can i "mix" load data?

[Craigman]

I want to load up some 30-06 with 180gn nosler partitions and silvertips (which i already have) and want to combine data from Speer manual and Nosler online data..... is this possible?
The difference is that the Nosler data only lists 4 powders, which i dont have, and a different OAL for a similar bullet. The nosler data is 3.34"OAL which is slightly more than Speer OAL. So if i load with some diff powder, H4350, and set the bullet higher in the case than in speer manual, with a charge reccomended by speer..... i would not exceed pressure correct? The deeper the bullet=more pressure right? generally?

 

[243winxb]

Bullet construction can raise pressure. A partition with a thicker/heavy jacket base will produce more pressure than a simple lead core bullet. The length of the bullets bearing surface, if longer, will raise more pressure. Start low on the powder charge and work up as alway and you will be fine. Seating a bullet into the rifling is said to raise pressures. Check the Hodgdon website for powder charges. http://data.hodgdon.com/main_menu.asp

 

[Grumulkin]

I mix data all the time. Of course, I cautiously work up loads and am quite adept at reading pressure signs.

 

[Craigman]

thanks guys! the OAL thing was just throwing me off cause it was something close to a difference of .10"

 

[rcmodel]

The Nosler partition is longer for a given bullet weight, due to the fact it has a lot more copper taking up space occupied by lead in a traditional cup & core bullet.

That not only makes the COL longer to get the base in the same place inside the case.
But as already mentioned, it is a harder bullet, due to the solid internal partition and thiocker base.

rc

 

[ranger335v]

"The deeper the bullet=more pressure right? generally?"

True for handguns, not true for rifles.

All loading data is generic for powder and bullet weight. If that were not true there are many bullets we couldn't use because no specific data is available for them.

Any book's OAL is what the manual makers used, no more, it's not a "law" to be blindly followed or KABOOM! Assemble your ammo at a length that will feed and chamber properly and develop the charges with that. After finding the best charge, experiment with OAL to find the best seating depth.

Not too many years back some manuals listed no OALs at all and some only listed a "normal" max length based on most magazines; some still do it that way. If we follow a manual in lock-step, we may as well just use factory ammo. Part of what handloading is all about is we can cutstom match the ammo to our rigs.

 

[rcmodel]

True for handguns, not true for rifles.

Not true.

Deep seating a rifle bullet raises pressure just the same as any other caliber.

Less usable case volume = More pressure in any caliber or type of cartridge.

While it may not be as critical as it is with small handgun cases and fast powder, the effect is still there at max load levels.

rc

 

[ranger335v]

"Not true."

Well, if we push a rifle bullet fully into the case body thangs would change but otherwise I disagree, especially if we are doing right and working up a load after a significant change but with normal and rational seating changes, no. Fact is, seating deeper in rifles usually reduces chamber pressures because it allows the bullet to achieve a bit of speed/inertia before it hits the lands; that's what "freebore" is all about!

So, I disagree. But it's a harmless fear, so no matter...

 

[GaryL]

I mix data all the time, seldom have the 'exact' recipe to work with. So that means looking over data from different sources, with different weights even, to come up with safe data to work with. If possible, I try to find data with a match to the bullet manufacturer and type in the closest weight possible to see how it compares to similar weight bullets. I might add that this is a good idea anyway, as a gut check to the data to see if it's inline with similar components.

And as rc mentioned, you'll have to figure out seating depth. You can always drop one into the chamber of the gun to figure out where to start, and a lot of people end up 0.010"-0.050" off the lands anyway.

 

[Ed_]

Not trying to antaginise but... I wonder why the powder manufactures do not publish what the freebore of the test rifles and barrels are in their load data?

I have know Idea who is correct. The question just popped into my feeble mind after reading the above posts.

Ed

 

[Jim Watson]

If they tested in SAAMI spec P&V barrels, the chamber dimensions are standardized.
A .308 has a 35 degree 43 minute bevel from the neck to the throat, which is .310" diameter and .090" long; then a 1 deg 45 min leade into the rifling of a .300" bore and .308" groove.
Diameter tolerance is +.0005" - 0; length tolerance is +.005" -0.

 

[Grumulkin]

Not trying to antaginise but... I wonder why the powder manufactures do not publish what the freebore of the test rifles and barrels are in their load data?

I have know Idea who is correct. The question just popped into my feeble mind after reading the above posts.

Ed

It's really not that important. They give you a starting load that is going to be safe in a wide variety of guns with that chambering. It's up to you to work up the load safely. They give you conservative starting and maximum loads.

There are also more differences between guns than just free bore. One barrel may be a tiny bit smaller in diameter than another. The bore of one barrel may be smoother than another. Though a barrel is supposedly a 1:10 twist it may be slightly faster or slower. In fact, on another forum a test was done using "identical" rifles with "identical" loads. If I remember correctly, 10 or so rifles were chronographed and the difference between the lowest and highest velocities was close to 200 fps.

 

[BeerSleeper]

I would think bullet seating depth has a bigger effect on pistol rounds, because the volume change, relative to the total case volume, is proportionately larger. I bullet set .050" deeper in a tiny pistol cartridge may reduce case volume almost the same as a bullet set .050" deeper in a large rifle cartridge, but in terms of a percentage of total case volume, the change is much smaller.

 

[918v]

In the 30-06, COAL is not much of an issue when working-up a load with H4350 and such.