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+---- Thread: Dimensioning a 2-D PPB (/thread-3044.html)
Dimensioning a 2-D PPB - Distant Thunder - 08-10-2020
After I had decided to have my old Shiloh rebarreled to .44-77 Arnie Seitz designed a 2-diameter elliptical paper patch bullet to roughly fit the .44-77 chamber using a Shiloh reamer drawing and my 17-twist Krieger barrel advertised bore and groove sizes. It took a year for the rifle to be completed and once I had it in hand I set out to get the dimension that would fit the actual chamber and barrel dimension of my rifle.
The first step was to do a chamber cast so I could determine the length of the freebore of my chamber. This is a little hard to measure precisely because it is measured from the end of the 45 degree chamber stop to the start of the 2.5 degree angle leading into the bore diameter. You are attempting to measure from one theoretical sharp corner to another and one is a very shallow angle. I decided it was pretty close to .080 - .090”.
I like my paper patch target loads to be pretty shallowly seated, a little less than .100” is my goal. Knowing cases are going to 2.240 – 2.250” long I went with .100” as my seating depth and just so I didn’t end up with a breech seat bullet I decided to dimension the length of the base band at .200”.
The paper you use to wrap the bullet will determine the final diameter. I like my 9# 100% cotton onionskin and that will add .007” to the as cast diameter.
For the diameter of the base band I will usually use the inside diameter of the fireformed cases plus .001”. I measure the cases using a gauge pin and I measure several cases to be sure what I decide on will fit them all. That will allow the patched bullet to be sized to a perfect fit to the fired and unsized cases. The JBA cases checked a very uniform .447”+ a little. I also have to consider the diameter of the freebore and to a lesser extent the groove diameter. You can go over the groove diameter by a couple but you can’t easily push an over size bullet into the case or into the freebore without damaging the paper. My freebore checked to the .447” that the reamer drawing I had from Shiloh showed. My size die is made to .4465” to allow for some paper spring back and to not be too tight in the cases/freebore. Figuring on a patched diameter of .448” minus .007” I dimension the diameter as .441”.
This bore diameter base band is meant to seat tight to the leade angle of the rifling. I have never had any luck getting paper patch bullets to "engrave" the way you can with grease groove bullet. At least not with my arthritic thumbs! The 3 1/2 degree angle seems to work very well with patched bullets.
The bore diameter section of the bullet is the most important. You can easily size the base band after patching but sizing the bore diameter on a 2-diameter is to be avoided. It can be done but it’s a PITA.
I measured my bore diameter at very close to .438” using gauge pins.
With a .4378” gauge pin sliding easily through my rifles bore I decided to go with .431” plus .007” for the as cast bore diameter.
The length of the bore diameter is set by the length of the base band and the nose style. For this first 2-D bullet I chose an elliptical nose for shooting Creedmoor matches. Arnie and I like to keep the nose length in any style to about 45% or somewhat less than half the OAL of the bullet as maximum.
The overall length of the bullet I like keep to about .020 - .040” short of what the typical twist rate calculators say a given twist will stabilize in that caliber. I figure a better stabilized bullet is a good thing. An unstable bullet won’t work at all well and a marginally stable bullet will cause hair loss!
The whole bullet length/stabilization thing is dependent on a number of things, caliber, length and twist rate are the obvious, but nose shape and length as well as velocity play a part also. Since I am not a ballistic scientist and I am just enough math challenged to get myself in trouble more often than not I much prefer to stay on the shorter side of things. You may have luck stretching the limits but I don’t. The choice is yours.
In the end I sent this drawing to BACO for them to consider listing in their catalog. They did list it under #JIM441505EPP and they made an excellent mold for my rifle.
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RE: Dimensioning a 2-D PPB - Don McDowell - 08-10-2020
It will be interesting to see how that bullet shoots at distance
RE: Dimensioning a 2-D PPB - Distant Thunder - 08-10-2020
Don,
Yes it will be interesting. The 600 yard at Rapids will tell me some, but the 1000 yard match will tell a lot more. Unfortunately matches are the only chance I have to shoot beyond my 220 yards here at home so load development can be slow and have many setbacks and I will only have one match to work with this year.
I'm not sure what I would change if it didn't shoot well. Increasing the charge opened up the groups and I can't really load less than 86 grains unless I develop some sort of wad stack to take up space. So far those efforts, what little there have been, didn't work too well. I don't think the bullet will be a problem and it's really the only choice I have right now.
If it holds up well at 600 I think there is a chance it hold out to 1000 at least reasonably well. The elliptical I shoot in my .45-70 has done well and I think this .44 bullet is actually a better design. So the real question is, will the load hold good verticals at 1000? There is only one way to find out and that will happen on September 26th.
RE: Dimensioning a 2-D PPB - Kurt - 08-13-2020
Well I guess I settled on a load for the .44-77 Farmer and the .44-2.6 Roughrider. I had to pull the scope off the Farmer and replaced the blocks with the 50 MOA blocks. I just couldn't get my thumb on the hammer right and I had problems loading the shell because the scope was too low.
The front Block I made .056" lower than the rear block and that put the sight setting at 4 points at 100 yards. I might mill off another 2K off the front block to drop the rear sight down on the bottom for 100 yds. I wanted a 100 and 200 yard setting so I can figure the come up for the 300 and 600 so I don't spend to much time at Rapids getting on paper.
