Temperture effect on H 380 powder in reloads

dannej

HI,
I have heard that H 380 is 'temperature sensitive'. I have a reload with this powder in .22/250 that shot .25 and .30 groups when I first worked it up last summer. Now I usually get .6 to 1.0 groups and the temperature is averaging 30 to 40 degrees colder then when I worked it up. Would this change in temp cause this much change in group sizes? I have some suspicions of my scope.

Thanks in advance,
Dan

RobOz

What primer are you using? I have always used magnum primers with ball powders and have never had a problem. I was always told that ball propellents are harder to ignite with colder temps and a magnum primer will help. Have you chronographed the load?

MG1890

30 to 40 degrees?

Lots has changed. For instance, are you wearing a coat now? Might not be the load causing issues. Benchrest, clothing, firing pin lubricant, who knows.

dannej

Not using mag primers, have not chronographed the loads. It may be me although my bench rest is very solid. Thinking I may not have the patience for this bench rest shooting with center fire.

Thanks for the info.

MG1890

What was the rifle and optics?

Consistent .25 to .3 groups is extremely difficult to maintain unless you have top quality equipment.

charliemeyer007

Back in the day I had loads for winter. They were used for cold bore shots at zero and below. Rounds will pick up heat from a hot chamber very quickly. Loose or blown primers could be the result.

I would think your second or 3rd sting should settle down if the time in the chamber and between shots is consistent. A cold barrel is stiffer and vibrates at a different frequency.

243winxb

Try some magnum primers.

Mobuck

If rifle and ammo are going straight from warm storage to range, there shouldn't be any diff.
The rifle I keep outside year round for coyote control shoots ball powder(WC846) and I'm using magnum strength primers. No noticeable change in performance between 80* and -10*.

dannej

Rifle is a Cooper mdl 22 and the scope is a Bushnell Elite 6.5-32X40. Scope would change the strike of the bullet when magnification was reduced. Also when adjusting it up it would move right as well as up. Put on a Vortex 6-20X scope and the worst flyers went away, but still didn't get 1/4 inch groups. I think this shows the scope had problems and so did I. I suspect when I did everything right I got the smallest groups, but I rarely did everything right.....

MG1890

Dan, not to sound like a know it all, but could the difference in groups be due to human error?

Okie743

Not to sound like a know it all but IMHO:

Probably that old junkie Bushnell Elite scope.

I would consider giving you maybe $30 for it just so I can recycle the plastic and aluminum and get it out of your way. (and you pay the shipping)
If I find out it's not the scope then might make you a offer on the temperature sensitive gun. (barrel may be warping with temp changes)

By the way: That powder you are using is what I call firecracker powder and it don't even make consistent ignition when used in firecrackers from one day to the next. I have some other powders on my firecracker list that I won't list now that will group consistent one day and not the next and vice versa. (and I did not get this info out of a book, the experience with firecracker powders came from bench rest testing)Some powders even leave dirt in the barrel when they burn.
Don't hurt the messenger!

People helping people with their problems and accuracy issues.

243winxb

Hodgdon discontinued H450 powder for a reason. H380 should follow it. Hard to light and temperature sensitive. IMO.

guntech59

I use IMR 8208 XBR for my 223 and 22-250. Very consistent powder and very temperature tolerant.

Cheechako

Everyone already knows this but, air temperature has very little effect on ballistics. It's the temperature of the powder that makes all the difference. When I was a lad I was given some good advice by some of the old guys. It went, KYPIYP. That means keep your pecker in your pants. The same can be said about ammunition, especially when hunting. KYAIYP. Keep your ammo in your pocket. If you are called on take a quick shot without having time to load a couple of temperature stable cartridges, you are probably going to miss anyway.

JMHO

243winxb

I have had H450 start burning with a mag primer in the 22-250 cartridge and then just stop for no reason. The bullets did not even move. This is when i stopped using H380 & H450.

dannej

More great information! Sounds like I was right in thinking it was a scope problem, a powder problem and me not doing my end all the time.

Thank you everyone!

charliemeyer007

I had ignition issues with the old surplus H110 even with mag primers. Regular primers and a duplex load solved the issue, but I never bought any more of it once it was gone.

Generally I like ball powder especially in mag rifles.

FrancF

Yes it is sensitive especially when using mag primers. I have seen a few Rem 700's in .22-250 take a hit with 35.5 H380 (55gr blitz king) and a mag primer on a 90 degree day. I have backed mine down to 34.2 and it keeps it in a safe zone on very hot days and High volume varmint hunting.

Okie743

I generally stay away from ball powders for rifles.

I've seen some ball powders that would group different if the rifle barrel was pointed up and then different point of impact down before firing. Powder against the primer vs powder away from the primer. Some leave what looks like dirt in the barrel after each shot.

Mobuck

If you are called on take a quick shot without having time to load a couple of temperature stable cartridges, you are probably going to miss anyway.

Methinks you don't hunt coyotes much.

lostriver1

Dan,its maybe just the fact its a lot colder outside. my groups get a lot worse in the winter. your body gets cold and you cant hold as good. in the winter the frist 2 groups are most likey my best