338 Win 10 shot load developement

[truck driver]

I've had some Swift Sirrocco II loaded for what seems like for ever since the weather hasn't been very cooperative, scorching hot or raining.
Today was a bright sun shiny day mid 70s and low winds so I grabbed my grandson and off to the range we went.
The load for today was 210gr Sirrocco II loaded on top of RL17. This bullet has set me in fits since every time I've tried it I ran into pressure problems but not today.
Ran the load weight from 71.3grs to 72.9grs and here's what I got for velocity.
Ruger M77 338 Win 24"barrel.
71.1grs - 2940fps
71.3grs - 2973fps
71.5grs - 2977fps
71.7grs - 2968fps
71.9grs - 2966fps <---- Node
72.1grs - 2996fps
72.3grs - 2987fps <---- Node
72.5grs - 2994fps
72.7grs - 3016fps
72.9grs - 3032fps
What do the experts think? :grin:

 

[hunter24605]

Looks like you're on to something there...Ya, that's been my experience with it in 3 different rifles, I ran into pressure issues way before the data indicated I should (Swift data included) But when you're dialed in on it, it's a stellar performer..Funny enough, it was RL-17 that I ended up using in the 270 WSM for the best results.

 

[TackDriver284]

Hoping to see the results on paper if you done the ladder at 300 yards, to help make an assumption. I would try 71.3 to 71.9 again and see in .2 grain increments.

Sirrocco is an absolute hammer with good weight retention.

 

[SJB358]

I've had some Swift Sirrocco II loaded for what seems like for ever since the weather hasn't been very cooperative, scorching hot or raining.
Today was a bright sun shiny day mid 70s and low winds so I grabbed my grandson and off to the range we went.
The load for today was 210gr Sirrocco II loaded on top of RL17. This bullet has set me in fits since every time I've tried it I ran into pressure problems but not today.
Ran the load weight from 71.3grs to 72.9grs and here's what I got for velocity.
Ruger M77 338 Win 24"barrel.
71.1grs - 2940fps
71.3grs - 2973fps
71.5grs - 2977fps
71.7grs - 2968fps
71.9grs - 2966fps <---- Node
72.1grs - 2996fps
72.3grs - 2987fps <---- Node
72.5grs - 2994fps
72.7grs - 3016fps
72.9grs - 3032fps
What do the experts think? :grin:

It looks like a wide node between 71.3-71.9 to me which is almost exactly where mine fell out as well.

72.3-72.7 doesn’t look bad either.

How far off the lands did you set them? Mine came in real good at .050”.

 

[truck driver]

Scotty the OAL to the lands in the my Ruger M77 off the ogive is 2.743" and these loads the bullets were seated to 2.693" .050" off the lands.
I like the looks of the 72.3grs load since it is a diffident flat spot.
You may be right about the other one also as a low node but only shoot will tell.

 

[Divernhunter]

You might try a bit more jump. They really like jump. That could also help with pressure problems. I have a super accurate load for my 257R and by mistake seated them out where I seat some other bullets(Noslers) and got a shotgun pattern. Went back and seated them quite a bit deeper and they produced little tiny groups again.

 

[Dwh7271]

I’d try 71.6 or 72.3 and as the others have said, jump em pretty well.
There’s not a real big difference between the two areas so I’d take whichever shoots best.

 

[truck driver]

Thanks for the input everyone.