had been doing the plunk test with the Lyman case gauge and failing the plunk test. The round sits atop the gauge, but I can press the cartridge into the gauge so it goes flat with the gauge, but it won't drop out. 

 

However, doing the plunk test in the barrel of the pistol, the round goes plunk, seats properly but doesn't turn. I don't see the problem with using the round. Am I wrong?  

[LeadDispenser]

46 minutes ago, Jeffsbooks said:

However, doing the plunk test in the barrel of the pistol, the round goes plunk, seats properly but doesn't turn. I don't see the problem with using the round. Am I wrong? 

You're not wrong - your case gauge is just a little bit tighter than the chamber of your barrel.

 

46 minutes ago, Jeffsbooks said:

seats properly but doesn't turn.

Bullet might be contacting the rifling. You could put some marker on the bullet and see if this is the case.

Edited October 31, 2023 by LeadDispenser

[Jeffsbooks]

LeadDispenser, I've gotta try that.

 

[Jeffsbooks]

LeadDispenser, Sorry to bug you. I just want to make sure I understand. If I plunk the round in the barrel, and it doesn't turn, it's still okay to fire. (Actually, I've been doing it, but I wonder if the pressures are too hard on the pistol.)

 

Same with the case gauge, if I have to tap the round flat atop the gauge, it's not a sign the bullet's going to harm the pistol (or me). I mean, all things being equal—the OAL, the crimp, etc.—it's really the same bullet as the others I've loaded that go plunk and can be spun.

 

Edited October 31, 2023 by Jeffsbooks

[LeadDispenser]

17 minutes ago, Jeffsbooks said:

I just want to make sure I understand. If I plunk the round in the barrel, and it doesn't turn, it's still okay to fire.

 

Yes, still ok to fire. When the round "plunks but doesn't turn", the bullet is making contact with leade / beginning of the rifling, but the bullet is not being jammed into the rifling. The problem you might experience is "tolerance stacking" (ie. variations in brass, bullet dimensions, seating depth variation from your press etc. adding up) and eventually loading a round that wont chamber. If the round is short enough to "plunk & turn" you have a little bit more margin for error, if that makes sense.

 

 

Edited October 31, 2023 by LeadDispenser

[shred]

3 hours ago, Jeffsbooks said:

ddc, I didn't know about the wasp waist effect. I thought I had a shell with the Glock bulge. If it's just wasp waisted,  I couldn't care less. 

 

I had been doing the plunk test with the Lyman case gauge and failing the plunk test. The round sits atop the gauge, but I can press the cartridge into the gauge so it goes flat with the gauge, but it won't drop out. 

 

However, doing the plunk test in the barrel of the pistol, the round goes plunk, seats properly but doesn't turn. I don't see the problem with using the round. Am I wrong?  

I'd guess you can probably use more crimp and a shorter OAL.  1.14" is fairly long for minor 9 with a JHP.  Here's a way you can find the max OAL for that chamber and bullet combo:

 

 

 

Take a strong (10x+) magnifier and look at the joint between case and bullet.  If there's an obvious gap, add more crimp.  Over-crimping is very rare IME debugging case gauge ammo issues.

 

 

[HesedTech]

17 hours ago, Jeffsbooks said:

I'm experiencing two oddities. In this first instance, using fresh Winchester brass, the loaded PD bullet creates a bulge at the neck. The other problem? The loaded bullet fails the plunk test. 

I used PD FMJ 147 RN for years and what I found is the jacket is the hardest FMJ out there. On some brass sized with Dillon die (basically same as Lee U die) the brass would bulge as the bullet is seated. The worst offender is CBC brass with the thickest side walls and quickest taper to the base. 

 

Solution is this, use a neck expander of .355 to pre expand, the MBF powder funnel to give a proper flair, the Hornady seating die (the one with the collar guiding the bullet in) and the Dillon taper crimp.

 

This reduced my bulged brass with PD FMJ to a minimum, because the bullet seated straighter.

 

Again, PD FMJ bullets are very robust, and the brass gives before the bullet does as it is seated.  Plated and coated bullets tend to get swaged down a little bit as they are seated into the brass. Don't forget HP has a completely wrapped base causing them to be even more resistant to being swaged down than the open base RNs.

 

Another thing to try is shooting some One Shot on the bullets, not the brass, and see if more lubricity helps them seat smoother. 

 

Hope this helps. 

[ddc]

I'd suggest following the process that @shred suggested to find the max acceptable OAL for that particular bullet.
Two bullets of the same weight can have different enough ogives such that the max OAL for one can be quite different compared to the other.

Yes, 1.140 is getting out there aways. I think I've pushed some test loads out that far for my X5 but usually I'm around 1.125 for FMJ and around 1.100 for JHP. I think I started running into trouble at a little above 1.140 with RMR 124 FMJ but I can't find my notes after I cleaned up my loading room... lol

 

Edited to add: I re-read your OP and realized I skipped by the fact that you are loading JHP. 

I think 1.140 for a JHP is way past what is typically done for 9mm minor in a standard 9mm barrel from a typical striker fired gun.

Edited November 1, 2023 by ddc

[Jeffsbooks]

Thank you gentleman. Helpful and thoughtful answers one and all.

 

@classifieds Oh my goodness, you cleaned up??? I try that and I can't find a darn thing. I'm going to decrease the OAL.  

 

Question (in the form of a statement), I thought it was a good thing for the bullet to get close to the lands. 

[Jeffsbooks]

I learned more about loading and seating ammo from this thread than from all the Googles and Youtubers I've read and watched.

 

I've shorted my OAL and road tested the result in my gun barrel to establish my plunk test, which also worked on the Lyman case gauge. Not vice-versa, however, not Lyman then barrel... It's barrel first for me to establish OAL. 

[HesedTech]

2 hours ago, Jeffsbooks said:

I've shorted my OAL and road tested the result in my gun barrel to establish my plunk test,

Something which we rarely mention here is in some barrels and bullet profiles the OAL can also be used to fix feed issues. Too short an OAL can hit low on the feed ramp and cause a mis-feed. I have a 40SW which feeds most reliably  at an OAL is 1.18+. I had to switch to 10mm mags to run that length. 

 

Oh the fun of the sport.

[ddc]

7 hours ago, Jeffsbooks said:

I learned more about loading and seating ammo from this thread than from all the Googles and Youtubers I've read and watched.

 

I've shorted my OAL and road tested the result in my gun barrel to establish my plunk test, which also worked on the Lyman case gauge. Not vice-versa, however, not Lyman then barrel... It's barrel first for me to establish OAL. 

 

Yes, your barrel is the ultimate judge of whether your load is viable.

 

A case gauge is a useful tool but can't be the sole decider on good vs bad.

Assuming your gauge is tighter than your barrel, and many are, as time goes by you will learn for your gun and your gauge just how far from flush a round can be and still be 100% functional in your gun.

[shred]

FWIW, Most case gauges (mine included) really only check the case dimensions and that the bullet is more-or-less centered and on size.  OAL and leade/throat interference is largely on you to sort out for your particular chamber(s).  Your barrel is the final arbiter.  Its not fun to plunk 400 rounds one at a time before a major match, but its the gold standard.

 

 

 

 

 

[Jeffsbooks]

Is there any virtue in the round coming closer to the lands? And while I'm asking, are the words leade and lands synonymous? Can they be used interchangeably? 

[ddc]

3 hours ago, Jeffsbooks said:

Is there any virtue in the round coming closer to the lands? And while I'm asking, are the words leade and lands synonymous? Can they be used interchangeably? 

 

They are not synonymous but are somewhat related.

 

Lands and grooves are what make up the rifling in the barrel.

 

The leade is a short portion at the beginning of the rifling where there is what you could call a bevel at the beginning of each land. This allows the bullet to be introduced more gently into the rifling than would be the case if the lands started at a 90 degree angle.

 

As to the virtue of where your bullet should be with respect to the lands; I've never investigated that but I'm sure there are many who have. In particular I'm sure bullseye shooters have strong feelings about that. It can be an important detail for accurate rifle ammo; I'm not sure it is as big a concern for pistol.

 

[shred]

Bolt-action rifle shooters like to seat bullets out to just touching the rifling (wherever that turns out to be) to reduce bullet-jump for accuracy.

 

It's a bad idea for semi-auto pistols because then any bit of dirt in the chamber or breechface or variance in OAL and your ammo now has to crush its way in, and worst-case, you go to rack it out and the bullet stays behind while the case and powder come out making a mess that's not good for your score.

 

Plus any accuracy gained by reducing "bullet jump" is meaninglessly tiny for typical pistol uses.

 

 

 

[Jeffsbooks]

@lead dispenser @ddc @shred Thank you for answering my leades-lands question.  

[Old3GNR]

I've loaded about 25,000 Precision Delta 9 mm using a variety of powder shot in my H-K VP9 and JP GMR-13 PCC.  Most Winchester brass but also whatever else I pick-up.  I load to 1.120" with no issues. 

[Ssanders224]

A lot of good suggestions and points have been made. I'll address a few..... 

 

If you are using the "standard" PD 124gr JHP, there is very little reason to load to 1.14" for minor. PD's factory loading with this projectile is 1.100".  1.100-1.120" is really the best window for standard pressure loads in most pistols. 

 

PD's jacket alloy is very common and widely used in the jacketed projectile industry. It does not need any special consideration. I'd never recommend adding One Shot, or any other lube to the projectiles themselves. Other reasons aside, it's possible that it could promote setback in some pistols. Especially with truncated-cone (flat point) JHPs. 

In the context of re-sized brass, "wasp waisted" 9mm cases are perfectly acceptable. In theory, they may even have merit in that they contact the bullet in a more uniform fashion. The wasp waist effect will be noticeably more prominent when using Lee U-die. Overall, don't get too hung up on the "aesthetic" of your loaded rounds if they case gauge, chrono, and shoot well.  

 

If the case bulge is not concentric, meaning that it is more noticeable on one side of the case than the other, it is possible that your seating stem is not contacting the projectile in a consistent way, and is not seating the projectile straight into the case. If the seating stem presents the bullet off-axis, it can stretch the case, create a bulge, and even cause case tension issues.