300 Weatherby 180 grain at 3200 plus

[NorthernWeatherby]

I have a Weatherby MKV with a custom 27 1/2" Ron Smith barrel. This rifle has a gain twist, ending in 1 in 9.8. I shoot 180GRN Nosler AB at 3350 fps with 84GRN of RL22, and the grouping averages 1/2" There are no signs of pressure and the load is well above Noslers "recommended" max load of 80GRN. Going to try for the 200GRN Nosler AB at 3200FPS. Also have fired the 150GRN AB at 3610FPS, but will not give the data as I had a lot of trouble getting the bolt open. Going out to try Retumbo and H1000 today......gun)

 

[betolatinlu]

Kraky,
I have pressure testing equipment, and I can tell you that even factory loadings with 180gr bullets at 3250fps are on the low side, contrary to what most say about Weatherby factory loads being HOT!
The difference is in how they're measured, SAAMI and CIP measure differently, and my testing has shown that you can get above 3400fps with the 300Wby depending on the powder used!

I do not advocate doing so without pressure testing equipment, that is why I didn't put up the load data, just stating that this cartridge is perfectly capable of such speeds!

The same as the 270Wby I own, it can get 3500fps with 130gr bullets, as does factory ammo, but if you look at any US data, it's a pipe dream according to them!
gun)

I have loaded my .300 Weatherby with 165 grainers using RL22 and chronographed them at 3450 fps with no pressure signs . However, when I go to my reloading manuals the velocities given for loads using the same powders are much lower --- and my Mark V only had a 24" barrel. I think I'll try 180 grainers after reading some of these posts .

 

[cmarcu1]

I wouldn't be using any of the above powders.
The best powder in both the 300WinMag and Weathery is RE25, it can give you velocities in the range of 3400fps with safe pressures!
A good starting load is 83gr's, max is 87gr's. Fed215's seem to work the best in my rifles.
Retumbo and RE25 use almost exact weight charges, you can use the same starting loads with either, work up carefully and stop at the first signs of pressure, but I doubt you'll see any with either powder.
gun)

I've been using RL-19 in my 300 Wby mag and am considering switching to the RL-25. I've read some reviews on temperature issues with Reloder 19 and 25, but have failed to see any evidence of this in Arkansas' seasonal weather. I was fortunate enough to find a Vandguard deluxe, with prettier wood than I've ever seen on a MK-V. I've been shooting a synthetic Vanguard for years now with the RL19, but I'm thinking of increasing the velocity with the RL25 and going from a 180 Nosler ballistic tip to a 180 grain Barnes TTSK. My original Vanguard seems to cut a tight clover leaf at 100 with the max load for the RL19, so I'm hoping a little additional velocity, better ballistic coefficient, and slightly lower chamber pressure will prove to be the ideal load for the new Vandguard deluxe. Has it also been your experience that the faster loads seem to group tighter in the 300 Wby mag?