Unique vs TightGroup load ratios????

[bangerjim]

I cannot find Unique. I have lots of TG ( and others).

There are some cal's that U is listed but TG is not. I built a little spreadsheet and grabbed data from Lyman CB book using known starting loads for the two powders as an example:




Unique
4
4.4
4.1
5
3
5.4
4.5
4.6
4.5
3.7
3.7
4.0
4.2
8.9
7.5
8.6
6.0
7.4
6.3
6.0
4.8
5.6



TightGroup
3.2
3.4
3.3
4
3
4.3
3.6
3.7
2.9
3.1
3.0
2.9
3.2
6.3
5.3
6.1
5.6
5.3
5.6
5.6
3.7
4.4





























ratio
1.3
1.3
1.2
1.2
1.3
1.3
1.3
1.2
1.6
1.2
1.2
1.4
1.3
1.4
1.4
1.4
1.1
1.4
1.1
1.1
1.3
1.3
28.2
























AVG
1.3



(sorry for the cramming, but that's just the way it cuts & pastes into here from Excel. JPG was only 1/2" long!)


The average difference is 1.3gn in the various verified load data. This is from 9, 38, & 45 charts.

TG is a much faster powder....#14 vs #31 according to Hodgdon charts.

Question is, can one use that ratio of ~1.3 as a good starting point for pistol loads that do NOT have TG data but do have U? I know this does not take into account CUP or other factors, but the load data for most pistol powders seems to be within a grain or so of each other anyway. In no way am I proposing anyone use this simple mathematical solution for MAX loads!

I am sure there are others out there that are pondering the same questions, what with the extreme regional scarcity of certain powders on the shelves.

Looking for a little input from those wiser than I in the venue of powder loads.

bangerjim

[bhn22]

No. Follow the manufacturers load data. You can already see by your chart that the ratios are not consistent. There is plenty of data out there for Titegroup, use that.

[fredj338]

There is no linear relationship between ANY powder. Powders burn at diff rates in diff calibers. Faster powders have a more vertical pressure curve, slower powders a more horiz pressure curve. So your assumptions could be catastrophic, follow printed data.
If you are trying to work off the books, then find a powder that is just faster than your powder of choice & use that data as a starting point for working up your loads.

[gray wolf]

No. Follow the manufacturers load data. You can already see by your chart that the ratios are not consistent. There is plenty of data out there for Titegroup, use that.
This ^^^^^ and what the others have said.

[dverna]

BJ

Just call or email the powder company if a load is not listed for TG. I have had really good luck doing that. Many times they have loads that are not published.

Don Verna

[RoyEllis]

I wouldn't use Unique data to work from, but I have had good results using Bullseye starting load data to work up Titegroup loads as they have very close burn rates.

[JesterGrin_1]

I use TiteGroup and I would only use Book information or contact the manufacturer and ask there suggestion for a start load. I will also say with TiteGroup Always work up from the starting load as I have found that TiteGroup will build pressure FAST. And it takes up so little case space one has to be careful not of just double charges but Triple or more. Thus I normally will not recommend the use of TiteGroup.

[bhn22]

I've had great success simply calling the powder manufacturer and asking for help. They want you to be happy, and they want you to be safe.

[bangerjim]

I use TiteGroup and I would only use Book information or contact the manufacturer and ask there suggestion for a start load. I will also say with TiteGroup Always work up from the starting load as I have found that TiteGroup will build pressure FAST. And it takes up so little case space one has to be careful not of just double charges but Triple or more. Thus I normally will not recommend the use of TiteGroup.

To avoid double loads..............I always stuff a boolit in the filled case right after I measure the powder in. That way, there is no chance of doubling up! I guess some guys do a whole tray of powder and then put the slugs in. There are too many distractions for that. That's why the "fill-n-plug" method has always worked for me!

thanks for the TG info!

banger

[bangerjim]

I wouldn't use Unique data to work from, but I have had good results using Bullseye starting load data to work up Titegroup loads as they have very close burn rates.

Your are correct, sir! There are a bunch of BE data that can be used. Thanks for pointing that out.

Mabe someday I can find an 8# bottle of Unique to add to my stores! Singles are just too expensive.


banger

[David2011]

What Jester said. I have used lots of pounds of TG in my .40 for USPSA but avoid it for anything/everything else. The pressure can build very quickly and even changing seating depth a little can make a lot of difference. It seems like pressure rises on an exponential curve if you do any little ting to cause an increase. Just going to a harder alloy can make more pressure.

David

[MtGun44]

BAD IDEA. Drop it and go with tested data.

The two powders use entirely different technology, developed 100 years apart
and burn at substantially different rates, further confounding the comparison.
Pressure changes will change the burning rate of each, at different rates.

Bill

[**oneshot**]

Unique is Unique . Plug your data into a load pressure calculator and you will find it is not linear.

Be safe.