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Reloader 25 Temperature Sensitivity (???)

H

Humble284

Private
Minuteman
Sep 25, 2009
23
0
54
MONTANA
#1
This is my first post...

I have been using R25 loads for my new 7mmRM. I am very pleased with the accuracy. A seemingly knowledgeable source told me to watch out for the temp sensitivity of R25. I have used H1000 and it opens up the groups very slightly. The source suggested that I stick with H1000 despite the very slight group enlarging. I agree, if it is true (???). How should I test this? Does anyone have quantifiable data on R25 purported sensitivity?

24" bull barrel, 1:9.5 RHT

162gr Amax, 68gr H1000, COL gently touching lands (3.680-3.679), AVGVEL 2900fps, AVGSD 11fps, 100yard AGR(avg) 0.291"

162gr Amax, 70gr R25, COL gently touching lands (3.680-3.679), AVGVEL 3023fps, AVGSD 7fps, 100yard AGR(avg) 0.204"

Thanks in advance for your help...
 
#2
Re: Reloader 25 Temperature Sensitivity (???)

I've used quite a bit of the RL25 in quite a few different calibers and cartridges. In hot weather and cold weather while hunting and target shooting.

The only concern I had with using it was in the 264 Win Mag.
I had pressure spikes with it.

I have clocked it's speed at different time of the year, hot and cold and never picked up that it was temp sensitive.

Just my experience, others may vary....
 
#4
Re: Reloader 25 Temperature Sensitivity (???)

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">Had a bolt get sticky going from about 60*F to 80+*F.</div></div>

That is no good. Have you (or anyone reading this) experienced dramatic vertical impact changes with temp changes.

I don't want to be out in 20-30F temps and have accuracy go to pot... I arrived at this max charge during the summer so I am not concerned that it will over pressure.

I guess the million dollar question is R25 unstable when it comes to temp all together or is it just a few bad batches?
 
#6
Re: Reloader 25 Temperature Sensitivity (???)

I use RL25 for my 338 LM. I developed the load in the winter time here in the desert, and have shot it in the middle of the summer (easily gets up to 110+ degrees) without any issue with pressure. I also load them very hot.
 
#7
Re: Reloader 25 Temperature Sensitivity (???)

So I went to the range today to test a little hypothesis I formed while pouring over R25 temp sensitivities in various forums. It was a balmy 86F this afternoon and I decided to take a known load that I had tested in colder conditions. On average, here it is:

51F, 70.0gr R25 162gr Amax, 3023 FPS avg, 7 FPS SD (same load in first post)

Today, 86F, same load, 3133 FPS avg, 18 FPS SD...

Not quite proof, but I will be watching this powder like a hawk for temp sens.

Can anyone (*who keeps really good records) correlate ambient temps with recorded velocities? I know I am asking a lot, mainly because I may be the only one that records everything but sun spots in my log books...
 
#8
Re: Reloader 25 Temperature Sensitivity (???)

Just wondering, but do you measure the distance form the chrono to muzzle everytime?

If it is your hypothesis that there is a temperature sensitivity with the RL25, perhaps, I would recommend that you measure the temperature of the ammo just before you shoot and create a temperature curve, if it exists.

Secondly, if you look at the "change" in temperature, the percent change is about 3.6%. Is that resonably within the "experimental" errors, or the ability of the chrono to read the speed? I am just saying.....
 
#9
Re: Reloader 25 Temperature Sensitivity (???)

Humble-
I tested RL25 for temp sensitivity (among many other powders) by chilling the loaded rounds on ice then firing them immediately in an ambient (95 deg. F) rifle. I repeated this test with ambient temp rounds and in a 300Wby there was over 100fps difference. RL22 was also sensitive. I did not make note of accuracy differences whatsoever, just watching velocity. IMR 7828, H1000, H4831 SC all had less than 20fps difference between ambient and chilled ammo, many velocities were identical. Hope this helps
 
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#10
Re: Reloader 25 Temperature Sensitivity (???)

Nice technique! I will try that too! It should be another warm day tomorrow.

Thank you for that info, it does help. Awesome data... keep it up. You also gave me another test and yet more data to record. I learn something every day.

What do you (any of you) think of the IMR 7828?
 
#11
Re: Reloader 25 Temperature Sensitivity (???)

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">Just wondering, but do you measure the distance form the chrono to muzzle everytime? </div></div>

Yes I record that info. I measure it to be 7 feet to the first screen. I use a CED and it seems to be accurate against my buddy's Ohler.

I don't know the published error rate on the CED... that would be worth knowing... 100FPS sensitivity is significant at the max load.

Thank you for the info!
 
#12
Re: Reloader 25 Temperature Sensitivity (???)

If you check out my post about RL25 in my 30-06 you'll see I am switching to a different powder with my 208 Amax's because of a pressure spike I experienced on a hot day. My 240 smk's shot nice with out an pressure spikes. I think it was a combination of compressed load and the heat.

I'm going to experiment with some Ramshot Magnum this week.
 
#13
Re: Reloader 25 Temperature Sensitivity (???)

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">I'm going to experiment with some Ramshot Magnum this week. </div></div>

Please let me know your results with the Ram Mag, I have wondered about that myself...

I will look for that post. Would you reply with a link to it. Thanks
 
#14
Re: Reloader 25 Temperature Sensitivity (???)

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Humble284</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">Just wondering, but do you measure the distance form the chrono to muzzle everytime? </div></div>

Yes I record that info. <span style="text-decoration: underline"><span style="font-weight: bold">I measure it to be 7 feet to the first screen</span></span>. I use a CED and it seems to be accurate against my buddy's Ohler.

I don't know the published error rate on the CED... that would be worth knowing... 100FPS sensitivity is significant at the max load.

