Home Forums Hunting & Shooting Ask The Gunwriters .243” 92gr. Cavity Back Bullet experience

All,

Any experience with this bullet to in a 243 Win or any of the 6mm cartridges? I just picked up a neat little Remington 788 from a guy I work with and am looking for a do all bullet. Have a friend that shoots a 105gr. CBB out of his 6.8SPC and he is doing his best to talk me into them as my go to bullet for deer/antelope! Have to admit they look like a great bullet.

Thanks for your replies in advance!!

Elk Country

Sorry, never heard if them. IF you find them and like them, better stock up before they disappear from the market.

If you can't find them, or they won't shoot for you, no sweat; there are lots and lots of good 6mm bullets out there since the caliber is so popular.


Good luck.

EDIT: Those puppies look pretty long. You might want to verify with the maker that they'll shoot in your barrel, presumably a 1-9", and that the listed COAL will fit in your magazine.

Pappy,

I’ve talked to the guy that makes them and he said they shoot fine in a 10 twist barrel. They are looong for sure. I’ve also talked to Barnes about their new 95gr. TTSX and they are adament about needing an 8 twist for those bullets!

Elk Country

So Barnes is (I think you meant to say, damn spellcheck) adamant about needing an 8 twist for what is probably a somewhat shorter bullet, but the guy who makes them says these shoot fine in a 10 twist. Okay.

While it's an interesting concept, and they may be very good bullets, there are a few things on the website that make me go, "hmmmm." First off, the pricing. They show, "list price" and "our price." I'm sorry, but this is the manufacturer. Their price is the list price. This is out and out flim flam.

They go on and on about supposed ballistic advantages with what, to me, looks like a lot of speculation and conjecture being presented as fact. I don't claim to know everything there is to know about this stuff, but they use terms that, in sixty years of level II obsession with guns, shooting, ballistics, etc, I've never heard before.

If it were I, I'd get some and try them if I had some money to spend on $.80/each bullets. However, there are a number of proven bullets, cup and core and mono's, out there that I know would work for what you are looking for. Did you ask the guy who makes them if he'd refund your money if your 10 twist rifle puts them through a 100 yard target sideways?

105s probably won't shoot well in your rifle. They likely will be too long, and won't stabilize. As to the magazine, the 788 will give you lots of room to set a bullet way out there. Much more so than other factory mags. I built my custom rifle (243) on a 788 action. I am shooting 105 Berger hybrids but have a 8 twist barrel to do it. If you are looking for a good all around bullet for your 788, try Sierra's 85 grain game king, or noslers 95 grain hunting ballistic tip.( Not the varmint bullet) Both are very accurate, and perform well on deer and other critters.

I’m also thinking about the 85gr Barnes TSX. Any experience/thoughts with this bullet would be helpful. I’m just a little concerned about expansion as it isn’t a tipped bullet.

Elk Country

Ok, so a lot of guys who have never used the bullet are giving advise. I, on the other hand, have been using them for over two years in 6mm, 6.5mm, and 6.8mm.

For those that are saying they are too long to stablize in a slower twist barrel, you have to remember that they have a hollow cavity in the base of the bullet so the weight is concentrated in the center of the bullet, rather than the base. Therefore the main bearing surface of the bullet is right where the weight is concentrated, so yes, they will stabilize in a slower twist barrel.
As for the comment about the bullets on the website, I know for a fact that a lot of testing went into those bullets. The statements being made are fact, not made up. Extensive ballistic and expansion tests were done with these bullets prior to them being released to the public.

As for how they perform on game, I have killed deer with the 105 grain 6.5mm MKZ and the 105 grain and 120 grain 6.8mm MKZ bullets.

Here is a pic of inside the chest cavity of an Axis deer that was shot at just over 100 yards with the 105 grain 6.5 bullet. You can also head over to the 6.8 Forum for many more examples of kills with these bullets. Edit to add, the bullet was shot from a 6.5 Grendel. As you can see, even at lower impact velocities, you still get great expansion.

Interesting concept. What is claimed does make some sense concerning center of mass and center of pressure. I'm wondering abut the 2.5x expansion and penetration though. I also wonder about copper fouling--no rings to reduce the amount of copper being sheared off. Might try some in my 243's.

Edit to add: After closer inspection I see the bullets do have rings............

We just ordered a couple boxes of the CBB’s! They are having a Black Friday sale! I figure I might as well give them a try!

HandgunHTR,

Thanks for the hands on info. I’m really looking forward to giving them a try. Which 6mm cartridge did you shoot them in?

