Old recipe deemed Unsafe in new manuals. Suggestions?

[Rich Coyle]

Despite having better measurements, guns have been safely using these loads for years.

This causes me to question the "unsafeness" of the apparent arbitrary "safe" max.

 

[asd9055]

Lyman 46 Edition, 180 grn bullet, IMR4350 71-79 grns (at 79 grns I had 5 shots, 1/2" back in 80's through 1998 when I reitred the rifle)
Lyman 49 Edition, 180 grn bullet, IMR 4350 68.5-73 grns
Nosler Number 3 180 grn bullet, IMR 4350 73-76 grns
Nosler Current (Number 7 to now) 180 grn IMR 70.5-74.5 grns
Like I said, I am very safety minded and will work up again, but if powders have not changed, did primers change that much?

 

[MagnumManiac]

The problem is that the powder switched manufacturers. DuPont no longer exists.
Therefore, there is no way to extrapolate what is safe with old lots of IMR powder to new lots…the recipe may have even changed when the new manufacturer took over.
I am not saying that your old load might be different or dangerous, just check it out by working up.
When IMR powder was available here, it said DuPont on the tin, I had a really old batch and a new batch. The old batch was producing velocities 150fps slower than the new batch and it popped primers on testing at the old powder max. Something on the order of 6g more powder would have been necessary to get an additional 150fps with the old powder. This needs to be taken into account.

Cheers.

 

[asd9055]

The problem is that the powder switched manufacturers. DuPont no longer exists.
Therefore, there is no way to extrapolate what is safe with old lots of IMR powder to new lots…the recipe may have even changed when the new manufacturer took over.
I am not saying that your old load might be different or dangerous, just check it out by working up.
When IMR powder was available here, it said DuPont on the tin, I had a really old batch and a new batch. The old batch was producing velocities 150fps slower than the new batch and it popped primers on testing at the old powder max. Something on the order of 6g more powder would have been necessary to get an additional 150fps with the old powder. This needs to be taken into account.

Cheers.

Thanks Magnum. Yes that old powder did say Dupont. Now it is made (or maybe just marketed) by Hodgdon. What you are saying makes sense even though Hodgdon says they did not change the powder. I still have two old tins made by Dupont (IMR4350 and IMR7828. They look and smell fine, debating whether to use or keep as "antique")

 

[MagnumManiac]

Despite having better measurements, guns have been safely using these loads for years.

This causes me to question the "unsafeness" of the apparent arbitrary "safe" max.

I still run loads from the 80's and 90's in quite a few of my rifles.
I have 3 338WM rifles, all get their best performance using RE19….the load I use is 4g over max in 1 manual and 6g over max in another. Have ran that over the Pressure Trace and it is still under max pressure for the cartridge. One rifle, my Kimber Select is 100fps faster than the other 2 and it is just under max pressure but it shoots so good there I'm not gonna change it.
This is just one example, I have several others I use in various other calibres that are just as safe.

Cheers.

 

[MagnumManiac]

Thanks Magnum. Yes that old powder did say Dupont. Now it is made (or maybe just marketed) by Hodgdon. What you are saying makes sense even though Hodgdon says they did not change the powder. I still have two old tins made by Dupont (IMR4350 and IMR7828. They look and smell fine, debating whether to use or keep as "antique")

Just a heads up for you, Hodgdon have never made ANY powder, they simply buy it and repackage it with their name on it.
All of their Extreme powders; H4895, Varget, H4831, H1000 & H50BMG & Retumbo are all made here in Australia by ADI/Thales.
IMR was sold off when DuPont closed it powder manufacturing. St Marks used to make all Winchester ball powder, that too was sold off as it was government owned.
It's not easy to trace who makes powders these days, but the Swedes and the French have a major stake in it.

Cheers.

 

[DUSTY NOGGIN]

The reloading data which I still have lists a max load at 102 grns of Retumbo. Hodgdon's site now lists max at 92 grn for the same load combination. I've using the same over max load for 21 years out of the same factory barrel and I'm still shooting between a half and 1 MOA...

what weight ??

 

[243winxb]

IMR (Hodgdon) claims the powder has not changed.

In its chemical make up. No change. Been using IMR 4350 for 243 win, many many years.

What does change is lot to lot variation, as much as 10% . This is from the fasted to slowest lot.

A chronograph may help. Sold mine in the 70s.

 

[243winxb]

try the load in a few others I have. (

Work up.

 

[robpiat]

Every chamber and brass and die is different. I have loaded to 10-15% over max and consistently had no pressure issues and I have had rifles/brass where I had to stay way lower than book. Use your noggin. I would load only 5-10 rounds in 1 grain increments and chrono them and see how it looks.

 

[Dankno]

As others have rightly said; work up to it in your rifle.

My 280 Ackley load uses a pile of Enduron 8133 powder with the bullet seated very long into the throat (Nearly 3.5" COAL) It shoots well, has very low SD, and produces velocities that I am after. But you'd likely never find it in a manual.

 

[JMB 1911]

first the French having a major foot hold in powder manufacturing make me nervous

Second I blame the Lawyers but please let us know if you can still use you old data I am very curious

 

[raider1v1]

what the other guys are saying makes sense. have you thought about calling them and asking? i have found all of the manufacturers to be VERY helpful on the phone with reloading support.

 

[Buster***]

u said it all right there (tin can) Dupont no longer exist that powder as we new it was good back in the day but it's re-loaders responsibility to keep up to date manual for the bullet he or she is shooting in the last few years i have never seen the new powder and bullets being produced as they are today it's ruff keeping up. have a good day i have rattled enuff.