Large difference in max 10mm loads for Unique?

[Trey Veston]

In developing loads for my new 1911 10mm, I wanted to try a couple of Unique recipes since it performed well in my Glock. I went straight to the Alliant website and they showed a charge of 8 grains max for the 180gr Speer GDHP.



I am using 180gr Hornady XTPs. I haven't seen Speer GDHPs for sale for years. I loaded up two recipes using 6.0gr and 7.3gr. The pistol preferred the 7.3gr.

So tonight, I am up in my reloading room and wanted to crank out some more of the 7.3gr rounds, and thought I'd try something a little hotter; around 7.8gr. I pulled out my Hodgdon book and was surprised to see them list only 6.8gr of Unique as the max load for a 180gr bullet.



I looked in another reloading manual and they list 6.5gr as max load.

Why such a huge disparity? Speer Gold Dots are a JHP, right? Same as the Hornady XTP. So what is the difference? I fired the 7.3gr loads and the pistol did very well with them.

 

[crestoncowboy]

Hornady book lists less though.

 

[crestoncowboy]

As far as disparity there are some huge ones. Myself and RC had a long private chat on how bad 44 magnum was off in some manuals. Lol.

I use blue dot for my heavy 10mm. I use a ton of unique with my plated and cast 180s though.

 

[Trey Veston]

Just all over the place. Spent casings at 7.3gr show no signs of overpressure. Pretty sure I'm safe. Maybe I'll try some at 7.0gr and see how they do. Best group so far is 1.25" at 25 yards. Hoping to hit 1", but am happy so far.

 

[N555]

Gold dots are a plated bullet. Should stick with plated bullet data which is usually milder than jacketed bullet data.

Yeah the speer13 manual has some pretty enthusiastic loads.

 

[ms6852]

There will always be disparities between manuals, I've learned that for me and for safety reasons, that if I am using hornady bullets I follow the hornady manual recommendations, if using Nosler bullets I follow Nosler manual and so on. If all manuals offer the same powder I feel safe using the manual that uses the most powder on a load without going to max loads.

 

[Charlie98]

Why such a huge disparity? Speer Gold Dots are a JHP, right? Same as the Hornady XTP. So what is the difference?

The differences are in bullet construction, and/or the testing parameters each respective manufacturer generated data from. As ma6852 says... it's best to follow data for the exact bullet you are intending to load, and even then, the same bullet from 2 different data sources may very well be different. The devil is in the details, however... when looking at things like barrel length, primer, and other factors. Data from two or more different sources are very rarely an apples vs apples comparison, even when using the same bullet or powder.

 

[Charlie98]

I am using 180gr Hornady XTPs. I haven't seen Speer GDHPs for sale for years. I loaded up two recipes using 6.0gr and 7.3gr. The pistol preferred the 7.3gr.

So tonight, I am up in my reloading room and wanted to crank out some more of the 7.3gr rounds, and thought I'd try something a little hotter; around 7.8gr. I pulled out my Hodgdon book and was surprised to see them list only 6.8gr of Unique as the max load for a 180gr bullet.

For what it's worth, I have the new #11 manual from Hornady... the charge weights for the 180grn XTP and Unique are 5.8grn to a max of 7.1grn, loaded to 1.260". It is the slowest listed load, BlueDot being the fastest. There are 9 other powders listed...

 

[Trey Veston]

I ended up just trying two new Power Pistol loads, lol. 8.6gr and 9.0gr.

 

[Charlie98]

I ended up just trying two new Power Pistol loads, lol. 8.6gr and 9.0gr.

For the sake of conversation, the new Hornady manual gives a start and max of 6.8grn to 8.4grn, with the 180grn XTP and PowerPistol.

As Riomouse says... stay safe.

 

[Trey Veston]

For the sake of conversation, the new Hornady manual gives a start and max of 6.8grn to 8.4grn, with the 180grn XTP and PowerPistol.

As Riomouse says... stay safe.

WTH?? The Alliant site specifically sets max load for 180gr JHPs at 9.3.

 

[GeoDudeFlorida]

WTH?? The Alliant site specifically sets max load for 180gr JHPs at 9.3.

Different bullets. Use the table data for the bullets you’re using, not some generic, unknown part.

Try doing a search on the forum for previous threads about reloading tables and variations in charges. There have been at least one or two a month for years. Possibly decades.

 

[Howa 9700]

Can't speak for the 10mm load data, but in 9mm, there are all kinds of different loads for same or similar bullets and most of the time the seating depth used is different.

Very evident for Sierra 125 gr JHP. And in 9mm there are also three standards being loaded to......standard or minor......+P and +P+. Some load data swerves into +P range without actually saying so. Speer load data comes to mind. But they show up as wildly different load data.

