Compressed load question

[Mr_Flintstone]

To what ratio can IMR 4227 be compressed? I’ve loaded a lot of 357 magnum with this powder, and many have been compressed, but I was just wondering if there was an upper limit to the compression. Reading on the internet, I see people saying they load from 105-110% regularly. Just wondering.

 

[Demi-human]

Make some trial rounds up, just how you would make any other round, with the various levels of compression. Put these in an ammo box and take them to the kitchen. Put them on the counter then on top of the fridge. Then put them on your night stand for the night. Take them in the truck to town, then back to the loading room.
Remeasure all the rounds. Some may have pushed the bullet back out, through the pressure and the vibration of moving around.
Pull the rounds. The ones that didn’t move might pull very easily, suggesting recoil might jump the crimp and bind up the cylinder.

Somewhere in there is the maximum you’ll be comfortable with compressing. It’s not a set number.
Hope that helps some.

 

[Mr_Flintstone]

Make some trial rounds up, just how you would make any other round, with the various levels of compression. Put these in an ammo box and take them to the kitchen. Put them on the counter then on top of the fridge. Then put them on your night stand for the night. Take them in the truck to town, then back to the loading room.
Remeasure all the rounds. Some may have pushed the bullet back out, through the pressure and the vibration of moving around.
Pull the rounds. The ones that didn’t move might pull very easily, suggesting recoil might jump the crimp and bind up the cylinder.

Somewhere in there is the maximum you’ll be comfortable with compressing. It’s not a set number.
Hope that helps some.

Thanks. I guess it does vary by cartridge and crimp type. I never thought of it that way before.

 

[Cheesemaker]

I just finished loading up 100 rounds of 44 mag with 22.4grains of IMR4227 behind a Hornady 240gr XTP. After the bullet is seated there is no space left in the case - could not say if there was a tad of compression or not. The Hornady max for this is more than one grain higher than my load - that will compress. How much I don't know. I will put them in the fridge and see

 

[Highland Lofts]

I started reloading again about four ago after a forty year break.

I never felt comfortable making compressed loads.
At this stage of the game I'll stick with non-compressed loads.

 

[AJC1]

The limit of some powders is how bad your seating stem deforms the bullet. How much neck tension you can generate would also be a limiting factor. I like full loads but stay away from truly compressed. Some of my 223 varget loads are crunchy and that's plenty.

 

[Demi-human]

Some of my 223 varget loads are crunchy.

Ditto. That’s just how I like it.

I’ll take this time to state we are all talking about published loads, that happen to be compressed. But the reason they are compressed loads is they are a slow for cartridge powder. They are still within pressure limits, and they aren’t more dangerous by being compressed, although they might be more inconvenient. An action full of powder is usually at the most embarrassing time.

Some manuals denote a compressed load with a “C”, like Sierra, or an asterisk. Some don’t bother, like Hornady.

Another thing, a compressed load won’t be position sensitive.

 

[Ironicaintit]

With 4227, my experience has been that if it isn't compressed, it's not going to be happy.
A roll crimp and a heavy bullet help it along too.