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Guest

Twice, I don't think we should take things quite that far. The ballisticians at Hodgdon are good at what they do. Whoever the customer service rep was that we talked to had his head in his shorts. I bet if you could talk to one of the ballisticians, you would have gotten the proper answer.

I just got off the phone again, with Hodgdon, they are only recognizing two basic hull designs. The compression formed and the polyformed style hull. Apparently Hodgdon is not concerned with slight interior differences in the polyformed hull so their data includes all of the polyformed hull designs regardless of who actually manufactured it.

The hull used for the DR16 wad was polyformed. Any data that Hodgdon prints that uses the Winchester X-pert Plastic Shells is polyformed, that is what some further digging into this matter and talking to Hodgdon has revealed.

My own personal take on this, considering the pressures involved. Any of the 3 polyformed hulls that Winchester has been using will be just fine.

What I do like about the data is that there is plenty of room for some velocity, as those are VERY low pressures at 1,300 F.P.S.

This is a simple matter of using one's gray matter. Determining the volume of any given hull in relation to another is easy. All it takes is some tap water and an accurate scale. I've done it many times with very satifactory results.

Reloading manuals are guides. They can help keep folks out of trouble, but they can't teach them to think. Some folks' eyes aren't blue, brown, or any other color. They are empty.

Guest

16 GG, you are back at it I see, questioning folks gray matter, flipping the thread around, and then wondering why guys get upset with you.

It would be best for you to stay out of this topic until you get a new set of reading glasses or learn to comprehend what you have read and what prompted this thread in the first place.

Go away and stop trying to drag guys into an argument, for your own twisted sense of amusement.

Guest

I will disagree with you Topcat. Volume does not tell much of the story, the shape of the combustion chamber formed by the overpowder cup and the basewad of the hull and the placement of the primer in the powder charge influences ballistics.

Like this, take a 2 3/4" hull and fold crimp it, take the same hull and cut it down 3/16" and roll crimp it, put the same compomemts in both hulls, different volumes same ballistic outcome.

Volume works with rifle and pistol cartridges it doesn't mean much in a shotshell.

Guest

Joined: 12 Oct 2008 Posts: 50 Location: New Jersey

Wow, reading this was enlightening. Nice to hear such good results with a 7/8 oz. load. Always figured it was doable.

I have been religious in saving my old WW compression-formed cases. I still have a few boxes of factory stuff that haven't been fired yet as well. And yes, those shells I bought sometime in the late 90's and have never seen them since. This hull I would pick over ANY hulls out there for reloading except maybe the old Fed. plastic hull. (I still have bins of the this hull when Federal was still loading their 3 1/4 x 1 1/4 high brass load.) Don't know if Federal still does today as all I use are reloads from what I can cobble from my bins. I've also had good results with the Rem. green or black hull with 1 oz. loads for nice crimps.

I have mixed emotions about the WW polyformed case. I never was happy with the crimp. For a 1 oz. load I still am using my old supply of WWAA16 wads.

Don't laugh, but I still have a good supply of once-fired Fed. paper shells that I reload. These I've had since the late 60's - early 70's.

Guest

Guest

I am not wrong, If you simply go by case volume YOU 16 GG are the one who is leading folks off the deep end and into trouble. You can only use volume if the interior of the hulls you are comparing are exactly the same configuration.

In a shotshell the interior design of the hull has a lot more to do with ballistics than volume alone.

Another item. You can work loads up when working with metallic cartridges, as you have measurements that you can take to determine when you are reaching maximum pressure. You can't do that with a shotshell. So you really shouldn't be guessing at what components(i.e. amount of powder to use when you get an off sounding load) to use, as you have been suggesting in previous responses.

You need to stop reading books and start actually doing something instead of talking about it. You haven't spent 2 seconds behind a pressure gun, as such you have no idea what really goes on.

Guest

DC I don't want to get between you and 15gg in this little dispute but I am curious about the relationship between shot shell interior case volume and chamber pressure. Given a 12 gauge, a 16 gauge and a 20 gauge hull all with the same interior design and loaded with identical loads of say 22 grains of Unique powder, a Remington wad appropriate to the hull, 1 ounce of shot and a standard primer why does the 12 gauge load generate less chamber pressure than the 16 gauge and the 16 gauge generate less chamber pressure than the 20 gauge?

