The 24 Mamba Project - Page 5 - Graybeard Outdoors
Reply
 
LinkBack Thread Tools
post #41 of 48 (permalink) Old 10-22-2018, 10:05 PM Thread Starter
Senior Member
 
Join Date: Apr 2008
Location: California
Posts: 1,604
Default Easy upgrade to 24 Mamba from 6x45

Great news for 6x45 shooters who want to upgrade to 24 Mamba for the extra case capacity/performance potential accuracy.

If we run the reamer in a few thou short you can simply fire a 6x45 (or any 223 Rem case necked up to .243/6mm) round to fully fire form cases and achieve about 8%, rather than the 9% case capacity increase by a full reamer seating, in addition to the more traditional fire forming.

Feb 10, 2019: We noticed in our 22 Mamba project that a 223 Short case may fit directly in the 22 Mamba chamber for fire forming.

The same "may" hold true, 6x45 inserted directly into a FL 24 Mamba chamber for fire forming, and is being investigated. Would be good if this holds true.

Last edited by briannmilewis; 02-11-2019 at 01:59 AM. Reason: Update Info
briannmilewis is offline  
Sponsored Links
Advertisement
 
post #42 of 48 (permalink) Old 10-23-2018, 01:44 AM Thread Starter
Senior Member
 
Join Date: Apr 2008
Location: California
Posts: 1,604
Default 24 Mamba AR..Say what?

In an off-shoot of the 24 Mamba project, here is a preview of what team member George in AZ has in mind.

"High BC's are in! Which = heavy for caliber bullets.

My plan for the 24 Mamba AR is a combination of short chambering and seating bullets deeper. As for how it all pans out, we'll hopefully find out before Christmas.

I ordered 2 x 24" blanks (1:8 twist) but I still need to save up for extensions, a required part for AR barrels where the bolt locks up.

Goal #1: Achieve a respectable velocity.

One unfortunate part of doing the 24 Mamba AR, is by being confined to a 2.3" cartridge length, a great deal of the case capacity is going to be consumed by having to seat the bullets deeper.

However, by utilizing high BC bullets it retains velocity longer and makes up for it on the big end. My benchmark is 2450 ft/sec from a 18" barrel with the 105gr bullet.
If I do this it will put the 24 Mamba AR in the same playing field as the 6.5 grendel which has long been the benchmark of long range/do all cartridges for the platform.

Goal #2: Accuracy

The second biproduct of the 24 Mamba AR is exaggerated bullet jump due to having to seat the bullet further in the case. This may or may not effect accuracy.

Some bullets are sensitive to excessive jump and some like it. Worst case scenario is I can buy a reamer with the correct throating if I meet/exceed my velocity benchmark. But I may get lucky and everything pans out with what we have."

Good luck George.
briannmilewis is offline  
post #43 of 48 (permalink) Old 10-31-2018, 05:10 PM Thread Starter
Senior Member
 
Join Date: Apr 2008
Location: California
Posts: 1,604
Default Fit up of Barreled Action - Savage Model 16

Incase you need to swap a barrel for a 24 Mamba adoption, here are the three videos I made of the full barrel fit up, head spacing and installation into the stock, for my 308x45 project.

https://www.facebook.com/308x45/vide...174113518/?t=0

https://www.facebook.com/308x45/vide...877552504/?t=0

https://www.facebook.com/308x45/vide...21913681/?t=10

Enjoy.
briannmilewis is offline  
Sponsored Links
Advertisement
 
post #44 of 48 (permalink) Old 01-31-2019, 06:40 PM Thread Starter
Senior Member
 
Join Date: Apr 2008
Location: California
Posts: 1,604
Default

Slow progress but have been working on a couple of other wildcats in the mix.

George is working on a bump die for the 24 Mamba, so we can bump the shoulder back into compliance if the cases shoulder go out of spec, without the need for FL sizer. We are guessing the cases will fail and be scapped eventually even with neck sizing only, and will be a long time before they exceed max case length if ever.

He is chambering his 24 Mamba AR - slightly shorter case length.

I have a 24 cal barrel being rechambered a tiny bit short so I don't have to do separate case forming at the expense of slightly less case capacity. Neck up to 6mm, load round, chamber and fire, case forming and decent loads in one process.

Thanks for following us even I these slow project times.

Update:

My Redding 2400 Trimmer is working beautifully, find the right length set it and it varies a tiny bit (0.005 - 0.0015) over large runs.

