Vote for 270 powder not sensitive to temperature

[rjfunk]

Hey all,

I live up in Canada so temps go from -25 to 90 F. looking for a powder that is not sensitive to temp changes for my 270 Win. I've tried RL22 with good results when it was warm (consistently less than MOA), but now when it got to freezing, the groups seem to open up. :banghead: Read from others that their MV changed 130 fps from summer to winter (Idaho) so that could explain some of it.

Looking at these powders (and other suggestions) to try next. Bullet is 130 SST and gun is Browning A-bolt with 22 in barrel.

H4831sc
H4350 (some say this is more of a barrel burner?)
Ramshot Hunter
RL17 (less temp sensitive than RL22?)
Others???

Anyone had experience with these in temp changes?

Thanks.

 

[ArtP]

I own a .270 and from everything I've read RL22 and H4831 (not necessarily the short cut) are the top powders.

I use RL22 but have considered trying H4831.

I'm not sure why RL17 would be on your list but not RL19?

Most powder makers claim insensitivity to temp and I'm skeptical of all those claims.

 

[Ridgerunner665]

Hodgden's Extreme line of powders are great (H4350 is one of them)...Anybody skeptical should test for themselves.

And I'm not sure why H4350 would be considered a barrel burner...RL 22 is VERY temp sensitive, I haven't used RL 17.

 

[rjfunk]

"I'm not sure why RL17 would be on your list but not RL19?"

Art, I listed RL17 because it "claims" to be temp insensitive, and it also gives a higher muzzle velocity than RL19.

"And I'm not sure why H4350 would be considered a barrel burner"

Ridgerunner, I'm not sure either, I read that in another forum, and thought maybe it had something to do with the burn speed of the powder?? Or maybe it was just someone saying something they didn't know about.

 

[Ridgerunner665]

The 4350 burn speed has been around for a loooooong time...if it didn't work it would have been replaced long ago.

 

[gamestalker]

I started with IMR-4350 and stayed with it for about 20 yrs. with no complaints in any temparature setting from summer deserts to high mountain cold winter's. And then I gave H1000 without problems, RL19 is where I am now and think it is probably the best performer. But that's a hard call against IMR-4350 because I killed so many deer, elk, and antelope with that powder.

 

[ArtP]

Art, I listed RL17 because it "claims" to be temp insensitive, and it also gives a higher muzzle velocity than RL19.

I have other sources, but the three I use most are Hornady 7th, Sierra 5th and Lyman 49th. None lists RL17 as viable with 130g .277, but all list RL19 and RL22. From Hornady, RL19 & RL22 are capable of 3100, Lyman says RL22 will do 3173 while RL19 will do 3066. With Sierra, the discrepancy is 2900 vs. 3100, RL22 more velocity.

Sierra lists RL22 as being the most accurate and best for hunting, from all the powders listed. Lyman favors H4831 as the most accurate.

If it would help I will give charge weights. Actually, I could scan the pages and post a flikr link.

I never shoot below 40F, so temp sensitivity isn't as important to me.

 

[NCsmitty]

If you go to the www.hodgdon.com and the www.alliantpowder.com and look over the different products offered, you'll see that some, not all of the Alliant powders will say if they are unaffected by temp extremes. Rel-15 and Rel-17 are mentioned as insensitive to temps. Of course Hodgdon lists a bunch of "Extreme" powders for that use.
Only IMR 8208 XBR powder is listed as unaffected by temperature extremes, in the IMR line.

Just take the time to research the powders that will give you what you're looking for.

You'll find that leaving your ammo setting out in the sun, or on your dash, will affect pressures, regardless of being an "extreme" powder or not.


NCsmitty

 

[Grumulkin]

IMR 8208 XBR is supposed to be very insensitive to temperature changes.

 

[rjfunk]

Art, the Alliant website lists max 54gr under a Speer 130 BTSP (which is one of the other bullets I use) for a MV of 3136 fps out of a 24" barrel.

If you have the sierra and lyman pages, sure that would be great to post them. Thanks.

 

[rjfunk]

NCSmitty,

Thanks, I've read on those sites, but I'm just looking for some real world experience. Everyone seems to make claims, I'd sure like to know who is actually performing as they say. That's why I included RL17 in my list but not RL19.

