I recently recieved my YHM 7.62 suppressor. I would like to be able to shoot subsonic handloads. The question is my current set up is a Savage 10FP with a Pac-Nor 27" 3 groove 12 twist barrel, What length will I need to cut it back to, and can I shoot 168 and 175 gr bullets at subsonic speeds?
Suppressors Subsonic question for the gurus
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Re: Subsonic question for the gurus
I'm not an expert, so I'll start with that disclaimer.
Others may correct me if I'm wrong, but my impression from internet research:
I don't think you could go any heavier than 175/180gr with a 1:12 twist, but there's no harm in trying. What your looking for are bullet holes in your target that tear it and are not circular. Once you see this, you know the bullet isn't stabilized by your 1:12 twist and you'll probably need to use lighter bullets. I think you should be able to shoot 168 just fine.
As for barrel length, if you plan on only shooting suppressed, and only sub-sonic loads, I would say cut it down to 16". I wouldn't go any shorter because of the SBR tax and hassle, and I think 16" is plenty long to burn the powder needed to push a .308 bullet at subsonic velocities. Longer barrels will simply add more drag to the bullet and slow it down. You're shooting handloads, so why not set them up for a 16" and save some powder over a longer barrel. I would suggest buying a chronograph so you can work up reliable and consistent subsonic loads at about 90% of the speed of sound at your elevation of shooting. 90-100% of the speed of sound is called transonic and will start to have audibly louder bullet flights.
The general trade off for stopping power (if this is to be more than simply a paper puncher) is with less bullet speed you need more weight, but what you should expect, generally, is bullet holes that act like arrows. You can try to rely on bullet yaw or tumbling (going through sideways once it hits the target) but you cannot count on it, and bullet expansion at subsonic speed is usually not even much of a consideration because most hollow points are designed to expand only at supersonic velocities. Generally subsonic .30 cal hunters want to use the heaviest bullets available (often 220 or 240gr). They count on shot placement (head, spine, vitals) and hope for bullet tumbling which can and often happens when a bone is hit. But, generally, subsonic hunting is considered the firearm version of bow hunting. The problem you face is that to shoot those heavier rounds, you need a twist rate of 1:8 not 1:12. So if you plan on hunting with subsonic loads, you might consider selling/trading your barrel for one with a faster twist at the length you want and save the money on shortening your barrel.
Note that my research has been focused on the .300/.221 (300 whisper) round, but subsonic .30 cal is subsonic .30 cal.
In short: If you only plan on shooting subs you won't really need more than 16" and there's not any great advantage to going shorter where the NFA hassles start. You barrel twist of 1:12 is not ideal for subsonic loads if hunting is in your future. If only punching paper, your barrel twist is fine, but you'll have to stick to lighter bullets than the 220-240gr most used for subsonic hunting.
Again, take all this with a grain of salt. Correction or confirmation requested for the original poster's sake.
Regards,
Nate
I'm not an expert, so I'll start with that disclaimer.
Others may correct me if I'm wrong, but my impression from internet research:
I don't think you could go any heavier than 175/180gr with a 1:12 twist, but there's no harm in trying. What your looking for are bullet holes in your target that tear it and are not circular. Once you see this, you know the bullet isn't stabilized by your 1:12 twist and you'll probably need to use lighter bullets. I think you should be able to shoot 168 just fine.
As for barrel length, if you plan on only shooting suppressed, and only sub-sonic loads, I would say cut it down to 16". I wouldn't go any shorter because of the SBR tax and hassle, and I think 16" is plenty long to burn the powder needed to push a .308 bullet at subsonic velocities. Longer barrels will simply add more drag to the bullet and slow it down. You're shooting handloads, so why not set them up for a 16" and save some powder over a longer barrel. I would suggest buying a chronograph so you can work up reliable and consistent subsonic loads at about 90% of the speed of sound at your elevation of shooting. 90-100% of the speed of sound is called transonic and will start to have audibly louder bullet flights.
The general trade off for stopping power (if this is to be more than simply a paper puncher) is with less bullet speed you need more weight, but what you should expect, generally, is bullet holes that act like arrows. You can try to rely on bullet yaw or tumbling (going through sideways once it hits the target) but you cannot count on it, and bullet expansion at subsonic speed is usually not even much of a consideration because most hollow points are designed to expand only at supersonic velocities. Generally subsonic .30 cal hunters want to use the heaviest bullets available (often 220 or 240gr). They count on shot placement (head, spine, vitals) and hope for bullet tumbling which can and often happens when a bone is hit. But, generally, subsonic hunting is considered the firearm version of bow hunting. The problem you face is that to shoot those heavier rounds, you need a twist rate of 1:8 not 1:12. So if you plan on hunting with subsonic loads, you might consider selling/trading your barrel for one with a faster twist at the length you want and save the money on shortening your barrel.
