Home Forums Reloading Varmint Rifles H 335 Temp sensitivity

Dump all your H335 out on your best-friend's sidewalk in the shape of a giant dick. Light it on fire and run away.

This will be the best use of that dirty azzed old powder. Also works well with H380.

I've been liking the accuracy and velocity I've been getting out of my 223s with H 322.. it doesn't pressure spike either like H 335 does...

I have never had an issue with 335 or 322 but I have never used a 223 for shooting prairie dogs.

I am really wanting to try some of the CFE223 powder hodgden came out with a year or so ago.

...pressure spikes... I'm not the sharpest crayon in the box but how are you folks determining all of these "pressure spikes"?? What equipment are you using?
When you have a "pressure spike" do you end up with smoking shards of steel sticking out of your head or what? I've been reloading for a lot of years and to my knowledge, I've never had a "pressure spike".

If you have ever shot a 30 round string with some powders the further you get into that string the more likely you are to have primers rupturing. Given the state of firing pin size to firing pin holes on rem 700s it is a wonder that we do not find more little circles of brass in our bolts. I have seen benchmark and BLC2 have what I assume to be pressure spikes when shooting long strings of fire. I do not know the mechanism causing the probable increased pressure other than temperature sensitivity. I really thought everyone would have experienced this at some point.

Apparently some people never shoot more than one round before letting their barrel cool down.

As far as temperature sensitivity goes, a more accurate term might be temperature resistance. EVERY powder gains pressure (and velocity) at temperatures above 70, whether the heat is caused by ambient air or a hot barrel. But powders like Hodgdon's Extremes and some others don't gain as much.

I mostly agree with you on the extreme powders, except H1000. H1000 is considered one of their extreme powders isn't it? Varget has worked well for me as has Retumbo. I know H1000 is popular but I hate that crap.

The reason I assume that it is a lack temperature "resistance" causing the issue, is because I could think of other reasons, but they mostly do not pan out. I have considered increased fouling when shooting long strings, but I guess I should think horses when I hear hoofs instead of zebras.

Eddy,
Kind of surprised about you saying Benchmark was spiking in your post as it is one of the extreme powders. Now I will admit that I am not running max with it but have shot it in 100 - 200 yard group and score matches in 90+ degree days. Haven't really noticed what I would call spiking as in the case of 335.

The problem with 335, and what I call undesirable effects was running max load in a group shoot, temps got to be around 98 and on the 3rd string for agg, 2nd shot I had a extremely hard bolt lift, and a fail to extract. My day was done.
I had shot this load in the same format before, but the temps were in the upper 50's to lower 60's and had no problems.
Thought I had screwed up some how until I ran a test the next day in the same weather and format. It wasn't me as it happened again. Lesson was learned.

I used to use a lot of H-335 as it was a great powder for accuracy in my .223s. After a couple of trips for prairie dogs in AZ, though, I switched to H-322. Accuracy was just as good and "temp resistance" was great. I'm gradually switching to TAC as I use up my stock of H-322.

EddyBo,

What cartridge/bullet combos have you used H1000 in?

In general, temperature resistance "works" better when a powder is used in an application especially suited to its burn rate. Usually this means where the case is full or nearly full when full velocity potential AND pressure level are reached. I don't use a lot of H1000, but have had very good luck with it's temp-resistance in the 6.5-06 with heavier bullets, where the powder charges fit the criteria I just outlined. But I wouldn't expect it to act exactly the same way in the .264 Winchester Magnum with 140's.

The only time I've ever shot 30 round strings, I had little concern with popped primers nor "pressure spikes". Beyond that, I've never shot a 30 round string. Why would you shoot one? And, FWIW, anytime I'm shooting for score or practice, there is indeed a cooling period between rounds. I go by the old rule, if you can't pick the rifle up by the barrel with your bare hand, it's too hot.

338 Edge, 338 Rum, 300WM, 338 Lapua 7RUM tried it several times and several different lots. My issue was always groups would be spectacular one day, crap the next. I dunno if it was temp or humidity swings but something would bring it out of tune. I was also in the group of guys who got one of their fast lots of powder. Like having to back off 4 grains to get back in tune with just a change from one jug to the next. My issues left a bad taste in my mouth for H1000.

