6 WSM Load Development

[SlimCreaper25]

I've started load development on a 16.5" 6 WSM. Goal is a 108-115 bullet at 3150 and be able to fit in a backpack. Most likely only get 600 rounds out of it if I'm lucky. Chambered with a zero freebore reamer and throated for 115 @ 2.960" to be able to fit in a magazine. I'm sure the smith will chime in at some point as he's a member here.

Rifle is built with the following specs.

Defiance Anti-X Action
#3 16.5" Brux 1:7.5 twist barrel (Hunting barrel)
SRS Ti Pro 4.
TT Primary Trigger
XLR Magnesium Chassis w/ Folder
NF 30mm Scope Rings
Tenmile 3-18x44 Mil

Currently has a Kreiger Fireforming barrel that was formerly a 6XC barrel that I had laying around for a similar action. I believe it's a 16.5" 1:7.5 twist?

Starting with Lapua 300 WSM brass that was resized to 6mm and neck turned (yuck...). I was hoping to use ADG 270WSM brass but it was unobtanium at the time. Maybe that would help with neck turning? I'm not much of a rocket surgeon in that department...

Started fireforming with some bullets I had laying around, 108 AMAX. I have H1000, H4831SC, VV565, VV568, VV570, RL23, RL26, IMR7828SSC and a handful of other magnum powders I can't remember off the top of my head. If you have suggestions from other similar cases/bullets feel free to chime in.

Utilizing 60.0 gr of H1000, initial speeds were in the 2800 for 108 AMAX and 2850 for 115 Dtac. Overall, good SD and ES to start with fire forming loads. I think I can stuff about 66 gr of H1000 in there before I start to see pressure, time will tell.

Follow along as I try not to blow myself up and see if I can't make something cool happen. I'm able to shoot about once a week so I'll try and upload as much as I can. As always, if you're reading this and want to start something similar, start low and work your way up.

 

[khuber84]

I'll be watching this thread, very cool cartridge.

 

[SlimCreaper25]

I'll be watching this thread, very cool cartridge.

Thanks! We'll see what happens. Should be pretty interesting

 

[The Fish Box]

Keep us updated on this one.

 

[Ice-kub]

I'm excited to see where this goes!

 

[PathFinder]

Very cool! It will be interesting to see how it compares to the 6UM-40. If it behaves similarly, N570 is going to be the speed king by ~100 FPS. You should be able to start very safely at 65 grains, and likely end up in the neighborhood of 70 grains.

 

[Ice-kub]

Very cool! It will be interesting to see how it compares to the 6UM-40. If it behaves similarly, N570 is going to be the speed king by ~100 FPS. You should be able to start very safely at 65 grains, and likely end up in the neighborhood of 70 grains.

I'm thinking 70gr should be close to max but not quite, should be somewhere north of 3100. I know it's not the same but I ended up at 72.5gr in a 7wsm with 175 bergers.

 

[SlimCreaper25]

Very cool! It will be interesting to see how it compares to the 6UM-40. If it behaves similarly, N570 is going to be the speed king by ~100 FPS. You should be able to start very safely at 65 grains, and likely end up in the neighborhood of 70 grains.

That's what I'm thinking too. Gonna try 64 gr and go from there.

 

[SlimCreaper25]

Shot 62 - 66 gr of H1000 today. Lots of pressure at 66 gr so I stopped there. Groups are looking ok, especially for fire forming, random seating depth (30 thou off lands), and a barrel that already had a 1000 rounds on it. Going to try VV N570 next.

65 gr did yield 3090 fps with slight pressure. Maybe after it's fire formed it will be better?

Shot 5 rounds at 650 yards for shits n grins that ran into a group about 7". I put my big NRL rig brake on there (.990 SRS Ti Pro 5) and could very easily spot shots.

 

[SlimCreaper25]

Shot 65 - 67 gr of N570. Very little pressure signs at 67 so I'm going to load up 68, 69 and 70 but I have a feeling I'll be cut short at 69, we'll see. 67 at 3070 is starting to get there. ES and SD of 570 hasn't been great though. Groups averaged about 3/4-1 MOA, pretty par for the course so far. I may try Retumbo after this.

Going to order some 109 ELDM as well and see what they can do. I have a feeling I can achieve 3150-3250 with those fairly easily.

 

[Arithson]

Following!

 

[SlimCreaper25]

Was able to get out early monday and shoot. Shot 68, 69, and 70 gr of N570. Results were meh. Starting to get some speed but saw pressure signs. I'm going to try Retumbo next and see what happens. Possibly H4831SC, N565 or 568. We'll see. I need to order some 108 ELDM soon.

Once all the brass is fireformed I'll put the other barrel on and fine tune from there. Looks like I may be able to get 3050-3100 pretty easily which I would be happy with.

 

[Dave Thomas]

It really doesn't matter what the groups look like since you will be switching to a different barrel.