 

[ArtP]

Here's the Sierra info I already had in digital form. I'll scan the Lyman page in a bit. I'm not going to make a new post with the Lyman info. Rather I'll add it to this post.

 

[rjfunk]

Thanks very much Art. It's really good to see some other load manuals. It's interesting to see that Sierra's max for RL22 is 1.8 grains less than Lyman and my Lee manual. I might have to get a Sierra manual to compare loads. I did work up to 59 grains in summer with no pressure signs, so my gun seems to accept a little more than the Sierra max.

 

[ArtP]

I can go 59 on the RL22 myself and I get the best accuracy at 58.0-58.6, depending on other factors. I've noticed, generally speaking, Hornady lists the hottest loads, followed by Lyman, then Sierra the mildest. Hodgdon's website tends to list on the mild side too.

For about $7, Midway sells a small book that is caliber specific, that gathers pretty much all published load data and puts it in one place. The data is kinda old and the print quality is horrible, but it's a cheap way to get pretty much all load data for any one caliber.

http://www.midwayusa.com/product/630977/loadbooks-usa-270-winchester-reloading-manual

 

[Kevin Rohrer]

Isn't Varget temperature insensitive?

 

[ArtP]

Isn't Varget temperature insensitive?

If it is indeed insensitive, as is claimed, it's really not among the best powders for .270 unless one is using extremely light bullets.

I don't really get a chance to test in extreme cold, because of my location. However, if I were faced with that issue, I just might develop a warm weather and a cold weather load that is identical with the exception of a 1/2 to 1 grain powder charge variation. I would find that less work than actually redeveloping a load, buying another powder, etc.

 

[Old Shooter]

Just wondering how much of that grooup size opening up at -25 degrees could be the difference in expanison coefficients between the wood stock and the metal action/barrel?

Seems like the bedding and tension from the mounting screws would be different at the extreme temperature variance.

If it was me shooting poor groups at -25 degrees I'd just blame it on my shiverin"!

 

[gamestalker]

I've chronographed my .270 loads for many years with various powder's and RL19 and IMR-4350 both produced nearly identical velocities with near maximum charges, if that helps?

More specifically, the 130 gr. Speer Hot Core BT's @ 3,000' elevation during the hot summer months, both powders were in the 3,150 fps range.
At 7,000' elevation during cold winter and same weight powder charges, velocities were just over 3,200 fps.
I've pretty much settled with RL19 now days though and mostly because it seems a little easier to manage pressures with when approaching max. charges, except when I loaded the IMR-4350 charges compressed.

But this is from my rifles, and all barrels/chambers are different of course, and other variables such as brass and general reloading methods can have major effects also. Browning A-Bolt II BOSS, Remington 700's, Savage 110, and a Winchester 70 mountain rifle or ultra light something, don't remember what it's labled.

 

[bobnob]

H4350 (which is called AR2209 down here) is one of the most temp tolerant powders available, and is great in the .270 Win especially with the 130g bullets.

Give it a try.

 

[TGReaper]

I have found that IMR 4350 is not particularly temperature sensitive. I use it in some loads for 5 different calibers.
It has performed very well in my Win.FWT with a 22 in.bbl.
I also am lucky enough to live in Manitoba.
TGR

 

[ArchAngelCD]

Depending upon what bullet you are using I would suggest either H4350 or the slower H4831. Both are in the Hodgdon Extreme Powder line which are very temperature stable. I think you will be very happy with both.

 

[rjfunk]

Just wondering how much of that grooup size opening up at -25 degrees could be the difference in expanison coefficients between the wood stock and the metal action/barrel?

Seems like the bedding and tension from the mounting screws would be different at the extreme temperature variance.

If it was me shooting poor groups at -25 degrees I'd just blame it on my shiverin"!

My groups went from consistent sub moa to more than 4 inches at 200 yards. it was about 20F or so. We Canadians don't shiver much at that temp, so I don't think it was me! (I did try to make is shot as consistent as possible)

I've completely free floated the barrel, but there could be other temp changes affecting the gun.

 

[rjfunk]

Sounds like H4350 and IMR4350 are the winners. Is there a big difference between them? Is IMR4350 from the extreme powders as well? The IMR is a couple of $ cheaper than the H here, so it makes we wonder a little bit.

 

[Ridgerunner665]

They are not the same...IMR is not in the Extreme line.