Old recipe deemed Unsafe in new manuals. Suggestions?

[RD57]

Don't forget that most producers of reloading manuals are now using up to date piezoelectric pressure sensors which are a more objective method of measuring pressures, bores and chambers are often minimum spec which reduces volume and increases pressure. Throw that in with what everyone else has said and you can find some huge differences in what used to be the norm and what is now considered max. This is not the universal finding though, I have reached velocities published in Alliant's reloading data a couple of grains before getting to their max load. Even though reloading components are difficult to find right now please don't take short cuts on the safe work up process in your firearms.

 

[esshup]

I think the OP will be just fine if he chrono's the old loads that he has loaded up and works up a load with the new powder.

I start low and work up when switching lots of powder, you never can tell how a new lot will perform. That's why I buy powder in big containers once I find a load that the gun likes. I don't have to work up new loads often.

 

[jerry moore]

i have been reloading since early 80s i use nosler manual, the most chge i have seen maybe 1 gr less than max, i load most cals 223 to 300wm i look at diff manuals not seeing anything that drastic, if i do definitely work up to desired load

 

[TRexF16]

Maybe I missed it but I never saw the OP post the actual cartridge and load he is wanting to use. I have the current Nosler, Hornady, and Sierra load manuals and would be happy to quote what they say for IMR if I knew the cartridge in question.

Cheers,
Rex

 

[jerry moore]

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?

 

[Clem Bronkoski]

You'll find this to be common with the ludicrous lawsuits out there. Those of us that have been reloading a long time have seen this over and over. I personally have been reloading for over 55 years and saw this a lot. IMO, if your rifle handles your pet load without pressure signs stick with it. Manuals or only guidelines and a listed max load MAY cause pressure signs in some rifles and, like in your case, be easily handled in your rifle.
I still load what today would be cause for alarm and criticism from new loaders because they believe that manual listed loads are gospel, even down to the brass and primers used. But for new loads it is always a good idea to start at the recommended manual starting loads.

 

[jerry moore]

i use manuals that produce bullets

 

[skipglo]

Personal Injury lawsuits

Absolutely correct. I said the same thing in another thread!

 

[asd9055]

Thanks for all the replies.
I was surprised by the drastic reduction in charge from one year to another. I did call Hadgdon (they market IMR powders) when I first noticed it, and I also email them and have their reply in writing. As some said, always friendly. The response was, no, the Formula has not changed, how ever ability to measure pressures, case capacities, bullets and primers, all those components changed.
Like I said early on, and several of you sugested as well, being safety minded, I will start with the new guidelines and work up.
Again thanks for all the responses.

 

[timo308]

Check to see if both manuals are loading to the same max pressure limit (C.U.P.).

 

[asd9055]

Maybe I missed it but I never saw the OP post the actual cartridge and load he is wanting to use. I have the current Nosler, Hornady, and Sierra load manuals and would be happy to quote what they say for IMR if I knew the cartridge in question.

Cheers,
Rex

You didn't miss it. I just did not want to get sidetracked with caliber and bullet choices.
Thanks.

 

[asd9055]

Check to see if both manuals are loading to the same max pressure limit (C.U.P.).

Very interesting suggestion. Neither Nosler, nor Lyman report pressures.

 

[Clem Bronkoski]

Yup it's a general reference. Burn rates can be slightly different for powders lot to lot. Brass capacities can change slightly. Even bullet dimensions can slight change from design, or due to forming dies being reformed. In the case of monos whether on cnc lather or swiss machines the dimensions are only as good as the operator checking the dimensions. Heck even temperature change can alter the dimensions during production. Same is true with forming dies on standard cup and core bullets. All this can affect pressures. As can a carbon build up in the bore.

Working in quality control for almost my entire career I will agree that powder burn rates from lot to lot may differ and also bullet dimensions from lot to lot as well as primers. HOWEVER, all of these components, including brass have tolerances that must be maintained in order to pass inspection and released for use. Manuals are written with these changes in mind and for safety lean toward the low end of the spectrum.
In this case using IMR4350 I am quite positive that the burn rate today is the same as it was when the powder originally hit the market (within its tolerance). If the powder's burn rate changes significantly it would have been given a different designation and new data developed for it.

 

[Veteran]

Out of curiosity, was the max load you were shooting a compressed load?