5.7x28 necked up

[pinkerton]

Saw a video of a guy testing the Ruger 57 and I hadn’t thought about the length of the round until it was mentioned “you could almost fit a 357 in this mag”. It got me thinking. Necked up to 9mm should be about the size of a 38 special but at a much higher operating pressure.

Any thoughts?

[bigbore5]

Buy a 38 super

[taffin]

Jan 6, 2021 23:45:20 GMT -5 bigbore5 said:

Buy a 38 super

YES!

[magnumwheelman]

good suggestions above... as someone who played extensively with the 5-Seven when it 1st came out... a couple things that will cause you problems "wildcatting"

as far as I know, new cases are not available... factory ammo had a lacquer coating to help with the delayed blowback action of the FN auto... stretching those cases is going to break the lacquer coating... which is normally pretty durable & can withstand at least 2 wet tumblings during reloading...

used cases fired in the auto have extremely short case life, as the shoulder blows forward about an 1/8" each firing, which results in work hardening of that area... also this case stretching produces "bright" rings ( stretch breaks ) towards to bottom of the case... I found a 10% failure rate at 1 firing, 30% failure rate at 2 firings... & quite honestly I never loaded more that twice on these cases, with the exception of fixed breech Contender barrels, which didn't exhibit the stretching...

the rim size is tiny, & coupled with the lacquer coating, often pulled off leaving the case stuck in the die, unless better lubes were used, which required an additional wet tumbling after forming...

try the 38 Super

[dougader]

Or a 9x23 Winchester, 125 @ 1450+ fps.

[magnumwheelman]

BTW... on the 5.7... the shoulder is only 7.95mm & the base is the same ( the body is straight ) so you couldn't put a bullet in that case bigger than the base of the case... so you would be limited to 7.95mm less the thickness of the case mouth X 2 for a bullet diameter... for example a 32 acp has a case mouth of 8.56mm... a 30 Mauser has a case mouth of 8.46mm... the 270 REN has a case mouth of 7.493mm... so you would need to drop your bullet diameter as small as 6.5mm to .270 to make a workable cartridge

[Bagby]

I have a dummy cartridge that my Dad an I made some time ago. We were thinking about necking it up to .251 to use .25 Auto bullets.
I will see if I can find it and post a picture.

Jonathan.

[Bagby]

Found it. 

And next to a .38 Special that I believe is a Tracer for scale. 


Jonathan.

[flyingzebra]

The 5.7 case is not *great* for handloading.

The case head has very little material around the primer.

In my revolver I'm getting about 8 loads per case.

For 25 caliber bullets I'd just go with the 25-20

[pinkerton]

Jan 6, 2021 23:45:20 GMT -5 bigbore5 said:

Buy a 38 super

I can’t argue with you there. I’ve got 2 38 supers, a team match and a pro carry.

I’ve never messed with the 5.7 and was thinking it was the same case head as the 223, which it definitely is not

[flyingzebra]

Nope

Definitely it's own thing.
I wouldn't consider it a great platform for wildcatting - *maybe* to a 20 or 17 or 14, but not up. Still, not so much.

It is what it is, which is pretty exciting.
I like my 5.7 Single Six.

[kaytod]

There are two ‘cats on the 5.7 that I know of
One is a .204 and the other a .172

I have a 17 VHA or now termed JAV by the co-designer

It is a 4.6x30 necked from .183 down to .172.
It is a simple forming task. Cases are of good quality. As for efficiency, it is VERY good!
8.3 grains of Lil-gun runs a 20 grain v Max at nearly 3400 FPS in a 16” barrel, 3550 plus in a 21” and upwards to 3700 in a 28”

This is my first tiny bore gun and I’ve not been disappointed. The fun factor is off the charts.
My friend Mic has one in a Savage and used it a lot on prairie dogs. His favorite memory was of two in a row at 518 and 519 yards with the little round