Well I just got my model 70 back from the gunsmith a couple months ago. New custom stock. Pretty and fits great. I decided to change from 165 ballistic tips to 180 grain ones. Problem I am having is my best groups come with 73 grains of IMR 4350 and that is a bit hot. My speer book lists it as max but my Sierra stops before that. I am getting only slight stiffness in the bolt after firing them. No other signs of over pressure but I don't like pushing the limit like that. I only neck size and have loaded for this rifle this way for about 13 years with no trouble. My old load was 70 grains of IMR 4350 under the 165 grain bullet. I am thinking of picking up some benchrest primers and see if that helps with the lower weight loads. Also I am thinking about a powder change. All my friends swear by H4831 and I always wanted to try IMR 7828.
Is this a good place to start?

I always attain the best accuracy and highest velocity with Reloader 22 with both 180g and 200g bullets. It's a slower powder, comparable to IMR7828, but gives me much better accuracy.

For some reason the 300 win is different than 300 wby and Imr 7828 and H-4831. with the 165 in 300 win rel-22, and 180 and heaiver rel-25 seems to be the best and most accurate.

My 300 WM shot 150-175gr bullets (MK's), really well with H4831.
After 175gr., my rifle loved IMR7828. And did not like RL25...I dont understand all I know about that.
Someone mentioned RL22, and I concur w/ that.

I have RL22, 79gr. w/ a 168gr. Barnes XLC, 210 Fed. primers, 3.460 and H4350 77gr. 210 Fed. primers, Barnes XLC 168gr.

Go ahead and try IMR7828, and see if she likes it.
But, I did'nt have good results under 175gr...sakofan..

reloader 22, loads right out of the book, start low, use fed 215 primers...

165 is the perfect weight bullet, if you want it fast

jeffe

H4831sc gives me my best hot loads with my 300 win mag. I don't claim to be a powder expert but when pushing to find my hottest loads this powder seems to give good feedback when I am starting to get a litte too hot, along with velocities as good as any other powder at max and the best accuracy.

When I start to see those shiny extractor marks on the bottom of the brass I back off a grain and don't load it any hotter. And if I am going to shoot when it is really hot outside I back it off another grain.
If your bolt is sticky you are definitely loading too hot.

Give H4831sc a try, I use it exclusively in all my big game calibers 25-06 to 300 win mag. I tried several other powders but like to keep it simple and no other powders I have tried have beaten its performance to a significant degree.

My 300 WM is an easy 1/2" gun, usually better if I do my part, with 180 Ballistic Tips or Partitions (both shoot the same from my rifle) over 76.0 RL-22 and Fed 215. I quit trying different powders.....it seems RL-22 was made for the 300 WM

Ditto the 76gr RL 22 with 180gr. I also have great success with 70 gr IMR 4350 and Nosler Partitions. H-4831 ia also a superb powder but I don't have the data with me. jorge

I've had some great loads with RL-22, for both 200 and 220gr Partitions. Next up is the 165gr Partition, just to see how fast I can go and keep it accurate.

I have one question for everyone: How come no one ever mentions AA-3100?

My best paper punching load is 70gr AA-3100 behind the 168gr Sierra MatchKing. I can get less than 1/2" with it. It's also done well with the 220gr Sierra RN.

The Reloder 22 load mentioned is a true classic.

Perhaps even more classic is a similar load of H4831. With the slight variations in burning speed of this powder over the decades, it's prudent to work up from 10% reduced loads. But for some 40 years, the classic load has been a 180-grain bullet with 76 grains of H4831. That's the load I use.

Another load I've tried that may be even more accurate is 73 grains of IMR 4831 with the 180-grain bullet. This load surprised me by being such a tackdriver, clearly giving me smaller groups at 300 yards than the H4831 load. After reading a few articles, however, I found that many other shooters had similar experiences with this powder and load. Another winner.

IMR 4350 is an interesting choice in the .300 Winchester Magnum -- as you've noticed. It's one powder that does work well with really hot loads. It's also a powder that seems to have another sweet spot with slightly reduced charges. In the case of the .300 Winchester Magnum, the classic 1000-yard target load that has been used by Wimbledon Cup competitors for decades mates IMR 4350 with a Sierra Matchking. The load is something around 68.5 grains with either a 180-grain or a 190-grain Sierra Matchking.