Member Joined: 02 Oct 2007 Posts: 1975

If you're going to try 22 grains of Unique in say the 20 gauge, tie a string to the trigger and stand way back behind a tree.

Let's call it "working" volume.......

The dynamics of what goes on after we pull the trigger is W A Y more complex then simple case volume. It is but one facet and even it is a moving target.!

We see a graph when so called "pressure" is taken for a given load. Normally it is called a time/pressure curve. What we are calling "pressure" here, is the maximum pressure recorded when linear movement of ejecta along with the amount of resistance to such movement (like crimp or ejecta wgt.) along with time, show us a given maximum pressure at some point. Some call it maximum chamber pressure which is close and exact at some given travel and time period.

A LOT IS HAPPENING IN A LITTLE BIT OF MOVEMENT AND TIME!

A book could be written if every variable was explored, as the process is complex and the very nature of smokeless powder behavior a variable further influenced by many other variables..

Back to "working" volume....

Here the hull, along with its own dynamics of construction such as wall thickness, taper configuration if any, basewad shape and height in hull, total hull length.....
This volume must now be factored into the chamber dimensions, forcing cone, bore diameter... Basically everything the expanding gas works against as to volume... The internal hull volume being a subtraction from total volume in other words.

Complicated??? That ain't the half of it! To really understand it one would have to take the expanded in chamber hull and measure internal volumes for every fraction of an inch movement for a true comparison to what the time pressure curve sees....

These complexities are why a tapered hull is what some say "more efficient". Maybe...... It has its drawbacks. The tapered hull's real attribute was/is longitudinal strength! It took the reloader operator dummy of the year to squash an old compression formed hull for example!

Early on it was quite common for hulls like the old Remington/Peters "All American" to have very high basewad height and even a corresponding shorter wad. This reduced total combustion chamber volume by reducing internal hull volume first. Less powder could be used and the loading companies loved that!

Powder burning rates react to larger or smaller volumes. This is why small gauges (hence smaller volumes) require more progressive (slower) powders to keep the maximum pressure in check...

Bottom-line...... Case volume is an important dynamic.... But one has to look at the total picture and it is a very complex one indeed!

Slidehammer

DC, I understand a lot more than you are assuming. I do understand how the shape of an internal combustion chamber will affect the process. I understand that the process of internal combustion is not a simple one and that it can be affected by many factors. Discussing it here is not germain to the issue at hand and will simply confuse things for most folks.

You must understand that very few reloaders will ever even see any pressure testing apparatus or really need to if they stick to the simple guidelines in the reloading manual and apply some caution and some basic thinking. The manuals are written in such a way as to make needing a pressure gun to perform basic reloading unecessary. They've been designed and written by folks with a much deeper grasp of the matter and far more experience than myself and most likely, you as well. I'm taking my info straight out of these manuals. I've spent time reviewing and comparing the listed pressures and velocities of closely related loads for a long time now. I've noticed some common similarities.

Go back and look at my opening statement. I said that if folks stick to the loads recommended for the 16 ga WWAA compression formed hull (much more efficiently designed hemispherical chamber for combustion w/ a smaller volume), then the same loads will be safe if used in a less efficiently shaped (flat bottomed column) WW polyformed formed hull with a bigger volume.

Simple. This bit of deduction has never once failed me, nor have I ever been told by any ballistics lab tech that I would get into trouble. I've also made the phone calls over the years to Hercules/Alliant, Olin, Hodgedon, Lyman, and several other to check with the experts first. So I do have a basis of fact and expert opinion to go on.

You can now chime in and state once again that I'm full of BS as you normally do, but it will not change things one bit. All it proves is that you can't support your opinion anymore with facts or valid information here, so you must resort to insults. We get it DC.

We also do not have to go off on tangents or start exploring the minute complexities of internal combustion here. A bit of common sense will see us through. However, if anyone can't grasp or admit to the valididty of the basic concepts at work here, then all the pressure guns and other apparatus and all the manuals in the world will not help them one bit. In short, apply the KISS concept and some basic understanding and everyone will be just fine.