Note that my research has been focused on the .300/.221 (300 whisper) round, but subsonic .30 cal is subsonic .30 cal.
In short: If you only plan on shooting subs you won't really need more than 16" and there's not any great advantage to going shorter where the NFA hassles start. You barrel twist of 1:12 is not ideal for subsonic loads if hunting is in your future. If only punching paper, your barrel twist is fine, but you'll have to stick to lighter bullets than the 220-240gr most used for subsonic hunting.
Again, take all this with a grain of salt. Correction or confirmation requested for the original poster's sake.
Regards,
Nate
Re: Subsonic question for the gurus
1-12 is kind of slow, especially if you want to suppress it and eliminate any baffle strike concerns. Are you planning on using that can for standard supersonic loads? I have a savage with a Pac-Nor 1-12 (wish I got the 1-10) that shoots 168 better than 175g. While I could use subsonic ammo in it, I do not think I would be able to stablize anything heavier than 150 grains and not get a baffle strike. I am not going to test it either.
I have a 300 whisper for the subsonic stuff, it has a 1-8 twist for the 240 grain bullets.
If you really want to chop it, then ten inches is a good length unless you do not want to pay another tax for the SBR. Otherwise 16" is good. Start out with 150 grain reloads (I use H110) then work up in bullet weight. I would not test the ammo with the can attached until you verify that you are not keyholing. A shorter round nose bullet will stabilze better than a long HPBT with that 1-12 twist.
Ranb
1-12 is kind of slow, especially if you want to suppress it and eliminate any baffle strike concerns. Are you planning on using that can for standard supersonic loads? I have a savage with a Pac-Nor 1-12 (wish I got the 1-10) that shoots 168 better than 175g. While I could use subsonic ammo in it, I do not think I would be able to stablize anything heavier than 150 grains and not get a baffle strike. I am not going to test it either.
If you really want to chop it, then ten inches is a good length unless you do not want to pay another tax for the SBR. Otherwise 16" is good. Start out with 150 grain reloads (I use H110) then work up in bullet weight. I would not test the ammo with the can attached until you verify that you are not keyholing. A shorter round nose bullet will stabilze better than a long HPBT with that 1-12 twist.
Ranb
Re: Subsonic question for the gurus
Bullet length has more to do with stabalizing than just the weight, that is why RN hunting bullets work better, and for hunting the RN will transfer more absorbed energy than a hard pointed bullet. There are a lot of guys using the Horn 180gr RN in 1x12 twist. I guess because of the slow speed, the JBM calculator shows not much difference in bullet drop between weights and shapes. There is a difference in energy at 100yds, nearly 100 lbs between the 180 RN & 220 RN. Around 21%. You may also try the speer 200gr SP.
My .308 Bolt gun is a Shilen 1x10, I wanted to shoot it 1000yds, Hunt with it, and Shoot Sub-Sonic. I first Fitted it at 26", shot around 12rds, then cut to 20". Accuacy seemed to stay very good, better than I can shoot. With YHM QD I can get 1/2 MOA.@ 500yds. 168gr Nosler CC, 45.5gr Varget, 2.810 OAL. Subs are 180gr RN, 1" MOA @ 100 yds. This barrel length works for me.
I am no expert either, but I did stay at a Holliday Express once.
Have Fun Eddie
Bullet length has more to do with stabalizing than just the weight, that is why RN hunting bullets work better, and for hunting the RN will transfer more absorbed energy than a hard pointed bullet. There are a lot of guys using the Horn 180gr RN in 1x12 twist. I guess because of the slow speed, the JBM calculator shows not much difference in bullet drop between weights and shapes. There is a difference in energy at 100yds, nearly 100 lbs between the 180 RN & 220 RN. Around 21%. You may also try the speer 200gr SP.
My .308 Bolt gun is a Shilen 1x10, I wanted to shoot it 1000yds, Hunt with it, and Shoot Sub-Sonic. I first Fitted it at 26", shot around 12rds, then cut to 20". Accuacy seemed to stay very good, better than I can shoot. With YHM QD I can get 1/2 MOA.@ 500yds. 168gr Nosler CC, 45.5gr Varget, 2.810 OAL. Subs are 180gr RN, 1" MOA @ 100 yds. This barrel length works for me.
I am no expert either, but I did stay at a Holliday Express once.