A friend of mine loaded this charge of IMR 4350 with the 180-grain Ballistic Tip and reported one-hole groups at 200 metres -- more than good enough for any deer hunting at any reasonable range. The velocity hovers between about 2,900 and 2,925. That's plenty good enough with this bullet. If you can live with a bit less velocity, it might be worth experimenting with this classic load because it's been tested by the toughest competitors for decades and come up a winner at extreme range.

Neither IMR 4350, nor IMR 7828 gave the velocity I was trying to acheive. Using WW brass and CCI 250's and Nosler PArtition Protected point bullets I worked up to 77 grains of RL 22 and got 3,060 fps with good accuracy.

Rich Elliott

Another vote for AA3100. Velocity is running 3k outta my Sendero and groups are in the .3's. BTW, i AM using 190 grain MATCHKINGS!

[ 08-21-2003, 03:58: Message edited by: MSSmagnum ]

MSSMagnum,

I'll be playing with the 190gr MatchKing in a few weeks, care to share the recipe? Mine will be coming out of an A-Bolt.

If you could share the load you started with and the one that's giving you .3" groups I'd really appreciate it. And I'll be sure to work up slowly...

MSS,

How do you like that Sendero? I've been thinking about getting one as my anything rifle. Is it about 9- 9 1/4lbs with a scope and load? I either want a Sendero in 300WM or something else in 300WSM. I just can't decide! Regards,

Matt

P-17,
Thanks for the info. I never thought about dropping the load. I will give it a try.

I have shot my .300 Win mag since 1973. I started with IMR 4350, then went to IMR 7828 when it came out and thought it was very good. I then tried RL-22 and my rifle likes it to exclusion of all the others. My load is 75 to 78 grains and Fed 210M primer, depending on the powder lot. Good shooting.

Well lowering the 4350 did not work at all. However I got a couple promising loads. 67.5 grains of H4831SC shot a 3 shot 1 1/8 center to center group. I know I pulled the one that was out. The other two were touching. 68 grains of H4831SC came up with 7/8 center to center. Again one shot out and other two touching. This was with new Winchester brass and Benchrest primers. I will work with these two loads after I neck size the brass. I was shocked at the change in recoil between the two loads. The 67.5 load was mild but that extra .5 grain made it feel like what I am used to a magnum rifle feeling. I also plan to work up from 68 grains just to see whay happens as I know I am well below max.

I have been getting extremely good accuracy with the 180 ballistic tip and 80.0 grains of H1000. Sub- 1/2-inch groups @ 100 yds (if I am having a good day) and got a couple 5 to 6-inch groups @ 900yds. Velocity is a chrono'd 2990 to 3010 fps... and 80.0 gr is well below the listed max charge, which is 83.0 gr.

The 'smith who built my rifle (Custom .300WM Mod70, trued, re-barreled, McMillan stock, etc)- told me to try H1000. He said the burning rate was just right for good velocity at reasonable pressures... I hit on such a great accuracy load @ decent velocity right away, I never even tried anything else raised the charge a bit, but accuracy worsened slightly, and the bolt got a hair sticky, so backed it down to 80.0 gr.

YMMV

marc

I'm with jeffeosso, RL-22 is hard to beat, same with the fed mag primers. Been using RL22 in 300 win and wby mags for many years. I've had limited luck with 7828.

I have never loaded the 165grs bullets in my 300 Win mag, but have been loading the various 180 grs for more than 25 yrs. While most of the classic slow burners (H-4350..IMR 4350..H4831..IMR4831 ..etc) are all OK, if something better than RL 22 has been made
, then I would like to try it. In my experience when taking in to account velocity, accuracy, loading denesity, and pressure, this powder stands alone--In my humble opinion.

My magic powder for the .300 Win mag is RL-22. I shot all the others for years, then the RL-22 started giving me the great groups I wanted. 180 grain Nosler Partition or North Fork bullet, 78 grains (depending on the lot), with a Fed 210M primer, the 215's blow the group in my rifle. Good shooting.