.320 REVOLVING RIFLE “RANGE TEST”

[mmaher94087]

This is mostly useless information, but I remember a gun mag article from the 90's where David Chicoine (the elder) shot his .320 RR. I can't remember if he loaded his own ammo or was shooting vintage stuff. Really, all I remember is that I got very excited to read of a Revolving Rifle being shot in modern times. I have vintage rounds, but I won't shoot them.

 

[Kinman]

I have a few hurtles to get past that requires some research.

Tomorrow I'm doing a lot of bullet molding so I will include the 32 Ideal bullet. I'll cast about 50 and if I have time I'll run one down the tube and post the results.

The hurtles I have to get past involves mainly the modern case.

The 32/20 WCF cases I am using are modern Smokeless solid head type with a .082 flash hole. That won't work with a black powder load. It least it won't work "as originally designed."

All of the early black powder pistol and rifle cases have much bigger flash holes. As an example an 1884 45 Schofield balloon head black powder case has a flash hole that is huge measuring .126.

Where as a Standard Size Modern 45 smokeless case has a standard flash hole that measures about .082. Significant difference that would impact performance greatly down range.

I'm probably going to have to guess at what size to increase the .082 32/20 cases to over .100… no idea what the original .320 Revolving Rifle case flash hole was but I need to get close so the performance is correct and therefore accuracy performance will be as originally designed.

Probably have to open up an original black powder small caliber rifle case and mic it. That's gonna hurt.

This test will also include " THE DREADED" forearm "Flash" from being in proximity of the cylinder face when gripping the fore stock. Rumored to be an issue when shooting the Revolving Rifle. I plan on wearing a healthy leather glove and wrap a "WHITE CLOTH" around my left forearm to see if in fact there is impact from discharge at the forearm area. If it turns black we'll know. I always lube my bullets so lead spit shouldn't be part of the equation.

Murph

After reading the book on shooting the 45/70 by the guy that supposedly wrote the book on shooting the 45/70. I learned a few things, along with spending some time with guys shooting black powder cartridge long enough to remember when they switched to smokeless. Modern cases, in particular 45/70 are much thicker at the wall than the early black powder cases. There is also the issue with the extra powder that could get around the primer cup on old balloon head cases. It is nearly impossible to get 70grns. of 3F Goex in a 45/70 case, the case with the thinnest walls, thus allowing more powder are made by Winchester. When it comes to primer pockets, the old guru recommended opening them up to .096 with a wire size drill. I did that to eliminate variables and have never had any issues with any of my black powder cartridges from 38/55 to 45/90. When I mentioned that to my local BPC guys they said that it was a great idea but to remember to put a piece of newsprint over the primer pocket before seating a primer, in order to keep any powder from contacting the primer before ignition. These guys can go on for hours about the hyper-eutetic properties of lead and primer frizzyance...but excellent shooters should be paid attention to when they get things right. Just a note of interest to me...
I open up new cases that meet my specs for OAL, which is another issue to deal with, many fall below the standard of 2.105 even right out of the bag. I take unfired cases and drill them out, then anneal them in the same process, nothing fancy drill out the pocket, seat the case on the drill bit spin it up with the first 1/4 of the case in the flame til it first discolors. It flashes pretty quick and changes color in seconds, dump on a clean towel and proceed. Takes a little practice which is where the short ones come in.

 

[BMur]

Specs

Great info Kinman.

Question:

How did you arrive at the .096 flash hole and what is the normal size found on factory loaded cases?

Interesting concept to cover the hole with paper.

Murph

 

[wlw-19958]

Hi There,


"The Book" you referenced I assume is Loading Cartridges For
The Original .45-70 Springfield Rifle And Carbine by J. S. and
Pat Wolf.

