cast bullet load data

[markgna]

I was told that you can look up data for a similar weight bullet load an substitute it if you dont have the correct cast load data for the bullet you want. what is the safest way to do this? look up the next heaviest bullet and start at the minimum charge and work up? how do you know when you have reached max?
thanks
Mark

[303Guy]

I do that. Not just with different boolits but different calibers. That bit is not so simple and takes a bit of cross checking and double checking and heaps of caution.

The is a sort of formula for correcting for chamges in boolit weight. It's a case of percentages; reduce the powder charge by the same percentage difference in bullet weight then start with minimum and work back up.. As to when to stop - I can't explain. It's like reading tea leaves. I read primers. In an auto one can start low enough to not fully cycle the gun and work up until the gun cycles reliably and drops the cases in a neat pile just next to you.

[badgeredd]

All of the loading manuals I've read have a section that explains a lot about "reading" your cases. Because I have loaded for several wildcats, I have learned ways to get data that is somewhat close to what I need for the cartridge. It is prudent to use caution when loading ammo so using a similar bullet for data and using the starting loads is pretty safe, reducing the start data by a bit is even safer. I generally will go to the next heavier bullet and use the start data for it. I've never had a problem. Just use common sense and be safe after all you are shooting a device that utilizes a controlled explosion. Nuff said?

Edd

[Larry Gibson]

That is generally the accept method if you are working up loads in the usually manner.

If you are just substituting the load data and are using the "max" load then problems could easily arrise. This is not recommended or an acceptable method. It's always best to work up the load in your fire arm as per accepted practices.

Larry Gibson

[stubshaft]

Usually you will find your best accuracy with loads before you reach the max loadings. When I find the load that groups the best I stop.

[fredj338]

There is no "formula" for substituting cast for jacketed. Yo uhave to work it up. Yes, using starting jacketed data is fine for lead bullets of same wt, just don't expect the vel/pressure numbers to be the same.

[ku4hx]

I own dozens of loading manuals going back to 1970 or so. Every one of them has a section on working up loads. For me, the best of the bunch has always been the Lyman Cast Bullet manual and Lyman Load manual. Don't remember the editions since I have every one Lyman published starting circa 1970.

If you don't have a comprehensive load manual, you need to get two or six. Much better reading that a lot of stuff I see now days.

[tuckerdog]

+1 on what ku4hx says about manuals. Cross referencing different weights and calibers can work but be careful!!!! powders like H-110/W-296 have a very small window from starting to max, case design and volume play an important roll for powders like these. B.I.Bs and pressure spikes can occur VERY easily using the wrong data. Buy all the manuals you can afford. In many cases you will find none of them will list what you are looking for, in these cases call the powder manufacturer/importer most of them will be only too happy to help.

[runfiverun]

if the boolit has a similar bearing surface and shape, and the powder covers both the lighter and heavier weights.
i'll go with it.
the bearing surface/shape because it usually takes up the same amount of room in the case.
and the powder covered by both weights is showing that it is flexible enough and usually has low enough pressures to keep it from becoming erratic.

[Recluse]

Agree with everything said so far.

I always, always, always work UP to a load--with the exception being powders like H110 / W296 that call for near max loads all the time. Good reason for that, too.

Some reloaders, especially new/novice/inexperience get overly worried about not seeing a load for a "154.5 grain .358SWC" lead boolit. The key is to stop and think for a moment. Lots of data for 158 grain boolits. Check the percentage of weight over/under for the boolit you're loading.

For the fictional boolit I made up above, we're only talking less than 3% weight difference, and as runfiverun states, so long as the design and bearing surface are similar, then check out the charge data for 158 grain boolits.

Key is to always work up to the load and never start at max.

A trait a good handloader learns early on is patience. Too many want to start off with unknown boolits or projectile/powder/primer combinations and go with max or close to it.

Work up to the load.

[RevGeo]

When in doubt, start low. You can always carefully go up. It usually doesn't work too well to start too hot and then go down...just sayin'.

[oscarflytyer]

One caution - at least for me. With cast, there are some RN vs SWC bullets that are the same weight. However, if you look at the diff bullet designs, the Rn will typically have more bullet mass inside the case, and thus decrease the case capacity. For example, I have safe loads for a 255 grn SWC, but am very reluctant to use that date for a 265 grn RNFP bullet, as it takes up almost twice the case space as the SWC...

I am sure I would be safe using the lowest starting loads of the SWC for the RNFP, but haven't started the project yet.

[markgna]

Agree with everything said so far.

I always, always, always work UP to a load--with the exception being powders like H110 / W296 that call for near max loads all the time. Good reason for that, too.

I am loading h110 that is why i was asking for some more info. I have 13 manuals and no loads for the bullet i want 280 btb wfngc in a 45 colt FA M97

[geargnasher]

296 is a tough one. Hodgdon/Winchester says not to reduce maximum loads more than three percent for starting. Personally, for the .45 Colt +P loads of that boolit weight I tend to prefer 2400 because it's easier to work with.

Pay particular attention to what has been mentioned already about differences in boolit designs of similar weights affecting pressures due to seating depth and bearing surface. Copper jacketed bullet load data is rarely "interchangeable" with cast data due to vastly different friction/engraving dynamics, especially with magnum handgun powder.

Hopefully 44Man or someone else with lots more experience than I have will weigh in here on your specific situation.

Gear

[runfiverun]

this is exactly a scenario where the narrow window makes things difficult.
i would have to go by how much case capacity the seated boolit leaves compared to a 270 & 300 gr boolit.
if it is close i'd use that data to start with.
the problem with h-110 isn't putting too much in it's not getting enough in.
if you can find data for a 270 gr boolit of the same profile that'd be the place to start.
i'm thinking you should be in the 22-23 gr range.

[leadman]

Just call hogdon powder and ask the tech. Did you check the on-line info on Hodgdon's website?

They list data for the 260gr and 300 gr. since you are using a 280gr I would split the difference between the 260 and 300 starting load and use this.

[jandbn]

I could not find H110 load data for purchased boolits in my Ruger Bisley 45 Colt 5 1/2" when I first bought it, so I gathered data to extrapolate from reliable sources which contained pressure data (one data source being Linbaugh) with boolits of similar weight and bearing length in the case when seated. After calculating the volume of a known load's powder space, the volume can be calculated for a particular boolit. Using Lee's Volume Measure Density of H110 and the charge weight along with the loaded case volume of the known load, the unknown charge weight can be calculated as a percentage of the known load . Please note that extrapolation is not exact science and does not by any means take the place of a pressure tested load!

Below is a charge weight/velocity graph for extrapolated data in MY GUN with a Montana Bullet Works 280 LFNGC. This data should only be considered an example. Your results WILL NOT be the same due to all the variables involved. Each charge weight data point was either a 10 or 12 shot string. As has been mentioned elsewhere and can be seen in the graph, H110 has linear pressure increase. I saw the same linear pressure rise when I used extrapolated data for an MBW 300 WFNGC. **However, during H110 load workup of one combo which I don't remember off the top of my head, my starting load was too low. When shooting the starting load, the sound was not the the nice "crack" of a load with one more grain of H110; I was below the pressure required for that particlar charge weight/boolit combo to burn correctly!

[1Shirt]

Yep, starting loads and work up. Kind of reminds me of what an old time reloader told me years ago. He said that reloading ammo, he compaired to driving a car!
He said, that even tho the car might be capable of doing 110 mph, it probably wasn't safe, but at 50 it was safe, and burned less gas. Still holds true today for me. I also have found that seldom do I find the most accurate loads to be at or near the max charge level.
1Shirt!