7mm-300 Weatherby Berger Load Data

[pacowboy]

I just got off the phone with Bob at Capstone (owner of Berger), I was inquiring for load data for the 7mm 180gr VLD Hunting bullet. He informed me that they have not worked with this caliber but have had other requests recently for data for the 7-300 Wby and they are in the process of setting up to do some testing with this caliber in the next few weeks. I'm glad to hear they are working with this caliber.

He did not and would not verify that we could use the 7 STW data the I have heard many times over are basically interchangeable. It will be very interesting to see their load data results to compare the two calibers.

My dad built this gun back sometime between 1978-1980 and it will be awesome to finally see it in a load manual. We didn't have these types of bullets back then and with the 180gr out of a 28" tube it should be an impressive round. I'm in the process of switching scopes but there is one pic of it below.

Sierra had one page dedicated to this caliber in one of their 1970 load manuals. Mary-Louise Devitto used it to win at Williamsport. It's been used up there quite a bit over the years.

Can't wait for the load data to come out. Thank you Berger.

 

[Lefty7mmstw]

Barnes doesn't want to get sued for recommending something they haven't fully tested yet. Sierra did something similar with me when I asked for 25wssm data back when that was new. The data I got was so puffball that I scrapped it and went with other things.
As to your 7x300roy, I would use 7stw data starting 10% down and use rather slow powders (h50bmg, etc.) also to keep issues at bay as you get used to the rifle. You will need to know if your rifle is a standard throat or has a longer weatherby throat in it also. A standard throat in a rifle like this should make for 3.8" or so seating for a bullet like a vld. A roy throat would be a tenth or two longer. Also check twist rate as some of the big 7's were built with 10" twist and won't do well over 160 grain pills or so.
Stay safe by working slowly and asking questions... Good luck, it ought to be a hoot when you get her done.

 

[pacowboy]

Barnes doesn't want to get sued for recommending something they haven't fully tested yet. Sierra did something similar with me when I asked for 25wssm data back when that was new. The data I got was so puffball that I scrapped it and went with other things.
As to your 7x300roy, I would use 7stw data starting 10% down and use rather slow powders (h50bmg, etc.) also to keep issues at bay as you get used to the rifle. You will need to know if your rifle is a standard throat or has a longer weatherby throat in it also. A standard throat in a rifle like this should make for 3.8" or so seating for a bullet like a vld. A roy throat would be a tenth or two longer. Also check twist rate as some of the big 7's were built with 10" twist and won't do well over 160 grain pills or so.
Stay safe by working slowly and asking questions... Good luck, it ought to be a hoot when you get her done.

I have a lot of load data and was fortunate to speak with Howard Wolf the creator of the 7-300 before he passed. I just don't have any data for anything over 168gr. My rifle has a Douglas 9 twist bbl.

 

[Lefty7mmstw]

Compare your data with the known chambering (7mmstw) to see where you sit. A 7stw with a 175-180grain pill should eat around 86 grains of 50 browning powders like H50bmg, us 872, aa 8700, 867, or 869. You should net around 3100 fps in a 26" tube. My 7stw with a 8" twist shilen at 27" will do 3350 fps with a load I had doing 3400 fps in my old remmy sendero and around 3100 fps with 175's. I haven't pushed her yet but she seems happy with Retumbo and 183 Sierra pills. I'll get around to more load work up one of these days; I've been busy with other guns and work lately.

 

[Varmint Hunter]

Enough 7-300WBY shooters have used 7STW data to ensure that it is a good place to start. It's only inexperienced reloaders who think that you can just start at top end loads that get in trouble. I'd use the 7STW data without concern and work up loads as I normally would.

 

[pacowboy]

Just thought I would share this from the 3rd edition Sierra load manual.