Ran a batch of Underwood 165 JHP on the range today and am spooked on the brass!

[Ascension]

Ran a box of 165 grain JHP Underwood today through the S&W 1066 today and am glad I was not shooting my Glock 29!
When I started looking at the brass from the shoot today I had a number of rounds with the primers flattened and flowing, cases scored and bulged and saw clear overpressure signs with a number of the Underwood brass I picked up today.  This box looks to be loaded way hot and was dangerously over pressure! My phone crapped out and I can't lay hands on my camera right now but if I had run these through the Glock 29 instead of my big S&W I'm not so sure I would have had  a pleasant day.
Also seem the rounds seemed inconsistent in velocity the recoil brutal and the Underwood rounds today flat would not group in the S&W while the PMC 170 Grain JHP's I had on hand were grouping very well.
Been shooting Underwood for a while now (almost exclusively the 180 grain FMJ at the range) with out an issue but this particular box of the 165 JHP flat spooked me!   

[Intercooler]

   Post some pictures when you get a chance. I know the flattened primer term and what it looks like but am not familiar with the flowing term. If you still have some of that box, it may be worth sending a couple to The Shadow to see what the powder charge is like (unless you can pull the bullets).

[4949shooter]

I think by flowing he means deformed. Pics will help.

I shot some Underwood 165 grain fmj a few months ago and they were good. Are they loaded to the same pressures as the JHP?

Was this perhaps an older box before Kevin had adjusted the pressure?

Just thinking out loud here.

[Intercooler]

   I'm still trying to figure out how all this stuff works. I don't think I have ever gotten a double-charged round but the NFP 155's are loaded extreme but don't really see signs.

[The_Shadow]

Ascension, may I ask what recoil spring rate you are running in you S&W1066?  
I suspect you are starting to see the bulge and slight "smile" at the base of the brass where the feed ramp section of the chamber of your barrel.  The dreaded "SMILE" characterized by a distinct line, less case support at the fed ramp, can be formed from higher pressures and softer brass.  In the case of over-pressure you may experience a case blow out!
If you have any of those rounds left and want to know what's inside, I could do a pull-down documentation if you send it to me.  Contact me via PM if you so decide.

Please try to post pictures if you can. 

Best regards!

[Ascension]

Spring is a 20 pound. One round in particular the primer has only a tiny mark from the firing pin as the primer is flattened from the pressure and the area that was dimpled by the pin is slightly raised and looks flowed out almost like someone dropped a light coat of solder around the pin indent!
I have no "smiles" but the sides of the cases are scuffed from swelling. There is only some slight visible case bulging as the factory barrel in this particular pistol has very good case support.
The 170 grain PMC's I was also shooting showed none of this in that brass. This particular batch of Underwood seems really HOT and on the edge!
Will try to get some photos up today in particular of the round with that primer that "flowed".

[Ascension]

I think by flowing he means deformed. Pics will help.

I shot some Underwood 165 grain fmj a few months ago and they were good. Are they loaded to the same pressures as the JHP?

Was this perhaps an older box before Kevin had adjusted the pressure?

Just thinking out loud here.

I have had these two boxes of the JHP 165's for a little while now, the brass is marked Underwood not Star line so that are not that old. Only ran a few of the 165 JHP rounds to make certain they cycled properly as these were my carry rounds.
I  have been running the light Priv stuff or the 185 grain FMJ Underwoods mostly on the range.
I had the S&W out to set the new adjustable sights so I ran several type rounds today.

[Intercooler]

Do you have a camera phone you can get pics? Send them to me if you can't get them to post.

[The_Shadow]

Spring is a 20 pound. One round in particular the primer has only a tiny mark from the firing pin as the primer is flattened from the pressure and the area that was dimpled by the pin is slightly raised and looks flowed out almost like someone dropped a light coat of solder around the pin indent!
I have no "smiles" but the sides of the cases are scuffed from swelling. There is only some slight visible case bulging as the factory barrel in this particular pistol has very good case support.
The 170 grain PMC's I was also shooting showed none of this in that brass. This particular batch of Underwood seems really HOT and on the edge!
Will try to get some photos up today in particular of the round with that primer that "flowed".

OK that explains more, what you are seeing is what is referred to as Primer wipe!  The firing pin sort of gets trapped  on the primer and the wipe mark occurs during ejection phase as the barrel drops down during the unlock phase. 

