.300 Winchester Magnum / 180gr Peregrine Plains Master

[PHOENIX PHIL]

So calling load development in my .300WM done using the 165gr versions of this bullet, I moved on to the 180gr version this weekend. I had already shot a few of these in this rifle using IMR4350, but neither accuracy or velocity was all that great. Not horrible, but I thought it could be better.

So I moved in the direction of slower powders. I loaded both H4831 and scrounging around my various powders I found some Vihta Vouri N560 that I haven't a clue what I last used for. But why not. The N560 proved to be very accurate, but gave not exactly stellar velocity at about 2850fps. The N560 burn rate is also very close to the S385 powder in South Africa.

This the 3 shot group I got with it and about 2850fps.

This load of 71gr of H4831 didn't have quite the accuracy but a full 100fps faster at 2950fps.

In comparison to the results of the 165gr version of these bullets which was quite good too, I'm not sure why I'd use them now. The H4831 load above gives as good accuracy as the best 165gr load, but only about 50-60fps slower. With the increased BC, that pretty much washes out the small speed advantage of the lighter bullets. This was the first trip to the range with the H4831 loads, so I'll need to repeat this again, but both loads above and below this powder weight still gave decent accuracy. So I suspect this will be pretty close to the final load.

 

[Clayton]

Looks good to me. The magnums I've owned did well with H4831.

 

[PaulT]

Phil, I wouldn't worry about the groups.

I'm just relieved to see you hitting the target

 

[Shootist43]

Phil, how many grains of N560 did you use?

Do you by chance have a 35 Whelen? If so, have you worked up any loads for it using Peregrine bullets?

 

[PHOENIX PHIL]

Phil, I wouldn't worry about the groups.

I'm just relieved to see you hitting the target

Ouch, that's going to leave a mark!

 

[PHOENIX PHIL]

Phil, how many grains of N560 did you use?

Do you by chance have a 35 Whelen? If so, have you worked up any loads for it using Peregrine bullets?

Don't have a 35 Whelen, not sure I've ever even seen one in person to be honest. I started the loads at 71gr of N560 and worked in 0.5gr increments to 73.5gr, the max listed by Peregrine on their website. Saw no pressure signs at max load, but accuracy had dropped off significantly. The tight group above was at 72gr.

 

[PaulT]

Ouch, that's going to leave a mark!

All the very best to you and your family for a safe and festive Holiday season.
Enjoy Dallas, I miss the event and the people.

Best regards,
Paul.

 

[PHOENIX PHIL]

All the very best to you and your family for a safe and festive Holiday season.
Enjoy Dallas, I miss the event and the people.

Best regards,
Paul.

To and your lovely wife too!

 

[Jurie.300WM]

Don't have a 35 Whelen, not sure I've ever even seen one in person to be honest. I started the loads at 71gr of N560 and worked in 0.5gr increments to 73.5gr, the max listed by Peregrine on their website. Saw no pressure signs at max load, but accuracy had dropped off significantly. The tight group above was at 72gr.

Hi Phil

What was your COL for this load of 72gr N560?

 

[Dr Ray]

So calling load development in my .300WM done using the 165gr versions of this bullet, I moved on to the 180gr version this weekend. I had already shot a few of these in this rifle using IMR4350, but neither accuracy or velocity was all that great. Not horrible, but I thought it could be better.

So I moved in the direction of slower powders. I loaded both H4831 and scrounging around my various powders I found some Vihta Vouri N560 that I haven't a clue what I last used for. But why not. The N560 proved to be very accurate, but gave not exactly stellar velocity at about 2850fps. The N560 burn rate is also very close to the S385 powder in South Africa.

This the 3 shot group I got with it and about 2850fps.

View attachment 166841


This load of 71gr of H4831 didn't have quite the accuracy but a full 100fps faster at 2950fps.