Have Fun Eddie
Re: Subsonic question for the gurus
Just want to say thanks for everyones input. I think it has helped me make a decision. Sounds like I'd be safer just leaving it the way it is and shooting supersonic loads which I am impressed with. I don't want it to be soley a subsonic gun. I think I'll put a QD mount on my .223 (also bolt gun) 20" 1x9 twist and shoot it both supersonic and subsonic. If you guys have any input/info on that please add. Again thanks guys
Just want to say thanks for everyones input. I think it has helped me make a decision. Sounds like I'd be safer just leaving it the way it is and shooting supersonic loads which I am impressed with. I don't want it to be soley a subsonic gun. I think I'll put a QD mount on my .223 (also bolt gun) 20" 1x9 twist and shoot it both supersonic and subsonic. If you guys have any input/info on that please add. Again thanks guys
Re: Subsonic question for the gurus
I started developing a subsonic 223 load in my 1-9 twist AR. 6.5 grains of H110 and the Speer 70 RN did ok, did not cycle the action of course. They work better in my 1-8 NM upper though. I no longer have the 1-9 upper.
Ranb
I started developing a subsonic 223 load in my 1-9 twist AR. 6.5 grains of H110 and the Speer 70 RN did ok, did not cycle the action of course. They work better in my 1-8 NM upper though. I no longer have the 1-9 upper.
Ranb
Re: Subsonic question for the gurus
I'm in the same boat as you. I have a YHM 7.62 Phantom with QD mounts on 4 different guns, .22, .223, and .308. I have a 1-12 twist rem 700 that I am using primarily as a supersonic rifle but have developed some subsonic loads with 170gr round nose and trilboss with decent results. It is very nice inside 100yds! I think that I will keep a few in my gun bag for those times I want to be quieter. There is some good reloading information on subsonic rounds in the reloading section also look at the very top above the different topics more Reloading data.
Good Luck.
I'm in the same boat as you. I have a YHM 7.62 Phantom with QD mounts on 4 different guns, .22, .223, and .308. I have a 1-12 twist rem 700 that I am using primarily as a supersonic rifle but have developed some subsonic loads with 170gr round nose and trilboss with decent results. It is very nice inside 100yds! I think that I will keep a few in my gun bag for those times I want to be quieter. There is some good reloading information on subsonic rounds in the reloading section also look at the very top above the different topics more Reloading data.
Good Luck.
Re: Subsonic question for the gurus
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: packratt</div><div class="ubbcode-body">Since you have a Savage you can easily swap barrels. Get a barrel made to the specs you want for subsonic and change back and forth as required. </div></div>
Can't do this as easy anymore. When I rebarreled with a match barrel and chamber, we did away with the barrel nut. Many reasons this was done
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: packratt</div><div class="ubbcode-body">Since you have a Savage you can easily swap barrels. Get a barrel made to the specs you want for subsonic and change back and forth as required. </div></div>
Can't do this as easy anymore. When I rebarreled with a match barrel and chamber, we did away with the barrel nut. Many reasons this was done
Re: Subsonic question for the gurus
Just get a barrel vise with inserts to match the barrel diameter. I had a Savage 10 fcm rebarreled to 338 whisper. I expected SSK to just use the barrel nut to attach it, but they put it on without the nut. This makes it easier to swap barrels actually. I just torque the barrel back on then check headspace to verify it is not excessive, no adjustments needed.
Ranb
Just get a barrel vise with inserts to match the barrel diameter. I had a Savage 10 fcm rebarreled to 338 whisper. I expected SSK to just use the barrel nut to attach it, but they put it on without the nut. This makes it easier to swap barrels actually. I just torque the barrel back on then check headspace to verify it is not excessive, no adjustments needed.
Ranb
Re: Subsonic question for the gurus
Make sure you get a Lee Factory Crimp die. And a good chronograph. With the 1-12 try to get as close to 1150fps(speed of sound) it will help a little with a slow twist. If you keep a long barrel, just remember that the bullet is traveling ALOT slower and it will really show in your groups as the barrel has more time to affect the bullet as it's traveling down the tube.Shooting Sub ammo is a VERY good trainning item if you can shoot fuzzy groups @ 100 it will help you in long range shooting. I shot at a range many years ago and two old fellas had a couple 40x's and I noticed that the guns were not recoiling very much. They explained that the rds. were loaded with pistol powder and used lead bullets. Cheaper to shoot and also improved their shooting skils. Hope this helps. R/ Mike
Make sure you get a Lee Factory Crimp die. And a good chronograph. With the 1-12 try to get as close to 1150fps(speed of sound) it will help a little with a slow twist. If you keep a long barrel, just remember that the bullet is traveling ALOT slower and it will really show in your groups as the barrel has more time to affect the bullet as it's traveling down the tube.Shooting Sub ammo is a VERY good trainning item if you can shoot fuzzy groups @ 100 it will help you in long range shooting. I shot at a range many years ago and two old fellas had a couple 40x's and I noticed that the guns were not recoiling very much. They explained that the rds. were loaded with pistol powder and used lead bullets. Cheaper to shoot and also improved their shooting skils. Hope this helps. R/ Mike
