6.5-06 Retumbo Quickload request or info

6.5-06 A Square Rel 23
Win Cases & WLR Primers

130 Grain Bullet COAL 3.340:
Start 43.8 gr 2500 fps
Max Load 52.3 gr 2900 fps

150 Grain HPBT Match COAL 3.650"
Start 47.6 gr 2550 fps
Max 51.1 gr 2700 fps.

The above loads are from a well known reloading manual. I have no info for 140 grain bullets.
I think I now have a decent plan for starting to load this cartridge with Retumbo, thanks to all of you folks.

I'm firm on using an extreme, or temperature insensitive powder, and from some comments on here I've done some research on Reloader 23, it does look like another good powder to try out. However load data for it and this cartridge are basically non-existent, I've even called Alliant with no success. Can anymore point me in the right direction or give me some advice using RL 23 to cone up with some starting data?
Look at the 25/06 120gr data. Be careful but a place to start.
I'm building a custom 6.5-06, starting to compile load data to use when it's finished. I've found lots of information so far using H1000, H4831, and H4350, problem is I can't seem to find any of that powder in stock near me, and I'm pretty much set on using a Hodgdon extreme powder, it's just worked for me in the past. I've read lots about guys using Retumbo and I have a couple cans of that, but Hodgdon doesn't list any data for it.

So my question is, would someone when they have a free minute be kind enough to run a quickload for me? If not could someone give me some advice on how to come up with a safe starting charge for a cartridge without this data?

6.5-06, using Federal Magnum Match primers, Hornady 143 grain ELD-X bullet, Hodgdon Retumbo powder, 26" barrel with an 8" twist, and COAL is 3.500".

Thank you in advance

Is this what you are looking for?
6.5-06 A Square.png
Since everyone here was so helpful I thought I'd take a minute and share the results I've had so far working up loads for this build. I have roughly 65 rounds through the barrel now, been mostly using Retumbo, Reloader 23 (per lots of recommendations here), H4831SC, and H1000. I've only loaded 143 Eld-x bullets so far.

RL23 is a real dandy, I haven't started fine tuning groups yet, but it shoots really good groups at almost all powder charges, I'm getting about 2950fps with magnum primers, and about 2920fps with standard primers.

H1000 and H4831SC are both super accurate, but the velocity is considerably less with both, 2700ish with H1000, 2800ish with the short cut. I still have more room to work up on more speed with both these because I haven't ran into pressure yet but I'm more focused on other powders because of the speed so far and the fact that H1000 is so hard to come by.

On to the Retumbo now, which is why I came here looking for info in the first place. I'm hoping to get out this weekend and shoot some 5 shot groups and see how close the velocity numbers are and longer range accuracy. I ran into pressure with Retumbo and magnum primers at about 2800 fps, so I switched to standard primers and started working up again, this has been the first most surprising info that I've discovered so far, with standard primers and Retumbo I'm getting 2915fps and no pressure signs, 115 fps faster with standard primers over the magnums?? The second thing I've found really interesting is how much smoother shooting, considerably less jump, and way less recoil the rifle produces when shooting Retumbo vs all other 3 powders.

Best groups so far are jumping the bullets .010-.020, less jump I run into pressure and less velocity, more jump and groups open up considerably.

My barrel ended up finishing at 25 inches, I was hoping to get around 2950-3000 fps with the 143s but it's looking to be a little less than that. I've read lots of guys getting considerably more velocity out of this cartridge but I suspect using longer barrels? Also from what I've read a fairly tight neck and jumping bullets a short distance is not a combination for speed.

Should I be happy with the speeds I'm getting in the low 2900's? Anyone else ever had a certain powder give some of the upper end velocities with considerably tamer rifle behavior like I'm experiencing with Retumbo?

Again, thanks for all the help and info from all of you, much appreciated.
I had a custom 25/06, shot R#25 in it with Fed 215;s. Accuracy and speed with the 100 and 117g was tremedous, winchester brass. You probably will not see loads forR# 25 in the 25/06. A bunch of Texicans taught me the loads.
How many 6.5-06 shooters are out there? How well do you like the cartridge? What are some of the best bullets and powders that you've had good luck with?
Custom '98 Mauser 6.5-06, 26" barrel of unknown heritage, really nice piece of fiddleback walnut. I love this rifle with 125 Nosler partitions. .5" at 100 yards, kills like a howitzer at 400 yards.
I don't see why you cannot use 6.5-284 data for the 6.5-06 A-Square?

I read an article by a well known gun writer which states "If 2 cases of the same caliber have the same amount of powder room, when loaded with the same bullets and powders they'll produce essentially the same velocity at the same pressure"... He states there is no evidence that case shape can result in higher velocities. Most of his articles seem well researched.

What trnelson says is true there are vast differences in 6.5-06 chambers mine has .120 freebore with a 130gr Berger VLD seated with .264 grip.

I don't think it is much of an experiment to use 6.5x284 data in a 6.5-06 as long as the case capacity of each is known.

Never tried Retumbo in mine but I concur with the statements about RL22 and its accuracy in the 6.5-06 as well. H1000, H4831SC and 7828 are also great choices as well. I did not have very good luck with Retumbo in my 6.5x284. I have some RL23 to try but that project is pending.

Good luck and shoot straight y'all
Standard 6.5-06
140 gr
Retumbo down to h-4350 works great.
I shot them all, it depends on your rifle.

One Buddy likes 140 Berger retumb 3000+
One buddy rifle likes rl-23 147 3100
Mine likes 140 hyb n 165 3027fps single diget Es, shoot sub 1/4 to 1300
One buddy shoot H4350 at 2900

There are some new powders I have not tried, vit 565, vit 560 we'll not new but would work. My rifle did not like h 1000. Imr7828 would work too.
It's a great round.
Good evening, this thread popped upon a search for Retumbo with 6.5-06. I have a Sako 85 that started as a .30-06 and was rebarreled to 6.5-06, 1;9 twist. I'm just getting started with it. I have about 11 years of loading for .25-06, maybe 7 or 8 rifles, last one was a Rem 40X. I appreciate all the info here, if the original poster has more to add, please jump in. Thanks. Steve in SC