320 Revolving Rifle “Evaluation”

[BMur]

2nd R/R Slugged

I slugged another R/R and found the same .323 groove diameter. You can see the .325 slug has perfect contact with both the lands and grooves of the bore. See photo

Also a photo of the rear Flip Sight. Both high and low settings.

Murph

 

[BMur]

Maximum Pressure

I'm looking into the maximum safe pressure for the 32-20 rifle case and so far I'm not very impressed.

The original black powder load was 20 grains of FFG Black powder in the Winchester rifle chamber.

In order to use this case in the Revolving Rifle the case has to be reformed both at the case mouth and base. I don't see an issue using this low psi rifle case with the 32-44 Target after correctly reforming and cutting it down. Since the maximum load would be 11 grains of FFFG.

However, an increase to 17 grains of FFFG for the Revolving Rifle is concerning. I'm finding after close examination a very thing shell wall at the head of the case. After reforming the case it would be even thinner. Which makes things worse.

I'm going to see if I can locate some Super X High velocity shells and inspect them closely for case strength.

Standard cases in my researched opinion may not be able to safely handle a full load of FFFG powder in the Revolving Rifle. And that's not happening in my Revolving Rifle!!

If I can't find some Super X High Psi shells I'll likely just use 32-44 loads to be on the safe side.

Murph

 

[Ivan the Butcher]

Black Powder pressures do not require extra thick case walls at the base. 44 Henry was a single thickness rimfire case. and 45-70 originally had single thickness walls and rims and the internal primer could be set off through that thickness.

The 777 (Triple Seven) and Pyrodex powders are every bit as corrosive as black powder! They and lower velocity producing and much more difficult to ignite! If at all possible stick with Black Powder. Pyrodex CTG. is on the course side for a FFg powder. I would use Goex FFg (even FFFg) or Swiss 2 1/2 F powder, to get all the energy into your case volume. Use a Magnum primer if you can. I prefer CCI brand primers for small BP cartridges and Winchester for large cartridges.

Ivan

 

[cgt4570]

Have any of you considered 7.62x38 Nagant revolver brass? I haven't had time to do more than trim a few once-fired cases, but it's a closer parent than .32-20. I'll be loading for my .32-44 NM#3.

 

[DWalt]

I do not know, but I'd bet that .32-20 HV brass (assuming you can even find any) is identical to normal .32-20 cases. The Bible (Donnelley's case conversion manual) recommends cutting and trimming .32-20 cases to length then fire forming them in the .32-44 chamber.

 

[BMur]

Folded head cases

Black Powder pressures do not require extra thick case walls at the base. 44 Henry was a single thickness rimfire case. and 45-70 originally had single thickness walls and rims and the internal primer could be set off through that thickness.

Ivan

Ivan,

I agree that the early folded head case did handle Large volume loads. However, the 32/20 rifle case being heavily modified from A bottleneck to straight case and then used or supported in a pistol chamber vs a very tight rifle chamber does impact case strength in a negative way and in my opinion is very questionable.
I don't feel like "testing" any theories out in my expensive Revolving Rifle. If it was any other cheap brown gun I wouldn't care. This one has to be done right the first time. I think the best bet is to start out with a 32-44 load and go from there. That's likely where I'm going.

Murph

 

[BMur]

Nagant Brass

Have any of you considered 7.62x38 Nagant revolver brass? I haven't had time to do more than trim a few once-fired cases, but it's a closer parent than .32-20. I'll be loading for my .32-44 NM#3.

Have you done the research on case dimensions? Primarily base diameter? Will it chamber all the way without base diameter reduction? The Nagant round is tapered significantly.

Murph

 

[rct269]

I don't know that he's ever shot his, but you need to talk to our SWHF Assistant Historian, Don Mundell (Club Gun Fan). He has serial number 1---rescued it from door prop duty as I recall the tale.

Ralph Tremaine

 

[DWalt]

Donnelley's manual gives the .32-44 case base diameter as 0.346". The base diameter of the .32-20 case is given as 0.353", so a little downsizing is probably needed. The 7.62 Nagant Revolver case base is given as 0.358", even greater than the .32-20.

Just to provide a little more dimensional data for the .32-44, the case length is 0.970", the rim diameter is 0.410", the rim thickness is 0.055", and the mouth OD is also 0.346" (same as the base).

Donnelley provides a very light load. An 85 grain lead bullet (0.321") and 1.4 grains of Bullseye, with bullet seated inside the case.

