Advice Please - 300 WSM Load Development

[Lpart]

I recently got my new build in 300 WSM. Trued Rem 700 action, Timney trigger at 1.5#, Bartlein #4 contour barrel, new heavy recoil lug, Defensive Edge muzzle break and Greybull Precision stock. I am shooting 215 gr Bergers and had hoped to hit 2850 fps. The only powder I have been able to do that with is Reloader 17 with .5 moa groups at 200 yards and 2874 fps. Extreme spread on 3 shot groups is 14 fps. The only problem is I don't trust his powder as I have read to many reports of temperature sensitivity issues and pressure spikes. I have tried both H4831SC and H4350. Can get about .6 moa at 200 yards with each but only about 2700 fps with each. I have worked up to 67.5 gr of H4831SC and 63.5 gr of H4350. No pressure signs with either yet. How suggestions on how much higher I can go with these powders? Are there any other powders and loads I should try. I used these because I have a supply of each and it is so difficult to source anything today. I did get my hands on some of the IMR 7977 which is supposed to be for the WSM's and can get velocities up to 2800 fps with very compressed loads at a max of 72.0 gr. but accuracy is not good.
I should mention this build is on a long action. I am using Norma brass and Fed 210M primers. Bullet seated out to 2.51" at ogive with COAL of 3.282. .056 off the lands and have experimented with deeper seating as well.

I would appreciate any suggestions any of you may have.

 

[Doublezranch]

Try RL 33. My 13 year old dumped 71.5 grains under a 165 matrix in his 270 wsm. Accuracy is extremely good and your looking at 3k +\- fps. I also think RL 26 might work for you to get your achieved velocity.

 

[Engineering101]

Lpart

RL-17, RL-26, RL-26 and RL-50 are all made by Nitrochemie in Switzerland and all share the same technology and have a temp drift rate of ~ 0.5 fps per degree F. This drift is much less than RL-22 and RL-25 which are horrible. I use the RL-17 family of powders for their outstanding performance and find I can live with the temp drift if I develop the load in temperatures within 15 degrees of those in which the ammo will be used. RL-23 uses a new tech and should be very temp stable. I haven't tried it yet but I don't doubt Alliant on this point. That one would be a good choice if you can find it. RL-33 is too slow to give top performance in the 300 WSM though it might be good in the 270 WSM which is much more overbore.

 

[Predator 22]

You might try imr 4831 or imr 4350 and try jummping your bullets less if you have room. I start at 15 thou off the lands and work back from there 10-15 thou at a time.

 

[Rick Richard]

I use RL 17 and I find very little difference in accuracy with changes from the 30s to the mid 70s. I would not be afraid of using this powder for year round use.

I find the 215 Hybrid performs well at @.040 plus or minus .010 from the lands.

 

[FEENIX]

I am right behind you in the load development. I'm not sure if I can but my goal out of a 24" barrel is also 2800 FPS, however, I don't have the LA advantage as you do ... my CBTO is 2.231" (COAL 3.03") with the 215s -- that's .046" off the lands.

My initial load is with IMR 7828SSC, WW brass, and CCI250; excellent group but tops with very light pressure signs at 2700 FPS (there's nothing wrong with it) with 64.4g.

I too have loaded H4831SSC but have not shot them yet. I have other powders to try but in line awaiting are Retumbo, IMR 7977, and RL 22.

 

[FEENIX]

I did get my hands on some of the IMR 7977 which is supposed to be for the WSM's and can get velocities up to 2800 fps with very compressed loads at a max of 72.0 gr. but accuracy is not good.

I should mention this build is on a long action. I am using Norma brass and Fed 210M primers. Bullet seated out to 2.51" at ogive with COAL of 3.282. .056 off the lands and have experimented with deeper seating as well.

IIWY, I'd play with the seating depth and see where accuracy gets you.

I am right behind you in the load development. I'm not sure if I can but my goal out of a 24" barrel is also 2800 FPS, however, I don't have the LA advantage as you do ... my CBTO is 2.231" (COAL 3.03") with the 215s -- that's .046" off the lands.

My initial load is with IMR 7828SSC, WW brass, and CCI250; excellent group but tops with light pressure signs at 2700 FPS (there's nothing wrong with it) with 64.4g.

I too have loaded H4831SSC but have not shot them yet. I have other powders to try but in line awaiting are Retumbo, IMR 7977, and RL 22.

 

[tailbon3]

You could give the new IMR 7977 enduron powder a try. I have no experience with it but it has all the right buzzwords on the can - temp insensitive, copper reducer, etc...

 

[Lpart]

I have tried the 7977 and it just won't group for me. Started low and went up to a very compressed load. Velocity acceptable, no pressure but poor accuracy.

 

[livtoohunt]

I just bought a 300WSM and am starting with IMR4350 and Hunter. Would love to get a 180 NAB to shoot well and above 2850fps.

 

[FEENIX]

I have tried the 7977 and it just won't group for me. Started low and went up to a very compressed load. Velocity acceptable, no pressure but poor accuracy.

Is that with 215s? What kind of velocity were you getting and what's your seating depth? Would be a nice info for others like myself also doing load developments. Cheers!

 

[Lpart]

Yes, that is with 215's. I got the velocity up to just over 2800 with a very compressed load. Rifle is a LA so bullets seated at 2.51" to ogive. COAL 3.238. I can't even get to MOA and I tried 8 different loads after doing the Berger work up on seating depth.

 

[FEENIX]

Yes, that is with 215's. I got the velocity up to just over 2800 with a very compressed load. Rifle is a LA so bullets seated at 2.51" to ogive. COAL 3.238. I can't even get to MOA and I tried 8 different loads after doing the Berger work up on seating depth.

That's a bummer, thanks!

Magpro is supposed to be the ticket but I don't have any ... at least at this time. Because of my limited COAL/mag clearance, I might have to settle for 2700ish velocity. I'll take accuracy over velocity anytime.

 

[Shortmagman]

I have had very good luck with two different powders in my Winchester Model 70 Coyote with 185 and 190 grain Bergers. With N165 and IMR-7828 I am getting over 2900 ft/sec and the accuracy is very good. I am not aware of how temperature sensitive either powder is but both work very well in my gun using Norma brass and WLRM primers.

I have used IMR-7977 in my 270WSM with good results, but I think it is a little two slow for the 300 WSM.