Designing the 2-diameter paper patch bullet.

[AzTBH]

Jim

Thanks for your detailed and informative reply.

It was surprising to me that that you and Arnie dry-wrap. Although the long freebore of the .40 caliber is a "perceived advantage" (my words) for your .40 caliber bullet, Arnie (albeit with a little practice) is also able to dry patch the shorter groove diameter base bullets. It was surprising because I visualized relatively loose paper on front of the bullet with dry wrapping. Which, is actually what you experienced, but it doesn’t seem to be a problem. I am not experienced enough to know for sure that wet-wrapping would be any tighter, but it seems that the wrap paper would follow the contour better than dry paper. It will be interesting to hear which technique works best for Matt.

I have never shot a paper-patch bullet, but I do have a bore-riding paper-patch mold that I purchased about ten years ago. My original intent was to give paper-patch a try, but it never happened. However, I did wet-wrap the sample bullets (.395 diameter) provided with the mold and they measure .400 with the Seth Cole paper. This discussion, along with others, has reinvigorated my interest in paper-patching and I am going to dry wrap to get a feel for the process. When I do shoot some bullets in my grease-groove chambered Shiloh .40-70SS, I will take your suggestion and patch .020-.030" short of the ogive.

I found your "very slight step, about .001”, at the start of the ogive” quite innovative. I am no bullet design expert, but I have never heard of this design feature before. Thanks for pointing out the “patch to line” step in the first picture in post #6. I can honestly say that I would have missed it without your explanation. Although different, it reminds me of the out-of-the-box thinking of Bryan Litz “Hybrid Ogive” bullet design (http://bulletin.accurateshooter.com/2011...-explains/).

I agree that this is the right forum for innovative design discussions and in your words "... a good place to do that without the negative replies from some that don't agree with this design.” Although the ODG experiences are great and we should draw upon it, I appreciate and applaud your and Arnie’s willingness to share innovative thinking of designing a 2-diameter paper-patch bullet for grease-groove chambered rifle. I also enjoy reading positive dialogs and thought-provoking questions that stimulate our collective learning.

Best of luck in your mold machining efforts and I hope your endeavors are a resounding success. I am looking forward to reading your next post with updates (and pictures) of Matt’s mold.

Ross