6.5-284 newbie, questions on powders, QuickLoad related

[DLrocket89]

Hi everyone,

I just put a Savage 111 XP on order at the local gun store, should be in mid-week. 6.5-284, 24" barrel. I've been eyeing up this caliber for awhile. Multiple applications in play: target shooting to 600 yards, whitetail hunting to 600 yards (from the same place I'll be target shooting from...can get solid/proven dope charts made), perhaps some competition shooting if I can figure this out well enough.

I'd like to develop two different loads with this gun - a hot/accurate load for hunting and a cool/accurate round for punching paper. Ideally I'd like to have the same powder and bullet for each, so I can buy in bulk when I find it. With that goal in mind, I went on a QuickLoad expedition. Went for the fastest safe accuracy node (as predicted by Chris Long's spreadsheet) and then worked to slower accuracy nodes from there. I put some boxes around it - I used standard case capacity, COAL, etc. I considered a powder "unusable" when the case fill dropped below 75% volume or the amount of powder burned dropped below 95% as I went lower in charge.

Really interesting results. The "typical" 6.5x284 powders I've read up on are H4831SC, H4350, H1000, etc. And those certainly showed that they can get up there for the fastest nodes, but their utility seems to drop off fast if running a slower velocity...they quickly get to not completely burned, case fill drops quickly, etc.

There were 4 powders that really seemed to shine in my analysis: Reloder 26, Reloder 25, Reloder 23, and Retumbo. H4350 comes in a distant 5th and at lower velocities across the board, especially at the lower end of pressures.

That all said, I haven't seen much info on any of those 4 powders being used in 6.5x284. One post on 6mmBR mentions RL-22 and RL-23 is supposed to be a temp-stabilized version of that. Those 4 powders should be able to span at least 4 accuracy nodes if not 5 each, so I'm hoping one of them that works. Having a single powder/bullet combo that can potentially bridge 3000+fps to 2500-fps and do so accurately would be a neat thing to have happen.

Otherwise, kinda flying blind here and wondering if anyone has any real-world data to support this? Nothing about these powders in any loading books that I have in print or have seen online.

Dustin
Milwaukee, WI

 

[Bart B.]

I'd like to develop two different loads with this gun - a hot/accurate load for hunting and a cool/accurate round for punching paper

Whats a hot/accurate load? Pressures way over 64,000 psi that's typical maximum safe average for cartridge brass?

How many rounds of that round's 900 shot barrel life with best accuracy will you use up testing with enough shots per group to be meaningful?

I would start with loads in 6mmbr's web site a few grains less than listed in not less than half grain increments. Shoot at least 20 shots per load.

Quickload's data is only an average; not exact what any one barrel and cartridge will do with a given set of components. All powder lots don't produce the same velocity for a given charge weight. All bore, groove and bullet diameters are the same for a given caliber. I called Quickload's rep to ask about that and he said the worst thing anyone can do is to take data it calculates as gospel; a 10% spread in actual numbers across all arms for that load is normal. Quickload is best used to show trends and averages; not what a given rifle and components will do.

Chris Long's shock wave speed in barrel doesn't match actual speeds mechanical engineers use. Speed in smaller round barrels is a lot slower than large bulk hunks of steel. Long says 19,000 fps; good for bulk. I say 16,000 fps is good for rifle barrels. That's about 19% different; greater than the OBT number spread his chart lists.

His accuracy standard is one MOA. Competitive shooters ammo with a 10% spread in charge weights will shoot MOA or better with any weight in that spread. I've had barrels' bore and groove diameters at the muzzle open up over .001" and no loss of accuracy. Chris Long can't believe that. His theories are easily and effectively challenged.

 

[DLrocket89]

Bart,

Many thanks for the detailed reply. As an engineer/technical person, I appreciate the detail.

To clear up some points - my goal for a "hot/accurate" load would be 3000fps and "minute of deer vitals at 300 yards" accurate to start off. 1MOA basically. My cooler practice round would be in the ballpark of 2500fps. The reason I want a cooler round is so I'm not burning the barrel up when practicing. And from what I've read, the 800-1000 round lifetime of the barrel is for benchrest guys, where they push the rounds hard and a barrel is considered "shot out" when the groups go from .25MOA to .5MOA. .5MOA would be GREAT from my point of view.

Understood about quickload. What I'm going for here is that there seems to be a broad range of useable pressures and velocities for the 4 powders I mention, less so for others. QL predicts 3100fps on the high end for RL-26 and 2500fps on the low end of usability. Does it really matter to me if those numbers are actually 2980 and 2400? Not really, I just used it as a comparative ranking.

That's really interesting on the speed in a small cylinder vs bulk. My friend is a PE mech engineer, I'm going to run that one past him. I assume the idea is something like it spends time interacting with the walls of the barrel and bouncing sideways in addition to forward? My friend and I were thinking about trying to find a super accurate/fast accelerometer and mounting it on a barrel tip and see if we can experimentally prove what's actually happening. I'll let you know what he says.

Wow, that's cool (the barrel bore opening up and staying accurate)! I never would have guessed that either. I think there's a lot going on here dynamically that no one really "understands" and there are just a group of collective experiences with a few theories thrown around. I'm the kind of guy who wants to understand the underlying principles, hence the questions here. And honestly, the journey is just as fun as the destination to me.

You say that Chris Long's theories can be challenged easily. Do you know of any competing theories I can read up on? Not necessarily challenging the validity of Chris's work, but more along the lines of something entirely different?

Thanks again for the input!

Dustin