This is the Bible for loading black powder .45-70 cartridges that
duplicate the Springfield rounds. Yes, they recommend opening
the flash hole to .096" (No. 41 Drill) but we're talking about a
cartridge that is substantially different from the .45-70-405 and
.45-70-500. So, a .096" flash hole may not be the optimum for
the old 32-44 round. Plus a little experimentation can't hurt and
will add to the knowledge base. Of course, there are a lot of
variables to consider and I won't go into this tangle now.


Cheers!
Webb

 

[Ivan the Butcher]

One of the contributors to "Black Powder Cartridge News" Rick Moritz, did a comparison between placing a tissue paper card over the 5/64" and not doing so over 5/64", 3/32", & 1/16" flash hole in test 45-70 modern brass. Taking velocity readings at 10' from the muzzel, the 5 shot strings (Wet patch between all shots. Cleaned & dried between 5 shot strings) were mathematically annualized and a 95% level of confidence of NO STATISTICAL DIFFERENCE! The opinion was that the FFg powder did not migrate enough to cause a statistic variation to be worth the effort. Summer Issue 2023 #122 pages 6 thru 9

I thought you might find this interesting before you start drilling out flash holes.

Ivan

 

[wlw-19958]

Hi There,

One of the contributors to "Black Powder Cartridge News" Rick Moritz, did a comparison between placing a tissue paper card over the 5/64" and not doing so over 5/64", 3/32", & 1/16" flash hole in test 45-70 modern brass. Taking velocity readings at 10' from the muzzel, the 5 shot strings (Wet patch between all shots. Cleaned & dried between 5 shot strings) were mathematically annualized and a 95% level of confidence of NO STATISTICAL DIFFERENCE! The opinion was that the FFg powder did not migrate enough to cause a statistic variation to be worth the effort. Summer Issue 2023 #122 pages 6 thru 9

I thought you might find this interesting before you start drilling out flash holes.

Ivan

That is very interesting! I'm not experienced enough and I don't
have the equipment to do this kind of research. I was not aware
of of the publication "Black Powder Cartridge News."

If one is going to cover the flash hole with paper to prevent migration
of "fines" into the flash hole, I would try a disc cut from cigarette
paper (rolling papers). They are thin, very combustible and reasonably
strong for their thickness (they are only .001" to .002" thick).


Cheers!
Webb

 

[BMur]

Optimum Powder burn

Just to be clear, my motivation is to achieve "Optimum powder burn"
I certainly appreciate individual studies and tests in the field.
However, I personally will always place above all the rest what the powder manufacturer states clearly in writing regarding their specific powder type.

This is a quote from Hercules powder company in writing from their early 1900's catalog;
" DO NOT ENLARGE OR REAM OUT THE FLASH HOLE OF THE CARTRIDGE CASES AS THIS CHANGES THE IGNITION RATE AND MAY RESULT IN OVER IGNITION AND HIGHER PRESSURES

I see this statement as gospel because they made the stuff! I also see this statement as rock solid that the flash hole diameter does in fact impact powder burn rate.

I'm not modifying these smokeless cases to fabricate a hot load. I'm just trying to achieve the original designed powder burn for the 320 RR cartridge. Or as close as possible for optimum range performance.

I also see those dated 1884 Schofield cases as absolute proof that larger flash holes were used with black powder pistol cases by the Frankford Arsenal in the 1880's. Military tests from all I have read are very thorough so there is something to this flash hole size issue.

To me the only real question is what is the most efficient size flash hole for the 320 RR case using black powder that will achieve the most efficient powder burn?

Murph

 

[Ivan the Butcher]

Couple of things:

I get the "Black Powder Cartridge News" at Barns & Noble. I could give order info if you wish.

Black powder burn rates (and other characteristics) are not uniform from brand to brand or Mill to Mill or even batch to batch over time. The paper over the flash hole in their experiment was plane old newspaper.

