I have a 243 Win that really likes the winchester supreme 55 gr BST does anybody know what powder winchester uses in this load ? Has anybody tried to duplicate it ?
I have always heard/read that companies use "special blends" of powder. Handloaders are not able to make an exact copy of the load, but the best way I would guess is to cronograph them. Then develop a load around that speed. The good thing about handloading though is you can usally beat the factory by 100fps and still beat the factory ammo accuracy.
Factory ammo and especially common rounds are loaded quite conservative. The quality of factory ammo has improved a lot in the past few years but I have always been albe to out perform factory ammo in either velocity and/or accuracy with handloading.
I have used the 55 grain ballistic tips in my .243 with good results.and as of yet not put much effort into the project. The accuracy is far greater than I can shoot it in a field situation. Their preformance on golphers is impressive. I used the RL 15 in Winchester cases; never did check the velocity but they sure shot flat.
I have put the effort into the 100 partions with excellent results and tend to use it on everything from deer and antelope to coyotes. It is just easier to keep the rifle zeroed for one load. If my primary target was non-fur bearing varmits I would get a lot more serious about working up a 55 grain ballistic tip load that matched my rifle.
In my 26" M77VT I used W748 powder with the 55 BTips with great success. Chronographed velocities were in the 4050 fps range, not max but highly accurate.
You can never duplicate the powder used in factory loads because it is not a canister grade powder like is sold to reloaders. The factories use bulk powders available commercially only; they can adjust loads with varying powders through the use of pressure measuring equipment. Too, the powder that a factory used in a .243 load in 2003 may be different than the one they used in 2005.
All were accurate (given the proper charge weight the individual Rifle preferred), and some were maximum velocity, while others were reduced velocity loads.
The accuracy winner in a couple different .243's was with Hodgdon's Varget. I do not have my load data sheet right in front of me, but if memory serves me correctly I was loading 1 1/2grs. below Nosler's published maximum.
In my current Ruger KM77RFP MKII .243 with it's 1 in 9" Rifling Twist I get the best accuracy with the 55gr. Nosler Ballistic Tips in the form of a reduced load at a velocity of 3300 FPS. When I get over this velocity level in this particular Rifle accuracy goes out the window.
This is not a huge problem for me as I mainly use this bullet-n-load for general purpose varminting in the spring and summer and rely on 70gr. Nosler Ballistic Tips for Coyotes and 95gr. Nosler Ballistic Tips for Whitetails.