My Lee Deluxe Perfect Powder Measure is now on a stand and works brilliantly compared to the non-deluxe version. I also sprung for a dedicated stand and can secure it to my desk through one of the bolt holes I use for the trimmer.
Attached Thumbnails
Click image for larger version

Name:	PowderMeasure.png
Views:	15
Size:	721.1 KB
ID:	226028  

Click image for larger version

Name:	Reamer.png
Views:	17
Size:	757.1 KB
ID:	226030  

briannmilewis is offline  
post #45 of 48 (permalink) Old 02-02-2019, 11:02 PM Thread Starter
Senior Member
 
Join Date: Apr 2008
Location: California
Posts: 1,604
Default

The three wildcat projects: 308x45 as shown; 24 Mamba without 30 shoulder and less case taper; 223 Short as shown.
Attached Images
 
briannmilewis is offline  
post #46 of 48 (permalink) Old 04-27-2019, 12:20 AM Thread Starter
Senior Member
 
Join Date: Apr 2008
Location: California
Posts: 1,604
Default

I've been loading case forming rounds recently. It is a 223 case necked expanded to 6mm, primed with CCI 400 Small Rifle Primers and three bullets and 2 powder combos so far. Cartridge Maximum length is approx 2.260" even though it will be in a bolt rifle, not an AR.

My version of the 24 Mamba is designed specifically to allow a 6x45 owner to get a rechamber, or anyone else to chamber a barrel a few 0.001" short of full depth, so they can just insert a 6x45 and fire form. Otherwise, a special fire forming load will be needed in order eke out every last grain of case capacity - more or less 6x45 + 9% rather than +8%.

My powders so far are Hodgdon Benchmark and Accurate 2230. Bullets are 60gr Berger Varmint, 65gr Hornady V-Max and 70gr Speer TNT.

Completed so far:

Benchmark & 60gr Berger: 24.0gr - 26.8gr in 0.2gr ladder
Acc 2230 & 65gr Hornady: 24.1gr - 26.7gr in 0.2gr ladder

I purchased powders before the bullets so Acc 2230 was the only listed powder for the 65gr Hornady in my stash.

My notations are a little rough, but I pair up each group of 5 with a numbered target with all the details so after the range session I am organized.

My barrel is so close I can almost smell it.
Attached Thumbnails
Click image for larger version

Name:	IMG_5040.jpg
Views:	15
Size:	1.19 MB
ID:	229798  

Click image for larger version

Name:	IMG_5042.jpg
Views:	11
Size:	867.5 KB
ID:	229800  

briannmilewis is offline  
post #47 of 48 (permalink) Old 06-28-2019, 02:01 AM Thread Starter
Senior Member
 
Join Date: Apr 2008
Location: California
Posts: 1,604
Default 24 Mamba AR Progress

From George in AZ:

Made some long overdue progress on the 24 Mamba AR. I rough profiled my blank tonight. Went on the medium/heavy(triple tapered from .980-.780 over 8.5") end of weight as I plan for this to be my 600+yd steel banger and if luck has it a Bambi slayer this fall.

This one will be a 13.7" barrel with mid length gas for my SBR'd lower and will wear my suppressor more often than not.

Hope to chamber it and thread it for the tenon tomorrow. This is not the full sized 24 Mamba. I plan on chambering it .100" shorter and seating bullets deeper so it will fit in AR mags. unknown if this will work but being that the case has minimal taper I think i'll be able to get away with it. Time will tell. Going to try the 103gr ELD-X for deer if I can get respectable velocity (2400+ is my goal)

Edit 6/24: Managed to make a go gauge and dummy this afternoon then chambered the barrel, cut the tenon for the threads on the extension and machined the feed cone and polished. Got too hot so aborted for another day.Managed to go into the sweat box and threaded the extension for the 24 Mamba AR barrel. Now I can fire form some cases and see what kind of velocities we can obtain.
Attached Thumbnails
Click image for larger version

Name:	BarrelExtThgreaded.png
Views:	14
Size:	923.2 KB
ID:	231734  

Click image for larger version

Name:	First Barrel.png
Views:	11
Size:	308.3 KB
ID:	231736  

Click image for larger version

Name:	BarrelBeforeAfter.png
Views:	8
Size:	783.6 KB
ID:	231738  


Last edited by briannmilewis; 06-28-2019 at 02:13 AM.
briannmilewis is offline  
post #48 of 48 (permalink) Old 11-01-2019, 05:18 PM Thread Starter
Senior Member
 
Join Date: Apr 2008
Location: California
Posts: 1,604
Default 24 Mamba Barrel Arrived Today

On a take off of an old Heinz soup commercial while growing up in Australia...Hooray, hooray, I heard Mum say, barrels are on for lunch today!

Just arrived from George in AZ, my 24 Mamba Barrel, originally sculptured by Randy Hutton, chambered and threaded by George. My barrel is chambered so I can load 6x45 crush fit and fire form.

Beautiful, beautiful...Including Case Gauge and Headspace Go-Gauge.

First range testing before the end of November.
Attached Thumbnails
Click image for larger version

Name:	24 Mamba Barrel - 1.jpg
Views:	5
Size:	239.4 KB
ID:	235944  

briannmilewis is offline  
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Graybeard Outdoors forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in










Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page



Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome