6mm Mongoose vs 6x45

[Wolfdog91]

Anyone have experience with both of these ? Which did you prefer and why ?
Thanks

 

[Kurz]

6mm Mongoosehttps://www.facebook.com/mark.kexel.5

Cartridge overall length 2.26"
Max case length1.700"
Trim to case length 1.690"
loaded rounds the neck needs to be under 0.268"
Bullet range 55 grain to 107 grain
The Mongoose is a wildcat round based on the .223/5.56 case. It uses standard magazines and can run bullets from 55 grains up to 95; the 105 amax will work at 2.29" COAL, but the heavy "VLD" bullets won't fit. The shoulder is 40 degrees and the case taper is blown out for increased case capacity, so it does require fire forming to reach its ultimate potential.
Making 6mm Mongoose brass consists of running through the die which pushes the shoulder back and then trimming to 1.690-1.695" (the rounds will shrink a little on the first fire as they stretch to fit the chamber). That is it - load them up and shoot to fire-form the case.

For load data, you can start with 6x45mm data. A good starting point is 1 grain under max loads for the 6x45 and work up. Max loads for the Mongoose will be above that of the 6x45 due to the Mongoose's larger case capacity once fire-formed.

 

[5spd]

I've built 6 or so 6x45s on savage & ar15 actions.
Super easy to form, just run in a 6x45 die as it's just a neck up job.
6x45 is super accurate, no issues 50y yo 600 yd.
My go to bullets are 55g, 65g 70g.
Deer, goat the 85g Sierra bt jhp bullet is tits up.

 

[epc308]

Looks an awful lot like a 6TCU.

 

[Bat Rastard]

Would a 6.5 or 7mm Mongoose be a feasible project?

 

[Bill K]

I would think the 6x45 would be the easiest, as dies are more available, it is much easier to form cases and has been around for years, so load data, etc is also available in most all manuals.

 

[swd]

I’ve never had a Mongoose but I’ve had 2 6x45’s and they are super easy to and fun to shoot. One pass with an expander mandrel and your all done. They perform way out of proportion to their size.

 

[lb-ft]

6x45 is awesome. Last time at Raton I put the hurt on pigs and turkeys at the HP silhouette range. 15” TC Contender.

It punches way above its weight.

 

[RussellJ]

6mm Mongoosehttps://www.facebook.com/mark.kexel.5

Cartridge overall length 2.26"
Max case length1.700"
Trim to case length 1.690"
loaded rounds the neck needs to be under 0.268"
Bullet range 55 grain to 107 grain
The Mongoose is a wildcat round based on the .223/5.56 case. It uses standard magazines and can run bullets from 55 grains up to 95; the 105 amax will work at 2.29" COAL, but the heavy "VLD" bullets won't fit. The shoulder is 40 degrees and the case taper is blown out for increased case capacity, so it does require fire forming to reach its ultimate potential.
Making 6mm Mongoose brass consists of running through the die which pushes the shoulder back and then trimming to 1.690-1.695" (the rounds will shrink a little on the first fire as they stretch to fit the chamber). That is it - load them up and shoot to fire-form the case.

For load data, you can start with 6x45mm data. A good starting point is 1 grain under max loads for the 6x45 and work up. Max loads for the Mongoose will be above that of the 6x45 due to the Mongoose's larger case capacity once fire-formed.

View attachment 1375127

6x45 has my vote.

 

[KMart]

If you are building your rifle on an AR platform, go with the 6x45. This keeps everything simple for the rifle and you. It only requires for you to add a new set of dies to form and load the rounds.. Fireforming may not be necessary. The 6x45 dies are relatively easy to come by off the shelf.
If you are building on a bolt rifle, and want to toy with a wildcat, go with the Mongoose. The dies will pretty much be custom made and the 40 degree shoulder will require fire forming and neck turning. Most likely, a custom reamer will be involved.
The 6x45 would be and excellent choice in a bolt gun as well.

 

[bobcat93]

So the mongoose is a 6x45 thats been ackly improved ?

 

[swd]

So the mongoose is a 6x45 thats been ackly improved ?

It looks like the shoulder is pushed back in a die like a 6SLR and then the neck shortened. So not an Ackley type design. The Ackley would be better, lol

 

[HandgunHTR]

It looks like the shoulder is pushed back in a die like a 6SLR and then the neck shortened. So not an Ackley type design. The Ackley would be better, lol

Old thread, but the 6X45 "Ackley" is just a 6TCU.

 

[bobcat93]

Who offers 6mm mongoose savage pre fit barrels
I dont see them as an offering from pac-nor, Kreiger ..that figures

 

[bobcat93]

Old thread, but the 6X45 "Ackley" is just a 6TCU.

So the case can be formed by blowing out a 223 case? Is that correct

 

[muleystalker]

So the case can be formed by blowing out a 223 case? Is that correct

Your better off doing a 6x45ai, its much easier to make brass, dies are available off the shelf. Or do a 6x204 like I did, just neck up .204 brass, use a .204 bushing die with a 6mm bushing. Use a Forster .204 micrometer seating die with a 6mm stem. a little more capacity that both, basically a .204 Ruger case is a .222rem Mag Improved.

 

[bobcat93]

Ive sent out a e-mail to Bob Green asking if he will make one up for me.
I want to take my LC brass, clean up neck and blow out to 6mm-223 improved.
I know he can do it..i dont know if he has time or is retired.
I dont know any one else can do it, i dont know what its called but i dont know if he uses a reamer for wildcats, i believe he actually drills it out and can pretty much make anything you can come up with .
I think that is how he does it.

 

[HandgunHTR]

So the case can be formed by blowing out a 223 case? Is that correct

Yes, TCU brass is formed by necking up a 223 case to the desired caliber and then fire forming.

 

[bobcat93]

Thank you HandgunHTR.

 

[Oso]

Once upon a time I decided to design a 6x45 AI… not knowing about the 6TCU. This is how I spent $$$ recreating the wheel.

Now if I was set on .223 Rem. boltface (.384) then I would go 6TCU. Aside from any increase in velocity from the “AI” over straight 6x45, I like the added safety of visibly being able to distinguish the TCU case from a standard 223 case.

For anyone who is looking to get the most out of a 6mm while balancing the case size efficiency then 6mm ARC (aka 6mm Grendel) should be contemplated. You can buy brass and even find ammo on the shelf in case you didn’t bring enough hand loaded ammo. Performance wise it beats out all 6x45 variants and 6mm-204 Ruger.