Home Forums Hunting & Shooting Competitive Shooting Reloader 15 & temp sensitivity; who has tested ii?

It's all here! New gun, scope, dies and components. My research indicates Reloader 15 is a solid performer with the 120-130 gr class of bullets for the 6.5x47 Lapua. I load Reloader 22 & 25 and am aware of it's sensitivity to temp swings. I read where some think Reloader 15 does the same. I'm not looking for heresay. I'm looking for individuals who actually witness temp swings when using Reloader 15.

Anyone!

Alan

My experience is with a .308Win. I have to add 2MOA to my usual 600 yard zero when running RL15 with temps hittting freezing and below.

Let's make sure we are talking about the same thing here. If you leave your ammo outside overnight, that's one thing. But you need to be aware that the air is denser when it's cold and this will slow down the bulllet faster. So it is important to attribute the impact difference properly.

If RL-15 creates that much variation at 600 just by its temperature, I would say it's a crappy powder that should never be used for anything related to accuracy. I suspect that most, if not all the impact variation is due to the denser air; 2 MOA is a great deal for 600 yards.

Well.... I don't have to add 2MOA to my Varget loads under the same conditions. RL-15 kinda caught me by surprise.

I add more powder for the cold and POI is close as it is during the hot weather. Typical 33 grain load gets bumped to 33.4 this is my plan for this Sunday as it is again time for our first Sunday of the month 600 yd match

Well, I only use Varget anymore. But did you have to add anything with Varget loads? I find that I have about 1 MOA or so at 1000 yards between temps in the 90s and temps in the 40s.

I am just shocked, and I mean shocked, that you need 2 MOA with RL-15. I did not realize it was that bad a powder.

The only difference i can see in cold and hot weather with Rel 15 is in my 338-06 Ack which I'm running max, in hot weather the primers are flat and in cold weather the primers or normal. I really need to back off a grain but the load shoots 1/2 to 3/4 and the only time i shoot in really hot weather with this load is to check zero before heading after Elk. Even in hot weather the empty cases fall right out the bolt works as smooth as glass

Lots of folks claim its stable, my experiences, even though a civilian champ that happens to do my AR work... was shooting it happily in IL... IE cold to hot... I just did not have luck with it. If I worked up a hot load, you could bet that in severe heat it would pop primers. And if I shot the same load in the 30s that was worked up in the 70s, I'd have to add a couple of clicks at 200... I never took it past that after I played with it some.

I know this though, I have a fair amount of 75s driven by it, and they are my house load for varmints, out to 300 in differing temps I've yet to miss a coyote with the gun zero'd at 200..

If I had to start over I'd go back to Varget or Benchmark. I happen to use to load N540 a lot, and it had the same issues as RL15, but it was so much better accuracy and speed wise, I just made notes and added the corrections as needed.....

RL 15 definitely would react violently in my 35-06 Imp when loads worked up in 60 degree weather were fired in 95+ degrees. 66 gr. powder charges with 225 grain bullets was its favorite load until the temp went above 90.

gotta wonder why the military chose R15 if it's a bad powder.

This topic pushed me to go do some very quick research. I postulated that the 2 MOA drop at 600 yards in different temperatures was due more to the denser cold air than the colder powder, but I wanted to see what the discrete effect of the denser air would actually be. I thought that having that we could then measure the effect of the cold powder required to bring about a total of 2 MOA in additional drop.

So, I went to JBM and not knowing AJs load, I used my F-class .308 load instead. At 90 degrees F, in 95% humidity my load would have a drop from a 100 yard zero of 13.7 MOA. I then calculated what the trajectory would be at the same velocity but at 30 degrees and 20% humidity. and that was 14.3 MOA, an additional .6 MOA of drop. This means that 1.4 MOA of drop is attributed to the cold powder. In order to get to about 15.7 MOA of drop at 30 degrees, I had to reduce the MV by 105 FPS. I also calculated what a velocity reduction of 105FPS would be at 90 degrees and it was 14.9 MOA (1.2 additional drop).

