ADI make Retumbo and it is packaged in the states under the Hodgon banner..................the equivalent Aussie powder is AR2225, the same system is used with Varget and AR2228, the latter can be exchanged in regards to loading data and I gather that Retumbo And AR2225 is the same.

Reason I ask is that AR2225 data for the .300 RUM seems mild but Retumbo loads that people are using in the states seem much more in line with what the .300 RUM can do. In particular with 200 gr bullets the data in the ADI book seems anemic and mixed up heaviver bullets using greater charges than lighter bullets etc. and it would seem that Retumbo is the same powder just as Varget and AR2208 are the same.

I want to follow Retumbo data........................can I ??

PC,
No 300RUM in the safe so this is speculation only. The ADI data I reckon is sourced from Hodgdon, that's why its pressure listed in the ADI manual. Ditto the WSMs,RSAUMs,RUMs. These cases are pretty strong and I'd not be surprised if what we reloaders consider "classic pressure signs" didn't show at above 65k psi pressures in these cartridges. Near 3000fps with AR2225 is pretty damn good. Why risk yourself and stress the brass for an extra 100-150fps? Also you need to ask "She who must be obeyed" for a chronograph for Christmas, without one your operating in the dark.
Cheers...
Con
PS: Regarding the 200gr and 220gr load data, unknown factor is what projectile was used. A long spitzer 200gr could take up more case space and have a potentially lower charge than a shorter blunter 220gr RN. Then again it may also be a misprint???? You need a chronograph and to work up in your rifle as there are some scary loads in the ADI manual.

Con,

the bullet that was used for the 200 gr data was a Barnex X bullet........................this makes sense withwhat your saying, I gleaned this from looking at the Hodgon website as the load data was excatly the same as the ADI book for the .300 RUM only they also give what bullet was used as well.

We know that you have to back off with the powder when using Barnes X bullets as they have a greater bearing area due tothere length.

Many RUM shooters both here and on Long Range Hunting use 88-97 gr of retumbo behind the 200 gr Accubond. At 86gr there is almost to much room in the case. So 81-86gr seems very mild (ADI's loads) and then they have 84-89 for the 220 gr bullet which is stupid, I got one of there standard reply's when I asked about this anomily.

ADI Reply Below.

Thankyou for your recent enquiry with regard to reloading using ADI Sporting powders.

The loads listed in our guide have been determined using calibrated test equipment under controlled conditions and are inside the pressure limits for the case.
It does seem unusual that there is an increase in charge weight when using a heavier projectile in the case between the 220 and 200 grain projectile but differences in projectile manufacturers and even test conditions can allow this. You will notice that the pressure is lower in the 220 grain data. The loads have been developed so the maximum charge weights chamber pressure produced fall slightly below SAAMI limits and different projectile types will not produce be the same pressure as one another.

This emphasises the point that loads should be worked up carefully from starting loads for individual firearms, as drastic differences in chamber pressure are possible.

Unfortunately the 0.585 Nyati information you have requested is not available. As you can imagine with the vast number of different firearm types and components it is impossible for any one company to completely cover all possible loads.

ADI has made the commitment to supply data for the most popular loads required by the Australian and New Zealand market. We do this by undertaking our own test firings and exchanging firing data with our American distributor.

Unfortunately we do not have the resources to conduct testing firings for each individual enquiry that we receive. Your request has been logged, if or when more enquires are received in relation to this load ADI will conduct its own test firings, and the data will be posted on our web site.

Extreme caution should be taken and loads should be worked up accordingly. Refer to our website at http://www.adi-limited.com/handloaders-guide or our handloaders’ guide for more information, warnings and reloading safety.

We thankyou for using ADI Sporting Powders.
Yours Sincerely
ADI Technical Centre


I filled one RUM round with 92 gr of AR2225/Retumbo and there is still plenty of room in the case but the right amount if you know what I mean.

I will be careful of course.