Quick question regarding powder charges

[.308 Norma]

I looked for the data in the Lyman manual and the closest they had was 155gr lead bullets. Am I ok to go off that data when using a 158gr bullet?

Yeah, probably.

No, you cannot use data for a lighter bullet for a heavier one, the heavier bullet with more bearing surface will give more pressure.

Generally speaking, I agree with Walkalong whole-heartedly..."don't use data for a lighter bullet for a heavier one." But I'll bet you're looking at data for the 155gr. Lyman #358156 cast bullet in your Lyman Manual. Right? That's the 357 Mag, 155gr cast bullet that's listed in my Lyman Manuals anyway, and when it's cast out of Linotype (as Lyman says) it weighs real close to 155grs. However, by the time you add a gas check, which the Lyman #358156 was designed to accept, it will weigh real close to 158grs.
So yeah, you'll probably be alright in this case to use the data for a 155gr cast bullet for a 158gr cast bullet. Start low and work up of course, but we're only talking about 3grs difference here anyway. And besides, both the Lyman #358156 and your bullets are SWCs, so their bearing surfaces are about the same.

 

[Jim Watson]

Have they reduced the coverage in Lyman 50? My Lyman 49 shows 160 and 170 gr cast bullets out of two old line moulds, the 358311 Roundnose Police Special, and the 358429 Keith.

 

[LiveLife]

50th edition Lyman ... I'm brand new and want to get everything right. I have 158gr Hardcast bullets for .357 and ... closest they had was 155gr lead bullets. Am I ok to go off that data when using a 158gr bullet?

Generally speaking, I agree with Walkalong ... But I'll bet you're looking at data for the 155gr. Lyman #358156 cast bullet ... when it's cast out of Linotype (as Lyman says) it weighs real close to 155grs ... by the time you add a gas check, which the Lyman #358156 was designed to accept, it will weigh real close to 158grs ... besides, both the Lyman #358156 and your bullets are SWCs, so their bearing surfaces are about the same.

+1.

I too agree with Walkalong that matching bullet weight, nose profile/ogive and bullet base length (which affect bullet seating depth) of published load data is important which all contribute to chamber pressures and you could use load data for slightly heavier bullet.

But keep in mind Lyman load data lists bullet weights without lube and depending on lead alloy used, bullet weight could vary by several grains from published. And depending on the number of lube channels, weight of lube could add additional from less than 1 grain to 2 grains.

Add to these, there is bullet-to-bullet weight variance. Depending on brand and bullet type, I have found jacketed bullets to have around 1 grain variance, plated bullets up to 2-3 grains and lubed lead bullets up to several grains.

 

[LiveLife]

Bullets are 158gr Lead Hardcast SWC ... I'll be shooting it through a rifle, Marlin 1894 CSBL 16.5'' barrel

And if you experience leading in the barrel with lubed bullets, may want to consider coated bullets.

MBC offers both regular 158 gr SWC and grooveless - http://missouribullet.com/results.php?category=20&secondary=10

 

[Joseph Dawson]

So from what I'm gathering it's ok to use the data for the 155gr lead bullet when I'm using 158 gr I just have to make sure I'm careful while working the load up.

 

[Walkalong]

If they are both lead and the data is from the same source, no. Use same weight or heavier data.

bds gave one example comparing two bullets, not a blanket statement that you could use lower weight data and just be careful.

Being careful, especially when new to reloading, is using the correct weight data.

 

[LiveLife]

I too agree with Walkalong that matching bullet weight, nose profile/ogive and bullet base length (which affect bullet seating depth) of published load data is important which all contribute to chamber pressures and you could use load data for slightly heavier bullet.

So from what I'm gathering it's ok to use the data for the 155gr lead bullet when I'm using 158 gr I just have to make sure I'm careful while working the load up.

Note from my quote "you could use load data for slightly heavier bullet" and not the other way around.

When I am conducting load development and can't find load data for specific bullet I am using, I tend to reference more conservative load data to start out as you can always go higher.

Be safe.

 

[Jim Watson]

I would consider the gun to be used. A below maximum load in a modern gun, three grains of lead does not bother me.
Frex, I routinely load 160s on 158 gr data. But it isn't +P or full charge magnum, either.

 

[Joseph Dawson]

The next one up from 155gr in the Lyman book for rifle data is 170gr. Could I use Handgun data even though I am using a short 16'' barrel? For Handgun 357 data there's 160gr lead bullet.

 

[Jim Watson]

Yes.
Pressures and load limits are the same, just more velocity from carbine.

 

[Joseph Dawson]

Alright, so I'm gonna use the .357 160gr bullet for handguns in the Lyman manual to work my loads off. That sound good? Also, I'm used to using bullseye and that doesn't have a lot of room to move like 2400 does so how fast should I work the load up. WIth bullseye, I did .1-.2 increments, with 2400 how many grains should I work up each time from the starting load.

 

[Dudedog]

2002 Alliant Data (so Old data)
Show MAX of 15.3 2400 with a 158gr LSWC Reducing 10% to start is normal
That would put you around 13.7 which is higher than Lyman shows as a MAX with the 155gr bullet.
I have never loaded .357 with 2400 and a 158 so I am just posting data, no experience to back up the numbers. (I like H110/W296)