6.5 x 55 and Hodgdon Benchmark

[Manitou]

Have any of you guys seen any loading data for Hodgdon Benchmark and the venerable 6.5 x 55 Swedish Mauser? I checked the Hodgdon website, and I couldn't find anything that paired the two together. Are this powder and cartridge a good match? Is the burn rate suited to a low pressure medium capacity cartridge? I'm always looking to better my groups with my sported '96. So far I've tried IMR 4198, IMR4064, IMR 4350, IMR 3031(best results) and Reloader 22. As you can see, I was stuck in the IMR mode for a while, but I want to branch out and try different powders, so........
Jaywalker and Wild Alaska and any other Swede fans, what do you hear about this powder?
Manitou

 

[Wildalaska]

I am pretty happy with Reloder 22.....

WildsorryicantdobetterthanthatAlaska

 

[Jaywalker]

No experience with Hodgdon Benchmark, but it wouldn't be my first choice.
Hodgdon Benchmark:

As the name implies, this Extreme Extruded propellant was developed for precision cartridges. As such, it is ideally suited for benchrest and small varmint cartridges like the 6mm PPC, 22 PPC, 6mm BR, 223 Rem. and 222 Rem. Additionally, it performs superbly in the 308 Winchester with light match bullets like the 147 gr. and 155 gr. versions.

From this description, it appears to be aimed at light, fast bullets, and 6.5X55 bullets seem typically to be heavy and slow. The one reference to a .308 is a relatively light bullet. It might work well in the 6.5 Swede, but, again, it wouldn't be my first choice.

I'm looking past RL22 lately. My five-shot groups usually (but not always) started out well, then through the session they'd begin to get bigger. I blamed technique, but it might not have been.

There are two other powder possibilities. First, RL22 is a double-base powder, and some folks do have trouble with consistency with that kind. Second, RL22 (and all of Reliant powders, except RL15) are temperature-sensitive, with velocity changes directly related to ambient temperatures. Load at 70 degrees Fahrenheit, and if you shoot at 30 degrees you might lose as much as 200 fps; shoot at 90 degrees and you might be looking at a pressure event. At the very least, your finely-tuned load is no longer finely-tuned.

To fix these possibilities, I've decided to develop some loads using single-based, temperature-insensitive powders - Hodgdon'e Extreme line. I'm trying H4831SC (because I got it cheaply), but H4350 might be even better. No accuracy results until this weekend, however.

Jaywalker

 

[Manitou]

Thanks you guys! I'll probably stick with IMR3031 or Alliant RL22.
Manitou

 

[sumpnz]

Jaywalker - Do you know how temperature sensitive AA powders in general and AA4350 in particular are? Reason I ask is that is what was used in the handloads I bought for my Swede (the 8mm ammo used AA2520). Thanks.

 

[Jaywalker]

sumpnz,

Sorry, no, I don't know. I do suspect it's not one of the newer temperature-insensitive powders, however. That's a pretty big deal these days, and you would expect Accurate Powder to market the issue if they'd re-engineered it; their website doesn't mention the issue.

Jaywalker

 

[sumpnz]

Well, at least when we worked up the load it was hotter 'n Hades (100F in the shade, it was actually a cool day for late June in Tucson). So, at least I won't have to worry about a pressure event when I go shooting, whether it's target practice in the middle of summer, or deer hunting in the upper elevations in November. Will, of course, have to re-zero for the colder temps.

What are some of the newer temp-insensitive powders (other than RL15 and Hodgdon'e Extreme as you previosuly mentioned)? I'm itching to set up for handloading so I'd like to have some idea of what to try aside from what was used for the ammo I've got. Any idea which would be a good ones to start experimenting with for 6.5 Swede and 8x57?

 

[Jaywalker]

Ramshot powders are the only other line of which I have heard are reputed to be temperature-insensitive, though they don't reference it on their website, either. As theirs is double-based spherical, it kind of ruled it out for me for awhile - looking for single-based. (Double-based isn't bad - it generally gives higher velocity, but I'm wondering about consistent, bughole-sized groups.)

I think if a manufacturer introduces a powder, or a powder line these days, they might have designed it as "insensitive," but you'd have to check that, since it's only a supposition.

Opinion here, but I think you could try almost any of the slower powders in these lines for the Swede. I'm trying H4831SC, and will try H4350 next, but writer John Barsness got good results with Ramshot Magnum and Hodgdon Varget.

Also, keep in mind that outside air temperature isn't the only temperature-related issue. If the cartridges are in direct sunlight, they'll be warmer than shade temperature. A hot chamber will heat the cartridges to oven temperature, also, increasing pressure and probably widening groups.

Jaywalker

 

[threefeathers]

After much experimentation I have gone with 4350, Lapua Brass, and 140 grain Sierra HPBT.