7mm Weatherby and 160gr Accubonds - which powder?

[Dr. Vette]

Hi guys,

New to this forum but not new to shooting.

I'm getting ready to work up a load for a 7mm Weatherby that will be used for an elk hunt this fall. The plan is to use 160 grain Accubonds to give us good longer range performance, and I am using brass that is once-fired and has been shot in this same rifle. The rifle is a stainless Weatherby Mark V with a 26 inch barrel.

The 160 grain appears to be the point at which I could use either the H-4831SC or the H-1000 that I currently have on hand. Both appear to be good for this caliber and I don't see a clear reason to choose either one. I am currently leaning toward the H-1000 but that may change by tomorrow. :grin:

Any thoughts or recommendations before I get started?

Patrick

 

[onesonek]

While I don't have experience with the round, I would do up a load ramp with each powder and see what happens. But I also wouldn't negate the use of slower powders also.

 

[onesonek]

Oh,,,and Welcome to the forum Patrick.

 

[Elkman]

Welcome to the forum! You will find a wealth of info here. I have a 7mm STW, (slightly more capacity) that likes H 1000 with the 160 TSX and RL 19 with the AB. As you already have it give it a try. Nothing wrong with 4831 either. It has been a go to powder for the medium mags for years? Let us know how you make out

 

[nvbroncrider]

Probably 7828 SSC RL-22 or 25 Retumbo H-1000 any of your slower stuff as with any heavy for caliber and overbore rounds would be a good starting point.

 

[JD338]

Patrick,

Welcome to the forum.
I would suggest you load up both H1000 and H4831-SC and see which powder your rifle likes best. From there, you can tweak your load.
Let us know what we can do to assist you with your load development.

JD338

 

[DrMike]

Patrick,

Good to have you aboard. The 7WBY is a great cartridge that is woefully neglected today. I believe you are correct to look at 160 grain bullets, and the AB is an excellent choice in bullets for the velocities you will generate. As to powders, I've used both of the powders you list in the 7WBY, and each worked well. I believe the advice you have already received is sound. Test either powder and choose the one that gives you the best performance in your rifle. Were I to suggest another powder, I would likely encourage you to explore Retumbo and ReLoder 25, either of which give you good fill ratios and a tad more velocity.

 

[SJB358]

Welcome to the forum!

Can't really add too much, but I am with Mike and the others, hard to go wrong with RL25/RL22 in the 7 mags and 160's. Should be a pretty great combo.

 

[jmad_81]

Well, Not much to add from what has already been posted. I have played with H1000, Retumbo, and am starting on RL-25 in my STW. H1000 gave me the best velocity spreads so far, but not the most velocity. It has not gave me a stellar goup of any kind yet, but I got one or two that I think I could work into shooting pretty well.

I would give H1000 a try first, then move on if that doesn't work.

 

[FOTIS]

RETUMBO start at 70 and work up

 

[Dr. Vette]

I've got Retumbo as well, and was staying away from the RL-25, etc for temperature stability reasons. I've been on elk and deer hunts at 60 degrees as well as 15 degrees, and don't want to have issues with the powder if possible.

Sounds like I could flip a coin for either of my preferred powders and do well.

 

[DrMike]

I hunt in weather still more extreme than you mention. Winter temperatures can drop to -40 here, and August hunts can be in weather than is as warm as 70F. I use a lot of ReLoder powders, including RL22 and RL25 without problems. I've never lost an animal or missed a shot due to temperature insensitivity. To be sure, I work up loads using a number of Hodgdon powders for people that are convinced (on the basis of advertising) that they have a better powder if it is not "temperature sensitive." These powders work very well, but I've not been convinced that unless you are hunting in high heat you will realise an advantage.

 

[Guest]

Welcome to the Nosler forum, Patrick! You're getting great advice here, and you know which ones I'd try first. Can't wait to see the targets!

 

[Dr. Vette]

Welcome to the Nosler forum, Patrick! You're getting great advice here, and you know which ones I'd try first. Can't wait to see the targets!

Hey, didn't know you were here too! :grin:

 

[wildgene]

...this is from Ramshot Powders FAQ Section

"Most of our powders are not insensitive, and will show some effect at hot and cold temperatures.

However, we test at -40F and +125F and the deviation in most cases are ca 3% to 5% at these extreme levels. Therefore most shooters do not notice much difference under normal practical hunting conditions.

More elaboration on the subject:

Complete temperature stability can only be achieved with tubular extruded powders designs, either with double base (NG) and/or with other coating technologies.

Because the ballistic performance at extreme temperature is completely dependant on the specific combination, it is very difficult to quantify and qualify.

Our standard powders perform very well at extreme temperatures, and usually pass the strict military requirements by a large margin.

This is a subject that often fraught with misconceptions and inaccuracies.

The term is used loosely by manufacturers without qualifying the subject, and is obviously exploited for marketing purposes and perceptions.

The facts are:

Although powders can be improved, it’s really only possible with advanced coating procedures and additives which increase the cost.
A particular powder can be improved re temperature stability for certain combinations, within a certain envelope which is specific to the following three main parameters/aspects
The caliber.
The weight of the projectile/bullet.
The performance level.

If any of these parameters/aspects go beyond or outside the intended ratio/s, the results will change and the performance will sometimes be different.

It is also very important that when a comparison is made, that all conditions re weapon i.e. components primer, case, bullet and the velocity are equal, and preferably done at the same time on the same day."

...there are a lot of factors/ changes that can affect your loads, temp sensitivity is just one, more of an issue w/ match/ target shooters. I'm a fan of checking my "cold bore zero" as often as possible, if there's a problem that's when you'll find it...

 

[Guest]

Welcome to the Nosler forum, Patrick! You're getting great advice here, and you know which ones I'd try first. Can't wait to see the targets!

Hey, didn't know you were here too! :grin:

Glad to see you found your way over here. This is one of the best three or four forums on the internet. You're going to love it here!

 

[Elkman]

Dr. Mike Says
I've never lost an animal or missed a shot due to temperature insensitivity.

Mike what are the symptoms of "insenistivity" I have shot down to 0 F. and near 100 F, but I really don't know what to look for I guess?

 

[DrMike]

Good catch, Bill. I meant to write "sensitivity," but my fingers were moving faster than my brain. :grin:

 

[R Flowers]

Lot of responses already, all good.

I shoot a 7mm Weatherby Magnum and have pretty much used 160 grain bullets all the time.
I used to use the 160 Nosler Partition with great success, but have had to switch to the 160 grain Barnes TSX for use here in California.

My top two powder choices are RL 22 and IMR 7828. Besides my own 7mm Weatherby I have loaded for a few others and one of those two powders has always worked out best for me.

My own rifle prefers a max load of IMR 7828 over a Fed 215M primer.

 

[REDGREEN]

I have found that IMR 7828 gives the greatest velocity. Reloader 22 gives excellent accuracy, but nowhere near the speed of the 7828. Best accuracy is at maximum.