1st batch of 380 failing plunk test

B

BondoBob

New member
Need some help here. My first batch of 380 I made just 10 rounds. Only 4 of them passed the chamber checker. I tried adjusting the factory crimp die which improved things a bit. I'm using the Lee 4 die set and Challenger press. But some rounds are rough going in and none of the 6 drop out on their own. The plunk test in the barrel showed all 10 go in fine but the same 6 do not drop out on their own.

I used Berry's 100 grain plated bullets. 3.0 gr of Universal, Win SP primers and mixed once fired brass from my lgs.

At first I thought something was up with the bullets. I noticed some resistance on seating on several of them. Maybe that caused it, maybe they didn't go in strait.

I measured 10 more of the berry's bullets with calipers and find the diam .3545 and length to all be within 1/2 of 1000 of each other. I have not extracted the bullets from those rounds yet.

The finished bullets measured the same way, very close at the head as well as the neck. I did have to adjust the seating die several times to get the same COL .982 is what I was going for. And I had to reset the Factory Crimp Die for all the 6 rounds with little improvement.

Then I started to suspect it was the brass being of mixed types. But the results don't indicate that. It's basically the same mix between the good rounds and those that don't drop. Win, CBC Aquila, OBC, HRTRS and Speer.

I was going to at least fire the 4 that passed, and maybe try and see if the 6 bad ones cause FTF or FTE.

Any thoughts?

Maybe I should just buy some fresh never fired brass.
Did I wast $70 on Berry's Bullets?
Is it my technique?
Wrong brand of Die's?

Thanks,
 
Does the sized brass alone plunk 100%? How about factory ammo? Step by step process of elimination will lead you.

-TL

Sent from my SM-N960U using Tapatalk
 
I have a "maybe" for you. Do you bell your case mouths? Its been decades ago,memory fuzzy,

But I messed up loading 38 Super. I guess I figured if I could load jacketed bullets in cases without belling,I could load plated bullets without belling.

Bad idea. The case mouth scrapes copper forward,and it stacks on the case mouth. As the cartridge headspaces on the case mouth,its a bad place to stack anything.

It can lead to a pistol being almost,but not fully locked up in battery.

Inspect. You can scrape it off a few rounds. But much better to bell your cases a bit.Better,maybe,get a Lyman"M" die. Look it up at Lyman.

Another issue I had loading 9x18, bullets seating tilted in the case. It makes the case bulge out a bit on one side. The may not chamber.
I found the more expensive floating sleeve type seater die solved the problem for me. The Lyman "M" die may help. It lets you finger start a bullet square in the case.
 
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You have to get your bullets seating depth worked out for your guns barrel .
Then you have to get the correct amount of crimp worked out . Not enough crimp and the round wont plunk ...too much crimp , the case bulges just enough so the round won't plunk . There's a fine line between not enough , just right and too much .

Advice ...Make up a dummy round , no primer , no powder and use the dummy to work out the correct bullet seating depth and the correct amout of crimp so they plunk .
Keep the dummy and use it to set your die adjustments the next time you want to load that bullet ....this saves a bunch of time adjusting dies .

Don't get discouraged ...there is a learning curve to adjusting dies , keep working with it ...it's not the dies or the bullets it a matter of getting the adjustment right .
Also when seating bullets make sure they go in straight ...if they are leaning , they will not magically straighten themselves out...crooked seating and they won't....you guessed it , Plunk !

Read and follow advice in post #3 ...good info.
Gary
 
Well, I just made another small batch of 15. Only 5 passed the plunk test.
I presorted the brass by headstamp, checked with chamber checker after resizing and thought I was very careful.

I don't get it. If my crimp die was set wrong, how do 5 of them work perfectly? I'm guessing it's that the bullets are not going in strait enough when seating. Maybe I got spoiled with 38/357, never had to worry about bullets being perfectly strait. Should I bell the case more, Maybe?

I'm going to disassemble the rounds I made. Can those bullets be re-used since they are plated? I guess if they measure .3545 it should be ok.

I remember reading in another post that for Lee it may be necessary to get the extra small sizing die. But these rounds already look like it's a very tight fit they are skinny in the middle and wider at the base and neck.
 
Standard sizing die should be ok . Does a resized case slip into and out your chamber ?
Flare the case mouth only enough to get the bullet started ... if the cases are all trimmed to the same length it makes flaring and crimping easier .
Seat the bullet in one step and make sure it is started straight in and no metal / plating is being scraped off .
Taper crimp just enough to remove the flared case mouth and keep the bullet from being shoved deeper into the case with pressure from your thumb ... don't go all Magilla Gorilla on the thumb pressure just a firm push on the bullet nose .
Now will the round slide in and out ?
Forget the case gauge...you pistols barrel is the only thing that matters .
Gary
 
Are you seating and crimping in one step or separate steps? If you’re doing it in one step that may be the problem. Try crimping as a separate step and go as light as it takes to do the job.
 
The resized cases do slide in and fall out no problem. I pulled the bullets from the first failed batch and there is no plating or lead being scrapped off. I’ve tried increasing the expansion, now I’ll try minimizing that. And, I’ll try minimizing the taper crimp. I am using a 4 die set. These bullets are so damn short I must be having trouble starting them strait.

