Danderdude
10-02-2013, 07:22 PM
I'm having a hard time reconciling some data with reality, and need a hand guys.
I'm trying to design a boolit for Tom at Accurate Molds to make for me, but have just hit a wall. It's going to be a .357 diameter boolit for 9mm Luger, tumble lube design, and as close to 150gr as I can get. I sent him an e-mail this morning with this drawing I came up with, modifying the 35-147A he already has in his catalog, to add another full length driving band while maintaining overall length, weight and shape by "moving" the bevel base.
83315
Full size: http://i.imgur.com/e2vcWNM.png
Measurements of the original
http://www.accuratemolds.com/img/bullets/detail/35-147A-D.png
However, while testing some Lee Autodisk sizes with Unique, referenced against the new Lyman Cast Bullet Handbook data and how charges of Unique fill the case, I realized there's a problem. Lyman lists a max load with the Lyman 356 637 147gr bullet as 3.8gr Unique, with a rather short OAL.
Looking at Tom's drawing, the amount of the case occupied by his 147A is right at .30". However, a 3.8gr charge of Unique only leaves .27" of case length to work with before compression. This fact, coupled with my CZ 75BD Police having a .03" throat, is causing some trepidation. I couldn't take even the stock 147A design, seat it on 3.8gr Unique and make it chamber. It's a physical impossibility. I could back off the charge to the 3.2gr range, but then I'd lose a substantial bit of velocity in my 9mm rifle. I could also shorten the bullet to about 140gr but I'd rather not.
Does anyone have a Lyman 356 637 147gr bullet they can measure the length of for me? Any ideas or suggestions?
And before you ask, I have big jugs of Promo (aka Red Dot), Unique and 2400. I'd rather not have to buy other pistol powders.
I'm trying to design a boolit for Tom at Accurate Molds to make for me, but have just hit a wall. It's going to be a .357 diameter boolit for 9mm Luger, tumble lube design, and as close to 150gr as I can get. I sent him an e-mail this morning with this drawing I came up with, modifying the 35-147A he already has in his catalog, to add another full length driving band while maintaining overall length, weight and shape by "moving" the bevel base.
83315
Full size: http://i.imgur.com/e2vcWNM.png
Measurements of the original
http://www.accuratemolds.com/img/bullets/detail/35-147A-D.png
However, while testing some Lee Autodisk sizes with Unique, referenced against the new Lyman Cast Bullet Handbook data and how charges of Unique fill the case, I realized there's a problem. Lyman lists a max load with the Lyman 356 637 147gr bullet as 3.8gr Unique, with a rather short OAL.
Looking at Tom's drawing, the amount of the case occupied by his 147A is right at .30". However, a 3.8gr charge of Unique only leaves .27" of case length to work with before compression. This fact, coupled with my CZ 75BD Police having a .03" throat, is causing some trepidation. I couldn't take even the stock 147A design, seat it on 3.8gr Unique and make it chamber. It's a physical impossibility. I could back off the charge to the 3.2gr range, but then I'd lose a substantial bit of velocity in my 9mm rifle. I could also shorten the bullet to about 140gr but I'd rather not.
Does anyone have a Lyman 356 637 147gr bullet they can measure the length of for me? Any ideas or suggestions?
And before you ask, I have big jugs of Promo (aka Red Dot), Unique and 2400. I'd rather not have to buy other pistol powders.