R26 temp sensitivity test

[eoperator]

I'm new to r26 so I thought I would do a highly scientific temp test myself.
280ai 1:8 24"
peterson brass
215m
155hh
61gr r26 (mild load)
1/3 fcd crimp
68° outside temp
labradar

4rnds kept in my pocket (warm to touch)
mv 2919, 2934, 2938, 2924- avg 2929

The other 4 rounds were put in a zip lock bag in a large covered coffe mug filled with ice sitting over 2hrs fired quickly as possible.
mv 2955, 2948, 2942, 2958- avg 2951

I understand this may not be the most accurate test (20ish deg to 90ish deg)but good enough for me to proceed loading with r26 and throw most of that temp sensitivity BS posted about r26 to the curb.

 

[wind gypsy]

Not saying I wouldn’t go forth and hunt comfortably with the testing you’ve done but there are lots of things that come into play with temp sensitivity. Ambient air, barrel temp, and pressure of the load all seem to impact temp sensitivity.

 

[Dioni A]

I tested this years ago just keeping track of the same load with different range days. From low 90s to temps in the teens it was around 30fps swing. It's pretty temp stable. I think it could vary more depending on primer and load density but for most people in most situations it's a non issue.

 

[mtnwrunner]

Interesting. A shooting friend and I did a temp test on RL 26 also by using ambient air temp and some thrown in the freezer for 2 hours. Accuracy was okay but 80 to 100 fps in the spread. Fwiw.

Randy

 

[CApighunter]

Very similar data for my 280ai, but I’m getting about 50 FPS more with .5 gr less powder. Nosler brass though, not Peterson. Mine tapped out at 61.5 for max pressure at 3050.

 

[JakeSCH]

Seating the bullet "far" off lands and adding a light crimp helps along with higher neck tension. Temp impacts burn rate and its affects can be significantly reduced with the above things. At least that is what I have found with hammer bullets and barnes bullets in my testing.

 

[eoperator]

Seating the bullet "far" off lands and adding a light crimp helps along with higher neck tension. Temp impacts burn rate and its affects can be significantly reduced with the above things. At least that is what I have found with hammer bullets and barnes bullets in my testing.

This load is 3.422oal about ~.040 off jamb with 1/3turn lee fcd crimp, fairly new barrel

 

[MallardAddict]

R26 has been pretty temp stable on my testing from 20-80 degrees. Stiffer loads pushing max have been known to get squirrelly about 85 degrees though.

 

[dashender7]

RL-26 has also proven to indicate temp stability for me in observations with a chrono at sub-30 to 90 degrees and varied atmospherics during load development and testing for 6.5 Creedmoor.

 

[eoperator]

I did another similar test with 300win/199hammers/r26 75.5gr
4 on ice =3062 avg mv
4 warm in pocket= 3073avg mv
4 on dash of truck with heater on =3205avg mv

r26 does seem to have some issues with very hot temps

 

[Morgan1776]

The temp instability issues I've heard of related to RL-26 were mainly POI change. Anyone perform these tests looking for POI change over 200 yards?

 

[wind gypsy]

I think there is a lot of factors in how temperature impacts things. My understanding is that barrel temp, air temp, powder temp, chamber pressure, and cartridge/bullet can all impact results in regards to "temperature stability". I've given up fully trusting anything beyond shooting in different temperatures where the ammo/rifle has been allowed to reach ambient temp. I know that isn't very helpful when trying to validate loads in the summer.

 

[docdoc]

Hot loads with higher temperatures (85+) seem to be where people have had problems with RL26.

 

[nksmfamjp]

I really appreciate you doing this. Wish we also knew if Sd changed across temp range.

 

[tdhanses]

Interesting tests, I’ve shot RL26 for many years now in temps from 5* to 95*, never saw much of a swing in velocity or pressure. Now my shooting doesn’t involve bullets in ice or sitting in the direct sun on a dash. The bullets on a dash is very flawed as dash temps in direct sunlight can get way above the hottest day you’ll hunt or shoot in.

Personally I keep my ammo covered and shoot it, when hunting I don’t strap my ammo to the outside of my pack in direct sunlight nor do I put it in the snow and drag it along.

So in ways we normally would care for ammo and actual shooting during cold and hot temps I haven’t had a big swing with RL26.

Personally I wonder if some of the internet banter on RL26 being temp sensitive is to scare more people away from it so it becomes easier to obtain.

 

[tdhanses]

The temp instability issues I've heard of related to RL-26 were mainly POI change. Anyone perform these tests looking for POI change over 200 yards?

I’ve not had any issues in poi changes.

 

[Ryan Avery]

RL26 seems to have issues with temp stability from lot to lot. Some are good and some not some much.

I don't have time for that shit

 

[Brokenbone]

Exactly!

 

[N2TRKYS]

I’ve not had any temp sensitivity or lot to lot issues with RL26, either.

 

[eoperator]

Interesting tests, I’ve shot RL26 for many years now in temps from 5* to 95*, never saw much of a swing in velocity or pressure. Now my shooting doesn’t involve bullets in ice or sitting in the direct sun on a dash. The bullets on a dash is very flawed as dash temps in direct sunlight can get way above the hottest day you’ll hunt or shoot in.

Personally I keep my ammo covered and shoot it, when hunting I don’t strap my ammo to the outside of my pack in direct sunlight nor do I put it in the snow and drag it along.

So in ways we normally would care for ammo and actual shooting during cold and hot temps I haven’t had a big swing with RL26.

Personally I wonder if some of the internet banter on RL26 being temp sensitive is to scare more people away from it so it becomes easier to obtain.

I agree 100% with your evaluation of my test parameters. I did this to represent the most extreme temp swings that I would encounter while shooting, and expose r26 weaknesses (if any).