The impact was 22" higher than the blocks I took off that is a great help if I want to shoot longer with the MVA silhouette scope mount.
I took 60 rounds 30 each loaded with 81 gr and 83 gr of 2F OE and the DDPP and they both shot very well many cutting the last shot, none went past 2-1/4 vertical. so I feel that is a good start with the variable 12 O-Clock head wind I shot into today.
I think I got the quirk that showed up now and then worked out of the farmer but it still falls behind the .44-77 hunting rifle.
Now I have to get busy and do some more casting and loading for Rapids. I will bring the 2.6 for backup incase the 77 falls on it's nose.
RE: Dimensioning a 2-D PPB - Distant Thunder - 08-13-2020
Kurt,
I had to switch out my scope bases for taller ones also, the scope was just too close the that big Sharps hammer. I changed the bases awhile back and I can't remember how much higher I went but it is much better now. They are tall enough that they prevent me from using iron sights at 100 yards, the rear block covers the bottom half the front sight. I don't shoot 100 yards anyway so it's not a problem for me.
I ran the numbers (that's usually when things go to poop) and with my DZ mounts I should just have enough adjustment to reach 1000 yards as is. I'm at .115 at 220 yards and if my math is correct I would be around .386 at 1000 yards. I still need to see if I clear the barrel at the 1000 yard setting. If the barrel isn't a problem I would like to shim the rear base up just a little to give me some extra at the 1000 yard setting, 25 minutes would be plenty. Right now I have about 7 minutes above my estimated 1000 yard setting. I'd have to get to someplace to do some actual shooting at 1000 yards before I started changing things.
I've got the iron sights on the .44-77 now so I'm ready for Rapids and the little bit of shooting I did to get a 220 yard sight setting looked pretty darn good so I'm in no hurry to move to a scope for paper targets. I do like my scope though.
I'm looking forward to seeing that Farmer .44-77 and seeing how it shoots with that 2-D bullet. I also hope my shoots pretty well so I can use this same load at Lodi in September. That will be fun as heck.
I adjusted my set trigger like you told me to and it is so much better! Thanks.
I'll be very busy this coming week until about Thursday and then Friday I'll head over to Rapids. Are you driving up Thursday? Where will you be staying? Maybe we can find some time to talk this time I hope. Saturday will be too busy I know. I'll see you next week.
RE: Dimensioning a 2-D PPB - Kurt - 08-13-2020
My sight setting @200 is 12 points higher then yours. So I think I can take off .003" more off the front block. I also don't shoot 100 either except here in my yard at 130 yds when the kids come up I put a target up for them.
Jim I leave early in the morning for the shoot. It's only a four hr trip and I usually get there before the gate is open. I thought maybe taking the Gypsy wagon and maybe head up to the lake for a few days in the UP or go the hunting grounds at Trout Creek and fish the Ontonagon River. I haven't done that for a spell. But the Gypsy wagon is still winterized so it will probably sit there till next year if this bug hangs in that long.
RE: Dimensioning a 2-D PPB - Distant Thunder - 08-13-2020
It's been a long time since I was over by the Ontonagon river. I did some camping over there with friends years ago. Beautiful country, but most of what up this way is like that. It's getting late enough in the summer that the bugs are down during the middle of the day anyway. Now it just needs to cool off another 20 degrees and lose the humidity.
Rapids is 4 hours away for me if everything goes well, but I figure 4 1/2 to be safe. That means I'd have to leave the house by 3:15 am! I'd have to get up 1 hour before that in order to consume enough coffee to be semi-functional enough to drive. I don't think that works for me, so I will drive over Friday afternoon and avoid all the deer that are on the road in the early morning hours. I've made it a whole year without hitting a deer and I'm hoping to stretch that even more if I can! The buggers are everywhere!
RE: Dimensioning a 2-D PPB - Kurt - 08-13-2020
I get up at 3 and pull out a couple minutes before 4 and this gets me through Madison before the traffic gets nasty. I Load the car the night before so all I do is make the coffee and take off.
Deer are a problem around my neck of the woods but I don't see as many as in the past. The DNR got some what they called biologists to thin them out because of the waste disease.
RE: Dimensioning a 2-D PPB - Kurt - 08-18-2020
Well my work with the .44-100 and the DD bullet is on hold till I get my resizing die I ordered, the chamber is just to tight.
I ordered two dies one for the bare bullet and one for a patched bullet. Trying to seat a bullet in a sized case fired form this rifle using the 55 Y paper it hurts my thumb getting it in the case .100" and I had 7 cases separate over 5 range sessions. First I thought it was the cork wad doing the dirty work but it turned out it would even do it using a .023" OJ carton wad pulling the cases apart.
I loaded a few DD rounds patched with .002" thick paper and shot them in the Farmer and the .44-77 Shiloh hunting rifle with it's 19 twist standard chamber and both rifles shot well @200yds, actually the 19 twist printed them closer then the 17 twist Farmer.......I will pull the .44-90 bn 19 twist Shiloh out maybe next week and put some through it.
One good thing and that is a lot of fine trigger time.