Skip to main content
Help Center Community Shop

Sub-Sonic 300 Win Mag

tmcbp
Does any one have a load that they use or know of for a 300 win mag sub-sonic load using either 220 or 240 gr Sierra Match Kings? I just got my SAS TI Arbiter can and Im anxious to see how quiet I can get this thing and hopefully still have a 200-300yd capable gun.

Any insight on this would be greatly appreciated. Also, if yo advise against sub-sonic 300 win mag cause of the cavernous case size I would also appreciate and negative experiences.

Thanks to all!!
0

Comments

10 comments

Date Votes
  • Hawk Carse
    Hodgdon shows .300 Win Mag with Trail Boss down to 1300 fps, but that is with a 150 grain bullet. If you went by their guidelines and used a heavier bullet, you might be subsonic. If you go lower, be sure the bullet exits the barrel EVERY SHOT.
    http://hodgdon.com/PDF/Trail-Boss-data.pdf


    Bullet stabilization might well be a problem. I think a real Whisper uses an 8 twist for 240s at 1050. I know one cutrate experimenter was shooting a CZ 527 in 7.62x39 with roundnose bullets to get by with its 9 twist. I think the standard for .300 Win Mag is 1 in 12. As said test without the supressor in place, a tumbler would be expensive.
    0
  • Nwcid
    I am sure someone is doing it but it will have to be done carefully. Also before you use it with your can make SURE you gun will stabilize that long of a bullet before using it with your can.

    I know you have the gun already but if you really want to shoot SS .30 caliber I would look at the 300 Whisper. When I got my .30 cal can for my .300 WM I did some research like you are. I now own a 300 Whisper.......
    0
  • 22hipower
    You can do it but 300 yards is going to be stretching it. If you zero the 240 grain Sierra bullet for 100 yards at a muzzle velocity of 1000 fps I think you're going to be some three feet low at 200 yards and nine feet low at 300. . .or somewhere in that range. Much faster and you probably won't get the sound reduction you're looking for. Maybe not the best use of a 300 win mag but it can be done. I'm no expert but from the suppressed rifles I've seen in use the best results seem to be at 150 yards or less with the heaviest bullet that can be launched at just under the speed of sound. A 44 mag with 300 grain XTPs works pretty well.
    0
  • 1KYDSTR
    What about puff-lon as a case filler? Big issue is obviously the bullet leaving the bore consistantly...seems like the filler would average things out a bit better as the position sensitivity would be mooted?
    0
  • tmcbp
    I am in the process of starting a 300 whisper build, but now im considering that 300 AAC Blackout now.. They want to have ammo on the shelves by januay, for around the same price as .223. its sort of a "commercialized" 300 whisper that way other manufacturers can produce the ammo as well.. Check it out on the Advanced Armament website.
    0
  • 1KYDSTR
    Fairly sure Mr. Jones and SSK Industries will little appreciate the knock off...I'm sure they stayed just far enough out of spec to avoid the litigation at least! 300 and the various other Whispers are waaaaay cool. Have shot most of them (I work at a range and most definately haven't the cash to purchase my own) andas longas you shoot risers they are amazingly accurate and yes...uber quiet!
    0
  • tsr1965
    quote:Originally posted by tmcbp
    I am in the process of starting a 300 whisper build, but now im considering that 300 AAC Blackout now.. They want to have ammo on the shelves by januay, for around the same price as .223. its sort of a "commercialized" 300 whisper that way other manufacturers can produce the ammo as well.. Check it out on the Advanced Armament website.


    Just so you know, the 300 Whisper is commercially loaded. Also, the if you load the Lost River, 220grain J40, it has a very high ballistic coefficient(0.930), much higher than the Sierra MK's. You will need around a 1 in 7 to 1 in 8 twist to stabalize it though. You will need a sighting arrangement that gives you about 40 MOA of adjustment to get you to 300 yards.

    Stay away from using any type of case fillers when using a can...it can have adverse effects.

    Best
    0
  • beantownshootah
    The only thing I'm going to add here is that if you want a subsonic load, .300 Win Mag is probably not the best place to start, for the exact reason you mention.

    Super-low loads are intrinsically problematic since lots of extra case volume can lead to erratic accuracy and performance.

    I remember reading about some actual risk of case detonation too, though I can't remember the exact mechanism. . .but I *DON'T* think it was because of a simple double-charge.

    Case fillers are a way to offset the low volumes, but they offer their own set of problems.

    I'm with the others. If you really want to play around with subsonic .30 cals, there are better platforms to work from. .300 Whisper, obviously can work. I've heard of a few people basing these off of 7.62x39s as well.

    Yes, you can probably end up being subsonic with a high volume powder like Trail Boss and a heavy bullet, but I question the ability of the gun to stabilize a really heavy bullet at the relatively low speed. You might get bad accuracy, or even overt bullet tumbling.
    0
  • gunnut505
    Not to be flip about a potentially serious legal subject; but I've seen excellent sound reduction DOWNRANGE using a 3-liter soda "can" and "normal" velocity ammo.
    0
  • dfletcher
    I believe the approach in the Hodgden manual regarding Trail Boss and reduced loads (mostly subsonic) is to fill the case to just below the rear end of the bullet and that this works on all rifle loads. Hornady uses Trail Boss for their subsonic 338 LM loads.
    0

Please sign in to leave a comment.

Recent Activity