.300 Blk question for subsonic

[c&rdaze]

I am fairly new to reloading. In slowly upgrading some equipment I was given, I recently added a chronograph. I really got to check some .38spl that i thought might be hot, reloaded from the Lyman book. An it indeed comes in at just under +p velocities.

That aside, I have some reloaded .300 Blkout subsonic that was loaded to spec from internet sources (clearly not the best info but .300 Blk info is hard to come by). Anyway, chrono says 800-900 fps with different bullet types. Way under what I want, so do I pull the load and start over or just use the 50 rds I have and work up something better? It is quiet and cycles fine but does it really have any punch?

 

[BradMacc82]

Assuming a 220gr pill is being used, at 900fps you'd be looking at roughly 396ft/lbs of energy.

That punch is equivalent to a good defensive handgun loading.

 

[DutchV]

There's plenty of good info over at 300Blktlk.com. Most guys are trying to get their subsonics to run around 1050 fps.

 

[Flipz]

There's plenty of good info over at 300Blktlk.com. Most guys are trying to get their subsonics to run around 1050 fps.

My 208gr load gets 1075 fps.

 

[Sticky]

If the loads cycle fine, then just go ahead and shoot em... but I'd opt for a little over 1000fps to be most effective and still remain subsonic. With a chrono you can measure a couple handfuls of rounds, see what the deviation is and load accordingly to keep the higher velocity rounds under 1100fps. I usually shoot for around 1050 average, as it allows a little leeway to still remain subsonic. I may load a little higher or lower, depending on accuracy performance of a given load, but rarely over 1100, as it's starting to knock on the supersonic side..

 

[outrider58]

Are you shooting suppressed?

 

[DutchV]

You want to start at the high end of velocity, and work down to subsonic levels. There's a risk of detonation from too small a powder charge, or possibly a stuck bullet from too low a velocity.

 

[Jmorrismetal]

What are you trying to "punch" with it? If its paper, cans and such just go have fun. If you are not sure 900 fps will have enough energy to take down something living, you might need to rethink your choice of caliber/velocity as another 150 fps won't matter much.

 

[Klunatic]

What rifle are you using as your platform? SBR, Bolt, AR? I get 1050fps with by SBR AR 10" using 194gr Lehigh Defense with 11.7gr Accurate1680. That is 475 lbs. at muzzle(equivalent to .357 magnum round). If your going for knock down power the 194 Maximum Expansion is the best subsonic round as it will expand. None of the other rounds will expand, they will punch through or tumble.

 

[c&rdaze]

Thanks for the replies. A few more details that I should have included to start with: 16" CMMG 300 Blk upper, suppressed; night vision scope; thinking for coyotes and such. Using 208 to 220 gr Gameking, Barnes XXX, Speer bullets. These were loaded using Hornady data. Cycles fine but to slow, so do I pull what I've loaded or first work up a better load?

I'll try to find the suggested bullets for better expansion. After I get this issue settled, I will load some lighter gr bullets supersonic use.

 

[ironpony]

One factor is cost, I keep hearing prices are at a low and more than likely will go up (political cycle) so my thoughts are shoot them (at things already dead) and buy more .... now while prices are steady.
A second thought is altitude, don't loads speed up at higher altitudes? Probably not that much and probably difficult to get that close to a mountain goat, lol, just a thought. I'm curious what the rifle is that will cycle at 800 fps. ?? That's pretty good I believe. AR ?

 

[Klunatic]

I'll try to find the suggested bullets for better expansion. After I get this issue settled, I will load some lighter gr bullets supersonic use.

The Lehigh are the best round subsonic if you want expansion. Nothing else will expand. Here is a video of the 200gr ME (no longer made) but is shows how well it works. It was replaced by the 194grME factory loaded to 1050fps in a 16" barrel. The video is a bit long the gelatin testing starts around 3 minute mark.

 

[Klunatic]

A second thought is altitude, don't loads speed up at higher altitudes? Probably not that much and probably difficult to get that close to a mountain goat, lol, just a thought.

Altitude wont really effect the speed of the bullet, it will change the speed of sound. So a round that is subsonic at sea level may be supersonic at 10,000 feet. At sea level on a standard day (temp/humidity/pressure) speed of sound at sea level 340 m/s at 10,000 fee it is 334 m/s.

 

[Speed3]

The Lehigh are the best round subsonic if you want expansion. Nothing else will expand. Here is a video of the 200gr ME (no longer made) but is shows how well it works. It was replaced by the 194grME factory loaded to 1050fps in a 16" barrel. The video is a bit long the gelatin testing starts around 3 minute mark.

Do these cycle well in mags?

 

[Klunatic]

Do these cycle well in mags?

No problem, cycle like a dream, even in my MG (although I don't normally shoot them full auto to much $$$) I believe they had issues with the 200gr ME getting stuck in the mag and that is why they went to the 194gr to trim the OAL.

 

[ironpony]

I always thought objects in motion would keep speed in less dense atmosphere and therefore faster ... and Pluto was planet. Darn public schooling, I'm going back to billiards as a hobby.

 

[Speed3]

No problem, cycle like a dream, even in my MG (although I don't normally shoot them full auto to much $$$) I believe they had issues with the 200gr ME getting stuck in the mag and that is why they went to the 194gr to trim the OAL.

I might try some, but they are salty $50 for 20. Will they sell just the bullets so I can load the myself? I looked briefly but couldn't find them if they did.

 

[Klunatic]

They are $$ but they do what other subsonics won't, expand. Definitely a hunting or self defense round. You can order the bullets and reload your own.

http://www.lehighdefense.com/collec...sion-194gr-subsonic-bullet?variant=1073832868

They also make a 110gr supersonic that is much more reasonable at .33/bullet that is also a tremendous hunting round. The Controlled Chaos, really does a number on hogs.

They sell a sample pack that gives you subsonic/supersonic mix http://www.lehighdefense.com/collec...whisper-bullet-sample-pack?variant=1073778784

 

[Speed3]

They are $$ but they do what other subsonics won't, expand. Definitely a hunting or self defense round. You can order the bullets and reload your own.

http://www.lehighdefense.com/collec...sion-194gr-subsonic-bullet?variant=1073832868

They also make a 110gr supersonic that is much more reasonable at .33/bullet that is also a tremendous hunting round. The Controlled Chaos, really does a number on hogs.

They sell a sample pack that gives you subsonic/supersonic mix http://www.lehighdefense.com/collec...whisper-bullet-sample-pack?variant=1073778784

Thank you so much, super helpful

 

[Blacksmith101]

I'm not a .300 Blk guy but will offer a suggestion. If you want expansion and subsonic speeds you might want to consider casting your own bullets. Cast bullets work well at sub sonic speeds and you can vary your alloy, lead hardness, to get the kind of expansion you want.