Thread: Testing a conventional approach to load development

Is there any evidence of anyone ever experiencing a dangerous pressure issue when loading the correct powder within book loads?


It probably is wise to be conservative if you're shooting a vintage rifle or a cartridge that isn't a modern bottlenecked case.

Originally Posted by gimp

Is there any evidence of anyone ever experiencing a dangerous pressure issue when loading the correct powder within book loads?


It probably is wise to be conservative if you're shooting a vintage rifle or a cartridge that isn't a modern bottlenecked case.

Greetings @gimp,
I do remember one reported on the forum a few years back where a max load had blown up a rifle. From memory there were two contributing factors. First the data was for a much softer projectile and second the action, although considered strong, was 100 years old.
To me older data, especially where there the actual projectile is not listed, is always suspect. In other cases the speed of the powder has been changed for whatever reason. I believe that the max load in your work is one of these. The Hodgdon/ADI data lists a max load of 44.5 grains of AR2209 in the .260 with the 142 grain Sierra HPTBT for 2,735fps. It also lists 42.9 grains max of AR2209 with the similar 143 grain Hornady ELDX for 2,759 fps at slightly higher pressure. To me something is screwy here. The 44.5 grain load dates from 2,000 or earlier and AR2209 was sped up around 2,002 and the Hornady ELDX post dates that.
I discovered the speed change in 2019 when working with the 6.6x55. Fortunately I had enough of the old lots of AR2209 and my old chronograph records so I could document the speed change. Your 44.5 grain load should have produced a little over 2,600 fps in your shorter barrel but I suspect you may have got about 2,700 fps. There have been suggestions that AR2209 has been slowed slightly since I purchase the lot I tested in 2019 but still leaving it faster then the 2,000 stuff.
I have posted about this load and change previously so my apologies for any repetition.
In answer to your question above. Is it dangerous? Probably not but the pressure will likely be higher than the 60,000psi book max.
Regards Grandpamac.

Originally Posted by gimp

Is there any evidence of anyone ever experiencing a dangerous pressure issue when loading the correct powder within book loads?


It probably is wise to be conservative if you're shooting a vintage rifle or a cartridge that isn't a modern bottlenecked case.

In a nutshell, that’s the question I’m asking. Bearing in mind that there will be new reloaders reading this, it deserves clarification, including me.
Let’s assume, when you say modern bottleneck cartridges, we’re covering rifles from the last fifty years or so. Do we ignore chamber differences and assume, even if we load to max, that nothing untoward is going to happen? No real damage and maybe the worst that’s going to happen is a stuck bolt or just some brass issues? Is this acceptable now?

Originally Posted by Sidetrack

In a nutshell, that’s the question I’m asking. Bearing in mind that there will be new reloaders reading this, it deserves clarification, including me.
Let’s assume, when you say modern bottleneck cartridges, we’re covering rifles from the last fifty years or so. Do we ignore chamber differences and assume, even if we load to max, that nothing untoward is going to happen? No real damage and maybe the worst that’s going to happen is a stuck bolt or just some brass issues? Is this acceptable now?

Common sense still applies. If you find yourself experiencing pressure signs, reduce the load.

Originally Posted by Sidetrack

In a nutshell, that’s the question I’m asking. Bearing in mind that there will be new reloaders reading this, it deserves clarification, including me.
Let’s assume, when you say modern bottleneck cartridges, we’re covering rifles from the last fifty years or so. Do we ignore chamber differences and assume, even if we load to max, that nothing untoward is going to happen? No real damage and maybe the worst that’s going to happen is a stuck bolt or just some brass issues? Is this acceptable now?

Ignore this, can’t seem to edit. GPM raised the 260 load data issue and you’re gone part way to explaining your thinking. The chamber differences still bug me but if they’re still within tolerances can we assume we’re still ok? I ask this as I was getting bolt lift issues at the bottom end of powder charge when loading for my 270. It was my first handload so I was being conservative but it stuck with me, hence the questions.

Originally Posted by Sidetrack

Ignore this, can’t seem to edit. GPM raised the 260 load data issue and you’re gone part way to explaining your thinking. The chamber differences still bug me but if they’re still within tolerances can we assume we’re still ok? I ask this as I was getting bolt lift issues at the bottom end of powder charge when loading for my 270. It was my first handload so I was being conservative but it stuck with me, hence the questions.

Two 270s get loaded for from my bench.one is near top of book load,the other sits between start and midpoint. No way would I load for the second rifle and hotter. Possible a short throat/ jump till pill hits rifling is the difference. If you look at Weatherby rifles of old( not sure of new ones) they had quite a spacewalk for projectiles which allowed a longer burn and higher charge perhaps? The new hypersonic shotgun rounds work on similar principle. By allowing payload to start moving forward it sort of increases the volume of the case....hopefully that makes sense??? It's why seating deep increases pressure,smaller volume.