After searching the threads, it appears that there are 3 different powders that give the "best" results Majority seem to favor REL 15, H4350, or 4064.

Since I plan on loading 270 grain Swift A Frames, I looked at the Swift Reloading Manual and have decided to try the Rel 15 first. Their Max load shows a load density of 89%.

Their max loads for 4350 show a load density of 102% with almost identical velocities.

Will loads that approach 100% density tend to give better consistancy? What about accuracy? I load my 416 Rem Mag to about 97% with Rel 15 and it is extremely accurate (first three shots touch).

Almost forgot, what is the brass of choice?

What is your experience?

JBoutfishn

Suggest you try Varget. I've found it gives equal or better results than any of the 3 powders you mention. It also is an "Extreme" powder meaning it is less sensitive to temperature extremes than the other 3. Work up to 73 gr with the 270 gr bullet. They run 2702 fps out of my M70 with excellent accuracy. Loading density is close to 100%.

Larry Gibson

Thanks for the tip, I use Varget in my 243, extremely accurate, and I have some on the shelf

Another vote for Varget. RE 15 claims to be temp insensitive as well. It may be, as it is used in military cartridges as well.

I like Winchester brass.

Jim

I've always used Winchester 760 powder with my 300gr. Swift A-Frames (I don't shoot 270gr. bullets).

George

quote:

I've always used Winchester 760 powder with my 300gr. Swift A-Frames (I don't shoot 270gr. bullets).

George I won't hold it against you

Will check out all suggestions. I am retiring my M70 416 Rem Mag, and have a new CZ 550 Safari in 375 on the way. I say on the way because the great State of California says I must wait 10 days before I pick it up.

I have used Rel 15 and Varget in my 375 H&H, 338-06's, and 22-250 (Varget only). All with satisfactory results.

I prefer the Hodgdon powders for simple economic reason over the Reloder series. I can buy it cheaper.

If I remember correctly I was using 74 gr Rel 15, 270gr Hornady SP and reaching 2775fps.

If you're loading 300gr bullets, Varget and R15 won't produce anywhere near the top velocities before you hit the pressure ceiling. I don't know if it's changed, but IMR4064 used to be very temp sensitive so I quit it in favor of newer and better powders. H414 is better and will typically do 2500-2525fps in most 24" barrels w/o high pressure, it is the same as WW760. H4350 will outrun all of them by a good bit, typically 100fps or more.
If you're loading the 260gr or maybe the 270s, R15 will be the best choice, in my experience.

I also have a CZ 550 375H&H but I been using 270grain Barnes TSX. When I purchased the gun I really wanted to try RL15 but the local shop was out. I did have some H-4895, I use that in my Lott, H-4895 was listed as a powder in the Barnes Manual so I gave it a try....

The load with H-4895 shot so well I never even thought of testing out anything else and it also works very well on animals I have shot...all one shot kills...

Nominal velocity is 2700fps and I have shot many sub MOA groups with it while testing from a bench. It is a "faster" powder so no powder compression...With the Barnes TSX it works, not sure about Swifts..

Don't know about Swift's as I never use them. With Nosler 260's I use IMR4350, in fact I literally use IMR4350 for everything I load for and have for more years than I care to number. I shot a 20 shot group of 260gr Noslers using 75Grs IMR4350 that measured .70. That's good enough accurracy for me. I have used it successfully for 8 trips to Zimbabwe and it's taken everything I've tried to take. I don't have a chrono and merely refer to manual for velocity. If the load shoots I use it. I'm really not too impressed by numbers other than group size. If the group is small and consistent then I figure I can put where it will do the most good. Most of the animals I shoot can't read anyway.

Accuracy is obviously very important, but knowing the velocity your loads generate will tell you a lot about what pressure they are operating at, and for me that's more important. Going by manuals is hit or miss because of the number of variables involved.
As an example, I was recently shooting some 416 Rigby loads that contained H4350 and a 350gr TSX bullet. The Hodgdon website shows their top load to give 2518fps with this combination. I started at 5grs less than their top load and 10 rounds chron'd 255fps faster on average than their top load. There were no pressure signs observed, so what's going on? I'm not sure but I came down from where I started. With no way of knowing how fast they were going I might have went the other way, and I don't believe that would have been a good idea.