Elk Country

I shoot them in a 6X45, a 6TCU and a .243.

Alpinecrick, in the picture I posted, the entrance is on the right and the exit is on the left. If you look closely at the entrance, you can actually see where the petals started to open up just under the skin. If you look at the exit, you can see it really did expand at least 2X.

One thing I noticed is that they don't seem to think their bullets are made of gold, unlike many premiums. Pretty decent prices, actually.

Worth a shot (NPI, really!).

They look very interesting; I'm going to order some.

My two biggest doubts are the claim that the cavity back allows more powder to be loaded. Maybe so, but if a certain monolithic bullet weighs X amount, then the rear end is going to take up as much space no matter how its shaped, when seated to the same approximate overall length as similar spitzers.

Have also become a little leery of monos with very small hollow-points over the years, having seen more than one fail to open properly--the reason I much prefer plastic-tipped monos. (Large-caliber monos with big hollow points have always opened well.)

Sorry for the brain fart I had.Too much time in the cold has frozen my brain.

JB, the hollow point is pretty small, but they also have very defined pre-skived petals. which facilitate quick opening. In all the gel tests I was part of and all of the wound channels I have seen on game, I have yet to see evidence that one didn't open. The only thing I have ever caught in an animal was a petal from a 6.8mm bullet on a large Texas pig that was shot at a quartering-to angle.

That's a new concept to me!

Yeah, me too....

Length has nothing to do with twist rate???
That flies in the face of everything I thought I knew about twist rate calculations.

Sorry for the brain fart I had.Too much time in the cold has frozen my brain.

Hey, I understand! Winter has started in Montana....

MD,

I’m surprised to know you hadn’t heard of the Cavity Back Bullets! I’m also very glad to know you will be putting them to the test. I too prefer a plastic tip in my mono bullets (I use the 129gr. LRX in a 270Win and a 270 Wthby.). This little 243 will be used primarily as an antelope/deer rifle out to 300 maybe 350yds and my original plan was to use the Nosler 90gr. Accubond. I would love your opinion on that bullet as well!

Can’t wait to see your results and read the review!

Elk Country

Good luck trying to order them off their website, I haven't been able to!

What issues are you having Jim?

I just ordered some and had no issues. I am using Chrome if that makes any difference.

FWIW CBB does make plastic tipped bullets, at least in 30 caliber.

To many many of their claims seem like BS. Also the three petal design will have less frontal area than a four petal mono like a barnes TTSX or Nosler E-Tip. Less frontal area=less cavitation=less tissue damage.

Which claims "seem like BS"?

As for the continued comparison to Barnes bullets, they were not designed to compete with Barnes. Barnes bullets were designed to provide a mono-metal solution for people wanting to push bullets to extreme speeds, so the goal was to hold together better than a cup and core at those velocities.
Cavity Back bullets were designed to be used in small capacity chamberings (6.8 SPC, 6.5 Grendal, 300 BO, etc), hence the cavity at the back allowing for a bit more powder space when loaded to max mag length. The goal was reliable expansion at lower impact velocities, while still maintaining good integrity at higher. The reason for the three petal design was to allow for larger petals, which will provide more cutting while transversing the animal. They don't rely on cavitation to cause a wound channel. They cut as they travel (remember lower impact speeds). They still do a tremendous amount of tissue damage.

Again, I suggest that if you are wondering how well they kill, head over to the 6.8 forum and do a search. Plenty of first-hand experience shared there.

Handgun- I can click on add to cart but it doesn't "add to cart", ha. I'm on Explorer. I'm in no rush.

Most all of them.
And bullets dont cut as you described. This was proven some time ago as it pertained to Keith Style pistol bullets.

Yes, it was proven that Keith-style bullets don't "cut". That should be quite obvious based on the fact that they are not designed to expand. Their primary bullet channel is mostly created by crushing the material in front of it. So, your claim is that the entire wound channel created by expanding rifle or pistol bullets is caused by cavitation?

As for the continued claim that "most all" of the claims are BS, I can say for a fact that most of them are not.

The BCs listed are pretty much dead on, as confirmed by Doppler and actual field experience.
The expansion claims are based on ballistic gel and field experience as well. Multiple animals have been shot and the wound channels clearly prove out the expansion of the bullets (see also the picture I posted earlier). If necessary I can provide zoomed in pictures of the entry and exit wounds to help with understanding.
The claim that you can get a bit more powder into the casing while seating the bullet to the same OAL as other monometal bullets is also true.

