Load Data Confusion

BRACES of Bristol - Sauer 100 XTA Stainless Package
Robby56

Robby56

Active Member
Hi All,
Just getting into reloading, and hoping for a bit of advice from those who are far more knowledgeable than me. (i.e. you lot) 🙂
I was researching loads for .308 win 150gr Sierra SBT Gameking using N135 and came across the XXL reloading site. This gave me a Start load of 34.1gr and a Max of 40.6gr, I then went to the Vihtavuori site, which gives me a Start of 39.4gr and a Max of 45.7gr for the same bullet.
Q1. Do different sources generally vary so much with their data?
Q2 Is there a load data source that is generally regarded as some sort of a 'bible' regarding load data?

I appreciate that this can be a dangerous business, and it's start at the bottom and work up.
After discovering what I consider to be such a vast difference in data though, I am wondering whether to believe what I read.
All answers/advice is greatly appreciated, and Thanks in Advance
 
As Pablo.222 has mentioned - use data published by powder or bullet manufacturers.

Even such mainstream published data can vary somewhat for a particular bullet / powder combination between (for example) Hornady & Nosler information. This is to be expected as identical test barrels are not used & one manufacturer may work to a slightly lower average pressure than another, etc. etc. etc.
 
reloading data is a guide,no two barrels are the same. starting low and working up is good advice BUT is costly in consumables. my personal advice would be check three or more sites and get the average for the bullet powder primer combination you want to used start mid way but be aware that a different case/bullet/primer WILL behave differently to the book data. work up in .5 grains until you are happy with the accuracy, velocity means very little<any one can miss using max load !> accuracy is your goal ,once you have an accurate load try .2 above and below to find the sweet spot. never exceed the bullet makers max velocity<bullets behave very differently when driven faster than the test limit. stay safe. check different data but if using sierra bullets use sierra data, hornady bullets hornady data etc
 
I have always gone with the poweder manufacturer's data when its an exact match to what I am doing for reloading. If the exact cannot be found, I would look for the bullet manufacturer. In this case Sierra has an app with load data. In most cases the load data can be found within both or at least one when it comes to well known powders and calibers. As I haven't reviewed or taken any load data from XXL reloading site, I cannot comment on the accuracy of the data from there.
 
Robby56 said:
Hi All,
Just getting into reloading, and hoping for a bit of advice from those who are far more knowledgeable than me. (i.e. you lot) 🙂
I was researching loads for .308 win 150gr Sierra SBT Gameking using N135 and came across the XXL reloading site. This gave me a Start load of 34.1gr and a Max of 40.6gr, I then went to the Vihtavuori site, which gives me a Start of 39.4gr and a Max of 45.7gr for the same bullet.
Q1. Do different sources generally vary so much with their data?
Q2 Is there a load data source that is generally regarded as some sort of a 'bible' regarding load data?

I appreciate that this can be a dangerous business, and it's start at the bottom and work up.
After discovering what I consider to be such a vast difference in data though, I am wondering whether to believe what I read.
All answers/advice is greatly appreciated, and Thanks in Advance
Click to expand...
Stick with published load data, either from a book or powder or bullet manufacturers website or app.

Even then you will find variance, you need to decide which data to go with, if unsure start with the lowest start load and work up to your required speed / accuracy but stop if you hit pressure signs.

First and foremost, get a reloading manual and read it a couple of times until you fully understand the process.

There’s a lot of good info on the net but also a lot of bad, reading a manual first will let you decipher between the 2.
 
Each primary source will only give you what they have found to be safe. If one source didn't test as far at either end of the envelope, their min/max limits will be different to those from a more ambitious tester.
 
Robby56 said:
Hi All,
Just getting into reloading, and hoping for a bit of advice from those who are far more knowledgeable than me. (i.e. you lot) 🙂
I was researching loads for .308 win 150gr Sierra SBT Gameking using N135 and came across the XXL reloading site. This gave me a Start load of 34.1gr and a Max of 40.6gr, I then went to the Vihtavuori site, which gives me a Start of 39.4gr and a Max of 45.7gr for the same bullet.
Q1. Do different sources generally vary so much with their data?
Q2 Is there a load data source that is generally regarded as some sort of a 'bible' regarding load data?

