Home Forums Hunting & Shooting Ask The Gunwriters Temp stability - RL22, n165, Magpro, IMR7828

Has anyone ever done any testing with the above powders for temperature stability? I remember reading years ago when Mule Deer tested RL22 and got significant POI/velocity changes.

I am looking for a load in my 280ai that is temp stable. I tried some of the Hodgdon Extreme powders, H4831 and 1000, but velocity was not impressive. I kept adding powder to increase velocity and accuracy suffered.

So, has anybody tested RL22, n165, 7828, or Magpro at temps 70+ and down to zero?

I run 7828 in my 257 Weatherby and never noticed a problem of any kind. I started using it when it first became available in the early 80's. I have killed a ton of game with it at all temperatures
below zero to in the eighties.

Add even more powder. It usually works.

Mag Pro works good from 40-100�F. I have no idea what zero is like

Thanks for the replies.

I've gone 3 gr over Noslers listed max with 4831sc and I'm only getting around 2850 fps. Noslers data seems a little bit relative to others so I'm a little weary adding more and more till I get close to 3000 fps.

Reloader 22 has gotten me there velocity and accuracy wise. Last year I shot a mule deer with another rifle when the low was -17. I'm not sure Re22 would have been the best then but I want to use this rifle if I get the chance.

I will admit that I have not used Magpro much in my testing but have used a bunch of RL22, VVN165 and IMR7828 (and the SSC version).

RL22 has been reported by many to be temp sensitive, I have found that to be greatly exaggerated. The biggest problem it has is lot to lot variation, dont buy a one pounder buy a five.

VVN165 is a great powder and as close to RL22 for a burn rate as you will find. Never experienced temp sensitivity issues but never quite got the velocity that RL22 gave.

IMR7828 (and SSC version) is also a great powder with not much in the way of temp sensitivity issues, but is a bit slower burn rate than the other 2.

Not an expert with 280AI, but guessing you could get the highest velocity with RL22, but would try all 3 to see the most accurate in your rifle.

I have found VV N165 to be slower than R22. MagPro would be slower yet but very flexible. I even use it in my 340 Wby with 250s.

If you want velocity, you might also try VVN560.

MagPro is indeed very flexible. I have gotten good results in a variety of cartridges, but have never tested it in real cold. The ballistic lab guys at Western Powders say it isn't all that temp-resistant, but that isn't a concern in a lot of hunting.

In my experience the "traditional" IMR powders like IMR7828 can be pretty good in cold temps, depending on the exact application. The .280AI might be a good one.

I have been told the Norma MRP is the RL22 equivalent but is also less temp sensitive.

I think they are the same damn powder but have never tried it. May be worth the research.

My 300wm is a rl22 junkie with Barnes
180gn TTSX. I have had some consistency issues. It shoots in the winter and opens up in the summer.

Velocity = pressure. Increase charges until you reach published velocities and you will be fine.

That's not exactly true. There are such things as "slow guns" and if you try to reach standard velocities, they will be over pressure limits.

I have a slow gun , a Ruger 7x57 , that you can not get enough 4350 in the case to show pressure........It has a huge chamber , a Loose bore and a mile and half of throat...... Sometimes a slow gun is just gonna be slow. Look for usable accuracy and decent usable velocity, not the velocity someone else tells you there gun gets....
also have a super fast gun , a .260 and with Reloder 17 most people would be eating gun parts to keep up else you knew it had a 30 " barrel Throated a little longer then most.

rifleman 700
You left out one part of the equation:

Pressure is the ability to do work.
Volume is the rate that the work is done.

Example:

308 Winchester 180 grain bullet at 62K psi can never equal the velocity of a 300 Winchester Magnum with the same 180 grain bullet running 62K psi

I don't hunt nearly the drastic shifts in temps that many on the fire hunt but I've not seen the changes in temps that others have claimed as well. Our lows rarely drop into the 20s (but can drop lower) and usually it's more like mid 30s during hunting season. Daytime highs can hit around 80 degrees many days and higher in the summer for sure.

I've put the Chronograph on RL22 with a 6.5x55, 300 Win Mag, and a .257 Weatherby and not seen more than 50 fps in any between the low 20s (super cold here) and the 80s.

I've not had a chance to try IMR 7828 in the colder temps yet.

Maybe for many of us it's not a factor but then again, if I can get the same accuracy and velocity out of a more temperature stable powder then that's just one less thing to have a concern over.

Check out the Dennis Hall article referenced in this link. He used a loose, long throated Ruger 7x57.

http://www.24hourcampfire.com/ubbthreads/ubbthreads.php/topics/8988337/Re_7x57_140_NPT_load

DF

That's because temperature affects it.

I'm with you guys in regards to the RL22, which is the first (and often last) powder I grab when loading for my 7mmRemMags. I load and test my loads in 50-70 degree weather which is mostly in the Spring here in W TX. Last Fall/Winter we had an unusually cold series of days in early November, wind chills down into single digits, temps in the 'teens at a ranch we hunt in the TX Panhandle. I could tell no difference in POI at these temps, yardages from 200-900 via CDS dials. I'd have to say the temp sensitivity with RL22 is a non issue nowadays for me.

Yup. As a hunter I have never had an issue with powder choice and hitting/killing over the years. Just another topic for a gunrag me thinks...

If you haven't tried it then obviously, you simply don't know do you?

FYI, they are NOT the same powder............in fact they don't even look the same.

'22 is lighter (more gray), & is flatter with much more irregular sized granules than MRP which is darker, rounder granules & much more uniform in grain size.

As for MRP being less temp sensitive, I've read & been told it is but since I've not done side by side testing, I really don't know with certainty.

As far as loading goes, manuals that list both are generally very close, but not exactly the same.

In my loading experience with both powders, I usually find that top loads with '22 are usually about a .5-1.0 grains less than with MRP........That's mainly in the 270 Win & 280 Rem where I've used both extensively.

In lots of cartridges, besides the 270 & 280, including the Rem 7 Mag & 300 & 338 Win Mags I've found that RL-22 is really hard to beat for both velocity + accuracy; never tested the extremes of it's temp sensitivity but from around +10F - around 65F, which encompasses 99% of my hunting, I don't see any issues.

'22 almost always out performs 7828 & 4831, IME, unless you are paranoid about the temp sensitivity issue.

MM