7 mag and Retumbo questions...

[oregonhuntr]

I would like to start developing a load for my 7mag with a 26" barrel using 160 gr. Nosler Accubonds and Retumbo powder.

My plan is to do a ladder test using muzzle velocity to find a velocity node or two around the 3k fps range in which to further develop possibly using seating depth (I like to shoot a lot).

Can anyone suggest a start load charge using 160 gr. Accubonds and Retumbo combo? Hodgdon website says start load is 65 gr. which is 2756 fps and max load is 69.5 gr. which is 2915 fps, this all seams a bit conservative to me, I know people are loading up to 73 gr. with 168 VLD's.

Any help would be greatly appreciated!

 

[Ranger619]

I just started developing a load for my Tikka 7mm with 160gr AB and Retumbo. I started at 66.2 gr and went to 68.0 in 0.2 gr increments. I had velocities from 2732 fps to 2801fps. I am not sure how much the shorter barrel on the Tikka makes, but hope this helps.

 

[mt100gr.]

I load the 168 VLD over Retumbo for my Tikka 7mag. My go to load is 70.0gr. Which is under book max in the berger manual. I played around some in the 71-71.5 range but I didn't see the benefit over my 70.0 load. I haven't shot this over my magnetospeed, but over my old chronograph it was right at 2930. Drops matched up there as well. This is using w-w brass and wlrm primers. This combo seemed very sensitive to which primer i used so keep that in mind if you don't see what you hope for right away.

H1000 is excellent in my 7mm as well.

 

[oregonhuntr]

I just started developing a load for my Tikka 7mm with 160gr AB and Retumbo. I started at 66.2 gr and went to 68.0 in 0.2 gr increments. I had velocities from 2732 fps to 2801fps. I am not sure how much the shorter barrel on the Tikka makes, but hope this helps.

Just curious as to why you stopped at 68, were you seeing signs of overpressure?

Very helpful info thanks.

Sent from my Pixel using Tapatalk

 

[oregonhuntr]

I load the 168 VLD over Retumbo for my Tikka 7mag. My go to load is 70.0gr. Which is under book max in the berger manual. I played around some in the 71-71.5 range but I didn't see the benefit over my 70.0 load. I haven't shot this over my magnetospeed, but over my old chronograph it was right at 2930. Drops matched up there as well. This is using w-w brass and wlrm primers. This combo seemed very sensitive to which primer i used so keep that in mind if you don't see what you hope for right away.

H1000 is excellent in my 7mm as well.

What kind of velocity would you expect with H1000 compared to Retumbo?

Thanks for all the info.

Sent from my Pixel using Tapatalk

 

[mt100gr.]

If memory serves, it was in the mid to high 2800s at the berger book max which I can't recall off the top of my head. At the time I was chasing velocity and new to reloading and the retumbo was faster. I believe with more load development however, the H1000 load would be more consistent in velocity.

I have been settled on that retumbo load for a couple years now and it has served me well. I was hoarding all my h1000 for my 300WM load and have plenty of retumbo.

My 7mm is waiting on a new scope and when I get that set up, I have considered revisiting H1000 for that rifle as I have a good supply and have since switched my focus to accuracy and consistency over velocity. I also have a lot more confidence in my new chronograph vs the old optical one I had at that time.

 

[oregonhuntr]

If memory serves, it was in the mid to high 2800s at the berger book max which I can't recall off the top of my head. At the time I was chasing velocity and new to reloading and the retumbo was faster. I believe with more load development however, the H1000 load would be more consistent in velocity.

I have been settled on that retumbo load for a couple years now and it has served me well. I was hoarding all my h1000 for my 300WM load and have plenty of retumbo.

My 7mm is waiting on a new scope and when I get that set up, I have considered revisiting H1000 for that rifle as I have a good supply and have since switched my focus to accuracy and consistency over velocity. I also have a lot more confidence in my new chronograph vs the old optical one I had at that time.

Just FYI, I am getting .5 MOA accuracy from my 7 mag and Berger 168 grain using 63 grains of 4831sc. Pretty slow load though, I think It was around 2, 800 fps.

I'm switching to the nosler accubond for a little heavier bullet that will be primarily used for elk within 400 yards. If I can get into the 3000 fps range using Rutumbo that would be great too!

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[LaHunter]

I load my 7 mm rem mag pushing 160 accubonds with IMR 7828. My mv is 3100 fps and accuracy is consistently sub .5 MOA. I have a 26” Krieger barrel on my rig. I am over ‘book max’, but I worked my way up to this load gradually. I do not get sticky bolt lifts or other signs of excessive pressure. May be another option for you

 

[mt100gr.]

I had really good accuracy with 7828 also. I worked with that a few years back when H1000 and Retumbo were scarce.

 

[Ranger619]

Just curious as to why you stopped at 68, were you seeing signs of overpressure?

Very helpful info thanks.

Sent from my Pixel using Tapatalk

I don't have a good reason for stopping at 68. I just started and ended below max per the reloading manual I have right now. I wanted to stay below the point where it became a compressed load. I may move up the next time I can shoot.

 

[Studd muffin]

I have loaded 70gr Retumbo using the 175ELDX and get about 2925fps. I would have to imagine the same load with the lighter 160gr Accubond would be 3000 plus. I have a few of this combination loaded up, just need to get time to do some shooting.

 

[oregonhuntr]

Thanks for the information everyone. Looks like I have some loading to do now!

 

[Pharmseller]

I tried Retumbo in two rifles and just never got the velocity I was looking for.
If you can find some Reloader 26...

A hair over 3,000 FPS.





P

 

[mmac]

OregonHunter, You may be aware, but Nosler has their manual online under the media section of the website. I find the accurate loads for each powder a good starting point.

I have a couple 7mm's and load the 168 ABLR over 71 gr Retumbo and it is .5 inch and my magneto speed says it is moving at 3020 in the 26in. barrel. About 2950 in the 24.

I found H48131 the most accurate for me for the 160 AB.

I haven't found anything more accurate or faster.

Now the big issue, Retumbo is basically nowhere....... I can't find it anywhere.

 

[oregonhuntr]

OregonHunter, You may be aware, but Nosler has their manual online under the media section of the website. I find the accurate loads for each powder a good starting point.

I have a couple 7mm's and load the 168 ABLR over 71 gr Retumbo and it is .5 inch and my magneto speed says it is moving at 3020 in the 26in. barrel. About 2950 in the 24.

I found H48131 the most accurate for me for the 160 AB.

I haven't found anything more accurate or faster.

Now the big issue, Retumbo is basically nowhere....... I can't find it anywhere.

Mmac, thanks for the info. I have a bunch of Retumbo, haven't used any yet but heard guys are getting good results using it.

My current load is using H4331sc. If the Retumbo route doesn't work I might just try reworking the load with the H4331sc.

 

[oregonhuntr]

I tried Retumbo in two rifles and just never got the velocity I was looking for.
If you can find some Reloader 26...

A hair over 3,000 FPS.





P

Thanks for the info. I am trying to stay away from less temperature stable powders as you mentioned. Temperature stability is a big concern of mine, there are days I would be shooting in 10 degree weather and other days I might be shooting in 90 degree weather.

 

[mmac]

I would stay with Retumbo if it groups. I am so jealous you have some.... It is like gold here.....