Testing NEW 6.5mm Cerberus 90 Bullet

[sneaky one]

Thanks ROS, I think it's a minimalistic issue, yet- who knows . If I spin the bases - it should fix the problems. ?

I'll need a more than a few to test the theory . You too

Johnny, why did you sell so many ??//?/ AHHHHHHHH!!!!!!!!!

Eagle calling Raven!




The next run of copper pills is on hold , until the results of the next run of Brass pills come alive.

From BFT's fone today .

[ricsmall]

Got some numbers. Phone crapped out for a while but here goes.

Pill Groove width Band width Groove diameter

Gmx .072" .050" .250
TSX/ttsx .068-.070" .068-.070" .247
C90 Don't have .020front .256
.075 rear

Now, what this tells us I'm not sure, but I would think having all groove and band widths the same might help, might I say! I think after measuring the Barnes and hornady pills groove diameter that maybe the cerb90 grooves should be a little deeper. About .008-.009" deeper. My theory is that the deformation of the bullet may be causing erratic grouping. Something to look at. Anyone have pics of a ttsx or gmx recovered from gel they could compare to rickoshays pics of cerb90 recovered?

Richard

[sneaky one]

I sent all the numbers to RS , via the cell fone My specs were on the 90 Cerb. Ahh!

The depth of the grooves is not the issue .

Huh , upon his results ? Wait a minute ! ?

[kmon]

Not a 6.5 but a .375 270gr TSX recovered from a Nilgai, looks like the groves on this bullet are deeper in relation to the amount the lands go into the groves and not fully bottoming out like I remember the lands did on the Cerberus bullet. Not my bullet in the pic but borrowed from a thread on another forum.

[PA_Allen]

Here is a 100 TTSX that I recovered from water filled milk jugs.





- PA

[BluntForceTrauma]

Pix of a fired Cerberus 95 are in Post #4 of this thread if you want to closely examine the rifling marks.

Below I'm attaching a photo of what I'm trying to describe as a machining burr on the base of the Cerberus 90. Will try for a better picture later.

The way I am addressing any accuracy issues is to wait for and then test the upcoming brass version, the Cerberus 85CZ. Remember that everything we've been dealing with so far is Mk1 prototypes. This will be Mk2, the second iteration.

Now, granted, testing of this will not be rigorously scientific because we're changing more than one variable: 1) brass vs. copper (although external dimensions are the same), and 2) we are tweaking the aluminum tip design to try and get it to open up sooner. Gel testing reported it opened at 7 inches at 300-yard velocities. I would expect contact with real skin and bone might have helped it open sooner, but we tested as best we could at the time.

Speaking of testing, I would really like to test the new C85CZ on pigs. More on that later. And this is all provided we can get accuracy of 1 MOA or less at 100 yards. Not gonna risk needlessly wounding animals, even vermin like feral hogs.

[customcutter]

BFT, I think you've found the culprit. I don't think any of us would be happy if the crown of of rifle looked like that, and that is going to have the same effect whether it's on the crown or on the bullet.

In full defense of the machinist, copper is a nightmare as I learned when I was trying to duplicate what you first posted. It requires extremely sharp tooling, and the proper lubricants. I'll try cutting down some of the GMX's, but I don't think I'm going to bother making any more bullets from the copper rod I bought. That's a $25 lesson learned.

[BluntForceTrauma]

CC, hey, I've got zero beef with my machinist. I'm very excited to work with him now and in the future. Brass is his specialty. This copper is the first he'd ever tried it, so he's had a learning curve, as well. I'm sure Mr. Bartlein's and Mr. Krieger's first barrels, for example, weren't exactly screamers, and that takes away nothing from their talent.

Anyway, I'm HOPING that's the culprit, because it's easily solved. Stay tuned. . . .

[sneaky one]

That burr at rear edge of Tail may be! Dent is there too,. I'll spin my 5 left..... to see how they look.

[stanc]

Below I'm attaching a photo of what I'm trying to describe as a machining burr on the base of the Cerberus 90. Will try for a better picture later.

John, if you're talking about the little nubbin at the center of the base, I'm not sure that is likely to be the cause.

Consider the Lapua Lock Base bullet, which has a similar feature:

[Joseph5]

Stanc, if you look ar the edge of the boat tail there is a burr which is what they are talking about. I had to make the picture bigger to be able to see it clearly. There is also a small ding on the edge also that can be seen. It definitely looks like something the propel lent gases could be interacting with as the bullet exited the muzzle and they blow past it.

[BluntForceTrauma]

Stan, I'm not referring to the "nub" in the center of the base, but to a ring-like burr. Or is it a burr-like ring? I'd prefer the nub not be there, but it's part of the process, and as long as it's centered, it's not a problem. Which way are gasses going to push a perfectly centered feature? It's the burr out toward the edge where gasses start vectoring off, that I'm concerned about.

[ricsmall]

After those last pics I would think that ring is causing the problem. It'll be interesting to see the results of some of the cleaned up pills.

Richard

[stanc]

Stanc, if you look ar the edge of the boat tail there is a burr which is what they are talking about. I had to make the picture bigger to be able to see it clearly. There is also a small ding on the edge also that can be seen. It definitely looks like something the propel lent gases could be interacting with as the bullet exited the muzzle and they blow past it.

Stan, I'm not referring to the "nub" in the center of the base, but to a ring-like burr. Or is it a burr-like ring? I'd prefer the nub not be there, but it's part of the process, and as long as it's centered, it's not a problem. Which way are gasses going to push a perfectly centered feature? It's the burr out toward the edge where gasses start vectoring off, that I'm concerned about.

Roger. It looks like the copper is "flowing" slightly when the bullet is cut off the copper rod. I wonder if it's feasible to reshape the parting tool so as to clean up that burr?

[am4966]

Watch this video he talks about why you get the nipple in the middle and how to get rid of it. As always keep up the good work....

http://youtu.be/IK7nr352sjE