Not enough powder?

[J.D. Yellowhammer]

That's strange, never saw it do that??  What kind of primers do you use?

from Hodgdon:
125 GR. CAST LRNFP     IMR     Trail Boss     .358"     1.445"     3.0     753     11,600 PSI     5.3     952     13,400 PSI

I load my wife's .38 spl at 3.3 TB under couple'a different bullets and it burns well and seems to give her good velocity.

[Delmonico]

Also make sure the gun is not "broke" because  some gunsmith lightened the trigger and did a poor job of it.  A gun that is right will set off all primers fine and you don't have to worry about brand for proper ignition.  A gun that is "broke" will be selective about primers.

[J.D. Yellowhammer]

Also make sure the gun is not "broke" because  some gunsmith lightened the trigger and did a poor job of it.  A gun that is right will set off all primers fine and you don't have to worry about brand for proper ignition.  A gun that is "broke" will be selective about primers.

Here's an example of that:

About 3 weeks ago the ol' lady and me went to a shoot. One of the guys in our posse had some misfires. Not quite light enough to be squibs--I think the bullets kinda drizzled out of the barrel and plopped on the ground. But sounded like squibs. Yet some of the cartridges he shot were fine, and they were (I think) out of the same reloaded batch. It was mysterious. And I think that's exactly what happened: he (or some other knucklehead) had lightened the springs so much that he wasn't getting good strikes on the primers. We looked at the shells and the primers were barely dented.

[Stu Kettle]

I'm not sure, but I think if the primer goes off it goes off, light strikes will make them not go off, but I don't believe it will cause the week loads you describe.  More likely  the small powder charge was in a different place in the cartridges.  If the powder is mostly close to the primer some powders will work a lot better than if it's piled up against the base of the bullet.  some gamer convinced my wife she needed lighter loads so I loaded some per his recommendation & had that same problem.  Some went pop & some went poof.  The first one that stuck in the barrel of her pistol convinced her maybe lighter loads weren't going to improve her times.

[Delmonico]

Actually light primer strikes can cause weird things with the primers at times.  I don't remember the source but several years ago there was something about that in possibly Handloader, but it could have been elsewhere.  In fact I saw that problem back in the late 80's with a friend's 357 Blackhawk with some 38 loads, I can't remember the load at this time,( my old notes are not handy right now)  but I'd guess it was a standard 158 SWC and enough Unique to make about 850-900.  He put in a set of Wolf or Bullseye springs and things got weird, anything from good bangs to pops and watch the bullet.  He put the old springs back in it and everything was fine. 

Later when I had time a couple hours of polishing to reduce friction and everything was back to being fine again, this time with the new springs.   

[Professor Marvel]

As Our Good Del pointed out, there are generally good reasons for the recipe book.

However, I must say the Alliant website recipes are extremely limited - thus I recommend getting the
Speer and Lyman books (mine are elsewhere at the moment), and following them.

Monsiuer Yellowhammer gave us a lovely graphic demonstrating the laying-down of powder, which
"can" upon occasion  lead to erratic ignition.

http://www.cascity.com/forumhall/index.php?action=dlattach;topic=44988.0;attach=42151;image

-----------

ahhh the thread transmorgrifies into misfires ... (which can occur with light powder loads)
and light primer strikes...

===

He put in a set of Wolf or Bullseye springs and things got weird, anything from good bangs to pops and watch the bullet.  He put the old springs back in it and everything was fine.

Later when I had time a couple hours of polishing to reduce friction and everything was back to being fine again, this time with the new springs.   

====================================================

Whilst many noble minds insist that a primer "either ignites or it doesn't" ,  and some further stipulate
that "if a primer goes bang the powder must ignite" I submit that we are dealing with things that are a bit
more complicated.

Further,  we have empiracle evidence from our own good Del of direct correlation between light hammer strikes and unexpected "squib" results.

Also, while there are numerous learned minds who declare absolutely that "detonation" of low volume powder loads never occurs, I myself feel there are too many unexplained events with too little data.

Elsewhere on the interweb we find numerous discussions regarding small amounts of powder in large cases causing ... issues - these include reports of "poofs",  squibs, and some folk maintain the possibilty of "detonation".

the physical position of smaller amounts of powder in the case has been demonstrated to affect the pressure and thus accuracy.

These reports are all reason enough for me to shy away of  a load smaller than the current recipe calls for.

Disregarding those, let us focus our discussion on just "light vs "heavy" hammer strikes. Whilst it seems at first glimps to be some form of magical pixie dust which various in relation to the tidal forces of unseen planets, it can be explained when one investigates the compexities of the primer .