I've had great success with H-414 and like JohnS says, it's the equal of 760 ( or close to it). I shoot 300gr Swifts right at 2550 in temps ranging from the mid 30s to the 90s with no pressure porblems and very good accuracy. jorge

My 375 H&H gets 2530 fps from 80 grains of IMR4350 and 300g Sierra Gamekings. It is a compressed load, but impressive from a short (under 20") barreled Sako. No pressure signs either, but work up to it as most books don't list this anymore. BTW, new Win brass and Federal 215GM primers.

jorge and john s,
how many grains of h414 are you shooting? I've been getting good results with 76.5 grains in my cz550 w/ 300gr bullets but don't have chrono so don't know the fps i'm getting. I haven't worked the load higher yet, and am wondering if I should.

jjs,

quote:

The load with H-4895 shot so well I never even thought of testing out anything else and it also works very well on animals I have shot...all one shot kills...

Nominal velocity is 2700fps and I have shot many sub MOA groups with it while testing from a bench.

The Swift Manual has a load using 70gr of 4895 with a velocity of 2720...'bout right?

If my memory is correct, 2720fps was top listed velocity with max. load of H-4895, in the Barnes manual with the standard "X"..26" test barrel vs 25" for the CZ...

My starting load was 3 grains under max working up, the load I use is one grain under max. listed in the Barnes manual for the standard "X" but I use the 270grain TSXs.

I never gave the Swifts a try in my 375H&H...I am sold on North Fork Bullets and Barnes TSXs until something better comes along and Woodleighs Softs for the 470NE...

trekker,
until you can get your rifle shooting over a chrono I wouldn't go up any on the charge weights. Different barrels will digest differing amounts of powder and give somewhat different results. Your load is about maximum according to the Hodgdon data and I would estimate you to be getting somewhere between 2450 and 2500fps with 300gr bullets.

I've had good results with RL15 and Varget. Varget even gives you the load data you are looking for on the side of the powder keg. Isn't that nice of them?

Winchester brass and Varget work just fine.

My 375's shoot RL15,Varget and H414 extremely well. My go load in my M70 stainless is the Barnes 270 XLC's with 77 gr H414. Sub MOA at 200 yards. I have found that using a Lee taper crimper to put a light taper crimp on the finished rounds gives more accurate and consistent loads.

Each gun is a world unto itself. Several rifles like 74-75-76 gr of Re 15 with the SAF 270. Mine usually puts them under an inch. Best group of 3 shots is an honest .405 outside to outside. That combo works pretty dang well. "D"

I've had good accuracy results with IMR 4320, very accurate with 270 and 300 grains. No compressed loads. I have loaded 71 grains in a 270 (Hornady and Barnes X), 68 in a 300 (Hornady) I think RE15 is the most flexible powder with 375. Why not try H380 - a full capacity load with max velocity. I have some, just haven't had a chance to try it. Vit 150 might also be good, but no data I've found. WW brass, Win primers.

I have gotten very good results with RL-15 with 260 grain accubonds,a bit over 2700.I have also had excellent results with IMR 4350 with 300 gr loads.76.5 gr gives me a bit over 2500 fps with the hornady round nose,and I can't fit much more than 76 grains in the case with the Hornady 300 grain spitzers.Haven't chronyed any loads with 4831 yet but will this weekend.Out of a 25 inch tube.

Varget, RL15 and H414 work very well in my 375's. You should have good luck with these powders, most 375's are not finnicky to load for. Try H414 and some Barnes 270 xlc"s. Death Ray accurate in my M70 and very effective on critters.

JBoutfishin,

Just for grins, borrow a few or buy some Federal rifle primers (not the magnum, super flash ones, just plain rifle primers) and see if those dont tighten your groups with that .375 H&H. I'm betting they will. RL 15 works best for me to date but I'm going to try Varget.

The .375 H&H ain't at all finicky. I dearly love the Ole B*tch.

DB