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Thread: .308 subsonic loads

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    .308 subsonic loads

    I'd be interested in your best loads.

    I'll be shooting in a DPMS LR-308 so I know they won't cycle the action.

    In the little bit of playing I've done, I've noticed the bullet drops about 3-4" at 100 yards from a full pwoer load.

    Normal?

    Also, please tell me about this supposed secondary detonation due to not sufficiently filling the case.

    Thanx!
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    Re: .308 subsonic loads

    yes i just bought a can and will be shooting it in my pof does anyone have a sub sonic load for it

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    Re: .308 subsonic loads

    Originally Posted By: garandman
    I'd be interested in your best loads.

    I'll be shooting in a DPMS LR-308 so I know they won't cycle the action.

    In the little bit of playing I've done, I've noticed the bullet drops about 3-4" at 100 yards from a full pwoer load.

    Normal?

    Also, please tell me about this supposed secondary detonation due to not sufficiently filling the case.

    Thanx!


    POI shift is dependant on the load (Velocity). It is not uncommon for POI to be about 2" to 4" low with factory ammo. FGMM 168 is consistantly 3" low at 100 yards out of my 700 5R, and BH 175gr is consistantly 2" low. As long as the POI is repeatable and consistant you are fine.

    Secondary detonation is caused by the use of low density pistol powders similar to Bullseye that when in the case collect toward the bullet end and are not evenly distributed creating an air pocket between the primer and powder. The occurrance is created by slowed or delayed ignition, that causes explosive gases to build due to the smoldering, and once ignited causes a high order explosion. MAKE SURE YOU HAVE 30% CASE VOLUME.

    Experimenting with several different powders by many people here have led to many threads on the subject, try the search function and you'll see. Some pistol and shotgun powders will work but are very case sensitive creating uneven burn rate and a lack of consistancy with POI. To eliminate that sensitivity you can utilize a wadding material, but that gets to be a pain. I have seen people play with Titewad, Clays, Bullseye, Trailboss, and Red Dot. I have personally tried Red Dot, Clays, and Trailboss won out. Its very bulky, 15gr fills a 308 case (Can't double charge), its easy on the hopper, and very consistant.

    The next consideration should be bullets, heavier is often better depending on your twist rate and barrell length. The biggest concern is making sure they stabilize out of the barrel. Don't want any pesky baffle strikes, I particularly like this one, and besides with friends like this who needs assholes.



    I particularly like round nose bullets in the 170gr to 180gr range, they stabilize out of my 5R very nicely. ALWAYS TEST FIRE WITHOUT THE CAN ON THE GUN, and look for keyholing.

    Lastly, the search function is your friend, as there is a thread posted regarding the Speed of Sound, ambient temperature is the main factor determining it. The colder the the lower the threshold. If you stick to 1000 fps to 1050 fps who will be good pretty much anywhere inside the US.

    Here is my pet load for my 20" barrel with an 1/11.25 twist

    Win 1X fired
    CCI BR2
    10.5gr Trailboss
    Hornady 180gr RN
    OAL = 2.643
    velocity = 1001 fps @ sea level 68 degrees


    Try the search fuction and have fun.


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    Re: .308 subsonic loads

    Originally Posted By: Witch Doctor
    Originally Posted By: garandman
    I'd be interested in your best loads.

    I'll be shooting in a DPMS LR-308 so I know they won't cycle the action.

    In the little bit of playing I've done, I've noticed the bullet drops about 3-4" at 100 yards from a full pwoer load.

    Normal?

    Also, please tell me about this supposed secondary detonation due to not sufficiently filling the case.

    Thanx!


    POI shift is dependant on the load (Velocity). It is not uncommon for POI to be about 2" to 4" low with factory ammo. FGMM 168 is consistantly 3" low at 100 yards out of my 700 5R, and BH 175gr is consistantly 2" low. As long as the POI is repeatable and consistant you are fine.

    Secondary detonation is caused by the use of low density pistol powders similar to Bullseye that when in the case collect toward the bullet end and are not evenly distributed creating an air pocket between the primer and powder. The occurrance is created by slowed or delayed ignition, that causes explosive gases to build due to the smoldering, and once ignited causes a high order explosion. MAKE SURE YOU HAVE 30% CASE VOLUME.

