Heaviest .308 for 1/10" twist subsonic loads?
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Re: Heaviest .308 for 1/10" twist subsonic loads?
Don't think in terms of chambering,(until past 30-06 case size) think in twist rate, bullet weight, an exit speed. I've ran 30 cal carbine bolt guns with 220 gr bullets, but had a 8 twist barrel, an custom chamber cut. Printed 1/2 moa w/o issue.
I've a 30-06 (10 twist)that does well up to 220grs,... 208 Amaxs run the best in that one.
Just leave the can off and start working on sub loads until your getting the groups you are after.
Theres no need to run jacketed bullets either, just use cast ones,..but do not use any with gas checks. There is a mfg that makes a top fill mold that works the best, if your also into casting your own. With those you have a perfect base as theres no base sprue to worry about.
Don't think in terms of chambering,(until past 30-06 case size) think in twist rate, bullet weight, an exit speed. I've ran 30 cal carbine bolt guns with 220 gr bullets, but had a 8 twist barrel, an custom chamber cut. Printed 1/2 moa w/o issue.
I've a 30-06 (10 twist)that does well up to 220grs,... 208 Amaxs run the best in that one.
Just leave the can off and start working on sub loads until your getting the groups you are after.
Theres no need to run jacketed bullets either, just use cast ones,..but do not use any with gas checks. There is a mfg that makes a top fill mold that works the best, if your also into casting your own. With those you have a perfect base as theres no base sprue to worry about.
Re: Heaviest .308 for 1/10" twist subsonic loads?
Not sure if this is the answer he's thinking of, but I don't want a gas check coming off the bullet as it passes through my $1100 silencer.
Not sure if this is the answer he's thinking of, but I don't want a gas check coming off the bullet as it passes through my $1100 silencer.
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Re: Heaviest .308 for 1/10" twist subsonic loads?
Conqueror, is correct.
Years ago when cast bullets were being used more, many found out if the check was not seated correctly it would come off and the next round hosed the can. For years and years, bottom pour molds were all that were made and if either the mold or person casting had an issue, the groups sucked. Hence many started installing gas checks. As long as the check is installed properly there is not and issue, but if not 100% correct your looking at a repair at the least or another can at the worst.
Conqueror, is correct.
Years ago when cast bullets were being used more, many found out if the check was not seated correctly it would come off and the next round hosed the can. For years and years, bottom pour molds were all that were made and if either the mold or person casting had an issue, the groups sucked. Hence many started installing gas checks. As long as the check is installed properly there is not and issue, but if not 100% correct your looking at a repair at the least or another can at the worst.
Re: Heaviest .308 for 1/10" twist subsonic loads?
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Gunfighter14e2</div><div class="ubbcode-body">Don't think in terms of chambering,(until past 30-06 case size) think in twist rate, bullet weight, an exit speed.</div></div>
It's not as much bullet weight as bullet length. And temperature is important if it snows where you live. A bullet that stabilizes in hot weather, may not stabilize when it's cold out. A bullet that is subsonic in hot weather may not be in cold weather because the speed of sound decreases. 1080 fps. give you a good crack when theres snow on the ground.
JBM has a calculator for the miller stability number:
http://www.jbmballistics.com/cgi-bin/jbmstab-5.0.cgi
You want it to be above 2.0 for subsonic loads. Although, some people say that the bullet is more likely to tumble after impact if it is around 1.7ish
JBM's regular calculator will tell you the speed of sound for whatever temperature you enter for the load:
http://www.jbmballistics.com/cgi-bin/jbmtraj-5.0.cgi
You want to be a bit under (at least 50 fps.) to account for variation in velocity.
Run the numbers for the coldest temperature you plan to shoot in. Make sure the Miller number is at least 2.0 and the velocity is below the speed of sound.
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Gunfighter14e2</div><div class="ubbcode-body">Don't think in terms of chambering,(until past 30-06 case size) think in twist rate, bullet weight, an exit speed.</div></div>
It's not as much bullet weight as bullet length. And temperature is important if it snows where you live. A bullet that stabilizes in hot weather, may not stabilize when it's cold out. A bullet that is subsonic in hot weather may not be in cold weather because the speed of sound decreases. 1080 fps. give you a good crack when theres snow on the ground.
JBM has a calculator for the miller stability number:
http://www.jbmballistics.com/cgi-bin/jbmstab-5.0.cgi
You want it to be above 2.0 for subsonic loads. Although, some people say that the bullet is more likely to tumble after impact if it is around 1.7ish
JBM's regular calculator will tell you the speed of sound for whatever temperature you enter for the load:
http://www.jbmballistics.com/cgi-bin/jbmtraj-5.0.cgi
You want to be a bit under (at least 50 fps.) to account for variation in velocity.
Run the numbers for the coldest temperature you plan to shoot in. Make sure the Miller number is at least 2.0 and the velocity is below the speed of sound.
Re: Heaviest .308 for 1/10" twist subsonic loads?
to answer your question,
- 175 SMK
- Hornady 180 gr Round nose
- Lapua 200 gr Subsonic
everything heavier/longer than those bullets has tumbled out my 1:10 308.
