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general powder conversion question


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I am looking for a way to convert powder charge data for FMJ bullets to coated rn lead bullets. Is there a way to do this?

 

Looking to load for 9mm. a 124 gr. rn lead coated bullet in the velocity range 1040-1050.

 

If you can help it would be best to PM me.

 

THANX!

 

JJJ-D

 

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Well, generally, a lead or poly-coated lead bullet will need less powder than the same weight jacketed bullet to make the same velocity.   But the top end jacketed loads in 9MM are real high pressure compared to what a lead bullet can stand.   So if one were to start about mid-range on a 9mm jacketed load and try to apply  that to a lead or poly-coated lead bullet, one might be real close.  Still, it's really a guessing game because I don't believe there is a DIRECT correlation between jacketed and poly-coated lead loading data.

 

But with tons of lead-bullet data available in the Lyman Cast Bullet handbook, why not just look it up?  As SD suggested.  Here's a couple of loads directly from Lyman CBH with common pistol powders for 124 grain lead bullets (and the poly-coated will shoot just about the same load) to give you an idea:

 

231 powder at 3.9 grains makes around 1094 FPS

Unique at 4.4 grains makes around 1063 FPS

 

Both of those loads are starting level loads, so you would have lots of room to go up in powder if you needed it for cycling a gun.

 

Good luck, GJ

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Garrison Joe is right on point. 

But I go even simpler than this. Bullets are bullets for the most part. the big thing with lead is matching hardness with velocity, this insures the bullet will seal the bore and not lead up on you. that said you are using poly coated that claim they can be driven as hard as a jacketed bullet. so I'd say use like for like data. For a 9mm lead I'd back off about one grain of a jacketed load for the velocity you are looking for. This will be a god start. But there ain't a conversion and you need to buy some books. 

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IMHO: Data for coated bullets will be a bit different from regular cast bullet data. Closer to cast data than to jacketed data, but not the same. Probably close enough that you could use the starting load and check velocities with a chronograph. 

 

Although a Lyman manual is worth while having, download the Oregon trails manual, a bit dated, but pretty decent data, at least for the cartridges I've load for. They use Magma molds, the most common mold for commercially cast bullets, and that is a good thing. Oh, and it's free.

 

https://oregontrailbullets.com/xcart/images/filemanager/uploads/otbc-load-manual.pdf

 

BB

 

PS: https://www.egglestonmunitions.com/load-data.html

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Thank y'all so much for the info. I have the lyman manual but did not know they had one just for cast bullets. I ordered it! and thank you for the info regarding differences. Some research showed that with a high quality cast bullet the threshold for leading is about 2,000 fps. I will be nowhere near that.

 

AWESOME!

 

JJJ-D

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2 hours ago, "Big Boston" said:

IMHO: Data for coated bullets will be a bit different from regular cast bullet data. Closer to cast data than to jacketed data, but not the same. Probably close enough that you could use the starting load and check velocities with a chronograph. 

 

Although a Lyman manual is worth while having, download the Oregon trails manual, a bit dated, but pretty decent data, at least for the cartridges I've load for. They use Magma molds, the most common mold for commercially cast bullets, and that is a good thing. Oh, and it's free.

 

https://oregontrailbullets.com/xcart/images/filemanager/uploads/otbc-load-manual.pdf

 

BB

 

PS: https://www.egglestonmunitions.com/load-data.html

 This  is great info! It gives me 98% of what i need. I just now have to get info on casting hardness for the bullets I use. (Bayou bullets 124 grain 9mm)

 

Thanx!

 

JJJ-D

 

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19 hours ago, The Original Lumpy Gritz said:

What powder are you using Jim?

I use Blue Dot.

I wouldn't use coated 9mm in any bbl that does not use Ballard type rifeing. 

OLG 

I have an aftermarket barrel that has traditional rifling specifically for lead. (Glock 19)

 

I have Clay dot which I cannot get enough velocity with.....

 

I tried Titegroup and it was better but not quite sufficient.

 

I bought some Winchester 231 which another shooter here uses with good success. Gonna try that this week.

 

The ClayDot and Titegroup work fine in my other pistol and rifle. (Ruger PC carbine and Beretts M9)

 

JJJ-D

 

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20 hours ago, Garrison Joe, SASS #60708 said:

Well, generally, a lead or poly-coated lead bullet will need less powder than the same weight jacketed bullet to make the same velocity.   But the top end jacketed loads in 9MM are real high pressure compared to what a lead bullet can stand.   So if one were to start about mid-range on a 9mm jacketed load and try to apply  that to a lead or poly-coated lead bullet, one might be real close.  Still, it's really a guessing game because I don't believe there is a DIRECT correlation between jacketed and poly-coated lead loading data.

 

But with tons of lead-bullet data available in the Lyman Cast Bullet handbook, why not just look it up?  As SD suggested.  Here's a couple of loads directly from Lyman CBH with common pistol powders for 124 grain lead bullets (and the poly-coated will shoot just about the same load) to give you an idea:

 

231 powder at 3.9 grains makes around 1094 FPS

Unique at 4.4 grains makes around 1063 FPS

 

Both of those loads are starting level loads, so you would have lots of room to go up in powder if you needed it for cycling a gun.

 

Good luck, GJ

This is good info. I have some 231 and want a velocity at about 1060.

 

JJJ-D

 

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I have seen the best accuracy in all of the 9mm and .40 S&W chambered weapons I have fired, including select fire class-3 guns, when I used Blue Dot powder. 

Meters great and is one of the cleanest burning powders I have ever used. 

With those lead 9mm 'pills', try 6.8-7.0 gn of BD.

Glocks are built for NATO level 9mm ammo. Low end powder charge may not allow the slide to fully cycle.

OLG 

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