    Experimenting with several different powders by many people here have led to many threads on the subject, try the search function and you'll see. Some pistol and shotgun powders will work but are very case sensitive creating uneven burn rate and a lack of consistancy with POI. To eliminate that sensitivity you can utilize a wadding material, but that gets to be a pain. I have seen people play with Titewad, Clays, Bullseye, Trailboss, and Red Dot. I have personally tried Red Dot, Clays, and Trailboss won out. Its very bulky, 15gr fills a 308 case (Can't double charge), its easy on the hopper, and very consistant.

    The next consideration should be bullets, heavier is often better depending on your twist rate and barrell length. The biggest concern is making sure they stabilize out of the barrel. Don't want any pesky baffle strikes, I particularly like this one, and besides with friends like this who needs assholes.



    I particularly like round nose bullets in the 170gr to 180gr range, they stabilize out of my 5R very nicely. ALWAYS TEST FIRE WITHOUT THE CAN ON THE GUN, and look for keyholing.

    Lastly, the search function is your friend, as there is a thread posted regarding the Speed of Sound, ambient temperature is the main factor determining it. The colder the the lower the threshold. If you stick to 1000 fps to 1050 fps who will be good pretty much anywhere inside the US.

    Here is my pet load for my 20" barrel with an 1/11.25 twist

    Win 1X fired
    CCI BR2
    10.5gr Trailboss
    Hornady 180gr RN
    OAL = 2.643
    velocity = 1001 fps @ sea level 68 degrees


    Try the search fuction and have fun.


    This gentleman knows his stuff. I use this exact same load, but I have been using the 180 Sierra Round nose...I believe it is the Pro Hunter. I also use an OAL of 2.65" My 700 5r throws it at 1040 FPS and it impacts about 6" lower than my supersonic loads form the same gun. At 100 yards, I simply hold over by just shy of 1 mil in the scope. It is a solid 1.25" performer at that range, which is excellent for a round nose sub.

    Another excellent powder is Unique. That .308 load uses 8.6 grains but it does not fill the case as well as Trail Boss.

    If I had to pick just ONE powder for subs, it would be Trail Boss.

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    Re: .308 subsonic loads

    has anyone ever tried using a really slow powder like retumbo or 50bmg to get a subsonic 308.? seems to me that about <38gr of retumbo behind a 200-210gr would work well. any particular reason my thinking is off on this? seems like it would be more stable than using a pistol or shotgun powder.
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    Re: .308 subsonic loads

    I experimented when developing loads to cycle my AR 7.62x39 and the slower rifle powders will not have a good burn and will leave residue in your can. I don't know if it is still volital, but I cleaned my can and gun and went to something else. Win 296 was the winner. can not get enough trail boss in the case and still might be to quick to cycle. Trail boss works good for my 308 Shilen 1x10. Horn 180gr will MOA and less. 220gr RN did 1 1/2, but did not try to work a accurate load for it.

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    Re: .308 subsonic loads

    A slow burning rifle powder such as IMR-7828 will not give you consistent SD or stabilize the bullet as you'd like.
    Many years ago Dr.Mann did very extensive test on bullet shapes and true to form, the round nose bullet is the best performer at sub sonic velocities. This is by no means gospel, as the Whisper series of cartridges do shoot well.
    How well the bullet seals the bore,rifling twist rate, and bore time all seem to be a factor on how well a load will preform in certain types of rifles.
    Several of the above listed loads are proven performers in their rifles.
    I like to place a target,flag side out,close to the muzzle. 8-10 feet,and look for signs of unburnt powder grains and bullet wobble. A few minutes of testing can save you a would of grief later on.
    Years ago while still active duty, I played with a rifle chambered in .50 Alaskan. It's basicly a .50-110 with a long throat allowing a .50BMG bullet to be used. The barrel was a match grade Shillen made for the .50BMG. When pushed to just around 1,000 fps the rifle turned out to be very accurate at long range. True that the trajectory was that of a cinder-block, but still the bullets on impact were truly devastating. Special scope blocks had to be milled to allow enough elevation.
    With todays powders I'm sure the rifle can still perform its task.
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    Re: .308 subsonic loads

    Originally Posted By: jr81452
    has anyone ever tried using a really slow powder like retumbo or 50bmg to get a subsonic 308.? seems to me that about <38gr of retumbo behind a 200-210gr would work well. any particular reason my thinking is off on this? seems like it would be more stable than using a pistol or shotgun powder.


