I understand why some may want the design in the OP, as several others had posted orders already. However, without dimensional sketches, specifications, or range reports with load data specific for the 9mm I hope you can understand why most anyone would be hesitant to honcho a design blindfolded.
While the MP 125 HP and the 147 GCHP design are kissing cousins, I have spent considerable time experimenting and measuring seating depth, chamber bulge for variety of case headstamps, bnd proportions, and COAL to fit within SAAMI specifications for 9mm which the magazines and firearms are engineered. For reference, I'm using a Glock 19 9mm factory barrel (known for tighter chamber dimensions in the 9mm caliber than competing 9mm pistol manufacturers)
The Lyman design is from the beginning bevel based, and designed to be seated deeply as such. One cannot simply change the bevel base for a gas check, stretch the OAL to hit 147gr with a sufficient hollowpoint depth and width without changing the design entirely, or intending the projectile for different calibers. The thread title suggests the mold is 9mm specific, and I would assume most posters are expecting a design that was intended for the 9mm cartridge.
In my eyes, without a redesign from the ground up for a GC base in a max weight for caliber 9mm, you're juggling the following issues:
1. case bulge that impedes proper chambering
2. COAL that will not feed from magazines
3. bullet profile that fails to feed in all firearms or jams into lands of a barrel with tight throat.
4. living with a purely cosmetic HP, or a 147gr FP
The longer top band affords the reloader variable seating depth in relation to chamber/throat dimensions. With a seating depth of .25" you have a COAL of 1.14", under 1.16" saami max for 9mm. Just how much deeper you can seat depends on your individual chamber, load workup, head stamp, sizing dies and case expanders. Generally I found .25" to be the sweet spot that allows to adjust for longer or shorter COAL, with Federal, blazer, winchester, pmc brass allowing seating .27" below case rim without bulging( 1.12 OAL) , Tulammo, A USA, GFL, and S&B exhibiting more bulge at a seating depth deeper than .26" (1.13 OAL)
I should add I use a 38 S&W Lee case expander that reaches a bit deeper down into the 9mm case taper to prevent swaging down the base when seating PB bullets.
Lube grooves have been changed from the previous steep X design to traditional 30 degree angles, serving to protect bands and improve bullet release/fillout from the mold. I've experienced more than a few broken or deformed skirts on my 125gr bullets when I drop them too frosty. Serves an extra function to pack in extra lead, necessary when we work within tight parameters.
By working out seating depth, max OAL, and driving band proportions it was possible to work a larger HP cavity into the 147gr HP than the 125gr HP, and I also wager that using softer non wheel weight alloy we would be able to get away with using a larger HP pin for better expansion at 147gr subsonic velocities. By having a real HP on the 147gr version, it leaves the possibility open to play with the heavier 156 GC'd FP in a 9mm case with enough room for powder(please work up loads carefully) or crimp over the front driving band for 38/357 caliber revolvers, as in the 125gr HP (135gr FP) MP design.
Although I considered a larger meplat & changing ogive radius, I chose the MP 125 ogive & meplat, knowing the profile feeds very well at a longer OAL and carries a lot of lead outside the case to help balance the projectile, 147gr needing to be driven hard for stability, this is an all around benefit and good design.
My apologies for the long post, I felt it germane to include information regarding why I chose these design features, and apologize for not explaining earlier how it differs from the original, I can see how it would be easy to mistake this for a simple modification, given it's similarity to the design that inspired it and subtle changes for the chosen application.
Having said that, we all stand on the shoulders of giants that have paved the way for us, and there's a reason certain profiles look, use, or borrow similar features from previously well established designs, in order to push the envelope just that little bit further without compromising the intended goal.
I look forward to your feedback, ideas, and suggestions.
Have a great week, and thank you for your time and interest.
~z
zubrato_359-147_142_gr_Sketch.bmp
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Originally Posted by Lloyd Smale
