Old recipe deemed Unsafe in new manuals. Suggestions?

[asd9055]

Back in the 80's I had a recipe with IMR4350 from Lyman's 46th edition that gave me less than 1/2", 5 shots at 100 yards. According to the book, it was at the Max, but no pressure signs. Used this until late 90's when I retired the rifle.
I like to shoot that rifle again and perhaps try the load in a few others I have. (Its a Magnum round with Remington 9 1/2 Large Rifle Primer, not the magnum primer)

Current loading manuals (and for apple to apple conparison, Lyman's 49th edition) have the Max at a full 6 grains lower. IMR (Hodgdon) claims the powder has not changed.
Should I start at the much lower load and work my way up again? I hate to burn supplies in these market conditions, but Safety is ALWAYS Rule #1.

 

[Jud96]

I would start low and work up. I personally would chronograph the old load and see what the speed was. Then I would work up with the new lots of powder until you hit that speed and you should be good.

 

[asd9055]

I would start low and work up. I personally would chronograph the old load and see what the speed was. Then I would work up with the new lots of powder until you hit that speed and you should be good.

I had loaded 10 rounds with the old recipe (new powder), was about to go try them, then the little safety guy in my head kept nagging me, so I stopped. I think I still have a box of the old loads, I will try those. And work up with the new.
Thanks

 

[GLTaylor]

Agree! I've got loads in my journal from 20+ yrs ago that now are overpressured. Didn't used to have a chronograph, so no idea what velocities were back then.
Something has changed? Primers, powder formulation? Don't know.

 

[xsn10s]

Back in the 80's I had a recipe with IMR4350 from Lyman's 46th edition that gave me less than 1/2", 5 shots at 100 yards. According to the book, it was at the Max, but no pressure signs. Used this until late 90's when I retired the rifle.
I like to shoot that rifle again and perhaps try the load in a few others I have. (Its a Magnum round with Remington 9 1/2 Large Rifle Primer, not the magnum primer)

Current loading manuals (and for apple to apple conparison, Lyman's 49th edition) have the Max at a full 6 grains lower. IMR (Hodgdon) claims the powder has not changed.
Should I start at the much lower load and work my way up again? I hate to burn supplies in these market conditions, but Safety is ALWAYS Rule #1.

I'd start low and work your way up. I recently did that with a rifle that I've owned for over 30 years. 308 Win with an old load that I pressure tested on an Oehler back in 2008 or so. Started lowerish and got pressure at a mid level load. 168 gr going 2820 fps using IMR 4064 that I hand trickled. I used to be able to go to max loads with no signs of pressure. Something changed of which I have yet to figure out.

 

[Triple BB]

I bought a 300 RUM back 2000. 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...

 

[asd9055]

I bought a 300 RUM back 2000. 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...

Thanks. That is good to know

 

[P7M13]

Agree! I've got loads in my journal from 20+ yrs ago that now are overpressured. Didn't used to have a chronograph, so no idea what velocities were back then.
Something has changed? Primers, powder formulation? Don't know.

Personal Injury lawsuits

 

[bluedog69]

Personal Injury lawsuits

Beat me to it. Was gonna reply lawyers, and societies "get what I deserve/get my big money" attitude.

 

[P7M13]

Beat me to it. Was gonna reply lawyers, and societies "get what I deserve/get my big money" attitude.

Your reply better describes the change.... The attitude that, "I will be taken care of...." Sound familiar to today's hollow promises from the gub'mint?

 

[FrogFire7]

While that IS confusing (and frustrating!), Remember that reloading manuals are a "general reference". You still are going to custom build a load for your specific rifle. The manuals just give you an idea where to start and generally where the upper end of pressure may be. But that "depends" on a LOT of factors they can't take into account. Personally, I'd work up until you hit pressure (shooting over a chronograph), then take your last flat spot in velocity before pressure signs and use that to start shooting groups. Good luck!

 

[xsn10s]

While that IS confusing (and frustrating!), Remember that reloading manuals are a "general reference". You still are going to custom build a load for your specific rifle. The manuals just give you an idea where to start and generally where the upper end of pressure may be. But that "depends" on a LOT of factors they can't take into account. Personally, I'd work up until you hit pressure (shooting over a chronograph), then take your last flat spot in velocity before pressure signs and use that to start shooting groups. Good luck!

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.

 

[xsn10s]

I would start low and work up. I personally would chronograph the old load and see what the speed was. Then I would work up with the new lots of powder until you hit that speed and you should be good.

Pretty sound advise there. Sounds like the OP is already going to do this.

 

[marchboom]

New, more accurate methods were discovered to measure pressure and some loads were found to be over pressure. That and lawyers have caused the loads to be reduced. But who knows, the reduced loads may be more accurate.