 

[Howa 9700]

As to Unique.......another thing I have noticed is in the Lee manual, for "generic" 124 grain jacketed bullet........for most powders the OAL is the same, yet for Unique and some of the other large flake powders, the OAL is greater. I assume that is to accommodate the extra volume?

 

[Alaskamike]

10mm data definitely seems to vary more widely than data for other calibers. I strongly suspect it's due to some 10mm guns having less chamber support than others, so one data source may be setting their max pressure to be safe in all guns, where another is going by SAAMI max pressure.

This would be a good one to call Hodgdon (or others) and ask them about what pressure they limited their testing to, and why.

 

[AJC1]

Loads can change over time and testing methods. One would think it would not be problematic with a new cartridge like 10mm. Older cartridges are crazy. 357 and accurate #9 is all over the map. I deal with this by listing out all the loads and playing in the overlapping areas of charge weight. Disregard areas with no secondary support high or low... I prefer at least 3 sources.....

 

[Charlie98]

there are all kinds of different loads for same or similar bullets and most of the time the seating depth used is different.

That's why I mentioned that the devil is in the details of each set of load data... seating depth is a big one.

Another thing to consider when trying to use different bullet's data.... is the velocity envelope the bullet manufacturer wants it to be driven to. Speer and Alliant is a very good example of that, using the .45ACP as an example....

The Speer 230grn CPRN (Copper Plated Round Nose) bullet shows a max load of 7.3grn Unique. There is no way on this planet I would load that heavy, but the data is there.
The Speer 230grn TMJ RN (Total Metal Jacket Round Nose) bullet shows a max load of 6.5grn Unique. What's the difference between the CPRN and the TMJ bullet? According to Alliant... a lot.... based on the load data.
The Speer 230grn GDHP bullet shows a max load of 6grn Unique... limiting velocity to a mere 800fps.

So... even bullets from the same manufacturer, with the same general construction, tested with the same powder, can have different data sets. Then there is Hornady, that seems to lump all their bullets into one data set, which may explain why Hornady data is seen as conservative... or 'watered down' by some.

10mm data definitely seems to vary more widely than data for other calibers.

I think that may stem back to the original Norma 10mm loading, which was reported to be quite hot, and then a reduced version, that wasn't quite so robust.

 

[Walkalong]

So tonight, I am up in my reloading room and wanted to crank out some more of the 7.3gr rounds, and thought I'd try something a little hotter; around 7.8gr.

That’s a lot hotter

That Speer manual shows 7.2 start to a max 8.0, so a jump from 7.3 to 8.0 is a large one

 

[Trey Veston]

For the sake of conversation, the new Hornady manual gives a start and max of 6.8grn to 8.4grn, with the 180grn XTP and PowerPistol.

As Riomouse says... stay safe.

I believe the older manual had it at 8.5gr for max. In any case, I'm going to go ahead and try the 8.6gr loads in the 1911, and then shoot the 9.0gr loads in my Glock G29 with the KKM barrel just to be safe. Thanks for letting me know. Apparently, the new Hornady loading manual is only available online if you pay $1 per caliber, or subscribe to the app for $20 per year. The hardcover manual is $40, so I'll get one purchased.

 

[GeoDudeFlorida]

In developing loads for my new 1911 10mm, I wanted to try a couple of Unique recipes since it performed well in my Glock. I went straight to the Alliant website and they showed a charge of 8 grains max for the 180gr Speer GDHP.

View attachment 1181807

I am using 180gr Hornady XTPs. I haven't seen Speer GDHPs for sale for years. I loaded up two recipes using 6.0gr and 7.3gr. The pistol preferred the 7.3gr.

So tonight, I am up in my reloading room and wanted to crank out some more of the 7.3gr rounds, and thought I'd try something a little hotter; around 7.8gr. I pulled out my Hodgdon book and was surprised to see them list only 6.8gr of Unique as the max load for a 180gr bullet.

View attachment 1181808

I looked in another reloading manual and they list 6.5gr as max load.

Why such a huge disparity? Speer Gold Dots are a JHP, right? Same as the Hornady XTP. So what is the difference? I fired the 7.3gr loads and the pistol did very well with them.

Keep in mind when comparing Gold Dot data that it’s a thick-plated bullet, not a lead-core copper jacket bullet.
Also keep in mind when comparing XTP-HP data that they are long for their weight, thanks to the very deep hollow point. Sierra tends to use very thick jackets and softer, more dense alloy materials, which is why they tend to have data on par with Nosler. However, Sierra does testing on shorter barrels, on average, than Nosler. Lyman’s molds are calibrated for 5-5-90 Alloy or Linotype.
The front chapters of many manuals explain their testing methods and how to interpret them.

 

[sparkyv]

These and other reasons are why I (you too, likely) work up my loads.

10mm data definitely seems to vary more widely than data for other calibers.

Loads can change over time and testing methods

That's why I mentioned that the devil is in the details of each set of load data... seating depth is a big one.