Can we trust Lyman Cast Bullet Handbook

[modoc]

Well Pat, I'm a youngster who keeps looking for more info with my hobbies, of course for me the reloading and casting are just preludes to the main events . My son will be learning the joys/frustrations of the reloading presses also. It will just take a few more years, since he's only two . He wants to do everything that Dad does.

BTW, which part of the Golden State are you in?

[sundog]

No,

Gee, I have to add words to make is past the reqiured 5 letters.

The answer is still no. So, while I'm at it, I am not, nor have I been impressed with lyman data for a very long time.

[sundog]

btw, would I buy the new manual? No.

[PatMarlin]

Well Pat, I'm a youngster who keeps looking for more info with my hobbies, of course for me the reloading and casting are just preludes to the main events . My son will be learning the joys/frustrations of the reloading presses also. It will just take a few more years, since he's only two . He wants to do everything that Dad does.

BTW, which part of the Golden State are you in?

Welcome to the board Modoc... I'm just down the road from you on Hwy 36- this side of the great South Fork Mountain Ridge.

Right now I'm emailing from my little RV trailer out side of a fixer upper house we just bought north of Happy Camp, on Indian Creek.

You know Chris Cummin's over on Dodson Lane in Anderson? I see you guys are in the same field. He's a Cal Trans engineer.

[Paul5388]

Paul B,

If you look in the 1964 DuPont image I posted above, the max load of 4895 was 51.5 gr for a 150 gr bullet and it's posted as 51,000 psi for pressure.

I have several cans of DuPont powder produced in the 1980s that were made in Canada. IMR just bought existing facilities and/or contracts.

[Paul B]

Paul B,

If you look in the 1964 DuPont image I posted above, the max load of 4895 was 51.5 gr for a 150 gr bullet and it's posted as 51,000 psi for pressure.

I have several cans of DuPont powder produced in the 1980s that were made in Canada. IMR just bought existing facilities and/or contracts.

That's all well and good. Most manuals give a max load for IMR-4895 in the roughly 51.0 grain range. My rifle will not come close to 51.0 gr, let alone 51.5.
The point of my post was the load that did work had to be cut by two full grains. The lot of IMR-4895 I had must have been faster burning by quite a bit to have to cut back that much.
I'm trying to remember where I read about the change in materials for making the nitrocellulose, but I do believe the current IMR powder are somewhat faster burning than when made by Du Pont.
I don't know how to copy something and post it in a message, but the latest printed version by IMR shows 49.5 gr. of their 4895 to now be a max load at 50,000 C.U.P. That's a 1.5 gr. cut from your 51.5 gr. and suspiciously close to the 2.0 gr. cut I had to do. Methinks that dies signify that 4895 is now faster burning than before.
Maybe we'd both better tcheck out thier online load data for that powder.
As a propellant, 4895 has a mixed history. I've never been able to figure out when it was first produced other than it was for loading 30-06 ammo. After WW-2, you could buy Milsurp 4895 through the NRA and DCM. Each time you bought some, depending on the lot number, the instruction would say use data for IMR-3031, maybe IMR-4198 etc. Seems like the burning rate ranged from 4198 to 4320 depending on the lot. Good stuff, but you never knew what the next lot# would bring. Finally Hodgden bought up all there was and blended it into one big lot and Du Pont started making it for civilian use and the two batches were close enough that the data was, for all practical purposes, interchangeable with the Hodgden's version only very slightly slower. I burned up enough of all the above to have a good working knowlege of the powder. I've burned a lot of 4895s in the last 53 years, but now use it mostly for my cast bullet shooting.
Paul B.

[billt]

All loading manuals fluctuate in data. I have the Lyman 45th Edition Manual from the very early 70's and have used many of the loads in it that are in fact "overloads", by the more modern manuals, even Lymans. None of these loads have ever given me any problems. Today everything has to be "lawyer proofed". This makes a lot of data in these manuals quite conservative. When I want maximum performance from a given rifle or handgun, I will always consult an older manual for reference. The more manuals you have in that regard, the better off you are. Bill T.

[Paul5388]

At some point in time, after Speer #8 was published, IMR and H 4895 used different loading data and in fact, the 8# of Milsurp IMR 4895 I have actually uses something closer to H4895 data.

Speer #8 didn't distinguish between the two brands of powder, treating them as the same powder.

Regardless, I would suspect your rifle has the proper characteristics to produce higher pressure with less powder, rather than a gross difference in the powder.

You also said,

To be perfectly honest, I no longer trust any data in the Lyman manuals that have data marked as C.U.P., nuff said?

and I was merely pointing out the 1964 data was expressed in psi, not cup. Was it actually cup and not psi? Maybe, but transducers were used in the 1960s and a major powder manufacturer would have been more apt to have transducer technology than a re-boxer/distributer like Hodgdon or even a bullet maker like Speer.

Here's some comparison data for a couple of powders I have on hand with about 30 years difference in lot numbers. I used a piece of 6mm R-P brass filled and struck off level with the case mouth and then weighed the amount in the case.
1973 vintage DuPont 4831 48.4 gr
2003 vintage IMR 4831 52.3 gr
1974 vintage DuPont 3031 47.2 gr
2003 vintage IMR 3031 49.7 gr

The new IMR 4831 is very close to being the same as H4831SC which weighed 53.5 gr in the 6mm case. As you can see, volumetrically they are vastly different, but they produce the same results, if a weighed charge is used. Hodgdon says H4831SC loads at the same weight as normal 4831, it just takes up less space.