.44-77 and paper patch?

[Distant Thunder]

There are a lot of things about this rifle to be that I don't know for sure yet and won't until I get it back from Shiloh. I'll do a chamber cast then and that will tell me what I need to know that I don't at this point.

I am playing with designing a 2-diameter paper patch bullet for this rifle with the information I have, some of which is assumptions. So no mold can be made until I do the chamber cast.

However, assuming the .44-90 BN reamer drawing from Shiloh that Kurt posted holds true for the neck diameter of the .44-77 reamer I can start to calculate the diameters I'll need. I am way deep in the weeds here but the numbers are fun to play with and nobody will get hurt by just numbers.

With a chamber neck diameter of .469" and subtracting .001" for spring back I checked two brands of cases I have on hand. One has a neck thickness of .011" the other .0105". Then .468" (case neck OD) - .022" = .446" for the neck ID of a fired case. So I need a base diameter of .446" after patching.

Being the groove depth is not shallow at .0045" I will for sure use my .002" patching paper. Experience has taught me that this paper will add .007" to the bullet diameter, so an as cast base diameter of .439" is what I ideally want. This diameter can cast a .001" bigger or maybe even .002 and be ok because it's easy to size after patching. I size all my pp bullets after patching anyway because it just provides a more uniform fit.

The bore diameter from measuring the barrel is about .4363-ish. So the bore ride diameter needs to be .4293" as cast. It is possible to make a 2-diameter sizing die to size both the bore ride and base diameters, but it's trickier than a simple push thru size die. I'd rather not have to do that. This is the most critical dimension for the mold, 1) because it's complicated to size and 2) because it is what aligns the bullet in the barrel. I want it snug but not tight.

So I have my two after patching diameters, base = .446" and bore ride .4363".

The next critical thing is seating depth. I like it shallow, very shallow. I'm going to aim for .080" of the bullet in the case. The freebore length according to the reamer drawing is .050" and .4465" in diameter. The .080" + .050" = .130". That is the length I want the base band to be, .010" + or - won't hurt me. The .4465" freebore diameter matches the .446" base diameter well. You want to be as close to the fired case neck inside diameter as possible without going over the freebore/throat diameter.

For my 17-twist I have settled on an OAL of 1.450". I don't like to get too long for the twist rate on my bullets that are going to the 1000 yard target. If I'm only shooting 600 yards and less I might push this up .020-.030". Knowing me I won't do that with a bullet of over 450 grains because if 450 grain doesn't knock down a ram you just didn't hit it well! Aim better next time! Silhouette is where weight matters and I consider that if the bullet will be use for silhouette.

This bullet will be an elliptical for longer range shooting, 600 and beyond. When I design and elliptical bullet it takes me a little trial and error to get the nose length which I tend to like to be about 45-48% of the OAL. It takes me some guess work because I will generate and ellipse and taking 1/2 of that which will be the nose profile I'll cap the end with a radius that will be about 30% of the groove diameter. In this case that is about a .130' radius.

Arnie Seitz likes to go with about a 25% radius and that's ok too. I just go a bit more. This we both believe aids the bullet in maintaining stability in our transonic zone when bucking headwinds. Many people have trouble in these winds because their bullets are only marginally stable to begin with and a good slap on the nose is all it takes to cause trouble. The longer the nose the less of a slap it takes to cause problems.

We are all born out of the high velocity generation and we think that way whether we admit it or not, but we really need to think differently when shooting black powder and big cast bullets at transonic speeds.

NOTE:
There are those that fault Arnie and I for bastardizing the true elliptical from, but it's done for a reason and I think my bullets support that reason. I don't necessarily follow what others think I should, I tend to go with what has proven to work for me over an extended period of time. The nose shape I use wins matches for me, I believe that and that's why I use them. Other bullet profiles work too. If you have one you like and it works for you use that. YMMV

Sorry I just needed to get that out there for those who don't agree with my choice of designs. Now I'll return you to the regular programming.

I have to work with the major axis of my elliptical form so that when I cap the radius on it, which will shorten it, I'll come close to my desired nose length. I'm going with a nose that will be 45% of the 1.450" OAL or .6525"+/-.

There may be a way to mathematically come up with the ellipse length I need to end up where I want to be after the nose radius is applied, but being mathematically challenged I don't know how to do that. I just use my CAD system to generate the ellipse, split it in half, cap the radius on it and measure what I have. It will be too short but I can make a guessimate of what length I need to start with and go again. Usually I have what I want in 2 or 3 tries. Close enough.

So now I have my base band length and my nose length. Arnie likes a 3.5* transition from the base band to the bore ride shank (groove diameter to the bore diameter) and that works well. I have just made a step here and that works too. When the bullet upsets to groove diameter at firing it really doesn't matter any way.

The bore diameter length is just whatever is left over between the base band and the nose. A slight taper of about .001" in the bore diameter is a good thing, it just helps with chambering and aligning the bullet.

I like my 2-diameter bullets to chamber about .020" short of all the way so that when I raise the block it "cams" the bullet in all the way.

This is an example of how I design my 2-diameter ppb. I've been hesitant to put dimensions on these posts because too many people will just go with whatever dimensions are given to them in an example and then expect it to fit their rifle and chamber.

To do this right you need to make a cast of YOUR chamber and slug YOUR barrel and find the dimensions that YOUR rifle needs. MY rifle may or may not be the same as YOUR rifle. If you use my dimensions it may or may not work for you. I strongly believe that fit is very important to accuracy with paper patch, even more so than with grease groove.

I hope this .44-77 will be a continuation of my efforts to make the 2-diameter paper patch bullet a success for other shooters with rifles that have standard GG chambers and want to shoot PPB without having to neck size their brass each loading to use straight sided bore diameter bullets. Bore diameter PPB will work in many cases, but I believe a 2-diameter PPB will make it a bit easier for other shooters to get all of the advantages of PPB and not the disadvantages of using them in GG chambers.

Just remember, this is experimental ammunition in an experimental weapon...…, perhaps an experiment!

Most of all, HAVE FUN!