 

[DWalt]

Swaging the base diameter down a little will not weaken it. I do it frequently. You may need to fabricate a simple swaging die. An R or S drill bit (maybe both) should do it.

 

[BMur]

Case reforming

See photo,
Base diameter is listed at .354. I mic'd 3 manufacturers. Rem-UMC, Peters, Winchester. All mic'd at .355.
The Revolving Rifle is .346. Which requires at least a reduction to .343 for smooth loading.
So, the difference is actually about 10-12 Thousands between actual diameter and required reduced diameter.
For this thin case in my opinion that's way too much to size down or remove metal. Sort of a 50-50 proposition. Size it down 5 and remove 5. Or the case will dimple.

I still see a safety issue with full loads. Reduced loads only is my recommendation.

Murph

 

[DWalt]

Why not just shorten a .32 Mag case and fire form it or expand it? Case diameter is only slightly less than .32-44.

 

[BMur]

32 Mag.

I think you're onto something there! That 32 Mag case can handle the pressure and be expanded to seal the chamber of the RR without any impact on head strength. That I personally would feel comfortable max loading. Anneal, expand, done!

Problem Solved. Now if I can find some cases.


Murph

 

[nicky4968]

I have often wondered: would it not be better to slug the cylinder chambers than to slug the barrel?
I have used a dowel and a pure lead bullet in the past to get the chamber size correctly. It would seem to be easier than slugging the rifled barrel.

 

[rct269]

I've slugged just one barrel in my lifetime, and it was just 6" long! It most certainly has to be easier doing a cylinder chamber throat. I'll look forward to the thoughts of those who've been there and done that with both, and have learned the why or why not.

Ralph Tremaine

 

[BMur]

Cylinder Throats vs Bore Condition

What makes the Revolving Rifle so unique is the elimination of cylinder throat dynamics as an issue with potential bullet error.

The original cartridge extends to the bitter or absolute end of each chamber. The real purpose is to eliminate the individual chamber specs and variations between them. Resulting in rifle like performance.

The Revolving Rifle accuracy does match rifle accuracy because it must if you match bore dynamics. That's the reason you slug the bore. To match your bullet selection and design. The result must be rifle accuracy.

Our problem today is the lack of case availability. So unfortunately we must make do with modified cases. Which is not an accurate test of the guns capabilities down range.

Another way that I have found to reduce revolver chamber dynamics as an issue is bullet selection. The longer the skirt or the more contact with the bore the more accurate your bullets will be down range as a general rule. It also helps to eliminate bullet wobble.

A great example is the Wadcutter. It's pretty hard to get a barrel shaped bullet to wobble. The optimum design that almost eliminates chamber dynamics is seen in photos 1&2.

These bullet designs are proven to be extremely accurate from a revolver platform down range and were the primary choice of target shooters circa 1902-1905 and beyond.

You can actually pattern shoot with these bullets at distances over 100 yards with short barrel pistols.

Murph

 

[DWalt]

I was also thinking that an 00B pellet might make a good bullet to play around with. Seat it below the case mouth and put some Crisco on top. That is what I do with my Colt 1849.

 

[BMur]

Cases reformed

I went ahead and reformed 12 cases for the shooting test.

You can see in photo 1 that the case mouth is opened significantly from the original 32-20 case to meet the minimum .323 diameter of the Revolving Rifle bore.

I also found that the minimal removal at the base is from the original .355-.354 to a modified .346. So a reduction of no less than 8 Thousandths in order to safely chamber in each of 6 chambers. Photo 2

You can also see that the 32-20 case does a pretty good job at filling the chamber within 3/16ths of the end of the throat. Photo 3.

So, after the reforming and resizing I feel confident to apply a 70% Black Powder load for the test at the 50 yard target.

They also fit very well in the cylinder and eject easily.

Murph

 

[BMur]

Reloading

Just a quick update:
I'm ready to reload the RR cases but the weather here is terrible and it has been a very long winter. I refuse to work with gun powder when it's damp. I'm not in Alaska so this project is on the back burner for now.
When the sun finally comes out I'll get back into this accuracy test of this fine historical antique revolving rifle. To be continued….

Murph

 

[JSR III]

Just finished reading this thread with great interest. I do not have a RR but have decided to get back into reloading after a 30 year hiatus. The depth of knowledge expressed in the above posts is amazing and fascinating to read.

I cannot wait to hear the results of this effort. Threads like this really make visiting the forum a joy.

Best of luck......