    I've tried surplus 50 powder with a 220gr cast bullet in a 30-06. I was shooting down the length of a picnic table because I'd forgotten the chrono and there was a lot of unburned powder laying all over the table after just 2 rounds.

    Out of a 26" barrel there isn't enough time for it to burn.

    I've since moved to using Unique or Trail Boss or Red Dot.
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    Re: .308 subsonic loads

    My buddy picked up a #20 jug of 50bmg powder to play with cheap, it was dirty as all hell and was very inconsistant. The key to subsonic loads are fast burning powders. You can play with Unique, Clays, Bullseye, and Red Dot; but once you load up Trailboss you'll understand why so many have converted to it.


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    Re: .308 subsonic loads

    Originally Posted By: Witch Doctor
    My buddy picked up a #20 jug of 50bmg powder to play with cheap, it was dirty as all hell and was very inconsistant. The key to subsonic loads are fast burning powders. You can play with Unique, Clays, Bullseye, and Red Dot; but once you load up Trailboss you'll understand why so many have converted to it.


    Trail Boss has it's limitations, ultra heavy for caliber bullets in a small capacity case (ie, 44 mag with a 460gr bullet) is a nirvana result with Red Dot.

    I was pretty surprised, but it burns incredibly clean and it's more consistent than TB in that application.

    Point being, TrailBoss is wonderful stuff, but it's not the solution to all of life's problems.
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    Re: .308 subsonic loads

    Well I have played with enough Red Dot in 308 to say that I have not seen the consistancy that you get from TB. Is it the answer or magical stuff of pixie dust, I never said that, but for 308 it works very good for me.


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    Re: .308 subsonic loads

    I've loaded Sierra prohunters with TB (.308win)that shot good, needed 12 min up from std zero at 100yds.

    Played with 175 SMKs, much better, stacks them in one ragged hole at 100yds, needs 8 min of up. 10.8 grs TB win case F/H opened to 7/64 an cone'd both sides, WLRM primer, 2.8 OAL

    Next I'll be trying 190 SMK's an 208 Amax's,..thinking the 190/208's should work better because of case volume, in the .308 win case.

    Found 208's an 12.0 gr's TB works well in 30-06, trick is to seat the 208's very deep to take up 06 case volume. Case prep same as .308win above.

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    Re: .308 subsonic loads

    Yea the 180gr Hornady RN are 8 min low at 100 yards and consistantly half inch and smaller.


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    Re: .308 subsonic loads

    Any opinions on best bullet type / weight for sub sonic .308 with a 1:12 (rem 700 ltr)
    thanks

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    Re: .308 subsonic loads

    i will let you know, im working a load for a rem 700 .308 now. with TB and 180 gr RN and 175 smk's bullets.

    My question, how do you think a 175 smk loaded backwards for sub sonic would work? Get the BC dowwn...

    New to sub sonic loading. but will proceed with caution.
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    Re: .308 subsonic loads

    Originally Posted By: TX COWDOC
    Any opinions on best bullet type / weight for sub sonic .308 with a 1:12 (rem 700 ltr)
    thanks


    I use 170gr .30-30 bullets from Hornady for my subsonic .308 load. 10.2gr of Trailboss, FGMM LR primer, and loaded into a FGMM case. This shoots <1moa at 100yds out of my 700p (1:12 twist) cut to 22".

    I had one go supersonic on me the other day when it was really cold out. Guess I need to get a chrono and see where I'm at because it must be dang close to the sub/supersonic boarder.

