Reloder 26, Temperature Stability Sensitivity Data

[N2TRKYS]

Because your MV is changing inversely with temperature (which isn't most normal), could you confirm that your load shot 40fps higher MV when the temperature was 60 degrees colder? Slower MV at 80*F and higher MV at 20*F?

Were the rifle and ammo both allowed time to come to the outdoor temperatures prior to recording these MVs?

Last question... Which unit was used to measure these MVs? Light sensing chronograph, MagnetoSpeed, LabRadar...

Thanks

My rifles and ammo are laid out first on the shooting table when I arrive.
Then I get my sand bags out and set them up. Then I get my pen and my chrono(Caldwell) and tripod. Then I set up my tripod and chrono. Then I walk down range and setup my targets. By the time I do all of that and add in some chit chat with the safety officer, I figure everything is pretty close to the temp outside.

I've shot this load several times in the 80-50 temp range with not much movement in velocity. I've tested it with my chrono and a LabRadar. This is the first time I've shot it at this low of a temp, though. And I only shot that time with my chrono. So, I don't know?

 

[5RWill]

Loaded up some 143gr ELD-X over RL26 for dad's 6.5 SAUM from 58.5gr-60gr in 1/2gr increments. Idk when i'll get around to shooting it but i'll see if we can't find a load in two weeks when i come back, record the data and try it again later on to see how it compares. From what i've googled it seems to be pretty consistent.

 

[Timber338]

Tag.

 

[bigedp51]

Reloader 26 is a double base powder that is more temp sensitive than single base powders.
And the very reason that military long range 7.62 ammunition switched from RL15 to IMR-4064.

Cartridge, Caliber 7.62mm, NATO, Ball, Special, M118LR (United States): 175-grain (11.3 g) 7.62×51mm NATO Match-grade round specifically designed for long-range sniping. It uses a 175-grain (11.3 g) Sierra Match King Hollow Point Boat Tail bullet. Produced at Lake City Army Ammunition Plant. The propellant's noticeable muzzle flash and temperature sensitivity led to the development of the MK 316 MOD 0 for Special Operations use.

Cartridge, Caliber 7.62mm Special Ball, Long Range, MK 316 MOD 0 (United States): A 175-grain (11.3 g) round specifically designed for long-range sniping consisting of Sierra MatchKing Hollow Point Boat Tail projectiles, Federal Cartridge Company match cartridge cases and Gold Medal Match primers. The Propellant has been verified as IMR 4064 (per NSN 1305-01-567-6944 and Federal Cartridge Company Contract/Order Number N0016408DJN28 and has a charge weight per the specs of 41.745-grain (2.7 g).[22]

 

[STEEL SLINGER]

I shot RL26 for a while and thought it was the "Magic Pixy Dust"! It will surely wring out every once of velocity you can achieve from a cartridge before pressure hits, but everything others have posted .5 per ft./dg. to 2 ft.+ is correct and no, sensitivity is not linear. I switched over to RL23 and didn't give up much, if anything, for several calibers and it seems to be more temp stable. I live/load/zero in Central Florida and traveling out west and over the Northern border my loads are pretty spot on. Just my $.02.

 

[Smokinghole]

I shot RL26 for a while and thought it was the "Magic Pixy Dust"! It will surely wring out every once of velocity you can achieve from a cartridge before pressure hits, but everything others have posted .5 per ft./dg. to 2 ft.+ is correct and no, sensitivity is not linear. I switched over to RL23 and didn't give up much, if anything, for several calibers and it seems to be more temp stable. I live/load/zero in Central Florida and traveling out west and over the Northern border my loads are pretty spot on. Just my $.02.

I've been working with getting a RL23 load myself. I like the idea of RL26 but I'm not chasing top velocity, I want reliable velocity. I'm my SAUM I'm thinking 58.9gr is about what I need for my 175 Berger EH lo

 

[Pdvdh]

A lot of folk avoid RL33 because of the concern it's temp sensitive. It all depends on the temps you'll be hunting in. Because as has been stated, the rate of change of temperature on MV can be different, in different temperature ranges. I've documented that in the temps I hunt in, it's not a concern with RL33.

Somewhere less that 23*F, RL33 becomes more temperamental.
I've not tested it above 75*F.

 

[tbrice23]

I've found rl33 to be well behaved in 26 and 28 Nosler cases down to 10°F, my load density is more than 90% case fill. Which should be taken into account ,IMO.

 

[Smokinghole]

A lot of folk avoid RL33 because of the concern it's temp sensitive. It all depends on the temps you'll be hunting in. Because as has been stated, the rate of change of temperature on MV can be different, in different temperature ranges. I've documented that in the temps I hunt in, it's not a concern with RL33.

Somewhere less that 23*F, RL33 becomes more temperamental.
I've not tested it above 75*F.

Steel Slinger and I are talking about RL23 not 33. It's closer to H4831 but has the temp stability of RL16.

 

[Pdvdh]

Roger that...

 

[SMK1000plus]

I shot RL26 for a while and thought it was the "Magic Pixy Dust"! It will surely wring out every once of velocity you can achieve from a cartridge before pressure hits, but everything others have posted .5 per ft./dg. to 2 ft.+ is correct and no, sensitivity is not linear. I switched over to RL23 and didn't give up much, if anything, for several calibers and it seems to be more temp stable. I live/load/zero in Central Florida and traveling out west and over the Northern border my loads are pretty spot on. Just my $.02.

I too live in FL and have been developing loads with RL23. Have had great success with the 162gr Interlocks and 168gr Berger Hybrids in several of my 7mm Rem Mags. Also great speed/accuracy from 215gr Berger Hydrids and 212gr Hornady ELD-X bullets in my 30-06s. Seems very temperature stable from 96°F in summer to @ 48°F winter. I'll have to dig the recorded temperatures and chronographed speeds out of my log books. Love Reloder 23 enough I bought four 8# jugs of it!

Also having great luck with RL16! Works so good in my 7mm-08 Rems and my 416 Rem Mag that I bought two 8# jugs of it. Going to buy four more jugs as soon as I can.

I've not tried the RL26. Still using Retumbo in the 300 Win Mags and the 338 Lapua Mag. Retumbo is dirty and smoky but, it is so accurate and has great velocity that it's hard to change to something else.

 

[Smokinghole]

Does anyone here have RL26 temp data with loads worked up at moderate temps, then shooting in 80-95F? I keep reading that's primarily where it shows it's double base head. It doesn't seem to lose as temp drops but it seems to spike in higher temps.

 

[N2TRKYS]

Does anyone here have RL26 temp data with loads worked up at moderate temps, then shooting in 80-95F? I keep reading that's primarily where it shows it's double base head. It doesn't seem to lose as temp drops but it seems to spike in higher temps.

I haven't noticed any spikes with temp increase and RL26. It seems pretty consistent for me between the 50-80 degree range. I only noticed a spike when the temps dropped into the 20s. I'm gonna retest this to see if it was a fluke.

 

[bigedp51]

While the powder in question does not have the change in velocity for each degree of temperature change you can compare the double base powders against the Hodgdon's single base extreme powders.

Click on the image to enlarge.