Plated vs. Jacket 9mm & .45 Cromo

J

Jeffm004

New member
I ran an Extreme 124 gr PRN over 4.3 gr of Bullseye/1129 and jacketed 124 gr 4.7 gr W231/1159 fps in a full size 9mm (COAL 1.155) and

200 gr PRN over 5.5 gr W231/HP38 in a P220 and Commander - .45, COAL 1.253

Both those loads in the lee book are mid-range (or +) jacketed. for the 9mm, I ran about 50 fps faster than top end 4.4/1058 Bullseye jacket, the W231 was 60 fps over Speer #14 and huh, over book today by Speer #14 but still good in the Lee book.

In .45, I ran 50 fps slower than the 5.2 gr/794 fps book for jacketed,
225 LFP with 5.3 W231 was 740ish, Book 5.3/230 lead is max at 834 fps,
These were loaded in 1985 indicating to me that w231 has not changed much since plated is running 50 fps slower anyway.

So, you might estimate that you are 50 fps over or under jacketed book results with plated bullets in 9mm or .45 if you don't have a crono or are just starting. YMMV.

Generally, if lead overlaps Jacketed, that is where I start, YMMV. I'm not changing anything.
 
You should always use the powder manufacturers published data. They are the ones who tested pressure tested and chrono'd the loads, not a 3rd party reference book. Lead, moly lead, HiTek coated lead, and plated take less charge weight for the same bullet weight because the friction is lower.
 
So, your gun is exactly like all the other guns and they will all get the same velocity...
Take any manual or powder manufacturer's load data and ask yourself
is your gun is the same as the test gun (including barrel length and all dimensions),
are you using the same lot number of powder,
are you running the same COL,
are you running the same bullet,
are you running the same brand and lot number of primers,
and
are you running the same cases?
Since you probably don't match ANY of these variables with ANY manual, you start at the start load and work up and DON'T assume anything.
Finally, the history of guns has noted for over a century that some barrels, as identical as the next one, is faster or slower than the other. So, even if you do your best to match up everything, you will still get the occasional gun that shoots faster or slower than the bulk.
 
When I started reloading, it was with a little plastic scoop and a gadget that didn't even require a press. The crono is a relatively new toy. Reloading books have not updated their data much or their format any in 40 years. It is sad you cannot get info on case volume variation, primer temperature variation, lead, moly, hi-tec, plated, jacketed impact on a given caliber, much less load. COAL impact. It is disgraceful how little is known. My post is for that guy that I was once. Nothing but a scoop and a sheet of paper that came with the scoops. I hope it helps. Please, add your insight into the impact of all these mysterious parameters no one tracks and the links to powder manufacturer data for plated bullets. I'm curious. Winchester has none, I checked that.
 
"You should always use the powder manufacturers published data. They are the ones who tested pressure tested and chrono'd the loads, not a 3rd party reference book."
So, you're saying the Lyman manual isn't a good source? I call BS.
The LEE is simply a compilation of other sourced data(3rd party).
 
Work up to what?
"Pressure signs" are very elusive in pistol calibers.

In my early career, if it hit the target and functioned the action, I was happy.
Then I got into IPSC etc. where I have to make Power Factor, so I load by chronograph, although stepping off from published data.
I tried one popular powder that required an overload to reach the necessary velocity. I did not buy any more of it.
 
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