Let us perform  Die Methode des Gedankenexperiments, based upon experiential evidence:

Firstly, load a "dead" or oil-killed primer in an empty case, load and fire.
We will see what appears to be a light firing pin strike.

Now load a fresh primer in an empty case and repeat.
The primer backs out of the pocket and Nearly every time, jams up the action.
When we retrieve the case We see quite a deep  firing pin strike.

When we load normally and fire, the primer will still back out of the pocket, but the cartridge case
will then blow back, reseating the primer, and pressure from the expanding gasses will cause the primer
to expand and sometimes flow depending upon the primer hardness and pressure.

Now let us consider a light primer strike (ie weak springs) and remember this is a thought experiment and conjecture (but based on reported results of some squib-type bangs) .
could one of the following occur?
a) the additional "oomph" from the stronger spring helps to drive the primer deeper, sealing the primer more betterer producing more presssure?
b) a weaker hit might not hold the primer as well during primer backout, possibly causing reduced pressure?
c) a weaker hit might cause marginal ignition, possibly causing reduced pressure?
d) other?

yhs
prof marvel

[Professor Marvel]

Now to babble on and muddy the waters further  -

rickk related:

"My assumption about the dominant reason erratic ignition with Unique is that the variation in exposed powder surface from round to round becomes too great at some point.  This is just a "gut feeling" based on some experiments I did with gun position just prior to shooting. With slow burning ball powders (H110 for example) there definitely is a minimum pressure needed for proper ignition..."

and Monsiuer Yellowhammer gave us a lovely graphic demonstrating the laying-down of powder, which
can upon occasion  lead to erratic ignition.

and Del reiterated
"More complicated is Unique needs a certain amount of pressure (like most powders) to burn right..."

If we consider it carefully, the ignition of the primer compound is very little different from the ignition of powder -
both can be affected by container size, compression, gas expansion, and other variables.

We see interesting dynamics that are observable, but not completely understood (by myself) in  the movement of the primer.

We also see empirically the effects of variables in hammer weight, spring strength and momentum
which can cause further changes in  the movement of the primer.

Thus we see complex interpendencies upon a number of variables . Those variables we can identify so far include
- movement of the primer
- how the primer movement is affected by the hammer
- how primer ignition/burn rate is affect by the above
- how primer ignition/burn rate is affected by case volume and crimp
- powder volume  in proportion to case volume
- the amount of surface area of exposed powder
- the compression (or looseness) of the powder
- whether the primer flame is in close contact against compressed powder  or flashes broadly over a "puddle" of loose powder
- case crimp, which leads to changes in static "container strength" and "container volume" until the bullet begines to move

If the powder is "packed" and held closely to the primer, the amount of powder exposed to the primer flame is limited at first;
the primer "burn" is held  contained under increasing compression by the powder;   the powder burns progressively like a small rocket, and the unburned powder  becomes part of the moveing mass (like the bullet) .

If the powder is a loose puddle the primer flashes over it "uncontained" or with little resistance except that from the cartridge case itself. The surface area of powder ignited is much greater, and the powder burn ( and gas expansion, and thus instananeous pressure) is (or ought to be theoretically) much greater and faster than the above compressed example.  Here is the worse-case scenario that has led to the theories of "detonation" when using very small quantities of powder. However, we do know from observation that a primer alone can push the bullet from the case, sometimes some distance down the barrel - so the case for detonation suggests that the uncompressed loose powder develops a faster burn rate than normal, literally causing a rapid explosion (rather than expansion ) even before the "expanding gasses from the primer" can move the bullet.

Interestingly most of us who dabble in that "smokeless fad" and who use powders such as Unique, have settled on middle-sizeed loads that somehow magically ignore all of our above conjecture and which somehow mysteriously work.

yhs
prof marvel

[J.D. Yellowhammer]

Great exposition, Professor! Allow me to "expand" on this.  Jim Barnard, author, aerospace engineer and CAS shooter, wrote about powder position, detonation, etc.  He talked about what happens when the bullet goes into the forcing cone before the powder burns completely.  I think you could also have a situation where the primer pushes the bullet past the forcing cone, maybe out the barrel, and the powder never burns completely, leaving unburned residue in the barrel.  Somewhere I have an article that talks about what happens when the primer fires over the powder, like in my picture, and the powder burn goes out, like Jim says below.  Can't find it, though...

At any rate, it's not something to be fooled around with casually. Like Del said--the data in reloading manuals are there for a reason!

