I've been working with a .25 WSSM for about four years.
It is a Winchester M-70 FWT. Trigger job, bedding and all. It has been the most difficult rifle I have ever worked loads for.
Finally, I got her to shoot.
I had been workng with different bullets 70 gr. to 120gr. Powders like IMR 4064 to RS Hunter and RL-19. Primers from Rem 9 1/2 to fed 215.
Results were awful. 1.7" groups to 4.0.
I had a lot of H-4895, so I worked with it.
I worked with 87gr bullets first. I worked a load just around 3300fps and got less than .350 for five shots. Worked with the 100 gr bullets and H-4895. Got 3000 fps and .376 for five shots. Ten rounds of each print the same POI.
All bullets were seated .0015 to lands.
I am happy about this. The rifle has had about 2000 rds. I am working with my .270WSM and am starting to see the same results with different bullet weights.

1/2

I've seen a lot of these posts about the .25 wssm

I have a .243 wssm and it shoots 1/2 MOA

There must be a problem with the 25

Those five shot groups are excellent!!
Not too difficult to get less than .400 for three shot, but tough to do for five.

What 87 and 100 grain bullets were you using?

Don

DMB, The 87 gr were Hornadys. The 100 gr were Sierra Pro-hunters.
I am beginning to think that this particular rifle has some sort of crown problem, even though visual inspection with a 10X loope shows a very clean crown cut.
I had been working with only BT bullets and slower powders with the aformentioned crappy results.
It was when I found a short supply of bullets and powders that I started to experiment with a faster powder H-4895 (because I quite a bit).
The bullets just happened to be flat based because that was all that was available.
I again worked with what I had of the Nosler 85gr. and 100gr. ballistic tips with H-4895.
Results were improved, but not acceptable.