Load development and tuning ES results for 300 WSM

[JamesnTN]

I've been testing a different bullet in my 300 WSM and thru my testing I began with powder charge weights of increments of .5 grains. I had settled in on 63.5 grains of H4350 with a 210m primer in Winchester cases and the old Berger 190 VLD match bullets.
Once I got my powder charge I began testing seating depth and I started at .010 Jam and worked back in .005 increments and settled in on .020 off the lands.

Here are the results of the load with seating depth and powder charge I settled on, this was shot at 500 yards

With my ES in the mid to high 20 fps range I'm not happy with, so yesterday I shot the 210m and BR2 primers with same powder charge and the 210m came out on top, but ES still too high.

So today I decided to test neck tension hoping to get my ES and SD down. I had initially been using a .334 neck bushing thru all my other testing, so today I shot a .334, .333 and a .332 bushing. As I had figured it worked and groups held together. My velocity was way off and I'm not sure why but my guess it's just the barometric pressure. My loads up until today had been running between 2950-2960 fps.

Below are the three tests shot this morning with all the data wrote out next to them.
Again these were all done at 500 yards.

Reason for only four shots thru all my testing one is heat, next is once these bullets are gone there are no more as they have been discontinued. So I'm being stingy.

 

[tuttlefarm]

James, they tend to like more neck tension, .004 to .005 is common in my rifles I use a 332 bushing.

 

[nakneker]

Interesting, nice post.

 

[JamesnTN]

James, they tend to like more neck tension, .004 to .005 is common in my rifles I use a 332 bushing. They tend to like .004 to .005 neck tension.

Yes I found that out today ES dropped a lot from the .334 to the .332 neck bushing. Although the group showed a bit smaller today with the tighter bushing the difference I'd say overall would be a wash on a agged out avg. but the ES SD is what I was looking for.
I'm still a bit puzzled as to why my velocity dropped so much from this morning and yesterday mornings testing. I'm talking over 50 fps difference. All up until today this rifle and previous testing had always been in the 2950 fps range.

 

[Raythemanroe]

Twist? Barrel length? What is the intended purpose? I like the 210 VLD's H4350 somewhere around 2850fps using 210 primers.. They have .003 neck tension and jammed ten thousandths... What is the chambering? .339? .338? How thick are your necks?


Ray

 

[JamesnTN]

Twist? Barrel length? What is the intended purpose? I like the 210 VLD's H4350 somewhere around 2850fps using 210 primers.. They have .003 neck tension and jammed ten thousandths... What is the chambering? .339? .338? How thick are your necks?


Ray

12 twist 30" barrel I'm hoping to shoot 1k benchrest with the rifle.

I don't have a clue on neck thickness they are stock Winchester cases with a no turn reamer.

I started testing at .010 jam but it settled in liking to be jumped .020

 

[Raythemanroe]

WSM is kinda known to work well with a 28" 10 twist using H4350 pushing 210 VLD's somewhere around 2850 FPS..


Ray

 

[JamesnTN]

WSM is kinda known to work well with a 28" 10 twist using H4350 pushing 210 VLD's somewhere around 2850 FPS..


Ray

I had this built to specifically shoot the BIB 187 FB but I also went conservative on FB so when those dried up I could shoot 185-200 grain bullets. This is why the 12 twist and 30" pipe

 

[shawnmb]

This is the same load i used on my 25.5" 300wsm with 190s and 210m. I was right on 2900fps and had amazing accuracy. I cant remember neck tension or jump though. And those groups at 500 seem amazing to me, even if your es is 20fps.

 

[tuttlefarm]

Twist? Barrel length? What is the intended purpose? I like the 210 VLD's H4350 somewhere around 2850fps using 210 primers.. They have .003 neck tension and jammed ten thousandths... What is the chambering? .339? .338? How thick are your necks?


Ray

Ray, my load was H4350, 2830 fps, 210M, Berger 210 Hunt. My light gun neck was 340, In my heavy guns I used a 338 and a 336 neck. As long as I kept .004 + neck tension They all shot 5 inch groups at 1000.

 

[dragman]

Norma brass
S&Balance primer
208 amax
64.0 grains RL17
No pressure at all 3030fps from a 28" barrel. ES of 5fps

 

[BountyHunter]

I won a lot of matches shooting the 190 JLK and MRP with 210s in the WSM.

Do not be afraid to try MRP also.

 

[savageshooter86]

So neck bushing only changed ES?

 

[JamesnTN]

So neck bushing only changed ES?

Yes that's how I tweak my ES once I find a load that's working but the numbers aren't

 

[savageshooter86]

Yes that's how I tweak my ES once I find a load that's working but the numbers aren't

333B looks best vertical. Which did you settle on?

 

[JamesnTN]

333B looks best vertical. Which did you settle on?

332 bushing 63.5 grains H4350 210m primer