Help Diagnosing 9mm Issue Please?

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otisrush

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I loaded up my first 9mm rounds last night. (FYI - this is on a Rock Chucker single stage. Dies are RCBS Carbide.)

Using the barrel of my Walther PPQ:
* Factory round plunks fine.
* Sized case (no primer/powder/bullet) plunks fine.
* Finished round does not plunk.

Round: 124gr FMJ RN; CCI 500 Small Pistol Primer; 4.0gr Titegroup

I think my issue is that I don't have the taper crimp set up aggressive enough. I say this because of the following measurements I took:

Factory Round:
COL: 1.149"
Diameter At Case Mouth: .375
Diameter At Approx Base Of Bullet: .377-.379

Finished Loaded Round:
COL: 1.135 (This is the specified COL in my Speer #14 manual for the load I'm loading.)
Diameter At Case Mouth: .377
Diameter At Base Of Bullet: .377

The finished round numbers above was from a round that jammed in the PPQ. Measurements taken on other samples from the same batch show base-of-bullet measurements sometimes at .378 or .379 - but the mouth diameter is virtually always .377. (This is probably how I concluded during crimp die setup it was ok - because the instructions call for a "few thousandths" reduction from the bullet base.)

I'm thinking the .377 on my rounds vs the factory .375 is the issue.

What do you folks think? Do you think I need to lower my taper crimp die? Something else?

Thanks very much.

OR
 
Hi Otis. Since no one else has responded I'll take a guess. Is your expander die that should only slightly expand the case mouth set a little too deep/big, not sure of proper terminology, and then the taper is not enough to bring it back down to proper size?
 
It's quite possible I'm expanding it too much. I only say that because the "test" for having it set correctly (in the die setup instructions) was to open it enough so a bullet will "snap" into the mouth prior to seating. I kept setting the expander deeper until I got that "snap" feeling for the bullet. But maybe it doesn't need to be as deep as it is.

Thx.

OR
 
COL: 1.135 (This is the specified COL in my Speer #14 manual for the load I'm loading.)
Click to expand...
No it isn't.
(Unless you are using the exact same Speer bullet in the Speer manual.)

Different brands of bullets vary slightly in ogive shape, and will contact the rifling sooner or later then the bullet listed in the data.

Correct taper crimp should measure about .376" at the case mouth using .355" jacketed bullets.


I suggest you do this.

Completely 'color' a loaded round with a Magic-Marker or Dry-Erase marker.
And then force it into the chamber.

Where the marker ink rubs off the case, or the bullet, is your problem.

rc
 
Thanks rcmodel. Great ideas.

So - if it rubs off the case: Then taper crimp needs to be adjusted down so as to reduce mouth diameter?

And if it rubs off on the bullet - then reduce the COL?

BTW - I am not using a Speer bullet. (Zero Bullets)

Thanks again.

OR
 
Otis

Maybe you have your issue all figured out. You do not need to bell the case mouth very much to accept the bullet. The crimping step is removing the bell. I am not as expert as many others on this site. However, there is a tendency starting out to over do things.

Let us know what you find.

Swanee
 
My guess is that your bullet is jamming into the rifling as RC suggests. Your procedure for the case itself seems up to par. But what the manual states for OAL is only a starting point, not gospel.

You need to determain what works with your gun and specific bullet profile. Find what plunks and feeds. Adjust charge if need be. Sometimes it just requires some experiance. But that's part of the fun of reloading... it's an adventure, not a one shot deal.
 
You do not need to bell the case mouth very much to accept the bullet
Click to expand...

Or sometimes flaring isnt necessary at all. When i use plated bullets with my Win and RP brass i just resize, prime, charge and seat completely eliminating the crimp step all together.

Jacketed bullets may be different.
 
Heed rcmodel's advice. It is not a crimp issue. It is an OAL issue. If you don't believe it, pull a bullet from one round, dump the powder and plunk test just the case in your barrel. It will plunk just fine.

I have used the very same Zero 124gr FMJ RN bullet that you are using and had to seat it to an OAL of 1.114" to pass the plunk test in my most tightly chambered pistol. That's as opposed to a Remington 124 gr FMJ that passes the plunk test all the way out to 1.185" in the same pistol. I don't seat it that long, of course, but the point is that different bullet profiles in different pistols often require different OAL's.
 