Here's Jim's observation:

First let me explain that it is impossible for there to be a "detonation" with the propellants we use. Ballistically, the definition for a true detonation is an event that produces a shock front in excess of 25,000 ft/sec. There is simply NOT enough chemical energy in these propellants, in these quantities, even with a double charge of powder to produce a detonation wave.

Having said that, however, what we get in these instances is an overpressure. (Yeah, I know, the gun is still wrecked.)  There are several things that can cause that, first and foremost is an overload.  However, with a powder check die, that is less likely in this situation.

  What causes me to sit up and take notice is the fact that a relatively light weight bullet having no crimp groove, and held in the case by a taper crimp, may have caused a phenomenon sometimes called "ignition delay overpressure".  Smokeless powders require 5,000-7,000 psi (NOT CUP) pressure to burn stabily.  Generally, a powder reaches this level fairly quickly (in milliseconds).    But, if the bullet is pushed out of the case too quickly in the ignition cycle, the pressure may drop enough to have the powder nearly "go out".  If the bullet hits the forcing cone with less force than that required to engrave the rifling on the bullet's surface, it may stop! When that happens, any remaining powder that hasn't burned completely will take off under the increased pressure. Smokeless powders are "progressive burning", which means the higher the pressure, the faster they burn, and the faster they burn the higher the pressure. Chambers in .45 LC guns are traditionally cut pretty generously, which means the cartridge case has a ways to go before hitting the chamber walls. If the pressures exceed about 35,000 psi, the case will rupture, usually at the 3- and 9-o'clock positions. The hot gases then act like a cutting torch on the chamber walls, and at that point the cylinder splits and we have liftoff!  I would check to see if you can pull the bullets fairly easily. (You might need to rig a scale and see how much bullet pull you have in pounds, but it won't be easy to do.  We have seen this phenomenon before, and several ballisticians have been able to obtain data tending to prove this.

My recommendation is to use bullets that have a crimp groove or a forward driving band that you can use a ROLL crimp over. Also, check your expander plug to see if there is enough tension being placed on the bullet by the case, i.e. if your .45 LC expander is for a .454" bullet and yo are using a .452" slug.

[Professor Marvel]

Heavenly Carbuncles! My Good JD, I had not considered  in my Gedankenexperiments that too light a crimp would contribute to Kabbooms!

I am now coming to understand the rejection of the term "detonation" -
In the world of explosives, powders, burn rates, & etc  it is a specifically defined event that has unique properties -
to an expert in the field it would be like us lay-persons discussing "clip" and "magazine" and assuming everyone knows what exactly we are talking about 



I detect even More variables in the mix - cylinder chamber size vs case size, length and size of thoat vs projectile sice, forcing cone domensions ...

I am impressed, intrigued, and mortified by this information youi presented:

What causes me to sit up and take notice is the fact that a relatively light weight bullet having no crimp groove, and held in the case by a taper crimp, may have caused a phenomenon sometimes called "ignition delay overpressure".  Smokeless powders require 5,000-7,000 psi (NOT CUP) pressure to burn stabily.  Generally, a powder reaches this level fairly quickly (in milliseconds).    But, if the bullet is pushed out of the case too quickly in the ignition cycle, the pressure may drop enough to have the powder nearly "go out".  If the bullet hits the forcing cone with less force than that required to engrave the rifling on the bullet's surface, it may stop! When that happens, any remaining powder that hasn't burned completely will take off under the increased pressure. Smokeless powders are "progressive burning", which means the higher the pressure, the faster they burn, and the faster they burn the higher the pressure.  If the pressures exceed about 35,000 psi, the case will rupture, usually at the 3- and 9-o'clock positions. The hot gases then act like a cutting torch on the chamber walls,

And even more questions arise -
"how/and or why" would light hammer hits cause "poofs" ? - I can only see a change in primer movement/ignition dynamics.
what are the exact dynamics of primer ignition, burn, and burn rate?

We observe upon occasion unburned powder - It is a simple thing when using BP, but with smokeless, why is there unburned powder left?  what contributes to unburned powder?

JD were you are participant in that intriguing discussion on the Open Range regarding detotantion, wavefronts, etc in Naval Guns?
(I was but a fascinated fly on the wall)

yhs
prof marvel

[Delmonico]

I've found out with a properly set up taper crimp and a groove I can get a crimp much tighter than any roll crimp.  Roll crimps have a point where things go back the other way if things get to a certain point and a case slightly over the length of the one the die was set up on will do it.  I pull proper set up taper crimp rounds that need it with something besides one of those plastic hammers after breaking two of them.