    -X

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    Re: .308 subsonic loads

    180gr Speer round base round nose
    11.3 trail boss
    2.650 OAL
    6200' elevation at 45 degrees
    have not run it through a Chrono
    stays subsonic and prints nice groups
    shot out of M1a with usgi barrel

    11.7 barely broke the sound barrier

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    Re: .308 subsonic loads

    Range Update-
    Brass:Lapua
    Primer:Fed 210
    Powder;Trail Boss 10.5 grains
    Bullet: Sierra 30-30 Flat Nose .308 170grain
    COAL:2.735
    Rifle: REM 700 LTR LH 20"Barrel
    Suppressor: SWR Omega 7.62
    Muzzle Velocity: AVG 1030 fps
    Alt. 300 feet
    Temp: 65F
    Sound: Snail Fart
    SWEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEET!!!!!!!!!!!!!! !!!!!!!!!!!

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    Re: .308 subsonic loads

    With the above sub load zeroed at 100 yds, the Black Hills 175 BTHP is 12" High so fairly easy to go back and forth.

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    Re: .308 subsonic loads

    Is there such a thing as a hollow point round nose type rifle bullet in 30 cal?

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    Re: .308 subsonic loads

    tag
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    Re: .308 subsonic loads

    I've been wanting to do this for awhile, but never got around to it. I finally swung by a local gun shop to see what they had for 30-30 bullets. They had some 150 gain round nose. Maybe not ideal, but workable. I had some Unique powder and started at 10.5 gains, and worked down to 8.2 grains. If I go any farther I'll go with Trailboss as recommended above because the cases really weren't filling up. I loaned my chrono to a buddy years ago so I need to "borrow" it back to see just how fast I'm running. It sounds like I'm still supersonic. I'll load a video for you to see. I never thought I could watch my .308 go downrange like my .22 trainer.

    A lot of fun! Practical... maybe not.

    http://s173.photobucket.com/albums/w...t=DSCN1194.flv

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    Re: .308 subsonic loads

    Originally Posted By: TX COWDOC
    Is there such a thing as a hollow point round nose type rifle bullet in 30 cal?


    Sierra has a 125 grain HP for the 30/30 and also Speer has a 110 grain HP for the 30/30..and then there is a Sierra 90 gr HP that was meant for the 30 Mauser pistol round...

    all are 308 bore..

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    Re: .308 subsonic loads

    Trail boss is DIRTY stuff. It will leave lots of carbon, which will harden like concrete, in your suppressor and on the muzzle. If you use it, clean them right away.

    I've loaded a bunch of subsonic 308 rounds with it and while TB does fill the case better than other powders, there are actually better alternatives.

    N320 is very good, as is Unique and TiteGroup. N320 is the cleanest burning - and the quietest - of all the powders I've tried. YMMV

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    Re: .308 subsonic loads

    Originally Posted By: long-shot
    I've been wanting to do this for awhile, but never got around to it. I finally swung by a local gun shop to see what they had for 30-30 bullets. They had some 150 gain round nose. Maybe not ideal, but workable. I had some Unique powder and started at 10.5 gains, and worked down to 8.2 grains. If I go any farther I'll go with Trailboss as recommended above because the cases really weren't filling up. I loaned my chrono to a buddy years ago so I need to "borrow" it back to see just how fast I'm running. It sounds like I'm still supersonic. I'll load a video for you to see. I never thought I could watch my .308 go downrange like my .22 trainer.

    A lot of fun! Practical... maybe not.

    http://s173.photobucket.com/albums/w...t=DSCN1194.flv


    Still sounds supersonic... I've been looking for a good subsonic load for a while too. Still haven't tried it.
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    Re: .308 subsonic loads

    Originally Posted By: Insert Name Here
    Trail boss is DIRTY stuff. It will leave lots of carbon, which will harden like concrete, in your suppressor and on the muzzle. If you use it, clean them right away.

    I've loaded a bunch of subsonic 308 rounds with it and while TB does fill the case better than other powders, there are actually better alternatives.

    N320 is very good, as is Unique and TiteGroup. N320 is the cleanest burning - and the quietest - of all the powders I've tried. YMMV


    I would assume a few full power shots at the end of shooting session would partially fix the carbon problem right?
    Originally Posted By: black_ump

    I had a FFP falcon but it was a 10x fixed i never had one with magnification

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    Re: .308 subsonic loads

    bump
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    Re: .308 subsonic loads

    tag

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    Re: .308 subsonic loads

    I am running 11.1 of trialboss with the 180gr round nose bullet. I think the key is to get as close to supersonic as you can with out breaking it and use a round nose flatbase bullet. I am getting very good groups.

