40 S&W with Unique

[PistolShooter]

I'm loading 180 grain plated bullets with Unique and I want 950-1000 fps but I don't have a chronograph.
Can anyone tell me from experience how much powder to use? This is for my CZ75.

[painter]

What bullet shape?

There is data online for a Gold Dot, which is a plated bullet, at 1000 fps, and data for a CPFP in the same speed range.

[PistolShooter]

I'm using truncated bullets. The data out there varies a lot. I think max charge for the gold dot it 6.7. That seem like a very hot load.

[painter]

They also list a 180 gr CPFN over 6.5 (max) gr @ 1059 FPS.

What makes you say the gold Dot load sounds hot?

The data varying is why a chrono helps.

I'd trust the powder manufacturer, the bullet manufacturer, and everyone else...in that order.

[Matt101]

I?ve loaded AP70 (same burn rate as Unique and some say it?s the same stuff) with 180gn coated bullets.

5.0gn made 1000fps. I?d start there with a plated bullet & Unique.


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[PistolShooter]

I can't remember why it seemed hot. It's been a little while since I looked at all my data. I do know that the bullet manufacturers listed max is 6.0 grains but they don't give a velocity. From what I remember, I figured 5 to 6 grains should be enough.
I like to look at multiple sources to gain a better idea of what would give me the desired results but different sources also have different barrel lengths etc.

[Wobbly]

What load manual do you own and use ?

 

[Matt101]

I?ve loaded AP70 (same burn rate as Unique and some say it?s the same stuff) with 180gn coated bullets.

5.0gn made 1000fps. I?d start there with a plated bullet & Unique.


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 This was out of a CZ TS too


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[PistolShooter]

Thanks Matt101. That's what I was looking for.
I'm using the Lyman #49, Speer #14, a Handloader magazine, and Cam-Pro data.

[CPTKILLER]

http://www.alliantpowder.com/reloaders/RecipePrint.aspx?gtypeid=1&weight=180&shellid=29&bulletid=42&bdid=118

They recommend 6.7 grains of Unique for a velocity of 1000 FPS in a 4" barrel.

[Wobbly]

I'm using the Lyman #49...

OK, then you see the data for 175gr lead with Unique on p364 ? That's going to be very similar to your quest. Lead is going to be slightly faster than plated, but close enough for our purposes.

4.7gr = 898fps  and 5.8gr = 971fps

If we make a proportion from this data we can see that 5.66gr will result in 950fps. Since we'd need to bump it a tad for plated, then call it 5.7gr. Now, you need to understand that the load is not a straight line. Efficiency of the "burn" grows as the load increases, so our plot is a curved line. But proportions can be used when no direct data presents itself to some reasonable effect. At least it's built on some semblance of published data, and not an outright "guess".

Just so you understand, I used 175gr lead data becasue most plated bullets are closer to lead in behavior. If I knew the plating was extra thick (like a Berry RNHB-TP, or a Speer Gold Dot) then I would have opted for jacketed data.

From studying the data, apparently you'll barely make 950fps and never get to 1000fps with Unique.

 


Added additional thoughts this AM

[1SOW]

166 PF  ^^^^^^^^ with Unique

[PistolShooter]

Thank you for that info. The campro bullets do have a thicker plating but i'm not sure how they compare to the Berry or Gold Dot bullets .

[PistolShooter]

From the Campro website:
What?s the CamPro difference?
Thanks to our bullets' thick copper plating, barrel rifling cannot cut or tear the bullets to the lead core, which:

Prevents lead emissions
Prevents small copper particles from shedding off the bullet during its path to the target and reducing the precision of the shot
Protects the barrel from being ridden with lead
Allows the use of the maximum amount of powder recommended for your type of firearm (magnum)

They say their plating is .008" thick

[PistolShooter]

I found a chat forum where someone said the Gold Dot has .018" thick plating. If that's true that's a very thick layer.