Designing the 2-diameter paper patch bullet.

[Kurt]

Jim

A lot of matches seem to get won with a 2 MOA rifle/load.
I'm going to hold off because the snow still falling and the flakes are very small making it tough seeing 150 yards looking out of the window, like looking through a fog.
I will use my Shiloh rough rider that has a 1.3"X35" no tapered barrel chambered in the .44-100 straight that has shot very well at 200 enough that I could cover 5 holes with a halve dollar shooting the 507 gr KAL elliptical from time to time, and the next time out it would hardly stay inside the 9 ring. I have a couple boxes loaded for it that been out in the heat and sitting on the shelf for quite a spell that need emptying. I don't like this rifle because it's just to heavy and no way can I shoot this thing off hand any more at just under 20 lbs but it makes a time long range with very mild recoil.

[Kurt]

Jim,

This is what this rifle is capable of doing. It has shot some very fantastic load tests and I really should use it for the purpose I build this rifle. I had a mind of using it for the Toloffson class that was starting at the Nationals and for the long range at Lodi but I never drug it out to shoot except one at the Quigley and I shot a 41 using it but the offhand ended that win with only one hit I think a 43 won that match.
When I got this rifle I loaded rounds that would shoot with out fouling control just to fit the Starline brass for the chamber and I shot 100 rounds dirty except once blowing down the barrel after around 80 rounds at 180 yards and only three rounds drifted out to 4". The bullets were patched .003" or maybe .004" don't recall now under bore diameter. I think that long round barrel has very little vibration and flexing that makes it do so well. But again it makes you want to pull your hair out the next day you shoot with the same load you might just as well use a sling shot.
The right target has 5 shots each.
       

[Semtav]

Kurt,

I was thinking I would submit this one for that postal, but it just isn't that good. I ran the numbers and it would score at 93.6". That wouldn't be bad for 900 yards, but I would want better at 200. That would be just a hair more than a 2 MOA group at 900, not bad, but at 200 yards I'd want to be closer to 1 1/2 MOA. If you could hold 2 MOA plus a little at 900 and be centered that would be 9s and 10s which ain't bad. At 200 it looks not so good!






Still it was fun to get out and shoot. I haven't shot prone off sticks in four months and I could feel it!

You know you can enter more than once. If no one enters a couple average loads , no one will enter at all.

[Distant Thunder]

I thought I would update this project a bit. First let me say things move much slower here in Wisconsin this time of year because it's so darn cold much of the time. It was -22 here this morning and it's supposed to get colder next week. Outdoor activity slows way, way down in those kind of temps.

A couple of weeks ago I sent Matt some bullets I cast from the mold I cut for him. I held on to the mold to make sure the sizes fit his rifle, they do and I'll send him the mold after he shoots a few. Unfortunately he was pretty sick for a week and now the cold weather has the whole project crawling forward slowly. I did get the following info from Matt this week and just so you all know where we are and that we haven't given up yet here is what he said.

"ok, got a few loaded. the fit to a fired case is perfect, all I have to do is bump the taper crimp die and it holds it really well. I will have to get to the range to see how they fire. its going to be a few weeks for that, Its supposed to be really cold this weekend, maybe next weekend will be a little bit warmer. Im super excited to see how they shoot!!!! Im sure they will

load so far...…… 45-100 starline cases (fired, not sized), trimmed to 2.60", 100gr swiss 1.5F, .060 poly wad, yellow notebook paper under primer wad, CCi BR2 primer."

That sounds like a good starting load, but there can't be much compression on 100 grains in a 2.6" case. I load 100 grains in my .45-90 with a bore diameter PPB and I'm not compressing much there. It will be a starting point and he can always add more powder.

When I have more from Matt I'll add to this thread. Hopefully he'll have some targets for us to see.

