The 24 Mamba Project - Graybeard Outdoors
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post #1 of 46 (permalink) Old 09-09-2017, 02:22 AM Thread Starter
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Default The 24 Mamba Project

So no disrespect to Tennyson intended, "In fall an older man's fancy lightly turns to thoughts of more shooting projects."

Why a 24 Mamba? Cheap brass, cheap bullets and unbridled hubris that we can concoct the "universal round" that no-one else has been able to create to date! (I warned you it was unbridled.) Being the cheap ******* I am, I can preserve my investment in my 223 Short project rifle and just change barrels if I don't want to get a new rifle. Also the 223 Short is winding down for me when the final load testing is completed, hopefully by Spring 2018.

Short team AZ member George A's research has led us to understand that thru a case redesign using a larger case capacity, using new powders and bullets, a 30 shoulder to enhance accuracy and ignition, and using a Wylde throat specification that supports accuracy and higher pressures, we can build a single rifle that can excel at any varmint shooting, ethical large deer harvesting at extended ranges, and long range target shooting, while using 40% less powder than the 243 and 5% less than the 6mm BR.

What is the 24 Mamba?

A modified 6x45 that does not require a big investment in reloading gear or supplies to adopt it.

A 6x45 is a 223 Rem case necked up to 6mm/243 with no other changes.

The new design can use the cheapest and most common once fired brass; will need a custom PT&G finish reamer costing less than $200 for the team to purchase; will need a new barrel to be chambered; will need a neck expander before cases are fire formed; will NOT need custom dies; will be easy to develop loads for because of pre-existing data from the 6x45; will be economical to shoot for any required task.

The basic 6x45 design was revised until we reached a 6x45 + 8% case capacity, which brings it close to the classic benchrest 6PPC case capacity. George ran the numbers to discover the performance potential of the design.

A regular 6x45 has a standard 223 Rem .376 case body base and a standard .354 minimum taper, a standard 23 shoulder and a longer than standard neck length of .225", a standard 1.438 base to shoulder, and a standard 1.76 case length.

The 24 Mamba has a standard .376 case body base (0%) and a .369 minimum taper (-1.5%), a 30 shoulder (+30%) and a .203 neck length (-10%), 1.478 base to shoulder (+3%), and 1.76 case length (0%). We get the extra base to shoulder length from the 30 shoulder which is much shorter than the 23 shoulder, and the .020 neck length reduction adds to the case capacity.

We have not determined the maximum cartridge overall length yet.

Welcome aboard and stay tuned.

P.S. In pursuit of a more recognizable name for this new cartridge design, and in keeping with the team's first project recent official name change from the 223 Short v2 to the 22 Mamba, we decided to rename the 6x45AL, the 24 Mamba, in a direct reference to the small and deadly snake that bears the name, which is also known as "The Kiss of Death".

There are a few of common features the first two Mamba cartridges share, but we do not know if we will adhere to these with future designs. A 30 shoulder, a 0.007" case taper, a slightly shorter neck than is typical for the caliber, a 223 Remington parent case.
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Last edited by briannmilewis; 10-01-2018 at 12:26 AM. Reason: Rename
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post #2 of 46 (permalink) Old 09-09-2017, 11:16 AM
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Glad to be aboard Brian! I'll be sure to try and crunch the numbers today to find that max COAL were after.
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post #3 of 46 (permalink) Old 09-09-2017, 11:36 AM
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I have high hopes for this cartridge as I feel it will appeal to alot of people.

This cartridge in a bolt gun will give exceptional performance in the varmint fields and deer fields alike. This cartridge will open to the doors to our youth and our elder's that shy away from the heavy recoilers of yesteryears giving them a cartridge good enough to hunt with at respectable ranges, yet with less recoil and muzzle blast than most other cartridges in its class.

Being 6mm (.243) makes it hunting legal in most states and due to modern advancements in bullets and propellents this cartridge should yield performance beyond it's diminutive size.

