6.5-284 and Retumbo

[Greyfox]

I did a test last year with RL26 in a 6.5-06 AI. 58 grains with a 140 vld and 210M primer.

I took 3 rounds and put them in the freezer over night and left 3 rounds in my house.

Also left the rifle in the truck overnight and it was about 5 degrees.

The next morning I took the 3 out of the freezer and put them on ice in a cooler and took 3 warm rounds from the house and put those on the defroster of my truck as I drove to the range.

When I got to the range I put the frozen founds on the bench with the gun (it was between 5 and 10 degrees) went down and placed my target.

I left the truck running with the other 3 rounds on the defroster vent with the heat on high.

Then I shot the 3 frozen rounds, waited a minute or two so the rifle would be warm but not hot and shot the 3 heated rounds.

I had a 14 fps average difference between the frozen and heated rounds. POI was great also, no change. Only testing I did but the same test revealed a 100 fps difference in a 6.5 creedmoor with RL17 and Ramshot Hunter.
H4350 was about 10 fps if I remember correctly.

If I had to guess I would say the cold rounds were between 0 and 10 degrees and the heated rounds were between 85 and 90 degrees (they were very warm in my hand)

I will do a similar test in the 7 mag this winter and see how it works with more powder and a 215 primer.

Hope that helps a little.

Thanks! That sounds great. It looks like they have reworked the formulation compared to the older, Reloder series like 22. I'm a long term Retumbo user but will have to give R26 at try in my rifles.

 

[8andbait]

Basically same test as with the 6.5-06 AI except with the 7mm rem mag

66.4 grains of RL26 with 215 primer, 175 berger elite hunter bullet at .015 jump

Frozen rounds went 2962, 2939, 2956 averaged 2957 with a SD of 11
Hot rounds went 2997, 3013, 2988 averaged 2999 with a SD of 12

47 fps Difference and a 2975 average for all 6.

It was 1 degree this morning so the cold rounds from the deep freeze were probably 0 degrees and the rounds from the heater were probably 90 degrees or more, they were hot in my hand. So probably about 1/2 fps per degree or better.

A 210 primer like I used in the 6.5-06 AI load may also get things closer.

I am going to test Retumbo next since it's my go to powder in the 7mag

 

[Greyfox]

i have found Retumbo to have pretty good temperature stability over the past several seasons shooting game to 1200 yards in temps between 10F and 80F. While working on loads for a recent 6.5x284 build, I took advantage of the recent cold snap to check the ES and POI of a new lot of Retumbo. All cold bore shots, the left target was shot at 60F, the right target at 28F. The ES for all shots were 2983-2996FPS. POI was within .25MOA. Range was 200 yards. This was consistent with prior lots of Retumbo. My load was 140gr Berger Hunting VLD, 58Gr Retumbo,Fed210M.

 

[Wedgy]

Grayfox, my load is 57.5 of H1000 at 3030fps , all else is the same.

 

[Greyfox]

Grayfox, my load is 57.5 of H1000 at 3030fps , all else is the same.

If I swap 215M primers with the 210Ms in my Retumbo load I get a velocity of 3050FPS. Primers are slightly flattened and my groups are .25-.5MOA as opposed to a pretty routine .25MOA or better with the 210M's. While I have used H1000, I found that I had pressure signs at comparable velocities compared to Retumbo. That was quite a few years ago though. I may revisit it given your results.

 

[Wedgy]

Grayfox, I think the gains would be minimal if any, but look to Reloder 26 for something more substantial. When I get time I will do testing but I think I can get at least an additional 100fps and still be able to get several firings on the Lapua brass.

 

[8andbait]

I tested the Retumbo today in the 7mm rem mag
180 vld at .010 jump
215 primer
70.2 gr retumbo
Frozen rounds averaged 3023 fps
Hot rounds averaged 2993 fps

 

[jwing]

140 hyb, 57.0 rl 26 with cc
27 kreiger

3044 fps es 8

Still testing

 

[BucksAndBulls]

56.5 retumbo berger 140 hvld f210m 2960 24 inch factory savage 116. I have RL26 just need to find the time to do some testing.