Xtreme Plated RN Flattening When Being Seated

[otisrush]

I'm setting up my seat/crimp die for the first time for an Xtreme plated bullet. 9mm 124gr RN. (RCBS die set with taper crimp.)

When I follow the RCBS setup instructions I end up with a dummy round (no powder or primer) with a COL of 1.135" which plunks great in my Walther PPQ. At this point everything is seemingly fine.

But when I seat a bullet with this die setup the nose of the bullet flattens considerably and, even with that flattening, the COL is longer than 1.135". I don't have at my fingertips what that COL is.

I'm getting the following measurements from my calipers:
Base of the bullet: .3565"
Inside diameter of the case mouth: .3545

I'm not quite getting this. I can get the bullet to "snap" into the mouth. (Yes - it's tight. ) But given these measurements should I be expanding the mouth a bit more? It's feeling that way. I tried to follow religiously the RCBS instructions for the expander to do it "just enough". I'm figuring the case mouth is too tight for the bullet to be effectively seated without being crushed.

Am I not expanding the mouth enough? Or is there something else I should be checking or doing?

Thanks!

OR

 

[rcmodel]

You may be using too much taper crimp and it is tightening on the bullet just before it finishes seating.

Measure a loaded round at the case mouth.
It should be no smaller then .376".

If it is smaller then that, back off the seating / crimping die until it is .376".

rc

 

[JO JO]

I am sure someone will help you figure this out , just a quick question are you using the
correct seater plug, my hornady dies come with both seater plugs one for round nose and
one for flat point ?

 

[joneb]

are you using the
correct seater plug

^ this could cause that.
Sometimes seating and crimping in two steps is the answer, or what rc said.

 

[otisrush]

I am sure someone will help you figure this out , just a quick question are you using the
correct seater plug, my hornady dies come with both seater plugs one for round nose and
one for flat point ?

That is most definitely at least one of my problems. I had the wrong seater plug in. Geez. Each time I seem to ask a question it becomes a "D'Oh!" moment.

Now - with the right seater plug in - the nose is no longer getting crushed. But I'm still trying to find the recipe of COL and crimp amount. I've hit the stage tonight (frustration) I know I need to let it sit and I'll work on it tomorrow. When things like this get frustrating I tend to start rushing and this is something that shouldn't be rushed.

Thanks all! I greatly appreciate it. The knowledge AND helpfulness on this board is off the charts.

OR

 

[Walkalong]

Even the wrong seater plug should not be "crushing" the bullet. I think rc has it.

 

[otisrush]

I think I'm off and running. I've gotten some dummies made up that don't get crushed as well as plunk well.

Both rc and JO JO were right. I did neat a different seater plug. But the crimp was also down too tight. I couldn't see it manifesting itself in my calipers. I don't think I was ever getting less than .377. But when I was trying to get the mouth diameter down during the taper setup process I was tightening the die down pretty hard and far after feeling that initial resistance when it contacts the case. This time I basically set the die at the level right after it contacts the case.

As I said - they're fitting in the chamber beautifully. (Even with a slight nose crush it was screwing up the plunk. The gun in question is a PPQ which is known for having a tight throat.)

My only real concern is checking setback on rounds in the mag after some have been fired. That's what the next range trip is for.

Thanks again all!

OR

 

[Jesse Heywood]

Many here either apply no crimp to the 9mm. I apply only enough to straighten the belled end of the case.

 

[FROGO207]

I do the same as Jesse H. I find the less crimp the better the accuracy with all my autoloader rounds. YMMV

 

[SwaneeSR]

+2 to minimum crimp.

In my .40SW and 9mm, I use minimum bell on case mouth needed and just enough crimp to remove.

 

[Tcruse]

I use the 124 RN 9mm (Lee dies) with no issues. Now, my issues have been with 200g FN in .45ACP. They seem to not feed well, setting the crimp on a separate (Lee Factory Crimp) die helps but still not 100%. The bullet shape seems to be too sharp and not enough sticking out to function well in the mags, the bullets nose dive. Now, the 225 FN seems to not have the issue. COL as set to be as long as to not touch the lands in my 1911 barrel.

 

[Mr. Rowdy]

I use Lee dies, the crimp die is separate. On my 9mm I use just enough taper crimp to roll the edge of the case mouth. When setting the die up I'll crimp some dummie round and pull the bullet to inspect the amount of crimp. I like to just barely see evidence of crimping on the bullet. Bare in mind also, that if you change from a jacketed round to something softer, like a plated bullet or hard cast you'll need to reset the crimp. Not used an RCBS seater and crimp die, so I cannot offer any advice there.

 

[otisrush]

I just returned from the range having tested my new loads. (124gr RN Xtreme Plated Bullet; COL=1.130"; 3.6gr/3.7gr/3.8gr Titegroup; Walther PPQ 5"). I fired 6 rounds of each load.