One design goal we a shooting for which will make this cartridge a true triple threat is offering a affordable low recoiling long range ability. with modern high bc bullets like the nosler rdf, berger vld's, sierra match kings, and so on we can meet and exceed the tried and true 175 smk .308 load(m118lr) in external ballistics the military uses in their sniper rifles out to 1000 yards and beyond.

Last edited by squirrel_slayer; 09-09-2017 at 10:32 PM.
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post #4 of 46 (permalink) Old 09-09-2017, 02:36 PM
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Finally got a chance to make a dummy round with the 105 nosler RDF seated at 2.550"

From L-R .223 short, .223 Remington, necked up .223 with 105rdf prior to fire forming into 6x45AL, .243 Winchester
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post #5 of 46 (permalink) Old 09-12-2017, 01:33 AM Thread Starter
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Default Requested a PT&G Chamber Reamer Quote Etc.

I have requested a quote for a custom finish chamber reamer for the 6x45AL.

If you want to adopt the cartridge in a bolt rifle or single shot, you will need a new round barrel blank in .243/6mm, like the $110 1:9 from Green Mountain, or 1:8 if you can find one, if you don't already have a 6x45 barrel.

The potential performance improvement with an 8% case capacity increase and 30 degree shoulder invites the idea of upgrading current 6x45 rifles.

Ideally, you would be able to upgrade to the 6x45AL from a regular 6x45 by simply running the finish chamber reamer into the existing chamber.

Theoretically, because the body is longer, the taper is less and the neck is shorter, that should all add up to an easy upgrade.

However, if that does not work out technically for some reason, the alternative is setting back the barrel by cutting a small amount off the end, that should be enough to support an upgrade. <--- I have to run this upgrade idea past team member George first before we can confirm that. Stay tuned.

I will try and arrange either a reamer rental thru a commercial source, or some kind of reamer loaner program that will protect the investment in the reamer for everyone who adopts the cartridge.

Last edited by briannmilewis; 03-04-2018 at 01:31 AM.
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post #6 of 46 (permalink) Old 09-12-2017, 02:20 AM
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I will be following this closely!

Sent from my SM-G925R4 using Tapatalk
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post #7 of 46 (permalink) Old 09-12-2017, 09:06 AM
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Brian current 6x45 users should be able to do a straight re-chamber as the 6x45AL should clean everything up.(there are always slight variations from reamer to reamer) a single thread setback would be a wise idea to ensure a fresh chamber/throat.


While the $110 1:9 twist blank from green mountain is a great buy, if you want to run the long high BC vld's and have the full potential of the cartridge a 1:8 twist is a must have item. Cheapest I'm finding currently is x-caliber blanks at $175 unturned or $230 profiled (this is the route I plan to go) I still plan on hunting for a better bargain.
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post #8 of 46 (permalink) Old 09-12-2017, 09:46 PM Thread Starter
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Thanks slownsteady22 I hope we can keep your interest.

This should be a pretty quick and very low budget project for us to get some decent results.

It looks like 4D Reamer Rentals are willing to take donated PT&G Reamers and gauges into their inventory when offered. I have just started the conversation with them about doing such with the 223 Short v1.
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post #9 of 46 (permalink) Old 09-12-2017, 09:50 PM Thread Starter
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squirrel_slayer, AKA George, if I get a 1:9 barrel, I can play the role of the light bullet tester with another "truck axle" Savage barrel, optimal length this time, and that would free up the heavies for your testing.
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post #10 of 46 (permalink) Old 09-12-2017, 11:21 PM
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Fine by me Brian. you should still be able to stabilize the shorter hunting bullets fine with the 1:9 like the 95gr nosler partition possibly even 100gr spire points.

I think the 85-95gr hunting bullets will be optimal for deer. some say with good shot placement the 87 vmax is a good do-all bullet. I would feel better using a nosler partion or accubond or the sierra game king.

I could go on and on for awhile. lots of great bullets out there for the 6mm.

make sure you build a trailer to take that puppy into the field with.
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