Reloading Data

[Myrradah]

Alright,

So i have 3 different sources for reloading data.
Sierra
Lyman
Hornady

Now, all 3 have different values for 6.5 CM 130 grain Varget.

is it a good rule of thumb to follow the manufacturer of the bullets data over the others?

Varget:
Hornady - 130 Gr ELD match bullet

Hornady data - 35.5 - 38.2
Lyman data - 32.5 - 34.8
Sierra data - 40.5 - 43.8

H4350
Sierra - 140 gr SMK

 

[bocefus78]

Posted before OP listed the charge weights: The standard safe answer is to start low and work up. Take the lowest of the 3 and start your ladder loading there.

Edit to add: that is a very large swing between the 3 with sierra min being over the other 2 max. I'd double and triple check that data, but my above answer still applies.

Paging @Aszerigan

 

[Michigan Slim]

I use bullet manufacturer data or listed info for that bullet whenever possible. Different bullet construction and materials change things, sometimes dramatically.

 

[edwea]

My Hornady and speer manuals show the sierra load to be the outlier. The sierra charge weights do correspond to some of the slower burning powders though. Keep in mind that errors exist in books, even ones for reloading. You're doing it right by checking multiple sources. Fwiw, hodgdon online shows your first two ranges to be close.

 

[2tonic]

Personally, my first source is the powder manufacturer. They know their burn rates, regardless of what brand of bullet you put on top.

In general, however, you can't go wrong with the "start low and work up" strategy.
Just make sure to watch for the obvious signs of overpressure.

 

[Myrradah]

Personally, my first source is the powder manufacturer. They know their burn rates, regardless of what brand of bullet you put on top.

In general, however, you can't go wrong with the "start low and work up" strategy.
Just make sure to watch for the obvious signs of overpressure.

this makes sense, thanks for the thought.

 

[Jarvitron]

My rule of thumb is - When in doubt: follow the powder manufacturer's loading not the bullet manufacturer, which aligns with Lyman.

 

[Paul 7.62]

I go with bullet manufactures data, having talked to the Sierra's people and Berger people. I may not start out at the beginning or starting load but a quick 10 shot ladder test to see if I have any problems with a powder and record velocity, case head expansion, primer condition, and look for ejector marks. Case head expansion is the most telling as any movement over 0.0005" is a over pressure load. I use a blade micrometer and record case heads before and after. Powder charge increments depend on case volume, 0.2 for small cases, 0.3 for medium case and 0.4 for large cases.

As to using different data, bullets make the difference using Sierra's data with Hornady bullets is not smart. Bullet ogive, hardness, and driving band all make up pressure curve and each bullet will behave differently.

 

[Trapper Jim]

Bullet manufacturer data is first to source. There are so many variables in crafting loads.

Some things are never explained. Take typos for instance. I on more than one occasion have corrected data with sources over the years.

Then, the mysterious. I burnt a lot BlueDot for my .41 Mag days knocking over steel Rams at 200 Meters. Then, for no explanation, sometime in the late 80’s, Hercules unapproved BlueDot for .41 Magnum loads. They still offer it for .357 and .44Magnum.

To this day I have not found anywhere in print as to why Alliant did this. Was there a bad batch that tested wrong? Did someone in the field have a mishap? We may never know but consider this.

51st Lyman book still shows a BlueDot load. I notified them but the conglomerate is just too big to care I guess. Even though, it performed well for me, I took the recall seriously and stopped using it all together.

Thank you for your post and good luck in the field.

See you on the range

Trapper

 

[Paul 7.62]

Some times bullet makers drop powder because they can not get it or demand is low for that powder. Other reason is newer powders are more appropriate for the bullet.

 

[BE Mike]

Bullet manufacturer data is first to source. There are so many variables in crafting loads.

Some things are never explained. Take typos for instance. I on more than one occasion have corrected data with sources over the years.

Then, the mysterious. I burnt a lot BlueDot for my .41 Mag days knocking over steel Rams at 200 Meters. Then, for no explanation, sometime in the late 80’s, Hercules unapproved BlueDot for .41 Magnum loads. They still offer it for .357 and .44Magnum.

To this day I have not found anywhere in print as to why Alliant did this. Was there a bad batch that tested wrong? Did someone in the field have a mishap? We may never know but consider this.

51st Lyman book still shows a BlueDot load. I notified them but the conglomerate is just too big to care I guess. Even though, it performed well for me, I took the recall seriously and stopped using it all together.

Thank you for your post and good luck in the field.

See you on the range

Trapper


View attachment 326631

How old is that reloading manual? I don't think that pressure has been measured by C.U.P. for decades.

 

[Virch]

That looks like Lyman 50th. I have the same edition and there are rounds were CUP is listed instead of PSI.

 

[Trapper Jim]

How old is that reloading manual? I don't think that pressure has been measured by C.U.P. for decades.

51st edition printed Jan 2022

 

[Chewie]

I use Gordon's Reloading tool (software) as a check.
Almost every bullet (info from mfg).
Many powders (info from mfg)
And lots of variables to enter (brass trim to length, COAL, etc.) Shows ladder test expected pressures, expected vel, etc. Does a ton of stuff. A little difficult to understand and use but predicted information is plentiful.
Give it a look see, another reference to use.
Some reviews are on YouTube.

And it's free as well.

 

[Paul 7.62]

Pressures are still listed in CUP as data might be from different sources. Hodgdon lists both in their manuals, Hodgdon powders are listed as CUP and Accurate Powders are listed as PSI. It all depends on the pressure barrel used. Copper Units of Pressure uses a copper slug that fits the chamber, and is placed a specific location per SAAMI specs, the cartridge is fired and the slug is measured with a very accurate micrometer the measurment is looked up on the tables on the copper slugs giving you the CUP.

For a better explanation go here: https://saami.org/wp-content/upload...rfire-Pistol-Revolver-Approved-12-13-2022.pdf

 

[BE Mike]

51st edition printed Jan 2022

So they publish the same old data if it has been proven, over the years, to be safe?

 

[Trapper Jim]

So they publish the same old data if it has been proven, over the years, to be safe?

Good question.

 

[Paul 7.62]

They test some powders and if a company changes powder composition then it is tested, but lot of times old data is used. Writing and testing load data is expensive, and if they can reuse old data they do. Test barrels, and fixtures, electronics, and firearms are not cheap. Plus the time that goes into testing, labor wise, notes, pressure trace output, copper crushers, and equipment to measure is not cheap, plus recertification of micrometers and transducers. All loads they show are tested in a gun before publishing. If they find a problem they will do a pressure test in a fixture. A simple high quality blade micrometer can help you measure pressures. It's not as accurate as their tests but I have found it close.