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    Re: .308 subsonic loads

    Originally Posted By: cruizer
    I am running 11.1 of trialboss with the 180gr round nose bullet. I think the key is to get as close to supersonic as you can with out breaking it and use a round nose flatbase bullet. I am getting very good groups.


    What lubrication/cleaning practices are you using? I haven't heard of anybody getting consistent subsonic velocities (and thus good groups) on trailboss loads like that without something unusual done to the bullets, cartridge, and/or barrel.

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    Re: .308 subsonic loads

    If you can get them, I reccomend the Lapua SS 200 grain bullet which will work well out of a 10 twist at SS velocity. It has a rebated BT and very pointed. Kills well. I use IMR 4227. I have a huge lot of 150 180 and 170 FN and
    RN bullets if anyone wants to try them.

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    Re: .308 subsonic loads

    Originally Posted By: Insert Name Here
    Trail boss is DIRTY stuff. It will leave lots of carbon, which will harden like concrete, in your suppressor and on the muzzle. If you use it, clean them right away.

    I've loaded a bunch of subsonic 308 rounds with it and while TB does fill the case better than other powders, there are actually better alternatives.

    N320 is very good, as is Unique and TiteGroup. N320 is the cleanest burning - and the quietest - of all the powders I've tried. YMMV


    Could you please share what bullet you are using and charge weight. I have plenty of N320 as that is what I use in my pistols and would like to know where to start. I also picked up some Hornady 180 RN and some TB powder. With the TB I am going to start at about 11ish and work backwards as I do not want a bullet stuck in the barrel.
    The only shot that counts is the one you are about to take.


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    Re: .308 subsonic loads

    Originally Posted By: dbooksta
    Originally Posted By: cruizer
    I am running 11.1 of trialboss with the 180gr round nose bullet. I think the key is to get as close to supersonic as you can with out breaking it and use a round nose flatbase bullet. I am getting very good groups.


    What lubrication/cleaning practices are you using? I haven't heard of anybody getting consistent subsonic velocities (and thus good groups) on trailboss loads like that without something unusual done to the bullets, cartridge, and/or barrel.



    I also use large rifle magnum primers.

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    Re: .308 subsonic loads

    Originally Posted By: Witch Doctor
    Originally Posted By: garandman
    I'd be interested in your best loads.

    I'll be shooting in a DPMS LR-308 so I know they won't cycle the action.

    In the little bit of playing I've done, I've noticed the bullet drops about 3-4" at 100 yards from a full pwoer load.

    Normal?

    Also, please tell me about this supposed secondary detonation due to not sufficiently filling the case.

    Thanx!


    POI shift is dependant on the load (Velocity). It is not uncommon for POI to be about 2" to 4" low with factory ammo. FGMM 168 is consistantly 3" low at 100 yards out of my 700 5R, and BH 175gr is consistantly 2" low. As long as the POI is repeatable and consistant you are fine.

    Secondary detonation is caused by the use of low density pistol powders similar to Bullseye that when in the case collect toward the bullet end and are not evenly distributed creating an air pocket between the primer and powder. The occurrance is created by slowed or delayed ignition, that causes explosive gases to build due to the smoldering, and once ignited causes a high order explosion. MAKE SURE YOU HAVE 30% CASE VOLUME.

    Experimenting with several different powders by many people here have led to many threads on the subject, try the search function and you'll see. Some pistol and shotgun powders will work but are very case sensitive creating uneven burn rate and a lack of consistancy with POI. To eliminate that sensitivity you can utilize a wadding material, but that gets to be a pain. I have seen people play with Titewad, Clays, Bullseye, Trailboss, and Red Dot. I have personally tried Red Dot, Clays, and Trailboss won out. Its very bulky, 15gr fills a 308 case (Can't double charge), its easy on the hopper, and very consistant.

    The next consideration should be bullets, heavier is often better depending on your twist rate and barrell length. The biggest concern is making sure they stabilize out of the barrel. Don't want any pesky baffle strikes, I particularly like this one, and besides with friends like this who needs assholes.



    I particularly like round nose bullets in the 170gr to 180gr range, they stabilize out of my 5R very nicely. ALWAYS TEST FIRE WITHOUT THE CAN ON THE GUN, and look for keyholing.