Thank you for the info!
</div></div>

Don't happen to have my CED M2 manual readily available, but 7 feet is a bit too close perhaps?
 
#15
Re: Reloader 25 Temperature Sensitivity (???)

I suppose it could be. What would that effect. One other thing I should mention is that I have a brake on it, so there should not be much gas reaching the screens.

You have me wondering now, I will look in my CED manual.
 
#16
Re: Reloader 25 Temperature Sensitivity (???)

Humble284,

Better off to be 15 feet away with the chrono and add 7 fps to what the chrono shows for velocity.I've had screwy results with chronos even at 10 feet before.

I used to use R-25 in my 30-375R.I use h-1000 now and it does seem to be less temperature sensitive so far.Granted,I live at 6500 feet and temps get very cold in the winter but I was loosing around 100 fps in the winter compared to the summer.

Also I use R-25 for my 375 Cheytac and sometimes have ignition problems,more so in the winter.I think the problem has more to do with poor load density though.

I suggest looking into Retumbo personally for that cartridge with 240's.

Steve
 
#17
Re: Reloader 25 Temperature Sensitivity (???)

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Humble284</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">I'm going to experiment with some Ramshot Magnum this week. </div></div>

Please let me know your results with the Ram Mag, I have wondered about that myself...

I will look for that post. Would you reply with a link to it. Thanks

</div></div>

http://www.snipershide.com/forum/ubbthreads.php?ubb=showflat&Number=1314507#Post1314507
 
#18
Re: Reloader 25 Temperature Sensitivity (???)







<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: DesertHK</div><div class="ubbcode-body">Just wondering, but do you measure the distance form the chrono to muzzle everytime?

If it is your hypothesis that there is a temperature sensitivity with the RL25, perhaps, I would recommend that you measure the temperature of the ammo just before you shoot and create a temperature curve, if it exists.

Secondly, if you look at the "change" in temperature, the percent change is about 3.6%. Is that resonably within the "experimental" errors, or the ability of the chrono to read the speed? I am just saying..... </div></div>

I'm doing a lot of research right now prior to getting my 338 EDGE,RL25 is one of the powders tested by Shawn Carlock,he warns about temperture sensitivity with this powder vs. the H1000 which has very little sensitivity with temp.I tend to believe Shawn as the 338 EDGE is his baby.
 
#19
Re: Reloader 25 Temperature Sensitivity (???)

The Reloder series rifle powders are double based powders, having more energy than standard single based. The drawback is that they are more temp. sensitive. I shoot Re22 in varmint matches here in So. Ca., but we get sighters for every relay, so elevation changes are not a problem. In my tactical and long range rifle I use H4831, I lose 100 fps compared to the Reloder powders, but my elevation settings are always dead on, hot or cold.
 
#21
Re: Reloader 25 Temperature Sensitivity (???)

I am really in awe of the data I am getting from everyone... I would have joined this forum years ago had I known that everyone was this responsive and thorough.

I have heard of the 338 edge from a customer who does serious long range in ID. Anyone that can develop a new cartridge has my vote.

I am frustrated by how accurate R25 is when stable i.e. for me between 50F-60F At one point (really not significant stochastically speaking
grin.gif
), I shot 0.149" AGR with my 162 amax over 70.0 gr R25... it is very frustrating. Accuracy without repeatability is meaningless.
 
#22
Re: Reloader 25 Temperature Sensitivity (???)

Onemoretime,

For the varmint competition I use a standard .243 Win., 107 SMK,and 115 DTAC bullets, and Re22. For long range and tactical I use a 6.5x55 with 139 Lapua Scenars, and H4831, all bullets uncoated. The 6.5x55 is a great cartridge, not critical with respect to bullets and powders, good bullet selection, low recoil. It is amazing how much better I shoot when I have complete confidence that the bullet will go where it should.
 
#24
Re: Reloader 25 Temperature Sensitivity (???)

Yea, I am not going to mess with it anymore... At best it is too much to factor in another variable. At worst it could do some damage.

I got 4 lbs I have to get rid of... If anyone wants it... PM
 
#25
Re: Reloader 25 Temperature Sensitivity (???)

H284,

Not trying to dissuade you from your decision (it does seem well reasoned), however.....

Did your logs make note of the sun conditions from your cold weather shooting? I have noticed some pretty significant jumps in ES on my CED M2 with the passing of clouds. Bright and sunny conditions seem to make the speeds run high while an overcast day levels them right back out where they should be.

Additionally 7 ft is a might close for a magnum, brake or not. Stretch the wires out a bit.

The advertised error level for CED M2 is 0.5% so at 3K any ES's below, say 15 (.005 * 3000 = 15), are within the margin of error.

Now if you're having vertical spreads that correspond to the jumps on the chrony then that's a different story.

.02 for the pot.

Cheers,

Doc
 
#26
Re: Reloader 25 Temperature Sensitivity (???)

Actually I was wondering about the same issue, but with R15 in my .308. I shoot year round up here which means I'm shooting in temps ranging from the mid 80's in the summer and way down around twenty below during the winter.

My ffl FINALLY got in a supply of powder including the R15. I'm just about out of the 4064 I got from him about a year ago, which was the last time he was able to get powder in stock...
 
#28
Bugholes said:
Re: Reloader 25 Temperature Sensitivity (???)

Humble-
I tested RL25 for temp sensitivity (among many other powders) by chilling the loaded rounds on ice then firing them immediately in an ambient (95 deg. F) rifle. I repeated this test with ambient temp rounds and in a 300Wby there was over 100fps difference. RL22 was also sensitive. I did not make note of accuracy differences whatsoever, just watching velocity. IMR 7828, H1000, H4831 SC all had less than 20fps difference between ambient and chilled ammo, many velocities were identical. Hope this helps
Click to expand...
 
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