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Old 04-02-2019, 03:53 AM
squirrel_slayer squirrel_slayer is offline
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Default 22 Mamba

I have posted some information about this cartridge myself and Brian(.223 short) developed in the .223 short thread, but since I finally had a chance to get some hard data with the 22 Mamba, I figured it's worthy of it's own thread.

For those who haven't heard of it, it's a .223 remington based wildcat that is an improved variant of the .223 short which is Brian's baby where he wanted 22 Hornet performance but something that stronger/yet more obtainable brass. It is spec'd to be a no-turn, no ream just form, cut trim and go.

The 22 Mamba does benefit from fire forming however and gains 1/2 a grain with commercial cases (.3 with military brass) both cases are 1.125" long and the Mamba has a 30' shoulder with reduced body taper.

Test weapon 21.5" (as measured with a cleaning rod) Commiefornia compliant AR15 1:9 twist.

I decided to just try the 53gr nosler varmageddon with CFE BLK (man is this stuff like pixi dust! very fine)

Brass is 1x fired .223 FC brass which was converted to 22 Mamba and fireformed with 13.5gr of lil gun with a 40gr armscor bullet (which does 3316 ft/sec)

Used CCI 450 Primers with cases FL resized after fireforming (17.3gr capacity) 1.125" case length. 53gr Nosler Varmageddon seated 1.680" (we could have used .080" longer freebore with this bullet to my surprise) .275" of the bullet is seated into the case to keep it out of the lands.

I was only loading for pressure signs/velocity to try and find a ceiling before I open up the gas port and work on cycling. Powder is mildly compressed or right at the base of the bullet at 16gr I tested. I loaded 2 rounds of each increment.

On to the fun part.
15.0 gr 2807, 2772
15.2 gr 2766, 2789
15.4 gr 2789, 2855
15.6 gr 2861, 2867
15.8 gr 2855, 2904
16.0 gr 2904, 2936

Primers are just as round as installed so I could likely run a few 10ths more BLK until compression became an issue. Extraction was smooth and best part all 12 rounds fed flawlessly from the 10 round p-mag (did 10 then 2)

So how does this look on paper? using 2900 ft/sec with the .303 g1 nosler we have a 3" +/- MPBR out to 275yds where it still has 525 ft/lbs of energy.
I think we could eek 3000 ft/sec out of her if we leaned on it a little more but we'll see what Brian wants to do.

Been a long time coming but so far looks like it's paying off!

Last edited by squirrel_slayer; 04-02-2019 at 06:22 PM.
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Old 04-02-2019, 02:27 PM
visiter1 visiter1 is offline
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fantastic job looks brialllant
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Old 04-02-2019, 04:53 PM
Eagle_view Eagle_view is offline
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Very interesting, thank you for the report.

Lowell
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Old 04-03-2019, 03:28 PM
flyrod flyrod is offline
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That looks like a fun project, thanks for posting about it! I did a similar wildcat based on the 30 carbine because I wanted a better hornet. It's nice that it works out of a regular magazine. You should have plenty of room for any kind of bullet, which is usually a problem with the hornet. Do you plan to keep it in an AR? I'm always on the lookout for a small bolt action that would work well with this sort of thing.

Quote:
Originally Posted by squirrel_slayer View Post
It is spec'd to be a no-turn, no ream just form, cut trim and go.
Can you talk about case forming? It seems like the necks would end up really thick with the body of 223 cases formed into necks without being turned or reamed. Do you have a process worked out on sizing/trimming/annealing? It took me a few iterations to get thing working well. How variable are different types of brass? When necking down 30 carbine brass, I saw a wide variation in thickness and internal volume from different sources. To account for thick necks, the chamber must be fairly generous in the neck area?

How do you like CFE BLK as a powder? Does it burn clean enough? I'm pretty happy with 296 and 297, mostly because I can shoot a lot without needing to clean anything.

Sorry for all the questions; I'm interested to see a similar project!
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Old 04-03-2019, 04:45 PM
moorepower moorepower is offline
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How much shorter is this than the .221 FB?
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Old 04-03-2019, 10:33 PM
squirrel_slayer squirrel_slayer is offline
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Quote:
Originally Posted by flyrod View Post
That looks like a fun project, thanks for posting about it! I did a similar wildcat based on the 30 carbine because I wanted a better hornet. It's nice that it works out of a regular magazine. You should have plenty of room for any kind of bullet, which is usually a problem with the hornet. Do you plan to keep it in an AR? I'm always on the lookout for a small bolt action that would work well with this sort of thing.



Can you talk about case forming? It seems like the necks would end up really thick with the body of 223 cases formed into necks without being turned or reamed. Do you have a process worked out on sizing/trimming/annealing? It took me a few iterations to get thing working well. How variable are different types of brass? When necking down 30 carbine brass, I saw a wide variation in thickness and internal volume from different sources. To account for thick necks, the chamber must be fairly generous in the neck area?

How do you like CFE BLK as a powder? Does it burn clean enough? I'm pretty happy with 296 and 297, mostly because I can shoot a lot without needing to clean anything.

Sorry for all the questions; I'm interested to see a similar project!
This one is Brian's and he decided he wanted to try an AR. I also have a savage barrel to chamber for him. (won't work as a repeater so you pluck the ejector and manually remove cases) I have a 5.5" AR barrel I made for my PDW build and may re-chamber my savage barrel into a 22 Mamba

Yours in the spitwad correct? I was actually wanting to try a Howa mini like you have (unless I'm confusing you with another)

As for case forming thus far we are able to form from .223 straight to .223 short in 1 pass. I'm sure annealing would help but neither of us have taken the plunge on that yet.

On the 22 mamba using a homemade die (Brian purchased an FL resizer reamer) it will crush cases no matter what I try going from .223 (granted it's not hardened) however I played with the two dies and running the .223 short die backed off 2-2 1/2 turns I was able to size to 22 Mamba directly after (so 2 steps) again no annealing.

Necks are fairly thick (don't have an exact # off the top of my head but want to say .005" more than normal) and I'm sure the chamber is a little more generous than a match chamber, but with the .223 short we both were able to obtain sub MOA loads.

I don't have enough experience with CFE BLK yet to make a decision, however I will say the velocity generated and zero signs of pressure is a nice touch. seems pretty clean thus far but have only shot 12 rounds. we'll see how the accuracy goes. In the .223 short Lil Gun was the clear leader in the speed department however in my experience it has a very narrow window of useability. Accuracy and ES/SD were all over the place in the lower charges, once pressure got up both started to fall into place then boom your at the ceiling! (I gained 50ft/sec out of a 6" barrel with .2gr! then dropped 100 the next .2gr)

moorepower it's .275" shorter than .221 fireball and .100" longer than 22 TCM
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