Anybody have .308 Win. Subsonic Load Data?

[bluesea112]

I thought I had seen a thread on .308 Win. Subsonic loads, but my search came up empty.
Does anybody have load information for loading the .308 Win. subsonic?

Thanks,

Bluesea112

[AngelDeville]

It seems to me my Lyman book has data on 100-110gr lead plinkers, but I have to find my book....

What kind of bullet are you thinking of?

[bluesea112]

I would prefer to load a jacketed bullet. However, if the load data is for regular lead I will use it. I appreciate you looking that up for me AngelDeville.

[inplanotx]

A .308 is not meant to be subsonic. To be subsonic you would need to be under 1,050 fps. Loading that low would mean lots of air space in the case instead of powder. I would guess that a secondary explosion would blow up the gun because of it.

IPT

[AngelDeville]

I found Data in my Speer book for 100 grain Speer lead bullets part# 1805.
But the Velocity on these is still close to and exceeding 3000fps.

And my Lyman book yeilded a 113gr Cast bullet still over 1540fps

My plinkers are 150grain SP, at 2500fps.

the lowest velocities I found in my books are over 2200 FPS for the jacketed bullets.


even if data is found I wouldn't use jacketed bullets for lower velocities, if a jacket separates in the barrel your next shot could be costly...

buy at least 2 books if you don't already have some and cross reference the data between the 2 books, and never go below the minimums.

If you do decide to use data found online, still reference your books, you never really know who is posting data, and a miscalculation or typo could be dangerous.

[bluesea112]

Thanks for the information guys. I didn't see any loads listed in my manuals for .308 Win., so that is why I had asked if anybody had the subsonic information. I to thought that .308 Win could not be loaded subsonic until recently. I was browsing Cheaper Than Dirts website and they are selling subsonic .308 Win. However, the price is out of this world. In reference to InPlano's comment, I am curious about how much empty space is left in their cartridge. I wish I knew what powder they are using for their loads. If I can find a spare minute or two, I might call their retail store and ask a few questions. If I can find out anything about their subsonic cartridges, I will be sure to post it.
Thanks again for your replies.

[pasquot]

I was looking for the same info. What i found was an article by c e harris. It;s called the load. It can be used with any medium cartridge. aka .30cal The standard load is 16grains of 2400 in a 308, 3006, 30cal russian, 303, etc. You can use either lead or fmj. velosity averages about 1600 fps.

I don't know now where i found the article but it is availabe online. Suggest a search for c e harris or the load. etc until you find the article. Be advised, the old load was 13grains of red dot. Unknown why he changed it.

[Popgunner]

The only thing I can think of that a sub-sonic load would be good for would be shooting thru a silencer. There are "gallery" loads for the .308 but they won't be subsonic. The weakest load I've loaded for my .308s has been 5 grains of Unique with the Speer 100 grain plinker. An absolute pipsqueek of a load but I'm not sure it's sub-sonic.

[JLA]

try a relatively fast burning pistol powder that is not position sensitive and not double base...(like hodgdon titegroup) and cross reference data for bullet weights that match the ones you intend to use. you should be able to "wildcat" up such a load without much risk of personal injury. but be very very careful in your powder selection. double base propellants tend to explode if there is too much dead space in the case.

[bluesea112]

Thanks for the comments guys. I am not experienced enough with reloading to play around with different loads. In reference to one of the earlier comments, a bullet has to stay under 1150 ft per second to be sub sonic. Any speed over that will generate a sonic "crack" and make the bullet "wobble" as it enters and exits the sound barrier. Neither of those phenominas are desireable.
Here is the situation:
I have figured out that I can open the window about 3 inches in my back bedroom for the bullet to go through. If the bullet does not break the sound barrier, the bedroom itself acts as the suppressor and muffles the sound enough that the shot cannot be heard outside. I have run about 5000 rounds of sub-sonic .22 through that 3" window opening, and I am starting to get bored with the .22. I live outside of the city limits but I own an RV park. It is perfectly legal to shoot a gun out here in the country, but gun shots tend to piss off my guests. The nearest range is about 1 hour drive from here, and I get an itchy trigger finger between trips to the range.
Since a bedroom does not attach to the muzzle of my gun, I don't have to pay the jack booted terror squad $200.00 or even come within gagging distance of the air they breath.

[Popgunner]

With the rifling twist your .308 has you may not be able to stabilize bullets traveling that slow. What if the supersonic crack happened anyway inside your room? It may be worth a try to see how loud it is outside.

E
what was the situation with those two guys back east that were riding around in a car with a big trunk shooting people thru a hole in the trunk with a 223 Bushmaster? seems like that deadened the sound. I can't remember the story.

[bluesea112]

I tried your idea Popgunner. I had my girlfriend stand outside at the opposite end of the house so she could tell me how loud it was. She said it sounded like a crane dropped a bunch of steel from the top of a 5 story building onto a concrete slab. I guess the sound barrier crack must continue behind the bullet, so you hear it no matter where you are standing along the bullet's path. That was the first time I had ever shot a large caliber rifle inside a closed room. I'm surprised I didn't get a nose the bleed from the pressure. It was enough to blow the curtains down. Thank God there were no powder burns on them or I would have never heard the end of it.

