Risking an overpressure by crimping a full case

[neoconfection]

I was loading some .223 last night with a Barnes 55gr TTSX and 25gr of IMR 3031. I know that 3031 is not ideal for .223, but it's the only powder I have more than a pound of currently, and there was load data in my manual for that powder. 25gr of IMR 3031 leaves you with a very, very full case, just under the case mouth, and there's the distinct crunch of powder when I seat the bullet of a compressed load.

I'm concerned that having a very full case might create more pressure than normal, and crimping will make it dangerous. I don't know if this is unfounded or not, so I'm asking here. It needs to be crimped because the expanding powder is increasing the COL.

Thanks in advance!

 

[Eagleye]

In my experience, 3031 can be heavily compressed without any unusual results [i.e pressure spikes]
You should have no issues with that load in your 223.
Crimping should have little effect on the final outcome.
However, if that 25 grain load is listed as max, you should be starting from a couple of grains below that
just to be safe.
Regards, Eagleye.

 

[neoconfection]

Thanks, Eagleye. The load range is 24-27gr so it's well under the max.

In my experience, 3031 can be heavily compressed without any unusual results [i.e pressure spikes]
You should have no issues with that load in your 223.
Crimping should have little effect on the final outcome.
However, if that 25 grain load is listed as max, you should be starting from a couple of grains below that
just to be safe.
Regards, Eagleye.

 

[Al-Sway]

I have fired thousands of rounds of .223 with 55 grain and 25 grains of 3031. No problems with pressure or case life. Biggest problem is handling the full cases until the bullet is seated.

 

[Boomer]

Thanks, Eagleye. The load range is 24-27gr so it's well under the max.

Its under max in the barrel that was used to attain the data. Your barrel might prove to be something else, and you won't know until you've worked up the load whether the max for your barrel is the same, a bit higher or a bit lower. Start at 24 grs, and go up in half gr increments, then stop when pressure signs begin to show in the brass. Warning signs are when the bevel between the primer and primer pocket disappears, when the primer flattens, when the web of a previously fired case expands .001", when your chronograph tells you your velocity matches the max load in the manual. Don't rely on a sticky bolt as a fail safe.

As for the suitability of 3031 in a .223, it is pretty much right in the middle of acceptable powder burn rates. I always seem to have 3031 on hand, but won't use it in my .22 centerfires, preferring ball powder in those small cases (I dislike compressed loads) but there is no reason not to expect good results from it. If you seat to the cannelure, crimping tends to uniform bullet pull weight, and enhances accuracy when the bullet can't be seated with an optimum jump or jam to the lands. I'm unaware of any incident where crimping a bullet with a canneulure, or a crimping groove, has led to a dangerous pressure spike with a properly trimmed case.