I appreciate that this can be a dangerous business, and it's start at the bottom and work up.
After discovering what I consider to be such a vast difference in data though, I am wondering whether to believe what I read.
All answers/advice is greatly appreciated, and Thanks in Advance
Click to expand...

If you are new to reloading and working up loads, then the advice already given is sage and provides good guidelines to work within. Also, make sure you are familiar with pressure signs so that you know when to stop firing the rounds you have loaded if the rifle starts to tell you the charge is maxing out. Cratered or flattened primers, primers backing out, witness marks on the case head - you should make yourself familiar with these and more. I am sure others more knowledgeable than me can add to this.

Safe reloading.

Mark
 
markyw said:
If you are new to reloading and working up loads, then the advice already given is sage and provides good guidelines to work within. Also, make sure you are familiar with pressure signs so that you know when to stop firing the rounds you have loaded if the rifle starts to tell you the charge is maxing out. Cratered or flattened primers, primers backing out, witness marks on the case head - you should make yourself familiar with these and more. I am sure others more knowledgeable than me can add to this.

Safe reloading.

Mark
Click to expand...
Black sooty streaks along the fired case indicates insufficient obturation and potentially dangerous loads that are too light.
 
Pressure signs!
If you can't lift the bolt handle back off a grain.

It depends of the cartridge and rifle.
My Winchester 94 operates at pressures that are way off high pressure signs so I have to follow book closely but your standard bottle necked cases in turn bolts you have a pretty good envelope of safety.

In other words, don't worry unless you are using very fast powder for calibre and or bullet weight. For instance if you use a fast powder for a light bullet combo then later visit heavy bullets but hope to use the same fast powder some caution may be required!
 
Robby56 said:
Hi All,
Just getting into reloading, and hoping for a bit of advice from those who are far more knowledgeable than me. (i.e. you lot) 🙂
I was researching loads for .308 win 150gr Sierra SBT Gameking using N135 and came across the XXL reloading site. This gave me a Start load of 34.1gr and a Max of 40.6gr, I then went to the Vihtavuori site, which gives me a Start of 39.4gr and a Max of 45.7gr for the same bullet.
Q1. Do different sources generally vary so much with their data?
Q2 Is there a load data source that is generally regarded as some sort of a 'bible' regarding load data?

I appreciate that this can be a dangerous business, and it's start at the bottom and work up.
After discovering what I consider to be such a vast difference in data though, I am wondering whether to believe what I read.
All answers/advice is greatly appreciated, and Thanks in Advance
Click to expand...
Use load data produced by powder manufacturers, bullet manufacturers or from well established publications. They well have tested them thoroughly including pressure testing etc.

But there are a huge number of variables.

1) cases - not all cases are by any means equal. If you measure a few different brands, say PPU, RWS, Federal etc you will find quite a difference in the weight of the brass. Some have thicker walls than others which will affect case volume, thus pressure and powder amount needed to produce a certain velocity. Different sources of load data will use different cases.

2) barrels vary, test rigs vary etc etc. the only real consistency is for everyone to use the same test barrels - but they don’t.

Does this really matter? Not really. The whole point of reloading is to develop a load tuned for your rifle. Provided you work consistently, use an appropriate powder recommended for your cartridge and work the load up you should be fine. If you start getting a sticky bolt handle you are getting too much pressure so don’t go any further.

But modern rifles are built for and proofed at pressures well above what you can achieve with typical volume of a case and a normal rifle powder. A rifle will start showing pressure signs well before you reach critical pressures.

The dangers come from ultra fast pistol powders. These burn fast and it is perfectly possible to put enough pistol powders in say a 243 case for it to then let go.

Only ever take one powder at a time out to do reloading. Make sure other powders are not lurking in powder measures etc. (the valve can trap enough powder to cause major problems but the hopper is empty - there have been a number of cases where a reloader has been using pistol powder, emptied the hopper, filed it with rifle powder, and then started loading rifle cartridges. The first case however gets a full charge of pistol powder and cabooom).

And don’t follow loads suggested on the internet, especially if you do not know the individual who is posting.
 
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