This is a good cartridge for a special situation. That is, extremely flat long range shooting requiring 5 or less shots.(essentially hunting) This is not a good target rifle. Too many idiosyncrasies. There is a good discussion on the 6.5/300 WWH in "Wildcat Cartridges" combo edition. This case is essentially the same. Though I suspect their listed velocities are way over pressure.

Pros:
1. Choice of bullets- I have even tried Lost river ballistics 120 gr. J36 hunting bullet goes at 3600fps with a BC of .687- (66000psi)
2.One of the flattest shooting rifles in existence.
3.Retained energy- with the above bullet- 2000 ftlbs at 600 yds!
4. Low recoil (I can shoot this rifle all day) with more retained energy down range than most .308 and .338 cartridges with hunting bullets. (ballistic coefficient is key)

Cons:
1. Barrel/throat erosion- figure on .010" per 100 shots as a minimum.
2. Limited powders- H870 works the best as far as pressure/velocity. H870 provides inconsistent velocities if the rifle is shot too fast. H50BMG actually is faster burning than H870 in my rifle and produced lower velocities. I have tried WC860 which works out to be a slight bit slower than H870 and works as well. With bullets over 100 gr., most other pwders are too fast including RL25, H1000,IMR 7828, and RL22. These powders give you low loading densities(80%) and lower velocity at safe pressures.
3. Fouling- your good for 5 shots then the pressure starts to climb.

Advice:
If you want a long range hunting rifle for game (not volume varmint shooting) and don't want to be punished by larger calibers you can make this wildcat work well.

If it'seally bothering you about the STW velocities, I save all of the Shooting Times mags and saw the 6.5 one a day or so ago if you didn't find the FPS stats you are looking for. Lex rebarreld a 700 for me in 257 STW, it shoots pretty good. Probably burns barrels and I am reminded of this by every "expert" that has ever shot a rifle. I knew this going into the project. I am building a 6.5 WSM. It should come close to the .264 Win figures, but fall short of the STW/Wby .

quote:

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Originally posted by GEG:
You guys are great!! I thank you all for the
help. I am going to take the advice Darryl
C. and chamber the 6.5-300Weatherby. His very
words where " Its a killing machine." The
30" tube 8 twist should make those 140's
SMK rock. THANKS again!! GEG

---

Are you sure you want 1-8"twist at those velocities and 140 grain bullet?

Wally

One of the main problems : "Somewhere around 10 shots will generally produce accuracy-destroying powder fouling".

Well, today you are not forced to use powders that leave a teespoon full of manure in the barrel. N170, 24N41 and 20N29 are very clean burning, 20N29 significantly slower than H-870. If you buy the expensive Lost River bullets (have ordered some myself), why not try the expensive powders as well? A 6.5STW is like a F-1 car, they don�t use standard engines in them either, just to save a few bucks.

Personally, I would go with the STW. I�m not convinsed that there is any benefit in the Wby shoulder. Said a man who will build a 30-378 Wby this spring... AKI

Just haven't got around to the other powders yet. The 20N... Haven't seen any available other than 8 lb kegs. I don't think N170 is going to be much slower than H870 though it might be cleaner. What I've found out is you don't know till you try. I've seen lists of relative powder burning rates and they are not correct when I actually get down to testing them. Too many variables to account for.

I have used WC 872 extensively in my .264's and haven't found any powder fouling problems. In the lot I have, WC 872 burns just a bit faster than WC 860, and notably slower than H 870.

All things being equal, it would seem that a faster-twist barrel would foul more quickly than a slower twist. I would recommend a 1-9" , or even perhaps a 1-10" barrel for a 6.5 STW, given the choice. The faster the bullet is propelled, the slower the twist required to stabilize a given bullet. It would follow that if a .264 Winchester stabilizes 140 well with a 1-9" twist, the 6.5 STW should be able to get by with less twist for the same bullet. The 1-8's are really intended for something like 6.5 x 55.

I really don't think that you would find any insurmountable problems with the 6.5 STW, but don't expect miracles. I doubt getting over 100 fps more than a standard .264 Winchester delivers. With WC 872 this is 3150 with a 140 out of a 24" barrel from one gun and 3225 from the 26". Pressures appear in all ways normal.

I have no use for the Weatherby-style radiused shoulder. By the way, you can use .264 dies backed out to load your 6.5 STW.

As for barrel burn out, the only portion which is really effected is the first few millimeters of the throat. My thirty-eight year old Sako has been fired a BUNCH and shows significant throat-burn, but other than taking a grain or two more powder than when new, it shoots with outstanding accuracy.

[This message has been edited by Stonecreek (edited 03-18-2002).]

If you want the ultimate 6.5 and are willing
to take it easy on your barrel this is it.

Ross
www.prairiegunworks.com

My Barrel is a PAC-NOR prefit barrel so its their reamer this has a very short throat OAL seated to the lands is 3.6" with LRB bullet. My goal was to be able to stabilize Lost River Ballistics(LRB) J36 120 gr bullet (length of bullet 1.335"). I looked around at twist recomendations and used available twist rate programs on the internet. For Hornady's 140 AMAX bullet they suggest a 1 in 7.5" twist. The LRB bullet is longer than the Hornady 140 gr AMAX. I figured with the increased velocity I would be ok with a 1 in 8" twist. These bullets do seem to shoot well I have also had good luck with 120 Nosler BT, but I never could get the 140 gr AMAX to group well. Personally, I wouldn't reccomend a 1 in 10" twist unless your going to shoot 120gr or less you might get away with a 1 in 9" twist. However, I never tried a 1 in 10" twist and can't speak from experience. Now that I have barreling and chambering capabilities I'm looking to make another 6.5 STW barrel. The next will be 30".
It seems most reamer specs. I've seen have short throats .1" or so. I haven't experimented with longer throats but this is a goal.
The information on the 264 Thor looks to be very similar to the 6.5 STW. Once you get this overbore, a few grains of powder capacity makes little difference. The case capacity in my chamber is 98.3 grains H20. Their stated velocities look about right for a 26" barrel. However, the powder charges look a little light. Maybe this is because the case capacity is less for the 264 Thor. I think when you get to these types of cases all of which work about as well use the one that is easier to work with. With the 6.5 STW all you have to do is anneal and size the neck. I have to admit the 264 Thor sounds cool.

[This message has been edited by grkldoc (edited 04-02-2002).]

For the light bullet I picked the 95gr Hornady VMAX which has a better BC than the Nosler.(.395). Here are some of the loads. Keep in mind this is before I started monitoring pressure.
95grHVMAX (BC=.395) OAL=3.550 27" barrel encore frame 1 in 8" twist
N560
81 gr 3809 2.40" group
82 gr 3876 .550" group
82.5gr 3950 .668" group
83 gr 4015 .850" group probably too hot

108 gr Lapua VLD(BC=.478) OAL 3.640 27" barrel encore frame

IMR 7828
79.0 3699 poor accurcy
80.0 3736

95gr HVAX OAL=3.495" 28" PACNOR 1 in 8" twist
H1000
78gr 3600 57000psi
80gr 3654 59000psi
82gr ? 64000psi chrono battery died

Sorry didn't spend alot of time on the lighter bullets.

Beware H50BMG is faster than H870 in this cartridge.
WC860 is about the same as H870 but alot cheaper($4/lb before shipping).
WC872 haven't tried, might be getting too slow.
You can also see the information on the "share your favorite loads" forum.

Didn't do any long range shooting yet. Just trying to figure out the loading data for now. A longer throat sure would give you more powder capacity But when its this overbore , I think, it would most likely make a small difference.