No pressure or action-cycling issues. Flawless in that regard.

To check bullet movement (given the minimum crimp) I did 2 things:
1. After chambering a round by dropping the slide stop I ejected the unfired round and checked the COL. It had gone down a few thousandths - 1.128". I did the exact same test on that same round and it went down to 1.126" (give or take). I then fired it - no pressure issues.
2. I'd put a test round in the mag as the last round (i.e. first round inserted in the mag) and then put 8 or so known-good rounds on top of it. When that last round was chambered I ejected it unfired and checked COL. It had not changed: 1.130".

So for #1 - should I be concerned about losing a couple of thousandths in that scenario where the round is chambered by the full force of the spring from a standing still position? My guess is the experts here will say I'm over-thinking things. But when one isn't deeply experienced (and wants to learn ) assuming something isn't a big deal may actually be "careless" in some circumstances. I'm not sure whether I'm on the "overthinking" or "it needs to be addressed" ends of the spectrum.

Given I don't want to be careless I thought I'd check with the experts.

Thanks.

OR

 

[LiveLife]

Working OAL/COL vs chambered OAL is a variable we simply need to factor in when using mixed range brass with unknown reload history and condition of brass (Now if only all the rounds experienced same amount of bullet setback when chambered ... ). BTW, I experience very minimal or no bullet setback when using Berry's/RMR HM 124 gr RN at 1.135" and Glock/KKM/Lone Wolf barrels but the bullet setback maybe due to PPQ's barrel/feed ramp geometry.

As you found out, working OAL does not matter if the chambered OAL decreases and final OAL is the bullet seating depth you should be concerned about especially if you are loading near max/max charge (With 3.6-4.0 gr start to max charge spread, 3.8/3.9 gr is near max). These are reasons why I do not recommend Titegroup to new reloaders as you have narrower margin of safety. What one may thought was a "safe/below published max pressure load" using high range load data at published OAL could easily become over max loads, especially if bullet seating depth decreases from significant bullet setback.

124 gr BERB HBRN TP Titegroup 1.150" Start 3.6 gr (957 fps) 27,700 PSI - Max 4.1 gr (1,057 fps) 32,700 PSI

125 gr Lead CN Titegroup 1.125" Start 3.6 gr (1,002 fps) 22,900 CUP - Max 4.0 gr (1,096 fps) 30,400 CUP

Since Hodgdon lists 4.1 gr as max charge for Berry's HBRN-TP at 1.150" and 4.0 gr as max charge for Lead Cone Nose at 1.125", I would use the more conservative load data and work up your X-Treme plated bullets at 3.8 and 4.0 gr. As you can see, the very narrow start/max range is representative of significant chamber pressure increase from 0.4 gr powder charge increase.

I tested Berry's regular plated RN (solid base) with 3.8/4.0 gr Titegroup at longer 1.160" and while 3.8 gr worked well, 4.0 gr produced slightly greater accuracy. Since your OAL is limited to 1.130" due to PPQ's barrel and 1.125" is the chambered OAL, I think you would be OK.

If you like, you can load some at 3.8/3.9/4.0 gr and see which produces best accuracy.

 

[otisrush]

Thanks very much. The first pistol powder I could find (after watching for multiple months) was Titegroup. I was a bit nervous using it but I've taken some steps which make me feel more comfortable. (I've loaded and shot about 500 rnds with it - with a different bullet.) ONE of the things that makes me feel comfortable is that it meters extremely well in my (20 or so yr old) RCBS Uniflow. When charging cases I weigh every 10th charge and it always has been right on. I've never had to adjust the measure. (And this, BTW, is after calibrating the scale using check weights.)

My goal today was to just check function and look for signs of pressure. Now that that is ok I'll load up greater quantities and do some accuracy tests across the different charges.

Thanks again for the info.

OR

 

[LiveLife]

Great. Looks like you are taking all the right precautions working up the load with Titegroup.

Good job!

 

[Lman57]

minimum crimp +3 I use Lee dies and just finished 1000 box of Berry's and with just the minimum they work fine in 3 different 9mm I own.

 

[Scarpia]

bullet seating plug...

...when I seat a bullet with this die setup the nose of the bullet flattens considerably...

I had the same problem with the same bullet, Xtreme 9mm RN. Turns out the bullet seating plug inside my Lee die was the culprit. I came to this conclusion when I noticed my 380 bullet seating die did not distort those bullets. I swapped the plugs and now have round nosed 9mm's loads and use only flat points for 380. The 9mm seating die plug was too flat to keep the round shape of the 9mm RN's but it's OK if I use it for FP's in 380.

 

[Hondo 60]

What is the profile of the seating stem?
Sounds as if you need a different stem.
Contact the die mfg, many of them will help you without cost.