Anyone Shooting Wildcat 338 252gr RBBTs

[royinidaho]

Got the bedding straightened out. Rifle started acting like a rifle again instead of a shot gun.

Loaded WC 252s in the 338 Win w/75gr RL-22 in several times fired full length resized cases.

First group was pretty large with the bullets seated a few thou off the riflings. COL = 3.416 or so to the bullet tip.

Shortened the COL "a bit" down to 3.305 just a random setting.

Group went 1.1 moa.

Upped the powder 0.5gr. Group expanded a sizeable amount.

Lowered the powder to 74.5gr and WAA LAA group too small to mention. /ubbthreads/images/graemlins/cool.gif

With the long seat I get 2865 or so. The Wildcat 252 shoots ~40 FPS faster than the Sierra 250 SPBT with all things being equal. I think this is due to the much shorter bearing surface. The two bullets are about the same length.

With the short seat the WC goes right at 2800. I'll chrono to make sure before I shoot for drop chart development.

The question is: do I care about the 50 or so FPS loss for the increased consistency when anticipating shots out to 850 yds or so /ubbthreads/images/graemlins/confused.gif

 

[Fiftydriver]

Roy,

With that bullet weight and BC level, loosing even 100 fps is not worth worrying about as long as your getting the groups. YOu will be far over super sonic out to 850 yards.

As you know, always take consistancy and accuracy over velocity for long range shooting, that is a given everytime!

What jacket did Richard use on that bullet? I suspect it is heavier then the Sierra and if that is the case then it is the heavier jacket that is lowering velocity, again, for use on heavier game, well worth the 50 FPS loss.

I have seen this with other Wildcat Bullets with the heavier jackets. Again, if this is a heavy jacket, that is probably the reason for the velocity drop.

Kirby Allen(50)

 

[royinidaho]

Richard said they are "hunting" bullets. I'll check on the box and see about the jacket. Possibly J3s but not sure.

I dislike my posts when I read them the next day /ubbthreads/images/graemlins/frown.gif

RE: Velocity. The WC gives more muzzle velocity than the Sierra 250 SPBT with the same amount of powder and the same distance off of the riflings.

RE: Velocity drop. In this rifle as the bullet, any bullet, is seated deeper into the case, the velocity goes down AND with the powder charge remaining constant.

I was hoping that the WC would shoot best when up close to the rifling. Thus more velocity and more powder capacity. 75gr RL22 is a bit compressed. But I "feel" that the RBBT handles this better than a flat base or regular boat tail, as I hear very little,if any, powder crunching when the bullet is seated.

Hornady's always shoot better when "jumped" into the rifling. Sierras always shoot better when nudged close to the rifling. It seems the WCs, at least these WCs like to be "jumped" a bit. (Just my personal experience)

Now its off to the "long" range to develop the drop chart. I'm using a bc of .587 to start as that is the published bc for the Sierra 250 SPBT (#2600). We'll see.

 

[royinidaho]

Kirby,

Here's the skinny:

.338 Cal .338 dia RBBT ULD .030 Jacket 252gr.

I'm not knowledgeable as to what 0.030 jacket means.

The few I weighed went right at 252grs so that routine seemed unnecessary.

I like the idea of not having to worry about the shots after the first one getting blunted. The jacket goes clear to the end. /ubbthreads/images/graemlins/smile.gif

 

[Fiftydriver]

Roy,

The 0.030" is the thickness of the jacket used in those bullets. This bullet will be stout enough to handle... well, Anything you would every want to point a 338 rifle at!!

Good luck at the longer ranges!!

Kirby Allen(50)