6.5mm WSM Ammunition

6.5mm WSM is a wildcat rifle cartridge, formed from .270 WSM brass. I have had a custom precision rifle built using this cartridge. Its primary purpose will be as a target and tactical rifle, but I may also take it hunting.

Rifle: Lou Andrews Custom "Six-Five"

Current Load Development: I want to develop a good deer hunting bullet for this rifle.

Interesting. It has just been pointed out to me that the 6.5mm WSM is nearly the same capacity as the .264 Winchester Magnum (about 2 grains less). The .264 Win Mag also appears to have the same pressure rating as the .270 WSM. Hodgdon has told at least one 6.5mm WSM shooter to use starting loads for the .264 Win Mag. That gives me a lot of data to start with. Of course, my only existing load exceeds Hodgdon's data by at least one grain to achieve the same velocity. Still, it gives me something to play with for other weight bullets.

95 gr. Hornady V-Max

This is potentially my long-range (beyond 400 yards) varmint load. With a BC of 0.365, it should be supersonic out past 1000 yards. Assuming the bullet doesn't twist itself apart from the velocity.

The powder of choice appears to be H4831, and I would expect the velocity to be around 3750 fps.

123 gr. Lapua Scenar

This is my target load. The bullet weight is constrained by the R2 reticle I will be using. I am also going to follow my gunsmith's advice about the bullet. Therefore, the bullet used for this load will be the 123 grain Lapua Scenar bullet.

Bullet123 gr. Lapua Scenar
PowderHodgdon Retumbo
PrimerFederal 210
CaseWinchester (270 WSM)
Neck Diameter.290" (.2896")

My gunsmith will be supplying load data for this.

The target velocity for this cartridge is 3300 fps, and the 123 gr. Scenar has a .547 ballistic coefficient. The height of the sight is 2.115" above the bore.

RangeBullet Ht (in)Zero Adj (MOA)

135 gr. Hornady A-Tip

This would be a target load based on the new Hornady A-Tip bullet.

Deer Hunting

I would like to develop a relatively accurate deer hunting load for my Six-Five. I would eventually like to be able to take deer out to 600 yards. Whatever bullet I choose, I'll need to check the down-range velocity to make sure it will expand.

Hornady 143 gr. ELD-X NEW!
Hornady has released the ELD-X bullet, designed for hunting at long ranges. This bullet has a .625 ballistic coefficient. It would have 1500 ft-lbs of energy out to 700 yards and still be 1600 fps at 1175 yards. However, it's not bonded, and folks are complaining about the weight retention.
Nosler 142 gr. AccuBond LongRange NEW!
This bullet also has a .625 ballistic coefficient. 1500 ft-lbs past 675 yards and 1300 fps out to 1500 yards. This one is bonded, but may be too soft to perform at high velocities.
Federal 130 gr. Edge TLR COMING?
Another long range hunting bullet. They aren't being offered as components in this caliber, but they are being manufactured for the Creedmoor. I hope that means it is just a matter of time before it can be bought as a component.
Sierra 130 gr. HP GameKing
This bullet is a little tougher than the usual GameKing, and has an aggressive hollow point. The .355 ballistic coefficient isn't that great. 1500 ft-lbs of energy at not quite 400 yards. Not really a good long-range bullet.
Nosler 125 gr. Partition
Of the two Partition bullets I would consider, this one is closer to the weight of the Scenar I use.
Nosler 140 gr. Partition
This bullet might be more appropriate for a long range load. The heavier bullet will retain velocity better.
Nosler 120 gr. E-Tip
This bullet is a little on the light side, but if it is accurate, it might be a good choice.

August 4, 2008

This was my first day at the range with my Six-Five. We were using 123 grain Lapua Scenar bullets, Hodgdon Retumbo powder, and Federal 210 primers. Our target velocity, to work with the reticle near sea level, is 3300 fps (± 20). This looks like it is going to be in the neighborhood of 70.5 grains of Retumbo, although that may change as the barrel gets broken in the rest of the way.

We are seating for an OAL of 2.994"

65.5 gr. = 3030 fps
67.5 gr. = 3140 fps
69.5 gr. = 3250 fps
70.7 gr. = 3320 fps
71.5 gr. = 3350 fps

Lou recommends that I test from 70.0 to 71.2 grains in 0.3 grain increments.

Next Steps

Right now, I can load up a few more rounds using my existing brass and fire them at the range. I can fire form the rest of the turned brass I have, and break in the barrel a little bit more. And I can let Tim try it.

I need to get together everything I need to load up my own ammunition. I need larger neck bushings for sizing down brass. I need a neck turner, which means I also need a micrometer. I need a primer pocket uniformer and a flash hole uniformer. I might also want to get a new sizing die, since mine got shortened needlessly.

Once I have that stuff together, I need to work on developing a load.

Forming Brass

Cases for the 6.5mm WSM are formed from 270 WSM brass, manufactured by Winchester.

.288 = Normal neck size bushing
.289 = Alternate neck size bushing ... haven't tried

.305 = Necking down new brass, first step
.300 = Necking down new brass, second step
.295 = Necking down new brass, third step