Why would anyone shoot a 30 shot string....I mean besides prairie dog shooting? Because it is a freakin blast. I have fireformed 100 cases in a very short span of time on numerous occasions just to reload them for a match the following day.
I have 2 benches in my shooting room. Often me and buddies will race trying to shoot those little light sticks in the dark at 800 yards with the light sticks hung from a string. There are no wagers, just doing it for the hell of it.
Most of us chamber our own barrels and look at barrels as consumables so we are not all that upset if we run a 40 shot string. Often times we are just shooting rechambered take off barrels.
I shot 500 rounds of 300 whisper just as quick as I could shoot them one afternoon just for the hell of it. I have a pic somewhere of a 60 shot sub MOA .223 group fired at 100 yards just as fast as I could shoot them. Was using 55gr bergers and benchmark, which is when I realized that even a very light load could cause popped primers. That would have been a 100 shot group if a piece of brass had not got into my bolt. (If I recall I sold a bunch of ammo with that same load to school marm here. He can probably verify that is is indeed a very light load) It was no big deal, while I had the bolt out I ran over to the shop and bushed the firing pin and went ahead and screwed on the replacement barrel I had already chambered, was just getting the last bit of good out of an old tube. That same 223 has been rebarreled twice more since then.
I have shot barrels so hot that high pressure grease that I use for assembly was smoking and running out around the recoil lug. I have however not seen a barrel glowing hot, but they would sizzle if touched. If I get a barrel that is not up to my expectations I usually shoot them out pretty quickly.
At one time I had a near inexhaustible supply of 66gr benchrest bullets that a buddy had given me. He also gave me about 40 lbs of old 8208 that was a little too slow for benchrest with a 6PPC. To top it off He gave me 6 old HV BR barrels that all had less than 1K rounds through them. I sure had a ball with those bullet and powder and barrels.

stilbeeman,

You would have an interesting time shooting prairie dogs. Even with 2-3 rifles on hand to rotate them when their barrels warm, there will be plenty of times you don't want to grab them by the barrel, especially on July days.

A friend and I were once shooting on a day around 100, and he set the forend of his walnut-stocked .22-250 on fire. No, it didn't starting flaming, but it did start smoking, and we had to use ice-water from a cooler to put it out. I've also seen thin-jacketed varmint bullets either disintegrate in the air (unusual), or their accuracy go to hell when the barrel got too warm (not all that unusual).

Have also seen rounds "cook off" in hot chambers, without benefit of a trigger pull. H335 is a good powder for that.

EddyBo,

It sure sounds like you got a wonky batch of H1000 that time!

It's always interesting when a certain lot of powder varies considerably from others. That's one of the reasons I'm not too fond of H335: In the early 90's, before I learned better, I loaded up some .223's with a long-used charge of H335 and some 50-grain Ballistic Tips.

Turned out the new batch was hot enough to gain almost 300 fps in velocity from the old one, and it popped a primer after three shots. I had to drop the charge 2 grains to match the previous velocity and make everything safe again, a 7% reduction in powder charge. Have never seen anything like that when changing lots of the "same" powder before or since.

A "fun" result of temp sensitive powders can sometimes be seen when shooting long range p-dogs on a hot day. Once the barrel is good and heated up, long distance shots can be seen to impact at different points depending on the time the round is left in the chamber prior to firing. Strangely enough, this doesn't seem to happen nearly as bad now that I quit the poopy powders.

Have seen-and done- all that Mule Deer mentions, plus I got a Remington so hot one day your couldn't touch the floor plate, and its aluminum. You also couldn't hit anything with it at that point, so it got a "time out"

And what John said about rotating guns to cool is a reality, we always take two+ rifles apiece if we anticipate good shooting .

I usually take about 4 or 5

I highly respect both Keith and seafire here. I wish I would have known about the downfalls of H335 before I bought that damn 8 pound keg . I still use it in my .223 rem, but drop down to about 25.5 gr's for my 53 gr v-max loads. I haven't ran into any problems yet, but have heard the same thing seafire explains from other sources. So it's something to be mindful of.

I always shoot for the best accuracy. "Speed kills" only if you can put it in the right spot