[Popgunner]

As long as you're having fun

[bluesea112]

I wonder if I could pack bentonite (clay) (aka:catlitter) into the cartridge to take up space. That way I could use a reduced load of IMR 4895 without there being too much extra space left over in the cartridge. When bentonite is rammed, it packs down tightly and is as hard as concrete. After ramming it, I could use a 1/32" drill bit to bore a hole through to allow the primer to ignite the powder..
Anybody know of a reason packed bentonite would not work, or any other reason not to try this? The last thing I want to do is mess up my rifle, so I want to experiment safely.


bluesea112

[Popgunner]

Not a good idea. Good chance of ruining your barrel.

If you want to have a low noise load try 10 grains of unique powder with whatever bullet you have. Cast lead works fine. Very quiet. Fillers are generaly frowned upon.

[bluesea112]

Just the info I was looking for. Thank you Popgunner.

[goodstuff412]

8-10 Grains of Trailboss cowboy action pistol powder. 168 Gr SMK BTHP will produce SAFE, accurate and subsonic results. The powder is bulky and leaves less than 30% empty case volume. Velocity varries with powder charge of course. I have found that humidity and temp are a huge factor. Sonic crack occurs at 1050 and I like to keep mine right at 1000 fps to build a +/- 50fps "crack factor" depending on temp and humididty.

Good luck

[treeclimber]

I have been using 8.5 grams of Shotgun powder and yes there is alot of empty space in the cartridge. My barrel has a 1 in 10 twist and I'm using a 160 grain 3060 projectile its nice and long which should help with travel through the air. I haven't been to the range with them yet.

[zkovach]

I have zero to add here however i am wondering what purpose is there to have a subsonic load????

[Alpo]

Quiet.

You have two distinct sounds when you fire a rifle. You have the "BOOM" of the powder going off, and the much louder, sharper "CRACK" of the bullet breaking the sound barrier. If you can get it subsonic, you not only have no CRACK, but the boom is much quieter, since there is less powder being used.

I found loads, using a 190 grain cast bullet, that started at 1140. Still supersonic, but getting down there.

[GMFWoodchuck]

Buy something chambered for the 30 carbine. Subsonic loads ought to be easier and safer to produce with that caliber. And why are you shooting in an RV park anyway??????????????

[zb338]

A friend and I experimented with low powered loads in .243 Winchesters. We found
that if you pointed the gun barrel down the bullet would stick in the barrel. We tried
putting cotton over the powder. That worked but the cotton would lay on the range
floor and burn. We ended up with a little more powder and a magnum primer. As I
remember we shot some very good groups at 25 yards. We used lead cast gas check
bullets. Lyman mold.

[Alpo]

Originally Posted by GMFWoodchuck

Buy something chambered for the 30 carbine. Subsonic loads ought to be easier and safer to produce with that caliber. And why are you shooting in an RV park anyway??????????????

Why not? It's his RV park. I have a safe backstop in my backyard. I can safely shoot there, but if the neighbors see/hear me they might call the cops - discharge of a firearm inside the city limits. So I try not to get seen or heard.

It really is no different than someone shooting Colibri's in the living room, into a phone book. Or having a range for 22s in the basement. Both of these are (or used to be) fairly common throughout the country.

[echo431]

I legally own a Integrally suppressed FN Patrol Bolt chambered in 308 Winchester with a 1:12 Twist. I hand load 155 Grain Hornady A-Max Moly Coated; 8.5 grains IMR Trail Boss, CCI magnum primers, cartridge length: 2.77. These shoot excellent, sighted in at 100 yards. 2 of my friends have the same rifle and I loaded them a batch of the same load. We sighted our rifles in at the same time and they shot the same, 1" groups at 100 yards. I bought my rifle from http://www.johnsguns.us

[Ranb]

I load and shoot subsonic ammo in the 9mm, 300 whisper, 338 whisper, 510 whisper, 458 socom, .223 rem and 45 acp. I have been working on 380 auto, 308 win and 358 win for a little while. I use surplus WC820 for all of my subsonic loads except for the pistols. WC820 looks and meters like H110, but is a bit faster. I use NM04 (like bullseye) for the pistols. WC820 is temperature sensitive, but is just fine to load in amounts that only fill a small part of the case. I have never had a problem with detonation. Personally I think that light load detonation is a myth.

What was said above about the muzzle blast being much louder than the sonic boom and poor transonic performance I entirely agree with. The speed of sound varies most greatly with air temperature. It will vary from about 1060 fps when -40 F and a bit over 1100 fps when over 100 degrees if I remember correctly. I load my subsonic stuff to 1050 fps and generally have good results.

A chronograph is a must when loading subsonic ammo. You want at least 900 fps to ensure good power and adequate trajectory. Past 200 yards it is hard to hit a target at unknown distances and this gets worse if you are under 900 fps. Using a chrony is the easiest way to ensure you have the right powder charge. It will also show if you have consistent velocities which is required for good accuracy.

12 grains of H110 is a good starting load for a 308 rifle using a 200 grain bullet. You will need a 1-10 twist to stablize a 200 grain round nose bullet, 1-8 for up to 240 grain boat tails. A 1-12 might be ok for a 150 grain fmj or round nose.

Ranb