View attachment 166842


In comparison to the results of the 165gr version of these bullets which was quite good too, I'm not sure why I'd use them now. The H4831 load above gives as good accuracy as the best 165gr load, but only about 50-60fps slower. With the increased BC, that pretty much washes out the small speed advantage of the lighter bullets. This was the first trip to the range with the H4831 loads, so I'll need to repeat this again, but both loads above and below this powder weight still gave decent accuracy. So I suspect this will be pretty close to the final load.

I personally would rather have a slightly slower velocity ( note slightly) and very good accuracy.
In my case the more accurate load that would give me a great deal of confidence.
The lighter bullet is probably better for thin skinned animals and of course the 180 gn bullets are more stoutly constructed for bigger and tougher animals.
If hunting big animals I suggest you tinker with the 180 gn bullet loads. I've used the 150, 165, and 180 gn bullets in 300 win magnum.
The problem with the lighter bullets is their ballistic coefficient and sectional density which means that they shed velocity rather rapidly. The 180 gn bullet is much better and sheds velocity relatively slower.
My suggestion goes back to tinkering with loads such as dropping 1 gn of powder less and so on.
Let's face it, a slightly slower but highly accurate load is going to give you so much more confidence especially when the shot offered is difficult.

 

[PHOENIX PHIL]

Hi Phil

What was your COL for this load of 72gr N560?

My rifle likes bullets set a bit long, so I was at 3.36 inches. The extra 0.020 inch over SAAMI makes a huge difference in accuracy in this rifle. I've never tried longer than this as I'm limited by the magazine from going longer.

 

[PHOENIX PHIL]

Let's face it, a slightly slower but highly accurate load is going to give you so much more confidence especially when the shot offered is difficult.

Completely agree.

 

[PeteG]

@PHOENIX PHIL , i'm a little concerned now as my accurate load with S365 is at 65gr. I dont know what speed it is doing, but might be a little slower than i would like!
Bugger!!!
back to the drawing board?!?! *&#$

 

[PHOENIX PHIL]

@PHOENIX PHIL , i'm a little concerned now as my accurate load with S365 is at 65gr. I dont know what speed it is doing, but might be a little slower than i would like!
Bugger!!!
back to the drawing board?!?! *&#$

Do you have a chrono to confirm? Also you may want to give S385 a go.

 

[PeteG]

No chrono.
I will have to put one on the shopping list next trip to rsa.

 

[Shootist43]

PeteG, send Alchemist a PM. He has done some work on 300 WM using Somchem powders and 180 Gr bullets. I'm sure he'll share what knowledge he has.

If you don't want to do that, do a "search" on AH looking for 300WM loads using 180 Gr bullets to get 2900 fps. with Somchem powder.

 

[PeteG]

PeteG, send Alchemist a PM. He has done some work on 300 WM using Somchem powders and 180 Gr bullets. I'm sure he'll share what knowledge he has.

If you don't want to do that, do a "search" on AH looking for 300WM loads using 180 Gr bullets to get 2900 fps. with Somchem powder.

Thanks, will send him a message.

 

[Dr Ray]

Don't have a 35 Whelen, not sure I've ever even seen one in person to be honest. I started the loads at 71gr of N560 and worked in 0.5gr increments to 73.5gr, the max listed by Peregrine on their website. Saw no pressure signs at max load, but accuracy had dropped off significantly. The tight group above was at 72gr.

I suggest that once accuracy has suddenly dropped off, you have reached the maximum pressure and I suggest you go down a grain or two.
From what you have stated I believe when maximum pressures that appear to be safe are reached, groupings become erratic.
Try a different primer with two grains lighter and then tinker. Magnum primers that produce a short but fat spark might help.

 

[Shootist43]

PeteG, That old thread that I was referring to was originally posted by SlushPuppy. The title of the thread was "300 Win Mag 200 Gr Max Velocity with Somchem S385." Read the entire thread. Alchemist made a number of posts to this thread. Eventually it got down to 180 Gr & Somchem S365 powder. Hope this helps.

 

[Royal27]

Do you have a chrono to confirm? Also you may want to give S385 a go.

He uses @spike.t and a stop watch.