[Distant Thunder]

The following is what I sent to a shooter in response to his request for information on my 2-D PPB that I designed for MY .40-65. That design is proving to be very easy to get to shoot well in all the rifles I've seen it used in, including a .45 caliber version in a friend's .45-90 C. Sharps. His rifle is not my rifle and I attempted to walk him thru the process I use to design these bullets. Since I know there are others who are interested I thought I might answer those questions in a single effort by posting it here. I know I can never repeat this enough, but I am trying. I never really know how well I explain this to others especially in writing. I am, at least at time verbally challenged and even more so when writing. In my own mine it is perfectly clear what I am saying, to others, not so much.

So here is what I wrote:


You probably have a standard Shiloh grease groove chamber in you .40-70 SS. Shiloh puts good tight grease groove chambers in all their rifles that I know of. These chambers do very well with PPB and the correct 2-D PPB should shoot with very good accuracy in your rifle assuming the above is true.

They don't put any real freebore in their chambers and that helps a bunch when shooting PPB.

I have to assume some things to give you an idea of how a 2-D PPB should be designed to fit your rifle. The more information you can give me the better I can help. I do not know your level of experience either so I will try to give as much good detail as I can, please don't be offended if you know all or some of this already.

If you have a standard Shiloh GG chamber then the base should probably be about .200" long and .409" in diameter after patching. The bore diameter should be .399" to .400" after patching. The ogive on my bullet is fairly short, only .530" long. If you have a 1 in 16 twist and you should stay with a 1.325" OAL for that twist. This is what we have so far .530 + .200 = .730". Then you take the 1.325 - .730 = .595 which is the length of the bore diameter section.

Your patches would be cut to about .900 high and the correct length for your base diameter with two wraps of your paper, approximately 2.5" + or - a bit depending on your paper and how you wrap (wet or dry).

The bore and base diameters would depend on your paper. If you were to use Seth Cole 55W it would add about .005-.006" to your as cast diameter, lets say .005 to keep it simple.

.409 - .005 = .404" for the base diameter as cast and .400 - .005 = .395" for the bore diameter, as cast. These diameters are important, too loose and accuracy suffers, too tight and they are hard to impossible to chamber. The lengths are a little less important.

One down side to 2-D PPB is they are complicated to size after casting, especially the bore diameter section. The base diameter can be size either before or after wrapping. It is critical to get the mold to cast to the correct diameters. You'll need a mold maker who can do this, there are several.

Again, so much depends on YOUR chamber and YOUR paper that I can not say with any certainty exactly what would work best for you in your rifle. What I just laid out here should give you an idea of how to figure that yourself, or at least how I figure this stuff. If you need more or better info then you'll have to provide more info on your rifle. It is still somewhat of a guess to design a custom fit bullet without having the rifle in hand.

I hope this info helps. If you have more questions please ask, I will try to answer them.

   
This may help with my explanation.

[Semtav]

Jim
I'm really warming to the idea of trying out the dual diameter bullet for my Browning 40-65 and Shiloh 45-70 as they seem to be lacking a little capacity for Long Range Shooting With PP bullets of Groove dia and I'm not really interested in going to straight Bore dia bullets.
Keep up the experimenting !!
Brian

[beltfed]

Jim, how about this drg of a bullet for your "no freebore" 45-90?
I did this one for a guy with a no freebore 45-70.
Arnie


  45DDEPPfor18twistGGCh070218.pdf (Size: 369.22 KB / Downloads: 27)

[beltfed]

  40DDEPPfor16twist060915RevB.pdf (Size: 852.49 KB / Downloads: 29) Semtav,
Here is a design that has been very well performing in Bob Wood's
Brg 40-65 and in my rebuilt Hi Wall 40-65.

[Semtav]

Thanks Arnie,
Is that just a misprint that the length doesn't go to the base of the bullet?
Brian

[Distant Thunder]

Brian,

For your Browning .40-65 the 2-D PPB that Arnie just posted is an excellent choice. It was designed for that chamber.

My bullet was designed to get as much weight in a 18-twist compatible length of 1.250" so I could knock rams down with some confidence. So far it has been 100% on the rams, so far.

Arnie's .40-65 design is the bullet that really got the ball rolling on this whole 2-D PPB thing. If I had used Arnie's elliptical design I was afraid it would be too light in my 1.250 OAL for rams.