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Cavity Back Bullets Thread

65K views 151 replies 47 participants last post by  nonnieselman 
#1 · (Edited)
I was asked by the mods to bring the thread about my new product over here while waiting for the site hosts/owners to get a hold of me for becoming a sponsor/vendor.
I was given permission to include our website.
www.cavitybackbullets.com

We should bring all discussions on the product over here until such time as they contact me.
There is a thread in the bullets listings started for results of loads and testing.

Currently we have in the 6.8/.277:
120 grain MKZ (Maximum Kill Zone)
105 grain MKZ (Maximum Kill Zone)
120 grain TMT (Tactical Match Target)

There is another 6.8 bullet in prototype as well. Feel free to weigh in on what you would like to see.

In the 6.5mm/.264 we have:
118 grain MKZ (Maximum Kill Zone)
105 grain MKZ (Maximum Kill Zone)

I am working on a company road map of calibers and weights and purposes and will make it public when completed.

Thank you all for you awesome support in our new venture!

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#4 · (Edited)
Tagging on for the latest updates. I finished opening up the front of a PRI mag today. I can now pretty easily load five rounds. I loaded up five of the 120s in my 270AR out to 2.34" with 36 grains of 8208. I'll see how they shoot tomorrow. My chrony crapped out on me so I'll have to wait to give some velocity numbers. I ordered a new one today from Midway.
 
#6 · (Edited)
The shortest I recommend loading them is 2.28 or 2.285. As the ogive will start being inside the case mouth after that. At that length they will fit in any mag except a Barrett.
Yes you will see improvement over a 95 TTSX at 2.28. My bullets have less engraving friction and a higher BC. They also expand more.

My bullets are designed to fit loaded at mag length but not SAAMI length. They also show great improvement loaded long. All reports so far have them running 75 to 100 fps faster than a comparable weight bullet, across both 6.8 and 6.5.
 
#8 ·
They won't go poof, they could just loose petals over the listed speeds. The petals will come off causing a substantial wound channel and the body of the bullet will continue straight thru. The 3 petals will radiate outward but stay together like 3 small bullets themselves.
Xman shot them at 3000 fps and experienced this.
Unlike a lead bullet they will not disintegrate.
 
#12 · (Edited)
As far as other prospective bullets. A 165 ish grn pointy .358 bullet for the mgp, yeti, and I think 2 other wildcats for ar15 would probably go over well as the 180s are the nice zippy bullets but there's only 1 or 2 to choose from -anything lighter is a pistol bullet that is going way faster than its designed for and is no good for hunting . The 180s are almost at mag length so the 200s and 225s have marked fps decrease as it heavier and all the extra bullet is eating powder space.

Personally I'd love a 220ish pointy copper bullet for the .452 velociraptor. Barnes 460 s&w bullets are 200 and 275grn one a bit to heavy eats up powder space other loses energy to fast with low bc. Your cavity back at 220 would prob be a really decent bc for a big bore. Most of the FTX are the only other ok bc 452 bullets are probably going to fast at close in ranges. I realize both calibers are smaller market but there's definite holes in the useable bullets available


I don't have time to try out these new 6.8 bullets this deer season but I'm looking forward to crop permit does in the spring, I'm thinkin that 120 is made for the 12.5" arp barrel
 
#13 ·
I was able to get out for about an hour with the Ruger PR 243.
The 105Amax loads didn't do very well but the 92gr CBB and 95 Berger bullets shot well under 1/2" at 100. 1 group from each measured 1/4" and 3 groups each around 3/8".
This is the first time I have had this barrel out and just dumped 42.5gr Re17 in a Win case with CCI BR4 primers and loaded the bullets to 2.8". No load development at all or OAL tests. Pretty impressive for a bullet that has never been shot before.
Now I just need a good 6mm Predator barrel to test them in.
 
#16 ·
I have already shot two deer with the CB 105 this weekend. I did not develop or chrono just loaded 29.5 and 30 grains to zero and shoot at deer.
I noticed the 30 grain A2200 load was super accurate but a little too hot in my barrel and gave fairly deep swipes.

I had them loaded out to 2.295". Would love to see the "porototype" be an 80 grain screamer with higher BC versus other 80 and 85 grain bullets. That would be something.
 
#18 · (Edited)
Chris- how did they perform on the 2 deer you shot? retain the bullet? or pass through? DRT? or run a bit? lots/little meat damage?
 
#21 · (Edited)
What would be a comparable bullet to begin load data? Are they similar the the Barnes TTSX?
Yes, comparable load data to a 95 TTSX or 100gr Accubond.
All my bullets can be used with similar weight load data.
As always start 10% low and work up.
Even single load ladder, .5 grain increments. Stop and back down at any signs of pressure.
 
