338 whisper, 338 hush, 338 thumper?

[andym79]

Hi guys, perhaps I am not looking hard enough.

I am trying to find case drawings to see the difference between the 338 whisper (2 very different ones?), 338 hush (not sure) and 338 thumper (223 cut off at the shoulder?).

Can anyone tell me about the differences and pros and cons o each.

I am looking at build a 338 wildcat to shot big slugs slow, but can't get enough data on any of these like you can for commercial cartridges.

Thanks

Andy

 

[Another_Kelley]

If it's not in the SAMMI list, acquiring legitimate drawings will be tough. Typically THEY (the originator of said cartridge) will re-chamber your barrel, or provide a new one - for a price.... but releasing technical drawings so we can chamber something ourselves is typically not in their interest. Their interest is to be the only source for barrels/rifles/dies of whatever chambering you can't live without. So I'm betting that's why you're having a hard time finding legitimate data among the cartridges you listed.

How heavy do you figure you have to go with this subsonic thumper extraordinaire of a rifle? Very few of the larger rifle projectiles out there deform and transfer much of their carried energy at sub speeds.... so unless a very large critter is our subject with lots of bone mass - a 300 grain .338 matchking is going to produce a very similar result to that of a .30 cal 220gr matchking- at sub speeds. The heavier match bullets will arguably out shoot the lighter 30-cals at greater distance, but as far as energy transfer, they're both likely to penetrate right through whatever you hit in a very similar fashion.

Have you thought about a 44-mag bolt gun for the slow heavies? Certainly on my to-do list...

 

[andym79]

That sure explains why you cant just get a drawing!

My line of thought has been along the path of using either 222r or 5.6x50r as a parent case for a .284, .308, .312, .323 or .338 neck up version, similar to whispers but not the same.

I think cutting off the 222r or 5.6x50r at the shoulder and turning it into a straight wall would be the go if I decide I really want to go this route!

In some ways I am more tempted to use the 5.6x50r as the parent case than the 222r!

I know almost nothing about the finer details of cutting a chamber; but could a straight walled (or almost) .338" case about the length of a 222r be achieved by cutting a 221 chamber and then extending it with a neck and throat reamer thus making a chamber that allows for a case tapering from .377" at the base to .361" at the neck and being 1.65" long?

If this option is possible then I would probably fireform 222r brass or cut shorter and fireform 5.6x50r brass.

The other option going through my head to create such a chamber would be to cut a 357mag chamber and finish it of with a neck reamer up to 1.65", again the intention would to fireform either 222r or 5.6x50r brass. The thing that concerns me about this option more than the first, is can a gunsmith cut a nice tapered shoulder/neck as the 357 mag chamber would be a tiny bit oversized for a case with OD of .361-.370" at the mouth.

Are either of those options realistic or is only the third option of a custom chamber a realistic one?

Remember, whilst I prefer the idea of a 338-222r/338-5.6x50r does anyone think that 28-32 cal may be easier to do the smithing work for?

 

[Pete D.]

Whispers

Remember that the Whispers are not intended for hunting. They are designed to be used with silenced weapons as antipersonnel tools.
The neat thing about high BC heavy for caliber bullets is that they retain their velocity and energy for quite long distances.
I have an SSK fast twist barrel chambered for the 50 Govt cartridge. I shoot 647
grain BMG bullets at sbout 900 fps. At 1/4 mile they are still going about as fast as a 45 ACP ball round.

 

[andym79]

Okay, no good for hunting or expansion!

But are they accurate?

 

[redbullitt]

There are some pricey subsonic expanding bullets you can buy. Work kinda like a broadhead I believe. Definitely interesting stuff from lehigh. Maybe another if IIRC.

I do not see any reason a 45 or 50 cal subsonic cannot take game well. I mean, it is not going to be any different than a muzzleloader or 20 gauge slug, which are more than enough for deer etc.

1/2 inch hole in and out through the lungs or heart is plenty fine by my standards.

i shoot lots of 300 whisper. Subsonic I do not really like it for deer aside from close range CNS shots. 458 socom does work quite well on deer sized game. A nice flat nosed 600g cast bullet does the trick at sub sonic speeds. Brass is also easy to get from Starline.

I have gotten to play with a 510 whisper a bit too. Brass is a royal pain, but this will kill deer very dead too... a nice 1000g cast bullet with a good nose works very well at whatever range you can hit at. Velocity is maintained very well at range.

The trick is to know the drop very well and keep shots at ranges that you and the projectile are effective. 300 whisper or 510 whisper or anything in between can do fine, just know the limits. My goal for any subsonic is 2 MOA. Most rifles of mine can do that with good load work and some approach 1 moa. Often you will get wide spreads on the velocity, but once you get that worked out accuracy can be more than adequate. Good cast bullets seem to help too; jacketed is never as consistent for me in this application.

 

[andym79]

Thanks for that I prefer to use cast bullets whenever possible, in fact only my 22 cal centerfires get jacketed stuff.

 

[Mosin Bubba]

a nice 1000g cast bullet