Reloading data

[justinp61]

I've started working loads for my newest 260 build, a Savage mdl 10 LH action with a Shilen Select Match SS barrel. THis is a deer rifle that may see some coyote hunting from time to time. Since the heaviest bullet I am planning on shooting is a 130 gr and a 120gr being what I'll shoot most of the time I selected a 1-9 twist.

I have Sierra's 5th edition reloading manual that I bought about four years ago, Sierra's 6th edition reloading app and use Hodgdon's online data. There is a big difference in the data from min to max charge weight to the same weight charges velocity data. I understand different barrel lengths affect velocity but you'd think there would be a "standard" for testing. Even the Sierra 5th and 6th editions are different.

From Sierra's 6th edition app
.

5th edition book


Hodgdon.

 

[Jud96]

That’s pretty typical in my experience. If I’m loading for a combination found in manuals, I find 2-3 sources of data and average the max charges of them all and add 1.0gr to their max and that’s what I set as my max. Then I drop down 3.0 grains or so and work up in .2-.5gr increments depending on case capacity. I work up until I hit pressure and pull down any leftover rounds that are too hot. If I don’t hit pressure then I’ll continue working up until I do. I usually find a good node before hitting pressure signs though.

 

[0.1 Aggregate]

This is such a common comment I can’t believe it still gets asked. There is no such thing as a “standard” for testing. There are so many variables in bore diameter, chamber dimensions, powder lots and bullet diameter/hardness that there simply cannot be any “standard”. You have to work up your own load with your own rifle/components - that’s just the way it is and always has been.





.

 

[NZ_Fclass]

That's all part of the fun. Otherwise we would just be making "factory ammo"

 

[Doom]

There is a standard for pressure testing, SAAMI. That said, each of the manuals gives a maximum safe charge that is at or usually below the maximum per SAAMI. Velocities will vary from barrel to barrel and those listed in each manual are typically referenced to firearm and barrel length or to the universal receiver and test barrel.

 

[JimSC]

It's always safe to start with the most conservative data and work up.

 

[std7mag]

As Doom, says there are standards for pressure.
As far as barrel lengths go, it's still kind of an advertizing gimmick.
Sierra uses a lot of 26" barrels for their testing, leading to higher velocity numbers.
Kind of a "Sierra Bullets gives you higher velocities" thing.

But they are not the only ones that do it.

Nosler listed a 26" barrel in their 7mm-08 testing. How many 7mm-08 hunting rifles do you see with a 26" barrel?

 

[justinp61]

I expected Hodgdon's data to be different but Sierra's data changed quiet a bit. For example I'm loading IMR 4064 in this 260, the book lists 33.6gr for 2600fps, the app lists 36.2gr for 2600fps, the book lists 35.7gr for 2700fps and 37.8 for 2800fps. The app lists 37.5 for 2700fps and 38.9gr for 2800fps. The book max is 42.0gr at 3000fps, the app max is 39.4gr at 2810fps.

I can see their lawyers changing the max load, but what changed the min-max so much? I also noticed that Sierra doesn't list pressures.

 

[22vartarg]

I called Sierra when I noticed the change between the 5th and 6th edition. It was explained to me the reason it changed was the testing method. In the older manual they used a standard receiver and swap out barrels, but a regular rifle. The new one they used a rig that measures pressure and set up the mural using pressure data.

 

[justinp61]

Interesting.

 

[dellet]

I expected Hodgdon's data to be different but Sierra's data changed quiet a bit. For example I'm loading IMR 4064 in this 260, the book lists 33.6gr for 2600fps, the app lists 36.2gr for 2600fps, the book lists 35.7gr for 2700fps and 37.8 for 2800fps. The app lists 37.5 for 2700fps and 38.9gr for 2800fps. The book max is 42.0gr at 3000fps, the app max is 39.4gr at 2810fps.

I can see their lawyers changing the max load, but what changed the min-max so much? I also noticed that Sierra doesn't list pressures.