#26 ·
Just ordered 100 of the 105 grain 6.5mm bullets. I will be using them in my 6.5 Grendel Encore barrel (24") and my 6.5 TCU contender barrel (14").

I also posted a thread over on the Specialty Pistols Forum. Although these were designed for MSRs these bullets will work great in the single shot handguns as well.
 
#28 ·
They are, they both sold out today.
There are more on the production schedule so it wont be to long before they are back in stock.
I will do a bigger run this time.

When I do the .225/5.56 it will be 65 to 70 grain in the MKZ. It is farther down the list but it is coming.
 
#37 ·
Has there been a ruling on the *best* powder and primers to use for the 105s or the 120s in 6.8 yet?
If you are running mag-length COALs, I believe AA2200 will give you the best performance. AA2200 will also do well with any other bullet you us in the 6.8mm so you really can't go wrong.
 
#40 · (Edited)
Here is my data with the 105 MKZ on my first range session. I shoot single powder charge vs velocity ladders when I first get a new bullet to find the performance boundaries and look for indications of the accuracy node. In this situation, I used 0.5 grain increments. Note I load longer than mag length frequently to look for better accuracy. I found the node for my rifle 18" ARP. I have continued to maintain 0.5 MOA groupings with the 105 MKZ.

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#41 ·
Xman, Robert, have any suggestions on what kind of jump this hybrid design seems to prefer? I'm going to start at -0.030" as in my chamber that puts the case mouth right at the first "cannelure" for lack of a better term, with the 120 TMT. I will be doing single charge ladder to start then fine tuning with seating depth once I find a powder and charge I like.


-Alexander
 
#42 · (Edited)
fast14riot, there is really no wrong distance off the lands to start with. If you don't achieve the accuracy you desire at a specific COAL, its important to make adjustments in COAL and try again. I use 0.015" increments. Because I routinely load long, I start at 0.010" off the lands and work shorter from there. Even if I load mag length, I start at 2.295" then try 2.280" and 2.265" if needed. Others report measurable changes with only 0.010" COAL changes. I started with 0.025" increments and have worked down to 0.015" and still see noticeable changes. Here are some examples of the benefit of adjusting COAL. The first one shows there can be more than one COAL that is accurate. The second shows that best accuracy is not always found right off the lands.
 

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#43 ·
I have found accuracy with them from .010 off to over .120 off.
We have been very careful with the hybrid ogive design to make sure they are easy to tune.
As Xman said, I follow the same discipline.
 
#44 · (Edited)
Yes I know about tuning the coal and it's benefits, I also know that hybrid designs often tolerate long jumps. Was just curious if a good length had been consistent for some people. BTW, in my chamber the TMT at -0.030" puts me at 2.43".

Xman, I coincidentally shoot the 110bthp at 2.270 as well, accuracy is good enough for me at mag length, similar to what your target shows there.

-Alexander
 
#45 ·
#54 ·
I finally have shot enough deer to warrant a report.

I'm currently using the 105 MKZ, 30 grain A2200 load, at 2.305" but only shooting this in my bolt gun because the pressure is too high in the AR. My velocities are similar to what others are getting in a 20" barrel.

With the 9 deer we have killed, I have not recovered a single bullet. Even with one shot through both shoulders the bullet exited. All the wounds were similar. The entrance was approximately caliber in size and the exit almost always just under 2" in diameter. On some occasions I'm sure there was bone coming through the exit so this might have made the wound larger.

All of the neck shots resulted in instant incapacitation but two of those were still alive and breathing so we put another round in the head as soon as we came up on the deer. This is exactly what I had always seen with either GS custom bullets or Barnes TSX/TTSX. I will say that the CEB Raptor has left the highest percentage dead right there, but the bullet I use is only 82 grains and muzzle velocity is up around 3200.

I have only shot one hog thus far, since we are in deer season, and it was an instantaneous DRT. The bullet hit the hog in the neck just cephalad of the shoulder edge. Thump....dump, no bullet recovery.

All of my loads so far have been extremely accurate, and I use the same basic tuning technique as XMan and Yama. They have been very easy to tune. I think with the weights we have right now, these will be better suited to the thick hide and bone of pigs, than deer, but when we get something around 80 or so grains, I am pretty sure those will upset enough to kill extremely effectively.

So far, so good. Great accuracy and higher BC is an advantage.
 
#58 ·
The newest additions are in.

168 grain 30 cal MKZ. 1700 fps low opening speed, opens to .840 inches wide in ballistic gel, 2.8x caliber.
In stock now.


125 grain 30 caliber MKZ. 1400 fps low opening speed, opens to .800 wide in ballistic gel.
In stock now.


All others in stock tomorrow
 
#59 ·
has anyone pushed either of these 308 pills from a 16" barrel yet? wondering what kind of MZ they would show from a 16" barrel

what about BC for these 2 bullets? have any numbers back yet for the BC?
 
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