Today's primer cups have been made thinner and softer for more reliable ignition with striker fired weapons.  I have used some of my older primers (1988 vintage CCI) recently to duplicate some loading that exhibited that primer wipe situations and that situation didn't occur.

You might try a firing pin change out, but I don't think it will help.

Yes, casings that expand to fill the chambers fully can show stresses on the brass.  Taking case measurements will show if just how much.  If you did not have any cases stick in the chamber during the ejection cycle you are probably OK!  Sometimes cases swell and remain swollen too long (usually slower burning powders) as ejection starts and the extractor over rides the case's ejection rim.

I don't know how old the 20lb spring is or how many cycles on it, but you could try a 22 lb to see if it helps with slide velocities.

Good luck! 

[Ascension]

Do you have a camera phone you can get pics? Send them to me if you can't get them to post.

My phone died yesterday I am about to go over and see if i can replace it. I will find my camera and use it though instead of the phone. Looking at the rims I was also seeing marks where the ejector was having a hard time because of the case swelling with this batch. I need to really go back and look hard at the Underwood brass from other shoots as the velocities listed are WAY above what the reload manual I have on 10mm states is max velocities with 800X for bullet weights!! 
Stuff burns clean and hits hard but is it TOO HOT and over SAMMI spec?
There was also the issue with grouping in the 1066. It was shooting MUCH tighter groups with the PMC 170 than it was with the Underwood 165.
We had picked up a few boxes of Underwood .357 sig and ran it in a Glock 33 a while back. Not only was the recoil NUTS but we saw BIG time over pressure signs with those rounds ( flattened primers and smiles). It was bad enough that we were thankful we did not have a KABOOM and we both ( my son and I ) agreed to never run those Underwood rounds in .357 Sig again as they were WAY over pressure!! Never saw that kind of thing from the Underwood 10mm loads I have run till today and have some thinking to do on if I will continue to run the Underwood after this.

[The_Shadow]

Recently Underwood has switched some components to include powders with the current supply dilemmas...Most recent "pull-downs" of the 135gr  Sierra have shown LongShot vs. older loadings using the IMR800X loadings.... 

I don't know what's inside what you are shooting, but the pull-downs are just to show what is inside.  Yes they are higher than current handloading manual data.  The question is are they within the SAAMI pressure MAP for commercial Ammo?  Seeing that there are NO Warnings on the packages I would say they would have to be inside that criteria as set if he is having his loads pressure tested.

[Ascension]

Recently Underwood has switched some components to include powders with the current supply dilemmas...Most recent "pull-downs" of the 135gr  Sierra have shown LongShot vs. older loadings using the IMR800X loadings.... 

I don't know what's inside what you are shooting, but the pull-downs are just to show what is inside.  Yes they are higher than current handloading manual data.  The question is are they within the SAAMI pressure MAP for commercial Ammo?  Seeing that there are NO Warnings on the packages I would say they would have to be inside that criteria as set if he is having his loads pressure tested.

The 165 Underwoods are advertized at 1400 the max load velocity for 155 according to the manual I have using 800X is just under 1300, that is a substantial difference in pressure and velocity!!
I still have a second unopened box of the 165's from the same batch and it would indeed be interesting to see what is in these. My Son and I talked about pulling a round or 2 down if we don't I will send a couple your way.
The box of Underwood 357 Sig we got was way way over the top and we will not run that round again.

[The_Shadow]

Ascension, I actually did a pull-down of some Underwood 357Sig that blew up a KKM Barrel and Glock pistol.
here is the link to what was found inside those...they may have been bullet set back also that led to the failure.
http://10mm-firearms.com/factory-ammo-pull-downs/underwood-357sig-125gr-bonded-fmj-pull-down/

So yes those 357 Sigs of yours could be just that hot!
As handloaders we know you don't get anything for nothing!  If we push it can push back!

[Ascension]

Ascension, I actually did a pull-down of some Underwood 357Sig that blew up a KKM Barrel and Glock pistol.
here is the link to what was found inside those...they may have been bullet set back also that led to the failure.
http://10mm-firearms.com/factory-ammo-pull-downs/underwood-357sig-125gr-bonded-fmj-pull-down/

So yes those 357 Sigs of yours could be just that hot!
As handloaders we know you don't get anything for nothing!  If we push it can push back!

The "push back" is what I'm worried about as I am a musician and kinda need to keep the hands intact!! 

[Intercooler]

You know what I mean