The 175 SMK gave the best results in terms of accuracy. Granted, the Lapua 200 grainers were factory subsonic loads.
to answer your question,
- 175 SMK
- Hornady 180 gr Round nose
- Lapua 200 gr Subsonic
everything heavier/longer than those bullets has tumbled out my 1:10 308.
The 175 SMK gave the best results in terms of accuracy. Granted, the Lapua 200 grainers were factory subsonic loads.
Re: Heaviest .308 for 1/10" twist subsonic loads?
RN Cast lead (however I do use GC's on my loads) are stable up to 220gr bullets with 1:10's
I haven't had any issues with teh GC's, but I make an extra step in reloading to check that the GC is tight before seating the bullet. Never an issue, probably a couple thousand subs downrange. Your choice, if you do use them adn aren't careful Conqueror is correct and you can easily hose up your expensive equipment.
RN Cast lead (however I do use GC's on my loads) are stable up to 220gr bullets with 1:10's
I haven't had any issues with teh GC's, but I make an extra step in reloading to check that the GC is tight before seating the bullet. Never an issue, probably a couple thousand subs downrange. Your choice, if you do use them adn aren't careful Conqueror is correct and you can easily hose up your expensive equipment.
Re: Heaviest .308 for 1/10" twist subsonic loads?
220's keyhole out of my 16-inch 1x10 as do 210 VLD's, as well as 168 Nosler ballistic tips. 180 round nose or flat based bb's do not. i shoot 165gr Sierria #2140's. Hollow point boat tail design and shoots very well at subsonic velocities in my particular gun with trail boss. a 1x8 would probably be needed to spin up a 220 SMK to stabilize in a short barrel at subsonic velocities....IMO..
220's keyhole out of my 16-inch 1x10 as do 210 VLD's, as well as 168 Nosler ballistic tips. 180 round nose or flat based bb's do not. i shoot 165gr Sierria #2140's. Hollow point boat tail design and shoots very well at subsonic velocities in my particular gun with trail boss. a 1x8 would probably be needed to spin up a 220 SMK to stabilize in a short barrel at subsonic velocities....IMO..
Re: Heaviest .308 for 1/10" twist subsonic loads?
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Burnsome...</div><div class="ubbcode-body">220's keyhole out of my 16-inch 1x10 as do 210 VLD's, as well as 168 Nosler ballistic tips. 180 round nose or flat based bb's do not. i shoot 165gr Sierria #2140's. Hollow point boat tail design and shoots very well at subsonic velocities in my particular gun with trail boss. a 1x8 would probably be needed to spin up a 220 SMK to stabilize in a short barrel at subsonic velocities....IMO.. </div></div>
Load the bullet backwards and try 'em again if you have some more heavies to play with. The bullet orientation matters.
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Burnsome...</div><div class="ubbcode-body">220's keyhole out of my 16-inch 1x10 as do 210 VLD's, as well as 168 Nosler ballistic tips. 180 round nose or flat based bb's do not. i shoot 165gr Sierria #2140's. Hollow point boat tail design and shoots very well at subsonic velocities in my particular gun with trail boss. a 1x8 would probably be needed to spin up a 220 SMK to stabilize in a short barrel at subsonic velocities....IMO.. </div></div>
Load the bullet backwards and try 'em again if you have some more heavies to play with. The bullet orientation matters.
Re: Heaviest .308 for 1/10" twist subsonic loads?
<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">Load the bullet backwards and try 'em again if you have some more heavies to play with. The bullet orientation matters.
</div></div>
thanks. i tried loading some 168 SMK's backwards today over 9.5gr Trail Boss about .010" off the lands and they still keyholed. i've got some 135 SMK's and will try those next.
<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">Load the bullet backwards and try 'em again if you have some more heavies to play with. The bullet orientation matters.
</div></div>
thanks. i tried loading some 168 SMK's backwards today over 9.5gr Trail Boss about .010" off the lands and they still keyholed. i've got some 135 SMK's and will try those next.
Re: Heaviest .308 for 1/10" twist subsonic loads?
some success trying loading to OAL...
180gr Speer Soft Points/flat based bb's. 10.3 gr Trail Boss. one hold groups at 30 yards and will try at 100 yards this weekend and will report back. Also trying some 125 Speer TNT's and 135SMK's as well. using 7.5gr TB to push them at 1025fps testing them in the side yard today.
168 SMKs keyhole and tried loading them backwards and still keyholed.
Rem 700
Schneider 16-inch 1x10 twist
Amer Mfg Triple-X
Lapua brass
Fed mag primers
some success trying loading to OAL...
180gr Speer Soft Points/flat based bb's. 10.3 gr Trail Boss. one hold groups at 30 yards and will try at 100 yards this weekend and will report back. Also trying some 125 Speer TNT's and 135SMK's as well. using 7.5gr TB to push them at 1025fps testing them in the side yard today.
168 SMKs keyhole and tried loading them backwards and still keyholed.
Rem 700
Schneider 16-inch 1x10 twist
Amer Mfg Triple-X
Lapua brass
Fed mag primers
