RL 17 Temp Sensitivity

[blackfoot]

I'm running RL17 in my 300WSM hunting rifle and it performs extremely well. I've read some concerns about temp sensitivity. Was going to consider it for my 6.5x47 build, thinking it would be an excellent powder for the 6.5. I'm in Alaska so my temperature range that I'll mostly be shooting in will only range from about 40 degrees to 70 degrees. I'm thinkig it won't have too much effect at that temp range, what say you??

 

[BirdEyes]

Re: RL 17 Temp Sensitivity

I'm thinking that over that relatively narrow temperature range, you're unlikely to detect any differences at least to 600 yards. I don't know what range you expect to shoot at.

 

[Casey Simpson]

Re: RL 17 Temp Sensitivity


And, if you develop your load properly (OCW) ambient temp swings are even less influential.

 

[blackfoot]

Re: RL 17 Temp Sensitivity

Plean to shoot out to 1000.

Develop load properly? You mean with a proper ladder test and at the average temperature I'll be shooting in?

 

[Casey Simpson]

Re: RL 17 Temp Sensitivity


Optimal Charge Weight method. RL 17 works well in 6.5x47 if its done right.

 

[taliv]

Re: RL 17 Temp Sensitivity

how would OCW change the powder temp sensitivity?


i've shot around 7400 rounds now of 260AI with R17 from about 10* to 110* (but vast majority between 50-90*)

I've found it's sensitive, but very consistently so. Sensitive enough that instead of 90*, 60*, 30*, I made dope cards for 90*, 70*, 50*, 30* and they tracked very well.

my load is pushing 140g Berg Hybrids a hair over 3000 fps out of 26" bartlein and primer pockets are still tight after 3 firings at that load.

 

[Eznutz]

Re: RL 17 Temp Sensitivity

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: taliv</div><div class="ubbcode-body">how would OCW change the powder temp sensitivity?


i've shot around 7400 rounds now of 260AI with R17 from about 10* to 110* (but vast majority between 50-90*)

I've found it's sensitive, but very consistently so. Sensitive enough that instead of 90*, 60*, 30*, I made dope cards for 90*, 70*, 50*, 30* and they tracked very well.

my load is pushing 140g Berg Hybrids a hair over 3000 fps out of 26" bartlein and primer pockets are still tight after 3 firings at that load. </div></div>

Just curious. How much of a MV decrease did you experience over the 90 to 70 and from the 70-50 and so forth? i am just asking. I use RL15 and have heard the same temp sensitive but i have found it is absolutely consistent.

 

[taliv]

Re: RL 17 Temp Sensitivity

just some sample data. keep in mind the rounding involved with only a single digit right of the decimal

(note, this load is a 139 scenar load and not same velocity i mentioned above)

@400m
30 1.9
50 1.9
70 1.8
90 1.8

700m
30 5.0
50 4.9
70 4.8
90 4.7

900m
30 7.8
50 7.6
70 7.4
90 7.2

 

[Casey Simpson]

Re: RL 17 Temp Sensitivity


Research Optimal Charge Weight. I'm worn out from preaching about it.

Put it this way. Not knowing what it is is like a mechanic not knowing how to change earl in the motor like Goober on Mayberry, RFD.

 

[blackfoot]

Re: RL 17 Temp Sensitivity

Read on it. Honestly I've been reloading for 20 years, benchrest, black powder rifle long range, hunting, etc. I had NEVER heard of it. I read all the information and it's just another way to skin a cat. I wouldn't say it's like not knowing how to change the oil, I'd say it's like not know a particular way a particular mechanic drops the oil and at what mileage. Not saying it might not be useful, and I'll give it a whirl. But to say you can't develop a good load without it is quite a stretch.

 

[Casey Simpson]

Re: RL 17 Temp Sensitivity

This is an example of how rumors and lawsuits get started. I did not write that a good load could not be developed without OCW. Here's what I wrote:

And, if you develop your load properly (OCW) <span style="color: #FF0000">ambient temp swings are even less influential.</span>

Meaning, ambient temp swings will affect velocity, but less so if the OCW method is used to find the optimal charge weight - not an optimal charge weight, but the optimal charge weight. There is only one, usually.

Also, my other post meant RL17, as well as every propellant, is sensitive to ambient temp changes, but LESS so if OCW was used to find the charge weight.

 

[blackfoot]

Re: RL 17 Temp Sensitivity

My bad, I inferred from the tone of your comments that one had to use OCW or they didn't know what they were doing, thus couldn't develop a good load. I guess a mechanic that doesn't know how to change oil can still make a car run to it's potential.

 

[Casey Simpson]

Re: RL 17 Temp Sensitivity


I'm sure you know what you're doing, and sometime in a statement I actually mean for someone else to read it in addition to the OP.