The article about the magic marker test was great. I’m going to try that. Thanks!
 
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.982" is very close to the SAAMI Max of .984 for .380 ACP. My first guess is that the bullets are engaging the lands and that you need to reduce the C.O.A.L. a bit.

The plunk test is more than just "they go in." When you drop them in, do they land cleanly with an audible "plunk" as the case mouth hits the end of the chamber, or do they sort of "squish" in as the bullet ogive hits the lands? And do they drop out cleany? You said six out of ten did not drop out ... so they didn't pass the plunk test. Back to the drawing board.

What bullets are you using, and what load data are you using? Berry's lists two 100-grain .380 bullets. The flat base round nose is supposed to be loaded at a C.O.A.L. of .960 according to Berry's web site. The 100-grain hollow-base round nose is also supposed to be loaded to a C.O.A.L. of .960".

They also list a flat point and a hollow-point, all in 100-grain.
 
Ahh, first the failed rounds don't even make it into the barrel far enough to engage the threads. And, I'm also testing with a chamber checker gauge. The six rounds fail there but the 4 go in and out no problem.

I did the magic marker test. I think it looks like they are going in slanted.

The load data I'm using is from the Lee manual. 3.0 grains of Universal min COAL listed was .980. I was getting .983. I figured that was close enough to the minimum. Now I"m thinking If I do deeper to .960 maybe they will straiten out a bit.

BUT, would I have to reduce the starting load of powder due to pressure increase?

Here's what they look like with the marker test.

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BondoBob said:
Ahh, first the failed rounds don't even make it into the barrel far enough to engage the threads. And, I'm also testing with a chamber checker gauge. The six rounds fail there but the 4 go in and out no problem.

I did the magic marker test. I think it looks like they are going in slanted.

The load data I'm using is from the Lee manual. 3.0 grains of Universal min COAL listed was .980. I was getting .983. I figured that was close enough to the minimum. Now I"m thinking If I do deeper to .960 maybe they will straiten out a bit.

BUT, would I have to reduce the starting load of powder due to pressure increase?

Here's what they look like with the marker test.

attachment.php
Click to expand...

Measure that spot, too. It should be a little wider indicating it is bulged.

It's okay to load them deeper. They might or might not straighten out. Only one way to know. Try it.
 
BondoBob said:
I did the magic marker test. I think it looks like they are going in slanted.
Click to expand...
Very possible, since it's a stubby little bullet. This is where sufficient belling is necessary. The case mouth should be belled out enough that a bullet will sit level when placed on the case mouth, and stay level while you raise the ram to push it up into the seating die. But, even if they are slanted, the 4-die Lee set ends with a factory crimp die. That should do a final resize and mash everything down enough to fit any SAAMI compliant chamber checker. You might want to check the diameter of the carbide sizing ring in your factory crimp die.

The load data I'm using is from the Lee manual. 3.0 grains of Universal min COAL listed was .980. I was getting .983. I figured that was close enough to the minimum. Now I"m thinking If I do deeper to .960 maybe they will straiten out a bit.
Click to expand...
What Lee manual -- Richard Lee's big book, or the cheat sheet that came with the die set? I've never heard of any load data that gave a "minimum" C.O.A.L. They tell you the C.O.A.L. they used for that load, but it's neither a minimum nor a maximum -- it's just a statement. The SAAMI maximum for .380 ACP is .984" and the minimum is .910". Considering that the bullet maker calls for .960" (if you're loading one of the round nose bullets), I'd say you not only can shorten up a bit, I'd say you should shorten up a bit.

BUT, would I have to reduce the starting load of powder due to pressure increase?
Click to expand...
The safe answer is "Yes." If you want to fine tune, you could download a copy of Gordon's Reloading Tool and see what that says.
 
I was having a dickins of a time loading .380 with Lee bullet seating die. Cases would collapse, bullets would seat crooked. As you have discovered, it is tough to get fingers AND bullet under the seater die. Switched to a Hornady bullet seater. Cured my problems. It has an internal bullet guide that works quite well on the "little" lead pellets. I continue to use the Leee (FCD) factory crimp die.
 
Aguila Blanca said:
Thanks.

Interesting that he would list as a minimum a length that is so far over the SAAMI minimum, and so close to the SAAMI maximum.
Click to expand...

Yes, I suspect he was just listing the OAL the original source used for their data and calling it the minimum and meaning the "minimum without lowering the charge weight if you load deeper that this." Or something like that.
 
Bondo Bob,

The answer to straightness is to use an expander die with a Lyman M-die profile. It puts a little expanded step below the flare that the bullet can sit on squarely. This enables it to go straight up into the seater without your fingers guiding it, and to start the seating coaxial with the case, which is how it tends to stay until seating is complete. A crude illustration of the difference is below. If you want a powder-through version, the Lyman Multi-expander will do it. However, it is a kit for all common pistol calibers for .32 to 45, so it costs more than a sing-caliber M-die. Redding and Hornady dies have this profile, too. Lee does not.

attachment.php


That said, your COL is too long. From Berry's Bullets (originally, IIRC), the recommended COLs for their bullets in 380 are:

100gr FBRN: 0.965"
100gr HBRN: 0.970"
 
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