Reloading .416 Rigby with Retumbo

[HuntersStand]

I have some Retumbo on hand and was wondering if it would be safe to work up some loads for the .416 Rigby with?
I cant find load data for it and wanted to know if it would be a viable option as it is a slow burning magnum powder that's low on the powder burn rate chart.

Thanks.

 

[Andy]

Yes - compressed loads will be safe with bullets as heavy as 400 grs. Use H1000 data if none for Retumbo can be found.

 

[mbogo3]

I know IMR4350 and a 400gr Partition makes moose bangflop.......Harold

 

[Boomer]

Retumbo is pretty slow for a Rigby, but a case full is sure to go bang in a loud, obnoxious, and fun sort of way, if you just want to burn some up, but velocity won't be particularly impressive.

 

[HuntersStand]

I like the accuracy I can get from IMR4350 but I find the pressure curve too high with hot loads.

 

[nowarningshot]

I was rather surprised that most loads for the Rigby show mid range burn powders I have used for Calibers like 7x57, and 30-06 and 308 family.

Since it is the parent of 338 Lapua one would expect some of those powders, or powders for big Weatherby or Rum's. One doesn't see powders like Reloader 22 or 25, H1000, or Retumbo.

Might have trouble with getting velocity with the big bullets. It's a shame since I have a lot of Retumbo.

 

[Andy]

I was rather surprised that most loads for the Rigby show mid range burn powders I have used for Calibers like 7x57, and 30-06 and 308 family.

Since it is the parent of 338 Lapua one would expect some of those powders, or powders for big Weatherby or Rum's. One doesn't see powders like Reloader 22 or 25, H1000, or Retumbo.

Might have trouble with getting velocity with the big bullets. It's a shame since I have a lot of Retumbo.

The 416 Rigby can use such fast powders because it has a large bore diameter (hence a large bore area and larger bore volume).

Using Retumbo in the 416 Rigby is not like using US869 in the 223 as has been questioned.........In fact a compressed case of Retumbo will not give an MV much lower that the top achievable with faster powders, and it will do it at lower pressure.

 

[Slamfire]

Woodleigh load data lists some slow burn rate powders -

http://www.wwpowder.com/PDF/Burn%20Rates%20-%202015-2016.pdf



ADI lists Reloder25 as an approximate equivalent to Retumbo (??) -

http://www.adi-powders.com.au/handloaders/equivalents.asp

 

[HuntersStand]

Can anyone recommend a powder with a low pressure and high FPS for this cartridge?

 

[Slamfire]

IMR has chamber pressure data (in cup's) for the 416 Rem.Mag. but not for the 416 Rigby. However, using the same powders listed it would vary from their tests for a rifle having a different throat length -

I load 416 Rem.Mag. and 416 Ruger and do the usual thing watching for excessive pressure signs when working up handloads. Current hunting load is a 350gr TTSX bullet at 2450 fps in either using Re15.

What performance level are you expecting from your 416 Rigby?

 

[HuntersStand]

I'm looking to push a Barnes 350gr TSX to about 2500 t0 2600 FPS.

I need to get some of those TTSX bullets.

 

[nowarningshot]

Barnes are bullets that perform best moving fast. Most Rigby loads are going to be moving at 303 British to 308 speeds. Very good chance of pencil wounds, at the low.speeds. Something like a partition or.even standard cup n core would be.a.better choice. Add solids if in Africa/dangerous game.

 

[Slamfire]

Barnes Reloading Manual No.3 data for the 416 Rigby (26" barrel) and their 350gr TSX and Solid bullets. No problem achieving 2500 to 2600 fps. The 350gr TTSX has an impressive ballistic coefficient of 0.444.

Shown here is a 416 caliber 300gr TSX bullet recovered from a Bull Moose shot broadside through the shoulders at an impact speed of ~2400 fps. I've also used the 350gr TSX bullet on Moose. These have more of a tendency to shoot clear through. High percentage of DRT kills on Moose and Elk using 300 or 350gr 416 caliber X bullets at 2400+ fps impact speeds.

My 416 Rem.Mag. and 416 Ruger both have 20" barrels.

416 Rem. Mag. Zastava LKM70 Custom Full Stock Carbine with Nikon Monarch 1.5-4.5x20mm scope

416 Ruger Alaskan with Nikon Omega 3-9x40mm scope

 

[HuntersStand]

That opened quite nicely for 2400 fps.

 

[HuntersStand]

Your No.3 manual has higher max loads than my No.4 manual.I like the idea of 2700 fps even better but I don't want to be too harsh on the good Norma brass.
I have some on their 3 firing that have loose primer pockets with 102 grs IMR4350,avg 2650fps.

 

[Slamfire]

The petals disintegrate at high impact speeds. A 416 caliber 300gr X bullet that went nearly lengthwise at an impact speed around 2850 fps -

 

[Slamfire]

Which rifle is your 416 Rigby and what barrel length?

 

[HuntersStand]

Sako 85 Brown Bear,22 inch barrel.

 

[Slamfire]

Excellent rifle. I have a Kodiak model in 375 (that I wish was a 416 ). I would guess you would lose about 150 fps MV with the 22" barrel compared to a 26" but 2600 fps should be doable with a 350gr bullet using the Barnes Reloading Manual No.3 data.

Also good results with the Speer 416 caliber 350gr Mag-Tip bullet on heavy game. Other bullets I load are the Hornady 400gr and the Woodleigh 340gr. The 416's are impressive.

 

[HuntersStand]

Yep,love this rifle.Cant wait to blood it this season.Perhaps a bear in the weeks to come.
Looks to be quite the capable caliber and I like the article you posted from the 12th edition of Handloaders Digest in the "Grizzly Rifle" thread regarding 300gr bullets.
I also have some 300gr Barnes TSX on hand that still require some handloader experimentation with.Good dangerous game medicine by the looks of things.