Lastly: when placing the charge in the case, using a 30 inch drop tube allows proper compression when poured slowly (for 15 to 18 grains of powder think a "quick 5 count") for a full 70 grain charge of FFg Goex brand I use a slow pour of 15 seconds. The powder is already compressed at this point better than a compressing die can do (in this case, the powder is compressed from the bottom up). Surprisingly, you can get full original charge weight in modern cases.

Ivan

 

[wlw-19958]

Hi There,


I've used drop tubes also but I fine that compressing does a better
job of compacting the load. One idea I've seen is using an electric
razor. After pouring the powder into the case, touch the side of the
case with the razor (while running) and the vibrations will settle the
grains into a smaller volume. But everyone has their own ideas.


Cheers!
Webb

 

[Kinman]

Great info Kinman.

Question:

How did you arrive at the .096 flash hole and what is the normal size found on factory loaded cases?

Interesting concept to cover the hole with paper.

Murph

Murph, The .096 is what the author of the 45/70 book recommended, I have no idea how he came up with that number, he did not elaborate. I also never went to the trouble to figure out nominal hole opening, its not much under the .096, when I run the drill through it there isn't a ton of resistance, slight pressure and zip your through. I must have loaned that book out because I cannot find it for reference, I have a can of black powder only cartridges that has the marking on it.
The newsprint under the primer is just something those old boys figured while arguing over coffee in the morning, as mentioned if they got onto a particular subject you were ready to commit Harry-Kerry with a dull deer antler in around fifteen minutes.

 

[BMur]

Cases ordered

Well,
I did order 100 additional brass cases from Midway as per Webbs kind advice.
So that changes things a lot.
I'm going to include at least 20 rounds using the 32-44 82 grain target bullet for the range test as seen in photos. I have a mold for this bullet design.
Using this bullet I can get 20 grains of Black into this case without issue. This matches the 32/20 WCF case original specs that confirms 1300FPS bullet speed using a black powder charge. That should translate into respectable accuracy at 50 yards.


Murph

 

[cwneely2]

I loaded 320s for a friend some years ago. I had to use 7.62 Nagant brass to get the correct length. I think I may still have some loaded ammo that I no longer have any use for. If I can find them, I'll be glad to contribute to your experiment. I used a .321 swaged bullet with a dab of lube on top. There was no problem with leading. Mostly I used information from Chicoine's book. I believe we got best accuracy with a much lighter bullet. Maybe 90 gr, I'll have to check. I know I still have the swaging dies.

 

[BMur]

45/70

Thanks Kinman,

I took a look at a modern smokeless 45/70 case and the flash hole measures a tight .081.
Seems to be a common theme with smokeless cases of most calibers.

You can also see how much larger a .096 flash hole is in the 2nd photo of my index pins. It makes perfect sense it's just that I prefer an old written reference. The older the better!

Murph

 

[Kinman]

Thanks Kinman,

I took a look at a modern smokeless 45/70 case and the flash hole measures a tight .081.
Seems to be a common theme with smokeless cases of most calibers.

You can also see how much larger a .096 flash hole is in the 2nd photo of my index pins. It makes perfect sense it's just that I prefer an old written reference. The older the better!

Murph

Its going to be another hot day, I'll dig around in my basement while doing some cleaning of my gun area and see if I can scare that book up.

 

[wlw-19958]

Hi There,


One reason that they recommend opening the flash hole (and it
is the main reason) is the Mercuric primers of those days produced
a longer duration "flash" which produced better ignition of the black
powder charge. One of the reasons we went away from Mercuric
primers is partly due to the negative effects Mercury has on brass
(it makes it brittle). Contrary to popular belief, Mercuric primers
were not that corrosive. Black powder residue is very corrosive
when it gets damp and the residue is hygroscopic (i.e. it absorbs
moister out of the air) and if not cleaned right away, can cause
rust to form in less than 24 hours (depending on the humidity).

