Reloading recommendations for the Lee 356-147TC?

[LRRifleman]

Greetings!

It is my intention to develop a load for this bullet to be fired in a comped Sig P365 (specifically an assembled P365 Spectra Comp), and if it groups well, a Beretta 92x. I will be powder coating these bullets.

I am hoping to develop loads around either Silhouette or WW231. However, I do also have Unique, Bullseye, and Titegroup on hand. At the moment, I have data for the Lyman 356637 (which appears quite similar) for: Bullseye, Unique, and Titegroup.

As always, I appreciate any assistance that you can provide!

[Recycled bullet]

I would recommend assembling several inert cartridges with no powder no primers so that you can find out what seating depth/ overall length and amount of crimp is required to pass the plunk test.

The plunk test is where you remove the barrel from the pistol and you take your assembled cartridge and you drop it into the barrel and it needs to go all the way in so that the case head is flush with the barrel Hood without any additional help. It'll make a plunking noise as it falls in.

Then point the barrel up and it needs to fall back out under its own weight. This means that the ogive of your bullet and the measurable distance between opposing sides of the case mouth are not infringing upon dimensional shortcomings of a short-throated chamber or a sharp chamber mouth leade both of those are extremely common with 9 mm pistols.

I will personally run the largest bullet that will chamber in all of my handguns in my case I passed my bullets through a Lee 357 push through die.

Other people using similar pistols have their own problems that have been solved by sized either larger or smaller.... so I can only speak for myself.

Once you have confirmed that your ammunition will pass the plunk test and any possible magazine length limitations that may or may not be specific to your particular pistol then I would look at loading data for bullets that seat to a similar depth.

Remember that as you decrease the available volume for the initial propellant combustion event you increase the pressure in a way that may be expressed as logarithmic as in the pressure increase may not be linear at all.

Then just like any other new bullet start low and work up you will probably find accuracy somewhere in the middle between minimum and maximum. I found that in my guns in my hand the slower of the suitable propellant gun powders for 9 mm gave me the best results with powder coated cast bullets.

[LRRifleman]

@Recycled bullet,

Thanks for the refresher! After handloading for almost 50 years, you sometimes forget some of the basics! Just adding a new bullet and mold to the inventory!

[Recycled bullet]

You're welcome I'm glad that I could help you with the 9mm.

[fredj338]

I’m a TG hater so no, especially with certain lubes or coatings. Unique & lead bullets, like pb&j. W231 will also do fine. I run the same bullet over WST or Aliant SP.