NEW 6.5mm Prototype: A Tale of Two Bullets

[JASmith]

One way to get an early calibration is to run this code against the 123 AMax, then apply the adjustment to the Cerberus.

The 0.020" meplat is smaller than most. That is one advantage to the aluminum tip. Another is that it should be slightly more stable than the calculation suggests.

[newb]

Been following the topic, now subscribed.

[KentuckyBuddha]

I imagine I would do if I knew how. ; )

[stanc]

So, it's sort of combining the SOST and GMX into one bullet?

[BluntForceTrauma]

Stan, yes, probably as good a way as any to describe it. We want a core, after impact, that looks like that SOST core above.

Mushrooms would be fine, like a Barnes TTSX or Hornady GMX, I just felt they were too velocity dependent.

[Von Gruff]

You guys keep this up (superbly presented) and you will be converting me from the 123gn weight to these speedsters.

[KentuckyBuddha]

I imagine you might do fine with those considering the altitude and frequency of downhill dope...hard to image it would be too many goats you would have to let go because you didn't have enough pill to reach!

[BluntForceTrauma]

Got a USPS tracking order from my vendor, on its way!!

Next step is to develop and test loadings for velocity, accuracy, and terminal performance.

I'm a novice reloader, myself, so with Sneaky's help we're gonna do the grunt work to get in the ballpark so we don’t waste anybody else’s time or money. Then we’ll enlist the help of other experienced reloaders — who have chronographs! — to further refine loads.

I want to develop three loads: two using strictly XBR and CFE, and one using a “wild card” powder. I want to limit loads to XBR and CFE because I think they’re updated, widely available powders that the average guy can find, and can use for various bullets in the 6.5 Grendel, as well as for his other cartridges, so that he’s not stuck with a million different canisters. We’ll throw out the highest and the lowest and average what’s left to try and find a consensus.

BUT . . . the third loading using a “wild card” powder, will be just for FUN and to find THE single best powder for THE best velocity at SAFE pressures* with THIS particular bullet. We think we’ll start with 10X, but I am now looking for suggestions as to other good leads. I note that in Barnes' load data for the 6.8 SPC, that 10X gave best velocities with all their monometals, so I’m thinking it might be a good place to start with the Cerberus 90 monometal.

What say the unwashed masses of the Horde?

*Regarding pressures: I know Bill A. likes to keep it to an average of 50,000 psi. I'm willing to go up to an average of 52,500, because he’s very conservative and is thinking of a fleet of rack-grade military rifles that need to be wary of tolerance stacking and operate from Siberia to Arabia. I'm not so concerned with those limits for the average reloader who's tailoring to his own barrel and applying standard reloading cautions. Am hoping to provide pressure notes with loadings so you can decide for yourself what loads you're willing to shoot.

[lead chucker]

The more I read the more I'm liking this!

[customcutter]

Well I've only got 2#'s of 335, and 8#'s 322. But I haven't started reloading for the Grendel yet. I was planning on 335 or 8208, when I do. But, that was thinking about a 123gr pill. Don't know what would be best for a lighter one.... Hopefully some others will chime in with some thoughts soon.

[lead chucker]

Iv got plenty of CFE, XBR and benchmark. I think benchmark would be a good powder to try as well. It works great with the 90 gn TNTs and 95 gn vmax.

[BluntForceTrauma]

Have settled on three “wild card” powders to test under the Cerberus 90 bullet. This is not to take anything away from XBR and CFE, they may well give the best safe velocities with this bullet. I guess I’ve been assuming that they aren’t specifically tailored to the lightest bullets in the 6.5 Grendel, so I also want to try three whose powder burn rates are a little faster.

The three are Alliant Reloder 7, Hodgdon H335, and Accurate Arms AA2200. Each is a sperical powder with good flow and shouldn’t need much, if any, compression under Cerberus 90 in 6.5 Grendel. Hodgdon also had H4198, Accurate had AA2460, and Alliant had 10X, but they were close enough to the others and I wanted to spread the love among brands!

Why H335? Because it got the best velocities in Hodgdon’s 65G reloading data with the lightest bullets with pressures only about 49,500 psi.

Why RL7? Because Sneaky says it’s the heat! I’m not aware of any published data on it and the 65G so we’ll kinda be on our own with this one.

Why AA2200? Because AA2520 is MIA! Because Accurate says they developed it for the 65G, among others, and because it seems to have proven itself out in 6.8 SPC. In 65G with an 85gr it had pressure of 51,059 psi and second-best velocity to AA2520.

[JASmith]

Alternative Wound Theory for 90 Cerberus

The best bullet shape for maximizing a wound channel is a wadcutter, a flat-faced, sharp-edged cylinder. And the bigger, the faster, the better. But we are constrained by the caliber of any given cartridge, and so we try to make the best of it, and make bullets outperform their size...

An alternative explanation that happens to also fit part of John's description is to assess the area of the wound channel. Using this metric suggests that a needle point has the minimum possible channel area for a given penetration and a broad head arrow gets a much larger channel area for a given amount of penetration. The greater the channel area, the more veins and arteries are cut. Cut enough, and the cranial blood pressure drops to where the animal faints. This is the essence of the theory behind the Ideal Bullet Weight methodology.

Accepting just a small expansion for the design goal may affect the bottom line a bit, but we can turn to the underlying math to assess the bullet's effectiveness.

It should fare very well in that assessment, and its effectiveness on medium game likely close to that of the Barnes, Hornady, and GS Custom bullets.

[sneaky one]

We shall find the best way upon these bullets. Powders are fun, --if you have some experience with mid to quicker units.

For the newbs, rookies, and youngers,,,,,,,, chill. It is our time now to shine- you can learn a bit by studying powder charts, and more,- go online, do A Ton of research.

Learn it , Know it,-- Live It. AND , repeat it. Consistently.. Be a Marine.

[am4966]

Are you going to do gel test with the bullet before it goes on sale? Also how much does the aluminum tip weigh and copper bullet?

Love this, this is looking to be a great bullet for my sbr too!