Bullets for 9.3 x 72R Drilling

[mike ford]

Diz,
Aside from the fact that that group is about as good as I can shoot, it may help to tamp a tuft of kapok down over the powder. I also had variations of over 250 fps in loading 9.3x72R N, until I started using the kapok. Do not just add the kapok to the established load, drop the powder and work back up. I just added it the first time, and got flattened primer and too high velocity. Of course this may not do the trick, but it shouldn't hurt to try. BTW a 215 gr. bullet at 1918 fps will kill a deer "grave yard dead".
Mike

[sharps4590]

Anyone care to offer their powder choices and charges for the 9.3 X 72R utilizing generally a 200 gr. bullet, cast and jacketed?

[Diz]

I am of the idea that maybe it needs a bit more powder and so I am putting together ten with three more grains. I believe this may be what it needs as I still have some faith in this powder. I'll shoot them tomorrow along with some 12.7 x 44R with an unusual powder.

Mike was kind enough to send me some of his Kapok but I am planning to use it only in my 577-450 Martini. I have some nice loads for this but the gun likes Kapok best.

Sharps may be right, drink first and soak later because I made a mistake in telling Leatherman that the pressure was 11,000 psi in the 450 BP Express when it is actually 11 tonnes! This is why it is imperative to verify anything to do with loading. My apologies for that gaff. I did attach a drawing of the cartridge that I believe we are talking about. If Leatherman would like to come back with a comment I would appreciate it. By the way this is a Nitro Express drawing but essentially the same as the BP. Thanks, Diz


Cartridge Drawing 450 NE.jpg

[mike ford]

I use kapok, because I have it, have used it many years, and am used to it; not because it is magic. Others use Dacron, polyester, open or closed cell foam wads, backer rod, or even cotton; with complete satisfaction. Just work up the loads using the filler, do not just add it to an established load.
I know my powder choices, which are "old school"; I too am interested in other peoples choices.
Mike

[sharps4590]

Sherman Bell had a high opinion of kapok and polyester as fillers. His pressure tests showed good numbers.

[Diz]

Mike, You are correct on all the variations of filler but in my experience some of my guns prefer certain types. I find polyester is about twice as heavy as kapok, volume for volume but I have not seen any radical variations in pressure or velocity between them. As for my 577-450 I find kapok is more accurate in grouping. Easily an inch better over polyester. This is a shouldered case and other fillers don't seem to work as well like Cream of Wheat for instance. That is for me at least. I have tried cotton but it looks like a chicken flying out of the barrel! Everything else is very close but kapok wins in this cartridge. At least for me.

Sharps, I am glad you mentioned Sherman Bells' article. I believe it was in Double Gun Journal – Summer 2011 on tests he did with a double rifle in .450 Nitro for Black loadings. My tests on straight sided cases agree with Sherman that fiber wad fillers are best if you can fill the case full between the powder and bullet with a slight compression. I have been experimenting with the 12.7x44R in filled and unfilled plus various types of powders. I think fully filled with wads may be best but I shot a test today with Hodgdon’s Lil Gun that doesn’t seem to need filler. And shot the drilling with 3 grains more powder. I attached the chronograph print outs for both.

Sherman talks about the pressure trace showing a zig-zag up and down as the pressure is building with all loose fillers like polyester and kapok but is a smooth curve with a column of wads. I attribute this to the easy compression of the filler that slows combustion for a millisecond or so. I see this same effect in all of my low pressure shotgun loads as well. In the shotgun I am sure it is the wad collapsing just after ignition for it is this little delay that seems to hold the pressures down.

I planned to shoot for group while running the chrono on these two guns but my “portable bench rest” or my Ford 1510 tractor had a flat that required a new set of tires to fix. I had to shoot these prone and I was wiggly as a pre-soaked drunk. Both rifles came in at 3-3/4” at 50 yards and in the black which was better than I thought I would get but all I could do.

Chrono 93x72R with 43 grains N 135.jpg

The record above is for the 9.3 x 72R today with 3 more grains of N-135. I think it clearly has a little too much speed. The previous record with 40 grains was 1918 average with 66 SD while today the average was 2117 with a 52 SD. I had to recalculate the mean and SD as there was an error in the calculations. For some reason the chrono had 1202 as the low for the string but this was a carryover from the previous test. You will see this on the tape and it messed up the calculation. Why I have no idea unless it was the fool pushing the buttons. What I didn’t do today was shoot some S&B to get a base line velocity for factory ammo.

Chrono 127x44R with 23 grains Lil Gun.jpg

This record shows five shots from my 12.7 x 44R Cape rifle. The previous was with a 370 grain cast bullet over 23.5 grains of Accurate 5744 and a ½ “ thick 50 caliber fiber wad. This filled the case with slight compression. That shot a 1215 average and 18 SD. I should have left it alone! This is with a 450 grain cast and 23 grains of Lil Gun and no filler. I know that’s a shotgun powder but it kept coming up good in the program so I tried it. Well I got 1264 average and 34 SD out of it with that heavy slug. OUCH! But it printed to the sights and is clean burning as can be. However, calculated pressure is still only 10,330 psi and if I drop a grain it should go below 10K with velocity at 1200 even.