[Trailrider]

"We observe upon occasion unburned powder - It is a simple thing when using BP, but with smokeless, why is there unburned powder left?  what contributes to unburned powder?"

As was pointed out by J.D., quoting my previous dissertation, smokeless powder burning is dependend on the pressure in the combustion chamber. In point of fact, the process inside a cartridge case is not uniform. The primer flame contains both hot gases and burning particles which flash into/over the grannules of the powder, igniting each grannule, but not necessesarily in the same, identical way. Turbulence in the combustion process affects each grannule differently. (Think of a football being tumbled end over end, or wobbling around in flight.) Add to this the movement of the bullet, which causes the pressure in the confined space to drop as the combustion volume (case volume plus the extra volume created as the bullet moves) increases.  If the pressure drops below the 5000-7000 psi level (the required pressure depending on the composition of the grannules, evenness of the deterrent coating, the grannule's uniformity of composition, the uniformity of the dimensions of each grannule, etc), the grannule may cease to burn completely.  That's why you get unbruned powder grannules.

[Delmonico]

If you want to see a lot of unburned powder, just sweep a range where a lot of 22 LR has been fired.  Pile up the sweepings and put a match to it. 

So if unburned powder was as much of a problem as many think it is why have the ammo companies not figured this out and fixed the problem.  I'm more worried about the bullet doing what it is supposed to do than worrying about a little unburned powder.

[Trailrider]

Sorta depends... If you are getting good accuracy and not having hangfires or misfires, then a little unburned powder probably won't hurt anything. OTOH, if you are fouling the action of your gun with particles of unburned or semi-burned powder, you may want to look to modifying your load by increasing the powder charge, changing powder, putting a firmer crimp on the case mouth, etc.

[Professor Marvel]

Greetings again, Del -- no, that is not enough noodles !

My Good Trailrider -
Thank you for the further edification!
Is your article available anywhere? I would love to read it.

Can you possibly offer any insight or ideas into Del's "light hammer hit poof's" ?

I would dearly love to hear the various opinions on the use of fillers in these smaller volume smokeless loads .

back to the OP queries, I really must dig out my old Lyman manual and compare it to the newer loading data, but I cannot imagine that the powder formulation of Unique has changed in ( dare I say it) 40 years.

yhs
prof (waiting with baited breath) marvel



no Del, you really need to make more noodles! and you need to make a batch of rice flour noodles, too!

[J.D. Yellowhammer]

JD were you are participant in that intriguing discussion on the Open Range regarding detotantion, wavefronts, etc in Naval Guns?
(I was but a fascinated fly on the wall)

yhs
prof marvel

No, fortunately I avoided that one!    Usually I stay out of the discussions about detonation, etc.  I'd like to follow the principle of keeping my mouth shut and letting folks think I'm a fool, rather than opening it and proving them right. I'm sure I don't always succeed...      However, now that you've brought it up, I'm gonna go look for it.  Thanks!

I don't play around with loads--I stay well within mfctr specs.  If it ain't broke, don't fix it.

Trailrider, thanks for pitching in to the discussion and thanks for the great info. (fer folks who don't know, Trailrider sells great, authentic leather and has a book about CAS which includes a chapter on reloading: http://www.gunfighter.com/trailrider/tr_guide.html )  Sorry, but I don't remember exactly where I got your quote. When I run across valuable information I copy it and sometimes forget to include the link.

[Trailrider]

"Sorry, but I don't remember exactly where I got your quote. When I run across valuable information I copy it and sometimes forget to include the link." - J.D. Yellowhammer

Appreciate the kudos. I don't remember exactly where you got the quote either!    Probably from "Trailrider's Guide to Cowboy Action Shooting(tm)". I've posted essentially the same information a number of places, so, if you didn't see it in the book itself, it could have been on this forum or "the other one".

Ride careful, Pards!

[wildman1]

I am tryin ta digest alla this, so correct me iffen I'm wrong. What yer sayin is iffen I'm settin the paper targets on fire at 20 yards I prolly need ta tighten up my crimp a little?  WM

[J.D. Yellowhammer]

I am tryin ta digest alla this, so correct me iffen I'm wrong. What yer sayin is iffen I'm settin the paper targets on fire at 20 yards I prolly need ta tighten up my crimp a little?  WM

No, I think it means you're way too light on powder. If you ain't incinerating the targets, stiffen the load!! 

[wildman1]

   WM

[Lumpy Grits]

FWIW: I have been load'n 4.0gn. Unique with 125 & 158 lead bullets in .38 Specials for about 40 yrs now, with NO issues.
Do use a firm crimp.
LG