Just like the title says; which is least sensitive to temp? I know RL33 is not so good but have not used N570. Any info would be appreciated. Thx.........Rich
Here is what defensive edge found when they needed a powder for the 338 edge +p. Their findings are towards the end of the article http://defensiveedge.net/index.php/338-edge-p
Are you using a drop tube with 33? I use one with both powders you mentioned.
Saw this and thought I would comment on VV N570 powder.
While testing N570 in the 338 Texan, we found that n 570 was very well suited to the Texans powder capacity and very stable.
In the post attached is our results and the powder performed better than we though/hoped it would. the downside is the powder is expensive compared to other powders but the results out weigh the cost.
Testing the 300 grain velocity fell near the maximum velocity that the bullet could stand (3150 ft/sec) but the barrel contour was to light for such an intense bullet/powder combination and accuracy was poor. velocity was 3300 ft/sec with 250 grain bullets and accuracy was very good in the light weight barrel.
I have found that VV N570 is my powder of choice in the Texans and pressures are held to 62,000 to 63,000 Psi to make everything last with very good velocities.
I have been trying out N 570 in my 6.5 SS this summer. I have not done any real testing but when shooting over the chrono from 70-100 degrees it seems to be pretty stable. When I tried it in my 338 EDGE IMP velocities matched RL33, but I still stuck with H-1000 in that rifle since it was doing just fine with that load. I Shot along side a buddy on his steel course which has about 30 targets from 200yds to plates just under a mile. He was using a 28Nosler running the 195s at 3070fps with RL33. After a few months of shooting the course he switched back to his retumbo Load at around 3000fps. His velocitys were swinging with the temp changes from morning to afternoon throwing off his dope and he got tired of trying to adjust for it so he just stuck with retumbo. Although the accuracy was there with both powders.
Forgot to mention I gave him some N 570 to try with the 28 Nos. He saw a 100fps gain over retumbo with the 180s and hasn't tried it with the 195s yet. He also heated up one round to 100degrees fired it, let the chamber cool and fired one more round cooled to 34 degrees. I know 2 shots has no real validity but it can give a rough idea. I don't remember the exact difference but I know with the 2 shots it was less than a 15fps difference between 66 degrees.
I agree with what has been said about N570. It's my go to for 28 nosler and 195s. Saw a zero shift from 45-80. I love the stuff. Can be hard to find but since it shoots so good I bought 20lbs and store it accordingly.
Thank you all for the info! It just makes me want some N570 more than ever. I HAVE heard that it and RL33 are both hard on barrels compared to other powders, but have no personal experience......rich
It's worked well so far. This is the first load I tried after pressure testing a few rounds. It was 3150fps at .125" off the lands. ( had to seat them deep at first until I removed the mag plate). Well I tried uploading a pic of the group, but I haven't been able to since the software changed, but it measured .174 for 3 shots.
Couldn't quite pressure out with N570 but velocities were good. I have some RL26 I haven't tried yet but I'm thinking N570 will be right behind Rl26 velocity wise. Still need to test it and confirm though.
Hey Rich I have been using N 570 in my 6.5Sherman ,and its a real winner was out the other day only 1deg C out shot dead on at 600 yards shot rifle later on in day when it was +29 ,and same results dead on . I will verify again once weather gets colder out but for early season hunting I have no worries in temp swing so far.
65.5 GR with 140 Berger 50 tho off no pressure signs 3250ft/sec load shoots better that 1/2 MOA all day long .