Sorry, lots of blah blah from me but this is my experience. I love this stuff!

Thanks, Diz

[sharps4590]

Good stuff Diz!

[mike ford]

The 2117fps, is pretty much what my experience shows RWS and DWM factory ammo gives/gave, with S&B a little slower at close to 2000. This was with the common 193 gr jacketed flat point bullet. This velocity might "outrun" the 200+gr lead bullet, I don't know. If this load shows decent grouping, it looks like a hell of a deer load to me.
Likewise with the Lil Gun load, it looks really good to me. You might shoot 23 gr for hunting, and 22 on targets in the 12.7. I've used Lil Gun in little cartridges, and am glad to see how well it works in the "Big'uns".

With the filler, I just use a tuft, tamped down over the powder. I fully recognize that others insist on filling the case, citing a "stutter" in the pressure curve. Indeed, Bell's work does show such a stutter when the case is not filled. However, factory Kynoch NFB ammo shows the stutter, as does some filled case methods with open cell foam. Everybody should use whatever method and material, or nothing, that they are comfortable with. If something happens to my rifle, I am to blame, if something happens to someone else's rifle, they are to blame, not me. It's pretty clear to me that people that deal with these old cartridges, are so experienced and accomplished that they don't need my counsel, indeed I value theirs.
Mike

[Diz]

Spent the day and my SS check changing tires on my portable bench rest so there was no shooting today and now it's raining. Two or maybe three additional comments about these loads.

Mike, I have a feeling you are right about the MV on the 9.3 because I checked the S&B web site and they give 1952 fps from a 23.6" barrel. My drilling is 27.6" and the extra length should add some speed. I really need to get that baseline down and as soon as I do I will report it.

You were also right about the heavier bullets but what is very interesting to me is a close look at the numbers from the chrono for the 12.7. On the front side there is one at 1201 and then four within 6 fps of the hi and low. Three of them are only 1 fps apart. On the proof side there are three at 1281 fps, one at 1202 and one at 1276. The lows from each side are only 1 fps apart and the hi's are the same at 1281. I haven't seen anything quite like this before in a rifle and only once in a shotgun. I just wonder why the second shot in the string was seventy something fps slow. If it was at or close to the others the SD would be something like a 2 or less. I need to inspect those cases very closely to see if I can find something. Lil Gun has really gotten my attention in this one.

Last, I for one appreciate your counsel (sharps too) and from many others on this board as well. There are many things about these guns where my knowledge is lacking and it has forced me to look at a lot things much more closely. Everyone please use caution if contemplating the use of this data, your results may vary.

Thanks, Diz

[Diz]

Well I am still waiting for the Buffalo Arms bullets and getting impatient so I started making a set of dies to bump up a .358" rifle bullet. It was all going good until I got a little carrier away with bumping pressure and managed to split the point die while making the first bullet. That tells me I need more support in that area and fortunately I have the room in the body die so I can make the point die heavier. So it's back to the lathe tomorrow.

Thanks, Diz

[Nathaniel Myers]

Diz, if you are willing please post pictures of the dies you are making, and if you'd like, how you are making them.

[mike ford]

DIZ,
I would like to see it also, are you using 7/8" or 5/8" dies?
Mike

[Diz]

I had an orphan die that I had no idea what it was for so I used that. It's a 7/8" and I will be happy to post pictures as soon as I have something that will work.

Thanks, Diz

[Diz]

I ran into a few problems with making the 9.3 x 72R bump up tools. The problems mostly attributed to lathe operator error and the results are rather crude looking but surprisingly made a halfway decent bullet.

93x72R Bullet Forming Set I.jpg

The picture above is the bullet forming die set. Starting from the right is the bullet I used. This is a Remington 180 grain soft point for the .357 mag. Any .357 or .358 bullet of the appropriate weight will work. Next is the point plug. It is a small plug that closes the ejection hole in the end of the point tool and keeps the lead from flowing out. The next part is the point forming tool. After this is the base punch. This is what presses the bullet into the point die and expands it into the body die. The next picture is the body die. This is machined to accept the point tool and is bored to the correct bullet diameter. In this case the finished bullet is .365” diameter. The last picture is the first Remington bullet out of the die.

93x72R Point Tool with Plug I.jpg

This picture shows the point tool with the ejection plug inserted. The hole allows for a small punch to be inserted to knock out the bullet once it is finished. The plug is flush with the flat of the point inside the tool and keeps the lead from flowing into the hole.

93x72R Pointer with Bullet I.jpg

This photo shows the bullet as it comes out of the body die after sizing. The plug is removed and the bullet knocked out with a punch.

93x72R Body Die with Base Punch I.jpg

Here is the body tool with the base punch inserted. The punch expands the bullet and allows for pushing it out of the body die.

93x72R Die Set Assembled I.jpg

This last photo shows the die assembled as it goes in the shop press for sizing. I was planning to use this in my loading press but a mistake in machining prevented that from working so now I use my shop press to form the bullet. It works but is a lot slower.

Now to make a few dozen and load them up.

Any questions or comments?

Thanks, Diz

[mike ford]

Diz,
I have a comment- Wonderful. I'm sure I will have questions later.
Mike