Quick question: using Lyman 160 gn data for 158 gn bullets.

[Comrade Mike]

My Lyman manual doesn't have data for 158 gn bullets, only 150 and 160. I'm shooting a Keith style 158 gn SWC and I need data for H110/296. My Lyman manual has 160 gn data. I figure 2 grains won't make much difference and I know to always use data for the next heaviest bullet. Would you say I'm good to go with the 160 data?

[Dale53]

Comrade Mike;
As long as the bullets are of similar style, you will not have a problem. On the other hand, if you tried to use data for a SWC with a full wadcutter, you could have a problem due to the much deeper seating of a full wadcutter (which reduces powder space and raises pressures, sometimes considerably).

FWIW
Dale53

[bgokk]

If your boolits actually weigh 158 g you should be good to go.

[Comrade Mike]

I'll check the coal in the manual but they are similar style bullets. Thanks guys.

[MtGun44]

The main issues are
1) boolit weight
2) location of the bottom of the boolit - which defines the combustion
chamber volume. A substantially smaller combustion chamber than the
test situation reported in the load data book will cause higher pressures,
so you should be trying for approximately the same base location - or
higher.

[scottfire1957]

You have more than one manual, yes? You should have several, as in more than two. The ability to cross reference will save much internet time.

[Ido356]

The main issues are
1) boolit weight
2) location of the bottom of the boolit - which defines the combustion
chamber volume. A substantially smaller combustion chamber than the
test situation reported in the load data book will cause higher pressures,
so you should be trying for approximately the same base location - or
higher.

If the publisher's of load data would include the specifications of the projectile used for testing instead of just referring to a bullet No. it would eliminate a lot of confusion as to OAL.

[Comrade Mike]

I have several manuals but my Lee manual doesnt have H110 data for a 158 gn lead bullet. My Hornady, Sierra and Nosler manuals only have jacketed handgun data. I'm thinking Ill just pick up the Lyman cast bullet handbook as another good cross reference.

[SSGOldfart]

I have several manuals but my Lee manual doesnt have H110 data for a 158 gn lead bullet. My Hornady, Sierra and Nosler manuals only have jacketed handgun data. I'm thinking Ill just pick up the Lyman cast bullet handbook as another good cross reference.
Good thinking you might also have a look at RCBS cast manual.not as much load data but I find it Useful from time to time. Your going to run into this problem a lot with cast Boolits

[MtGun44]

The bullet number is well known by experienced casters. Sorry, but you have
to do your homework on this. They INTEND you to use the exact same boolit,
and if you want to extend this data, you have to do a bit of thinking and work.