Big bore .308 Win Wildcats

[ovenpaa]

This is why I restricted the build to ideally no more than 10,10mm/.400 diameter bullet maximum so the case still retains a shoulder to head space from. It would be interesting to build a couple of dummy rounds at the upper limit to see how they turn out.

[dromia]

If you want the fun of making a new cartridge then go ahead.

However from reading this and other posts on the subject of subsonic fullbore rounds there seems to be a bit of mystery about it which I cannot fathom.

For example a 308 win with a 230 gn 311284 over 4gns of N 320 will give you heavy and slow, this can be done with any 30-32 cal centrefire cartridge without chambering to blackwhisperout or whatever is flavour of the month is.

[ovenpaa]

My project will not be used for subsonic rounds and is as much about putting the donor action to good use and building a rifle suitable for reduced load use at short distances with the ability to shoot to 2-300 yards if the opportunity arises (Obviously not on the majority of MoD ranges)

[dromia]

It wasn't your original post I was referring to David.

[DW58]

For example a 308 win with a 230 gn 311284 over 4gns of N 320 will give you heavy and slow, this can be done with any 30-32 cal centrefire cartridge without chambering to blackwhisperout or whatever is flavour of the month is.

I'm looking at using .308 Win with a heavy jacketed bullet out to maybe 2-300yds but still subsonic, so I guess I'll need slightly heavier charge than that.

My aim is to duplicate or at least come close to the Lapua 7.62x51mm Subsonic round used by certain black rectangle units.

[Chapuis]

Ovenpaa you have really started something now. Having seen the picture of your dummy rounds I couldn't resist and made up a dummy using a 280 grain cast bullet pushed into a .308w case forming a 9.3x51mm wildcat. The big fat flat nosed bullet with a huge meplat in the dumpy case is just sexy.
I wouldn't know if such a round would offer any real advantage over any existing cartridges such as a 9.3x62 Mauser or even if such a cartridge would be ballistically feasible but it certainly gets my interest.

Chapuis, any chance of a picture I would build a couple of dummy rounds for myself however the largest suitable bullets I have are 9mm/.355

I would be embarrassed to post it as I haven't been able to completely close up the case neck as I've had to bodge it rather, using just what dies I had available. Unfortunately my 9.3x74r dies are to deep for the 51mm case to enter sufficiently for me to close the neck properly around the bullet in a nice neat fashion so I have a secondary bulge.

Incidentally I've done a little bit of a search on the internet and it looks like others have had a similar idea before but haven't pursued it. Also 8x51 using .322" bullets has been thought of previously.

[ovenpaa]

If anyone has a couple of spare 9,3mm or 10,0mm jacketed and or cast bullets I would be happy to try and stuff them in the end of a .308 case to get an idea of proportion and the antics required to form the brass. Personally I have a feeling it might be easier to just go straight to fire forming using a pistol powder and then use a modified Forster bush die to neck size to the correct size.

[User702]

The Russians built a 9mm centerfire SMG a while ago that was supposed to be able to defeat all current body armour at up to 400m whilst being silent. I'll see if I can dig out a link.

[meles meles]

This is it, oomans. The Czechs have something similar that we once had our paws on. It made an excellent dogbuster.

http://en.wikipedia.org/wiki/VSS_Vintorez

[Sandgroper]

If anyone has a couple of spare 9,3mm or 10,0mm jacketed and or cast bullets I would be happy to try and stuff them in the end of a .308 case to get an idea of proportion and the antics required to form the brass. Personally I have a feeling it might be easier to just go straight to fire forming using a pistol powder and then use a modified Forster bush die to neck size to the correct size.

David,
I looked at this a while ago while I was contemplating rebarrelling the Ishy to something bigger. I discounted the .40/10mm bullets after reading about the 400 Whelen and trying to neck the 308 up to 10mm - not pretty!

From what I've read 37 cal is about the biggest you can go while retaining a effective shoulder in a 308 case. In the end, before I pasted the Ishy to you, I decided that if I was going to do it then 358 Win would be the way to go.

BTW I also experimented with 9mm bullets in a 308 case.

Edit: 375 Scoville 30-06 necked up to .375


Another couple to consider is the 450 Bushmaster or 458 SOCOM.