HandgunHTR,

My 92gr. CBB for my 243 should be here today and I for one am excited to try them! I've run numbers comparing them to other bullets out there in 24 caliber and it is no contest!

If they are accurate in my gun I will order another 100 and will load them with utmost confidence they will do the job for deer and antelope and I may try them on a cow elk hunt planned for next fall!

Shoot straight!

Elk Country

And greater penetration.........

Not like a mono really needs greater penetration though.
If the CBB bullets really do expand to 2.5x their diameter than I wonder much that would limit penetration. Frontal area after expansion is primarily what determines penetration, there's no magic involved. Monos with their petals may expand to 2.5x their diameter, but the area between the petals means their is less frontal area to limit penetration. Which is why monos generally "penetrate like crazy".........

I never claimed that cavitation is the sole wounding mechanism.. However, the crushing action you mention is caused by cavitation starring shortly after the bullet encounters flesh.
As for the claims. Of the 5 made on the alleged benefits only one holds any water to me.. I could be wrong, but in the least they sound very fishy.

And one of the reasons monos tend to have smaller wound channels.

I've shot a bunch of deer and coyotes with the 243Win/85TSX combo @ 3200fps. Longest kill on a deer so far is 425yds and the wound channel looks just like it does @ 100yds.

What did they look like? size, etc?

I shot one with the tipped 80 from a 243 at 125 yards, broadside through both lungs and centered the heart. The wound channel was very narrow with little cavitation at all. That deer went over 100 yards with no blood trail.

The only way that's true is if they're putting more bullet weight outside the case, and that would be from nose design, not the hollow base. Doesn't look to me like the nose is designed that way though, given the bullet shape. The hollow base does nothing to increase powder capacity compared to the same weight with a solid base. There still has to be that same volume of copper inside the case, regardless whether it's a short solid base or a longer hollow tube, or triangular with a picture of Elvis inside. The only thing a hollow base does is make the bullet longer for more bearing surface or boat tail.

I took a look at their 6.5 Grendel bullets, and am super skeptical about some of the claims as well. There is no way that 118gr hollow point has a .501 G1 ballistic coefficient. Not a chance. Compare that to Hornady's 123gr ELD, which is a MUCH sleeker bullet with a finer tip, more weight than that 118gr, and field-proven ballistic coefficient between .496-.510 G1 depending on the gun and other details. The 120 SGK and 120 TSX are only .421 and .386 respectively; I think a realistic number for that 118gr would be closer to those, and at least lower than the 120 SGK.

These certainly might be decent hunting bullets, but it's wise to be skeptical of claims that are over the top like many on that website. Seems to me that they've implemented some very generous marketing, at best. Over selling stuff like that is way worse than underselling IMO; it means you're willing to lie to me to make a buck, AND think I'm too dumb to figure it out.

LOL I can't help it, some of the claims are pretty fun. Link here for those who want to read them. Cavity Back Advantage

This one is pretty good:
2. BY INCREASING EFFECTIVE CASE CAPACITY THE CAVITY ALLOWS THE CARTRIDGE TO “BREATHE” BETTER. RESULTING IN A SLIGHTLY COOLER BURN AND SLIGHTLY LESS VIOLENT ACTIVITY INSIDE THE CARTRIDGE CASE DURING PROPELLANT IGNITION.

The cartridge "breathes" better with this bullet, and burns cooler too. Sweet! Why aren't we all using these?


This one is good too, for those who understand pressure vs. surface area and the resulting forces:
6. THOROUGH TESTING HAS PROVEN THE CAVITY BACK SMOOTHES OUT THE PRESSURE CURVE BY CREATING A HEMISPHERICAL POWDER CONTAINMENT CHAMBER. AS THE POWDER BURNS AND PUSHES ON THE CHAMBER INSTEAD OF A FLAT OR DISHED BULLET BASE THE BULLET STARTS ITS MOVEMENT SOONER DUE TO THE INCREASED SURFACE AREA. THIS LESSENS THE PRESSURE SPIKE AS THE BULLET ENTERS THE RIFLING.

Cool, so drilling a hole in the bullet base means more surface area for pressure to push the bullet. It should go faster then, right?
(Yeah, that's not how this works. That's not how any of this works.)

Whoever wrote this stuff has made a fool of themselves, and doesn't even know enough to realize it.

Venturi effect? I doubt it, but Weatherby gets some mileage out of it.

Anyway, I'd care most about the terminal performance of light bullets pushed fast. I may try some to see how they work.

The claims are laughable, really..

Proof would be in the pudding.
Just may try some for the 762x39