Otis, any chance to test with RCs suggestion of the magic marker yet?
Clearance/bind marking is always a very handy technique!
 
I've been able to do a quick test with the dry-erase marker on a round. I've had limited time - so I did it quick and haven't tried it multiple times.

It appears the marker is getting rubbed off the case.

I'm figuring I should re-setup my expander and bullet seat/crimp dies. I don't have time to post a pic - but it seems on some rounds I can almost see some non-uniformity in the case about where the base of the bullet is. Maybe it's residual sizing from the expander. The bottom line is I think, in totality, I don't have confidence the expander and crimp dies are set up right - especially since sized cases drop in just fine. Something is happening after sizing which is causing the problem.

If that's bad logic please let me know. I hope tonight I should have some time to work on this.

OR
 
what the manual states for OAL is only a starting point, not gospel.
Click to expand...

Amen to that. Very well put. I like that, "not gospel", that's exactly right, and something that I did not understand at first. You can play with your OAL (starting low and working up of course). The range Ive loaded for 9mm is 1.10-1.155 or thereabouts.

How you like the PPQ? I was able to get my hands on an m2 at the last gun show in town, trigger felt sublime.
 
I have maximum length case gauges which I use to check if my loaded rounds will chamber. I can tell if the OAL is over or removing the bell is not quite right.
 
I have the Zero JHP-C 124gr bullets, and they have to be seated much shorter for my gun (1.080"). Don't know about the RN profile from them, though.

Try seating test round (no powder or primer) and seat the bullet much deeper, then try a plunk test.
 
I've made progress but I'm really confused.

I got more aggressive on the crimp - basically lowering the die. The bottom line: More aggression on the taper crimp did not change the shell's ability to fully chamber.

I then started reducing the COL. The good news: This did result in lowering the round into the chamber. COL right now is 1.101 but my guess is I could go a little longer and it would work.

What I'm really confused about is the factory ammo - which works flawlessly in this gun - has a COL of 1.148.

Why would 1.148 factory ammo chamber, 1.135 reloads not, and 1.101 reloads would? Difference in bullet profile between the rounds? This is REALLY confusing me.

Thanks.

OR

BTW: Can't COLs be too short - from a case volume and pressure perspective? If so - how do you know if the COL is getting too short?
 
Read post #4 again.

I explained it best I could then.

And don't want to type it again.

rc
 
rcmodel said:
Read post #4 again.

I explained it best I could then.

And don't want to type it again.

rc
Click to expand...

OK. Thanks for pointing me back to that. And thanks for sharing your knowledge. I greatly appreciate it.

OR
 
OR- you answered your own question. Different bullets have different profiles. I load 135gr RN Bayou bullets for my Glock 34. I can load them out to 1.170", and pass the plunk test, but choose to load them to 1.158" to easily fit in my mags, and run 150% reliable. My loads are OAL= 1.158", Dia @ case mouth= .377-.378". I run KKM barrels for my match guns, which are known for tight chambers. I use a combo of plunk test, and case gauge. I only bell/flare my case mouth the absolute minimum needed to seat bullet without damaging the bullet. I only remove the flare when crimping. If you are crimping correctly, you shouldn't see any crimp marks on a pulled bullet. For me the listed OAL is just a suggestion. I set my OAL for my individual gun.
 
I think you figured it out in post 12. Have you had time to go back and do that yet? For me I backed the expander all the way out then put a case in and screwed the expander down til it just touched the case then just a smidge more, maybe 1/8 turn.
Or another idea, but doubtful. Are the bullets themselves sized right? did they send you the right thing?
 
Look very carefully at the bullet. The most common problem is that the bullet is not set deep enough. Simple, experiment is to just seat the bullet deeper and see if that fixes the problem.
 
Yep, bullet profile is the important point to remember in this thread. I can tell you that, with most bullet profiles, I have to load to a shorter OAL to get rounds to pass the plunk test with my PPQ. So, I generally load for the PPQ, knowing that the rounds will easily function in all my other guns.
 
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