I shot retumbo loads 300RUM 180gr Partition at 300 Yards. This stuff cooks. The best I could get with 4350 and H1000 with 180gr bullets and still be 1 MOA accurate was 3185fps. This shit got up 3400fps with 3.5" groups at 300 yards 99gr of Retumbo with no pressure signs in 85degree day. Anything after 98gr thown a flyer here and there however. My question is when you get to a point where you have two shots within an inch, and then get a thrower, is that where the load is getting unstable. I see this all the time. From 93gr to 98gr, the groups was very uniform forming triangles. Then from 99 to 101gr, not so uniform. Wasn't able to chrono past 98gr cause a guy shot my posts in the chrono.

So now I am trying to figure out a depth to load to tighten up those groups.

I have used it in a WSM cartridge. The last three of my lot # is 937. I get the same type of stuff, but my problems are more likely gunsmithing. I backed off my max by 4 grains for NM summer heat. My Chrony sucks so I have no idea where I am at either.

I've ordered some Retumbo to try in my 7mm SAUM w/175 gr. loads. It was cheap, so I thought I'd give it a shot. Hodgdon got the highest speed for 175 gr. loads with this powder.

Honestly, I don't see people haveing the best of luck out of the short mags with it. It really shows it true potential in the RUM, or Weatherby rounds. Let us know how it does. I am still wondering about those flyers.

bigcountry ;
A few weeks back I shot some 140gr bullets in a 270WSM using "Magpro". With a 74gr powder charge I got just over 3400fps! I thought my Chronograph was maybe a little off but a good freind had brought his "Pact" chronograph out that day too, so I fired a few rounds over his and got velocities as high as 3450fps. Standard 24" barrelled, M-70 Coyote.

I have had great results with Retumbo in my 7mm Ultra Mag. 3400fps with 150gr bullets and 3300fps with 160s and no obvious signs of too much pressure. Have loaded cases five times now with no loose primer pockets, etc. Shot some groups during the winter in really cold weather and now this summer with no noticable difference in either velocity or pressure. I noticed my rifle shot erratic groups with a clean barrel until I had fired about ten rounds through it and then it seemed to settle down. I won't clean that barrel again until groups start to open up or until I change to a different bullet. The rifle will usually shoot under one inch at 100 but so will a lot of rifles. What I have noticed about the 7Ultra is that those groups don't seem to open at longer ranges like you would expect. I have fired groups at 300 and 400 with it that look like they were shot at 100. I really like the caliber and Sendero rifle.