300 whisper compared to 7.62x 39 w/heavy bullet

[skoger]

Just wondering, I have been reading a lot about 300 whisper, just wondering how close you could get to this with a 7.62x39 with a heavy bullet, 180 -200 grn? Anyone else have thoughts on this, should be a simple barrel swap, maybe a longer throat , should slow down, quieter, lot of punch. Been thinking about getting the stamp and suppressor. All thoughts appreciated.

[Crankfire Systems]

No first hand knowledge on this. BUT, I have now read several postings etc. on other sites that it does work quite well. One of the original main criteria for the 300 whisper was that COL would still let it be used in the AR platform, had to be ultra short with the longer projectile. But in a bolt gun that wouldn't matter a bit. Haven't seen any load data yet, but intend to build one in the near future. Too busy just now with a 12.7X48 AKA 510 whisper, and a 500S&W hybrid subsonic guns.

If you do go forward with one, please post anything you learn further about actually doing it!!!

Thank You,
Emory Jones

[tammons]

No comparison, but subsonic is subsonic and the 7.62x39 is a factory shell and regular ammo is cheap.

A Link. There are a few others on the internet, but I found this one a few years ago when I was
contemplating the same thing.

http://members.shaw.ca/cronhelm/762ProjectRifle.html

Switch barrrel usually has a rethreaded 7.62x39 barrel on their website for about $100. Not sure about twist or quality of work though.

You would need a PPC bolt head from SSS.

[learjet]

was talkin w a buddy about a wisper, he says forget that, i can do it sobsonic w cast or match bullets in a 7.62X39 now. never did see the results, but if u dont need a semi, id give the 7.62x39 a try

[skoger]

I had also read a similar article, been a while back. I was just wanting to tinker, been building rifles for 20 years,something new. I have loaded the 6.5x55 swede with 140 and 150grn cast bullets with a gascheck, and got great accuracy, very quiet, and hard hitting at 100yds. It would blow through a 5 inch cedar post, exit hole size of a quarter, and shoot right around an inch or less at 100yds. I could see the impact through the scope, sounded about like a .22mag, or hyper vel. .22rf. I took 2 deer with these loads, shot both on the shoulder knuckle 85-120 yds, both ran about 50 yds and gave up the ghost, Complete pass through, lot of tissue damage from secondary bone fragments, key to success with cast bullets.

[hitman49]

They are very similar. I have several 300 whisper uppers and 2 762x39 uppers. I can tell you that supersonic and subsonic they are very close. The 762x39 has a little edge in the supersonic range but also has more room in the case for powder. sub-sonic is sub-sonic but the whisper is able to send a heavier bullet downrange due to the shorter case in the Ar. But with the bolt rifle it really doesn't matter how long the round is. Each one takes parts that are not easy to find at times to build them but they can still be had. Whisper barrels are not easy to find at times due needing a 1/8 twist for the heavy rounds but everything else is pretty much standard for rifles chambered in 223. The 762x39 takes a bolt head that can be more difficult to find and if you want to shoot Russian surplus or the cheap rounds sometimes you have to modify the bolt you get due to the harder than normal primers.