They simply tested again between publications. There are a few things to note.

Different
seating depth
Powder lot
Bullet lot

If it’s true they changed methods, then also a different barrel and chamber.

All those changes will certainly change data.

 

[Rsadams]

I called Sierra when I noticed the change between the 5th and 6th edition. It was explained to me the reason it changed was the testing method. In the older manual they used a standard receiver and swap out barrels, but a regular rifle. The new one they used a rig that measures pressure and set up the mural using pressure data.

There was alot of changes in the new sierra manual including pistol loads I wondered why such drastic changes from the old manual....

 

[6.5 forever]

I don't believe any published data is "the law". All these numbers are always changing. Every time I change lot numbers there is a change in results.

I now spend all my shooting time with two rifles in the same caliber. Every barrel has it's likes and I try to meet them. My sessions show that if I can meet prior velocity, then my results remain positive. Love my Labrador, no more guessing or worrying about .2,.4 or one grain.

Only when changing a barrel do I start over. Even then it seems like the sweet spot is close to every other quality barrel.

Data is just what it is. No worry's.

 

[justinp61]

I don't believe any published data is "the law". All these numbers are always changing. Every time I change lot numbers there is a change in results.

I now spend all my shooting time with two rifles in the same caliber. Every barrel has it's likes and I try to meet them. My sessions show that if I can meet prior velocity, then my results remain positive. Love my Labrador, no more guessing or worrying about .2,.4 or one grain.

Only when changing a barrel do I start over. Even then it seems like the sweet spot is close to every other quality barrel.

Data is just what it is. No worry's.

I loved my Labrador too! Sorry I couldn't resist, LOL. LabRadar I'm guessing.

 

[chromatica]

I have shot a lot of SMK 123s in my 260 Rem using IMR4064. The manual version 5 had no recipes for this bullet. Version 6 has a whole page of recipes!

 

[BCBRAD]

~ 45 grains of RL-22 begets 2 960 ft/s out of a 26" bbl, with a 140 Berger Hybrid in the 260 Rem.
Barrel is a varmint profile Benchmark 1:8 twist, it will one hole 5 shots at 100 and hold ~1/2 moa all the way out.

 

[Mickal]

They simply tested again between publications. There are a few things to note.

Different
seating depth
Powder lot
Bullet lot

If it’s true they changed methods, then also a different barrel and chamber.

All those changes will certainly change data.

Same, for différent data from 2 différent Book. Since my reload was more then theire now max load . I contact thème , they answer me they use différent barrel , powder lot, etc. And if i use the same lot, same bullet in the same gun , it will be safe.

Mickal

 

[dellet]

Same, for différent data from 2 différent Book. Since my reload was more then theire now max load . I contact thème , they answer me they use différent barrel , powder lot, etc. And if i use the same lot, same bullet in the same gun , it will be safe.

Mickal

Don't forget to use the same COL as published.

This was the biggest change Sierra made between publications. People are used to adjusting for component lots, the seated depth of the bullet generally remains constant.

Seating the bullet .045" deeper with the new data is enough to work up a new load, even with the same components.

 

[Webster]

I've started working loads for my newest 260 build, a Savage mdl 10 LH action with a Shilen Select Match SS barrel. THis is a deer rifle that may see some coyote hunting from time to time. Since the heaviest bullet I am planning on shooting is a 130 gr and a 120gr being what I'll shoot most of the time I selected a 1-9 twist.

I have Sierra's 5th edition reloading manual that I bought about four years ago, Sierra's 6th edition reloading app and use Hodgdon's online data. There is a big difference in the data from min to max charge weight to the same weight charges velocity data. I understand different barrel lengths affect velocity but you'd think there would be a "standard" for testing. Even the Sierra 5th and 6th editions are different.

From Sierra's 6th edition app
.View attachment 1289806View attachment 1289807

5th edition book
View attachment 1289808

Hodgdon.
View attachment 1289809

Just work up an accurate safe load and go hunting. You don't need to see how close you can get to max.