I'm building a new rifle and want something subsonic. I'm torn between two calibers and would like some more pros and cons if I'm missing any.

We'll start with the 300 Whisper.
Very accurate subsonic round.
No need to use filler in the case.
Dies, barrels, brass avalible.
Limited factory ammo.
Dies and brass are expensive.

And for the 7.62x39.
Very popular round.
Could use surplus in a pinch.
Need filler in the case.
Brass must be modified for subsonic, can't be used for supersonic after modified.

These are just some of the thing I've been thinking about. I would like to be able to load supersonic if needed. The rifle is a Savage 10, I don't want to buy both barrels because I'm going to spend alot of loot on a very nice tube. I like the Whisper because its a wildcat, well not really anymore. I have everything but the barrel.

I'm not asking what one should I build, only I can spend my money, but what am I missing? If anything. Thanks for your help.

Why must the brass of the 7.62x39 be modified for subsonic?

Matthew

so build the 7.62x39, .308 barrel.. or buy a ruger 77 so chambered, and buy quickload ...

you do not need to use filler in the case, nor modify it for subsonic ... and using filler is a trivial action .. takes all of 10 seconds...

lee dies used to come with 308 and 311 stuff ...

you will be done and dusted in 2 months, for less than the cost of buying the whisper stuff from ssk.

I have loaded the x39 subsonic in the past and drilling the flashholes to 9/32nds was recomened to help prevent secondary explosion effect. I never tried it without drilling the flashholes.

I have RCBS x39 dies with both .308 and .311 expanders.

I guess I worded it wrong, do to the copyright on the Whisper name it would be a 300/221. Both Douglass and Shilen offer 300/221 chambering in a prefited Savage barrel.

okay .. never heard of that drilling thing to be subsonic .. i wouldn't do it..

go to walmart and get a bag of pillow stuffing for 2.99 .. that will last you a life time

There are a few sites on the x39 subsonic that talk about it. The larger flash hole allows more of the primer flame to contact the powder for a more consistent ignition. How much of this is true or necessary I don't know. The subs I have loaded with the drilled flash holes performed awsome, very little velocity spread and no delayed ignitions or signs of SEE. They were a project to see if I could get a modified AK to cycle with sub's. It worked, kinda, would cycle about 4-7 rounds at a time and than fail to eject.

Thanks Saeed.

I recieved similar advise to drill out the flash holes but I understood it to be because the initial pressure of the primer flash was higher that the pressure in the case and "may" cause the case to move forward in the chamber and consequently shorten it causing excessive headspace. This may or may not be relevant but a lot of the guys on the castboolit forum who shoot subsonic advocate this practice.

Von Gruff.

I've had the .300 Whisper, wish I kept it now, it was a wonderful caliber..Not surprising, its got a great lineage.

I have a CZ 7.62x39 and use Trail Boss loaded to 1000 to 1100 fps with a fat cast bullet of about 160 grains.Not being able to own a silencer in this state,it works good enough,sounds like a .22 going off...

In my opinion the .300 Whisper or 300/221 is a better selection than a subsonic 7.62x39. There are a number of reasons, first you are using a Savage model 10? What bolt face does it have? If it is currently a .223, you will be able to switch back and forth between the two by simply switching the barrel. Also, you can load .300 whisper to a supersonic load depending on what bullet selection you use.

Dies are no more expensive than say a 6.5x47 and brass is not overly expensive to purchase, though time consuming to make.

Be sure to get a 1/8 twist barrel for use with heavier bullets.

-myers

i built a 7,62x25 on a destoyer .. with a 1:8 twist, just for playing

All you need is a 100 brass cases and each will last at least a dozen firings.