Here is a little table:

• Temp / MV | 2850FPS|2745FPS
• 90 degrees | - 13.70 | - 14.90
• 30 degrees | - 14.30 | - 15.70

A drop of 105FPS from 2850 represents decrease of 3.6%.

In order to replicate my findings above you need to use the following data points.

Bullet weight: 180gr
Caliber: .308
BC: .570
Muzzle velocity: 2850 (base)
Distance from muzzle: 12 feet
Elevation: 300
Temp: 90.0 (and 30 or whatever you want)
Humidity: 95% (Nice Texas summer, but humidity has just a small effect.)

So this tells me that the cold air accounted for about 40% the drop and the reduced MV accounted for the other 60%.

I think I'll stick with Varget.

FTR we don't get that big of humidity changes durring the Winter here. Odds are my velocity data was shot at around 75~80 degree temps with 90% or above humidity, the Winter humidity could have been above 70%. I'll have to find my notes on the load/velocity.

Load was 43.5gr RL-15, 175SMK's, Lapua brass, Federal 210M's. IIRC summer velocity was 2750fps. out of a 26" barrel.

The military doesn't always do things for the reasons you think they do things....

AJ, that is exactly why I listed all my assumed values. I should also point out that the humidity difference by itself was minimal, almost inconsequential.

A quick check with your data and using 800 feet as elevation (is that correct for your location?)shows that temp alone only accounts for about .5 MOA in drop. So in your case RL-15 really sucks.

RL-15 was pretty darn temp-sensitive BEFORE the military chose it. Apparently the military's temp requirements were not being met by the original RL-15, but they got a chance to the improve performance. The "improved" powder was then accepted. (Or at least this is the story I was told with somebody who was fairly high up in the Alliant organization at the time.)

I have tested a bunch of powders in various temperatures and the present version of RL-15 is much than it used to be, but other powders have been more consistent in both cold and heat.

I'm going to guess the word "better" in missing in your last sentence so it would read:



Good information, thanks but I will stay with Varget.

RL15 was much worse than the newer iterations.... IF you know whats up, its not a big deal...
The military has some things they work with on parameters and it has to fit ALL of them, not just temp variations...
Plus the have all the data to use for temp corrections anyway...

I've shot Reloder15 in in my AR Service Rifle for probably the last 8 or 9 years. I don't know if that covers the period where they had temp sensitivity issues. I've shot it in the 40 degree temps of Illinois and the 90+ temps of Camp Perry, Ohio. I can't say that I can pin a zero change on the temps in either extreme.

When Alliant took over the LC contract and at the same time got Re15 accepted as the powder for the M118LR, they put out a press release claiming improvements in temp sensitivity and consistency over the previously used powder. If the temp concerns are true, I wonder how bad the previous powder was for temp. I never got to shoot enough to know.

Part of why I stick with Re15 is that it's been very consistent lot to lot. Varget's a good powder, but they've had problems with lot to lot consistency. Part of it was ADI's response to the US Market demands. Drove the US Palma shooters crazy. Funny thing is my Aussie Palma friends never had such complaints about ADI2208 (Varget's AU equivalent).

The change in RL-15 was quite a while ago, and before that the powder was quite temp-sensitive. I was running some cold-weather tests at the time, at zero F., and RL-15 didn't do well. I contacted my friends at Alliant and that's when I found out about the change. They also sent a batch of the new stuff, which was quite a bit better.

I have seen some lot to lot variations in RL-15 in the past few years but nothing major, certainly not enough to need more than half a grain of load change in a .223.

Just shot another 1000 match today with my regular LR load. The temperature was in the high 30s, near 40. I added all of .375 MOA in elevation over the zero I developed in September and I had a component of head wind in the mix. The wind was about 8-10MPH coming in from 2 o'clock.