H-380 pressure spikes
- Thread starter 240wby
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What do you mean by "pressure spike"? Every pressure curve has a "spike". Do you mean that a load that seemed fine in cold weather exhibited "pressure signs" when shot in warm weather? That all seemed fine and then with one more grain it was not?
All double base powders can be considered temp sensitive but the U.S. military loads the vast majority of its small arms ammo with double base ball powders.
On top of this the British double base cordite powder used in the British .303 had more nitroglycerin in its mixture than many double base pistol powders have today.
So how many WWI and WWII vets have you heard complaining that their Enfield .303 ammunition was temp sensitive.
On top of this the British double base cordite powder used in the British .303 had more nitroglycerin in its mixture than many double base pistol powders have today.
So how many WWI and WWII vets have you heard complaining that their Enfield .303 ammunition was temp sensitive.
This was more like a detonation...froze the bolt, after getting it open the brass was literally stuck to the boltface...this was on a 700 Rem, the brass had actually flowed into the extractor groove and it had to be machined out on a lathe. That is some serious pressure and it has happened twice, about 2 years apart. Fired brass shows no obvious pressure signs. This load chrono's at 3730. He is no longer a H-380 fan and has since started using H-4350.
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I've used quite a bit of H-380 in my 7mm/08 and 22/250. I've never experienced anything like what you have said. In fact I find it a great powder in the mentioned calibers and several other calibers.. What took place in your case is very serious pressure. Could there be some other unknown factor that is overlooked causing this.
Purple shoulder
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Ive burned several pounds of 380 in my 22-250 and I've never had any issues. I've run some pretty hot loads and even let them cook in a hot chamber and never any surprises.
I have loaded the Swift with H380 and 55 grain bullets since 1972 or so. Never had anything like what you are describing.
My load has been slightly stiffer in most cases though, around 43 grains, although one rifle would not take more than 41 grains.
It is still my "go-to" powder for bullets above 52 grains in the Swift and the 22-250.
I am thinking that there is some factor being missed here. H380 is not prone to spikes, in my experience. [about 45 lbs burned]
Does he weigh all his charges, or is he dropping them from a measure? Since they generally meter so nicely, it is easy
to get complacent with sphericals. They can bridge, despite their free-flowing characteristics.
As mentioned, H380 is somewhat temperature sensitive, but would not normally cause the very high pressure indications you
have described. I'll bet the "hot" load did not chrony at 3730!! Regards, Dave.
My load has been slightly stiffer in most cases though, around 43 grains, although one rifle would not take more than 41 grains.
It is still my "go-to" powder for bullets above 52 grains in the Swift and the 22-250.
I am thinking that there is some factor being missed here. H380 is not prone to spikes, in my experience. [about 45 lbs burned]
Does he weigh all his charges, or is he dropping them from a measure? Since they generally meter so nicely, it is easy
to get complacent with sphericals. They can bridge, despite their free-flowing characteristics.
As mentioned, H380 is somewhat temperature sensitive, but would not normally cause the very high pressure indications you
have described. I'll bet the "hot" load did not chrony at 3730!! Regards, Dave.
My friend is his 3rd barrel with the same load. He is a veteran handloader and reasonably prudent. But the lumpy stuff happens. How full is your case with the 41-43 grain load? He says he drops light and trickles. H-4831 will do exactly as above with a half charge. Maybe H-380 does too...and that "hot" load definitely exceeded velocity specs. Phil
I had the opposite problem with H380 in the 22/250. Loads developed in the heat of summer went to crap in the winter. Accuracy left, velocity plumetted and you could pour unburnt powder out of the barrel. Life's too short, and shots at coyotes too far apart to bother with it.
It isn't much of a stretch to picture pressures going through the ceiling in hot weather, especially if you were riding the ragged edge to begin with. That's sort of the nature of Swift shooters.
It isn't much of a stretch to picture pressures going through the ceiling in hot weather, especially if you were riding the ragged edge to begin with. That's sort of the nature of Swift shooters.
I recall a post here or on another forum about a mysterious excessive pressure case. Forget all the details, but the thread went on and on with all kinds of the usual suggestions as to what it was. The OP even sent cartridges back to the powder manufacture for analysis, but the problem was there were some that had high pressure and some that didn't. The thread went dead, and weeks, months, or perhaps even a year later, the OP came back and admitted what happened. He was loading a fast powder like pistol and dumped the remaining fast powder from the measure back into the original container of rifle powder, and as a result ended up with two canisters of powder, one of which was contaminated with some very fast powder, and the other one good. The contaminated powder was erratic and produced high pressure, as one might expect.
I took it as a reminder to always be super careful about getting powders mixed up.
My Fav 22-250 Rem Load has always being 40 grs H380 - CCI BR sparker loaded with a 50-55 gr Bullet ! Never a problem in summer or winter - RJ
Google WC852 and WC852f. The new H380 is not a surplus powder. Different lots, perhaps? Did he finish 1 can and move to a new batch?