    Lastly, the search function is your friend, as there is a thread posted regarding the Speed of Sound, ambient temperature is the main factor determining it. The colder the the lower the threshold. If you stick to 1000 fps to 1050 fps who will be good pretty much anywhere inside the US.

    Here is my pet load for my 20" barrel with an 1/11.25 twist

    Win 1X fired
    CCI BR2
    10.5gr Trailboss
    Hornady 180gr RN
    OAL = 2.643
    velocity = 1001 fps @ sea level 68 degrees


    Try the search fuction and have fun.



    This looks like it will be my starting load for a subsonic! Have you are anyone one this site tried to hunt whitetail with this round? From what I have read this round is devestating at higher velocities, but I am curious if at around 1000 FPS if the round opens up and functions correctly.(I believe in accurate humane kills of deer). In MS it is legal to hunt with a suppressor and I want to try it sometime.

    Thanks

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    Re: .308 subsonic loads

    Well I tried some TB out of my 19" 1:10 twist Kreiger. .308Win

    Lapua Brass
    CCI BR2
    10.7gr Trail Boss
    180 Hornady Round Nose
    2.650" OAL
    1065fps VERY consistant velocities.

    Nothing special either, such as moly or running a patch in the barrel. None of that just loaded up and shot great. No first round velocity drop or anything. This was out of a cold bore as well.
    The only shot that counts is the one you are about to take.


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    Re: .308 subsonic loads

    Not much expansion unless you hit bone. Up to 100 yards try for a neck or spine shot. Otherwise you'll have a looong long trail to follow. Over 100...speed it up. JMHO
    N.R.A. Life Member. If you aren't, you should be.

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    Re: .308 subsonic loads

    Originally Posted By: former naval person
    Not much expansion unless you hit bone. Up to 100 yards try for a neck or spine shot. Otherwise you'll have a looong long trail to follow. Over 100...speed it up. JMHO


    Very good advice.

    Expansion at subsonic speeds can be done if you cast soft lead, gas check it and keep the velocity low enough not to lead up the bore with the gas check installed.

    Aiming for the head is much less work.
    "The nine most terrifying words in the English language are: 'I'm from the government and I'm here to help.'" - Ronald Reagan

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    Re: .308 subsonic loads

    I have used Lapua 200 gr SS bullets for shooting deer to 200 yards and with a can, the deer just walk in a circle, lay down and die. These are not alarmed. For hunting, I would not use a SS load.

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    Re: .308 subsonic loads

    Does anyone use varget for subsonic loads? If not, why? I can't seem to find why not for the life of me.
    So low speed I'm in park

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    Re: .308 subsonic loads

    Varget won't get enough case fill for reliable ignition.
    Search ( secondary explosive effect ) for more enlightnment.

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    Re: .308 subsonic loads

    .308 is a tough caliber to take subsonic, especially without fillers. A standard 1:10 twist barrel limits you to 200gr roundnoses at transonic velocities for stability. Trailboss is the least dense powder but I have never been able to get consistent subsonic muzzle velocities with it. Next least dense powder is Clays but fill ratio is so low for subsonic velocities that once again I haven't been able to get consistent velocities without fillers.

    Typically you don't want to shoot fillers or gas-checked bullets through a can.

    I've concluded that shorter calibers like 7.62x39mm and .300 AAC in higher-twist barrels (1:8) are the way to go if you want a good subsonic rifle. You can put up to 240gr SMKs through those and get good fill ratios with Clays. And thanks to AAC's investment in the market we're supposed to see heavy .30" bullets with decent subsonic terminal ballistics within a year.

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    Re: .308 subsonic loads

    Tag

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    Re: .308 subsonic loads

    Originally Posted By: TX COWDOC
    Is there such a thing as a hollow point round nose type rifle bullet in 30 cal?


    30-30 bullets..
    if u cant find HP's, the FP are great..
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    Re: .308 subsonic loads

    this is my 260 with 160gr RN and TB..

    impact at 100


    shooting..




    260... 160gr RN with 10.5gr trail boss in a 26" 1n8 at 100y, crono said 960fps avg.
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