Most of today's primers are actually hotter than the Mercuric primers
but of very short duration. So, we open up the flash hole to allow
a bigger flash for igniting the black powder charge. But This Is
Dangerous if using a Smokeless Powder Charge!!! To prevent
mixing up one's brass, it has been the practice to mark those "Black
Powder" cartridge cases in some way (most put a punch mark on the
head to indicate a black powder case).


Cheers!
Webb

 

[BMur]

Consistent burn rate

Thanks Kinman,
Any study on flash holes would be interesting.

Just to be clear, the focus is on a consistent black powder burn rate from one cartridge to the next. If your flash hole is too small the result will be an inconsistent burn rate between rounds resulting in poor bullet placement at the target. Or another way to say it would be an unacceptable variance in bullet speed.

I was looking through my old ammo collection and realized the best early case examples to study would be very early non head stamped cases of all pistol calibers. Why? Because they are all pre-1882 cases and would clearly show early original factory black powder flash hole sizes. See photo

I hate to pull bullets on these early cases because they are rare now and quite valuable so I'm looking for empties, dug ups, etc

So far every example that I have looked at the flash holes are huge! Which supports that black powder loads required a significantly larger flash hole to achieve a "consistent powder burn" during the late 1800's black powder Era. What size for each specific caliber? No idea.

The 45's are huge! (.125+) I looked at a 38 S&W non head stamped empty and it mics at .105. We need to see a lot more to confirm a standard size per caliber. What I'm seeing so far is that each caliber is different.

Murph

 

[wlw-19958]

Hi There,

Thanks Kinman,
Any study on flash holes would be interesting.

Just to be clear, the focus is on a consistent black powder burn rate from one cartridge to the next. If your flash hole is too small the result will be an inconsistent burn rate between rounds resulting in poor bullet placement at the target. Or another way to say it would be an unacceptable variance in bullet speed.

I was looking through my old ammo collection and realized the best early case examples to study would be very early non head stamped cases of all pistol calibers. Why? Because they are all pre-1882 cases and would clearly show early original factory black powder flash hole sizes. See photo

I hate to pull bullets on these early cases because they are rare now and quite valuable so I'm looking for empties, dug ups, etc

So far every example that I have looked at the flash holes are huge! Which supports that black powder loads required a significantly larger flash hole to achieve a "consistent powder burn" during the late 1800's black powder Era. What size for each specific caliber? No idea.

The 45's are huge! (.125+) I looked at a 38 S&W non head stamped empty and it mics at .105. We need to see a lot more to confirm a standard size per caliber. What I'm seeing so far is that each caliber is different.

Murph

When enlarging the flash hole, one should consider that the "flash"
from modern primers will be different from the old Mercuric primers.
Therefore, I still believe in being somewhat conservative in opening
the flash hole. The .096" is probably a good starting point. If you don't
get the performance you want from .096", you can always make the
hole bigger.


Cheers!
Webb

 

[BMur]

Flash hole

I agree Webb,
I remembered that my 32 Smith & Wesson improved reloading kit actually came with about 30 empty casings. All balloon head. Several are very early cases. I looked through them and actually found a non head stamped long case that is likely a very early (Circa 1884) Harrington & Richardson case.
See photos
The flash hole mics at .090. I think I'm going to match this case flash hole to the RR cases. This should be a solid indicator to follow.

Murph

 

[Muley Gil]

I posted a comment & question on the SASS site, where there are LOT of folks that shoot BP cartridge rounds. No one over there was in favor of enlarging flash holes.

I have loaded a few .38 special cartridges with BP. All shot fine with standard small pistol primers and standard flash holes.

 

[rct269]

I posted a comment & question on the SASS site, where there are LOT of folks that shoot BP cartridge rounds. No one over there was in favor of enlarging flash holes.

I have loaded a few .38 special cartridges with BP. All shot fine with standard small pistol primers and standard flash holes.

Ditto------only it was .44 Russian---using cut down .44 Special brass/primers. They all went bang, and beyond that, I have no clue about anything else!

Ralph Tremaine