Unpatched bullet diameter after wrapping and final sizing

[outdoorfan]

Need a refresher. What is the optimum diameter for the bullet to be after wrapping and final sizing? Bore diameter, .001 over? Can it be .001 under and still shoot well?

[CJR]

Outdoorfan,

I have been using recommendations from this forum as well as from the NRA & Paul Matthews book on the proper bullet sizing. I size my bullets right after casting to bore diameter + 0.001"/0.0015". After PP, hand lubing (small amount of lube, i.e. match head), I size to groove diameter + 0.001"/0.0015". For my 308 my bare CB is 0.3015"D & my PPCB is 0.3095"D. I tried final sizing to 0.308"D ( required a lot of effort) and got wild groups. After unwrapping some patches I discovered my bare CB diameter had been reduced to about 0.299"D. To me that indicated my CB had too much slop on its way to the muzzle, hence the wild groups. Hope this helps!

Best regards,

CJR

[outdoorfan]

Hope this helps!




Yes, it does. Thanks!

[nanuk]

CJR: I plan on testing my PPCB just that way to start off.

[pdawg_shooter]

I size to bore diameter +.001/.0015 and size the patch as large as will fit the throat of the rifle. Interestingly, I once resized some 311466 I had made for my 303 SMLE (.304-.314) in a .310 die, loaded them in my 06 and they shot fine. I think as long as the bare bullet is over bore diameter they will work. docone sized his 303 stuff to .308 and it works fine for him.

[montana_charlie]

After unwrapping some patches I discovered my bare CB diameter had been reduced to about 0.299"D. To me that indicated my CB had too much slop on its way to the muzzle, hence the wild groups.
Your paper is too thick for the depth of your rifling. Pay closer attention to pdawg...
CM

[pdawg_shooter]

I use 16# green bar printer paper. It add almost exactly .010 to any bullet I patch.

[Smoke-um if you got-um]

Some time back I bought the book The Paper Jacket by P. Mathews because I was getting some very erratic results on the target. It took me several times reading it before I finally gleaned that bit of information from it. Specifically to patch the bullet to be whatever diameter was snug in the case neck of a fired round. On full length sized cases I run the neck up on a Lee 303 British Expanding button/rod in a 303 die being careful to not size the shouder portion any smaller than .440. I had (unsuccessfully) been patching and then sizing to .309 for my 30.06. My results became more consistent by installing the gas check with a pass thru the sizer and then patching with 20lb tracing paper .015 thick, 12 mm wide, long enough to make 4 wraps around the bullet, moistened in egg whites diluted with water. I ended up with a 12 mm wide patch because it extends past the case neck by about .030 and just barely bumps up against the rifling when chambering in my Savage 116. When everything is dry I lube the patch with a little bit of Johnson Paste Wax and seat in the cases after belling the mouth enough to just allow the gas check to be hidden. I let the nose of the bullet kiss the lands just enough to make a mark about long as it is wide and use a Lee Factory Crimp die to very lightly bring the case mouth into a good contact with the exposed paper. A little dab of JPW on the exposed patch end and the nose portion that contacts the lands and the cartridge is done. I use 27.5 grains of 5744 merely because I had/have a large quantity of it from using it with unpatched lead bullets. I have never chrono'd the load but judging from its drop at 200 yds it must be approx. 2000 fps or very close to that. Accuracy is 2 moa, acceptable but not outstanding. I plan to test other powders for accuracy as soon as I am completely satisfied I have the bugs worked out of this dadburn patch "formula". It's a lot of work but it keeps me busy and my mind active since I retired several yrs ago.

[outdoorfan]

I think as long as the bare bullet is over bore diameter they will work.

Thanks. That's the confirmation I wanted.