subsonic 308 load
- Thread starter ifsta4
- Start date
NavyShooter
CGN Ultra frequent flyer
- Location
- XMU Local .303
Subsonic loading is a tricky game.
Be very careful with what you're doing.
The minimum loads are set for a reason, it's to prevent flash-over.
If you don't know what flashover is, then you probably shouldn't be loading subsonic without doing a LOT more research. Flashover can cause extreme overpressure conditions. IE, gun blowing up pressures.
There is also the danger of making your load so soft that the round does not leave the barrel, which, if you don't check, might result in following the first with a second, and again, bad things.
There is a website in Finland that used to have a lot of good info, but I cannot find the link right now.
Do your research, there IS info out there.
NS
Be very careful with what you're doing.
The minimum loads are set for a reason, it's to prevent flash-over.
If you don't know what flashover is, then you probably shouldn't be loading subsonic without doing a LOT more research. Flashover can cause extreme overpressure conditions. IE, gun blowing up pressures.
There is also the danger of making your load so soft that the round does not leave the barrel, which, if you don't check, might result in following the first with a second, and again, bad things.
There is a website in Finland that used to have a lot of good info, but I cannot find the link right now.
Do your research, there IS info out there.
NS
"Flash-over" seems to be this weeks buzz word around here.....
Next week's will probably be "wandering zero" or....
I would hate to have to try to even estimate how many "plinking" loads I've fired in my 30-30's, using 5 gr. 700X and a 93 gr. Lee moulded WW bullet. I have fired a pile of 10-12 gr. 700X with 150+- gr. WW Lee moulded bullets as well, in 308, 30-06, 8mm, etc.
No. You are better to start clearly too high and work DOWN.
Working DOWN won't leave you with a bullet-plugged barrel that will blow your action apart due to a second shot.
If you're worried about burning issues, get some dacron filler from a hobby store and put a puff of that in the dead volume of the case.
-M
Be careful with "subsonic" loads and case volume, I use SR 4759 a bulky powder specifically designed for reduced loads that fills the case better than pistol and shotgun powders. You also need to consider rate of twist, bullet weight and stability meaning your "subsonic" mouse fart loads might keyhole.
Read the link below on .308 reduced loads, the photo below is a bolt action .308 dismembered and destroyed with only 3 grains of powder in a reduced load. (detonation)
http://guns.connect.fi/gow/QA6.html
http://members.shaw.ca/cronhelm/DevelopSubsonic.html
http://www.snipershide.com/forum/ubbthreads.php?ubb=showflat&Number=1447370
Clean burning, accurate "BUT" my loads are "supersonic" and I still pull the trigger, light a cigarette, and take three puffs while waiting for the bullet to hit the target. (these below are for shooting rats in the cellar when I'm out of .44 magnums)
Read the link below on .308 reduced loads, the photo below is a bolt action .308 dismembered and destroyed with only 3 grains of powder in a reduced load. (detonation)
http://guns.connect.fi/gow/QA6.html
http://members.shaw.ca/cronhelm/DevelopSubsonic.html
http://www.snipershide.com/forum/ubbthreads.php?ubb=showflat&Number=1447370
Clean burning, accurate "BUT" my loads are "supersonic" and I still pull the trigger, light a cigarette, and take three puffs while waiting for the bullet to hit the target. (these below are for shooting rats in the cellar when I'm out of .44 magnums)
Last edited:
Google "trail boss" and "reduced loads". You're looking for an article from a reloading magazine that gives a formula from Hodgdon for finding the load.
It's something like "fill the case to the bottom of the neck with TrailBoss, then weigh the powder, multiply by 0.75 and that's your load with a mid-weight bullet"
*Note* That is NOT the correct formula; but the correct one is in that style.
Following the advice in that article I came-up with a load of 2.0 grains of TrailBoss and a 55grain bullet as a 950-to-975 fps load in my .221FB
It's something like "fill the case to the bottom of the neck with TrailBoss, then weigh the powder, multiply by 0.75 and that's your load with a mid-weight bullet"
*Note* That is NOT the correct formula; but the correct one is in that style.
Following the advice in that article I came-up with a load of 2.0 grains of TrailBoss and a 55grain bullet as a 950-to-975 fps load in my .221FB
MudChucker
Regular
- Location
- Niverville, Manitoba, CA
forgive me for simply not knowing something...this is not a troll question... I want to know more...
Why would you want to make this sort of load ? does it serve any particular use ?
cheers folks.
Why would you want to make this sort of load ? does it serve any particular use ?
cheers folks.
1). For plinking with your hunting rifle, to keep in practice during the off-season.
2). For small game during a hunting trip for large game (grouse, rabbits, etc)
3). Finishing shots, a 200 grain bullet at 1000 fps is plenty when you just have to deliver the coup de grace.
4). Just because.
2). For small game during a hunting trip for large game (grouse, rabbits, etc)
3). Finishing shots, a 200 grain bullet at 1000 fps is plenty when you just have to deliver the coup de grace.
4). Just because.
Pathfinder
CGN Ultra frequent flyer
- Location
- Northeast Ontario
-------------------------
I would be interested in knowing what lab did the testing on these light loads and blew a gun up.[/QUOTE]
Norma actually proved it in a lab.
A member here (Baribal) blew up a M-96 swedish mauser with a light load...
Secondary Explosive Effect.
post #40 in this thread. http://www.canadiangunnutz.com/forum/showthread.php?t=408737&highlight=secondary+explosive
I dont' think this would there would be any issues using Trail boss as it takes up so much space in a case.
4895's can be downloaded quite bit too. See the hodgdon website .
I would be interested in knowing what lab did the testing on these light loads and blew a gun up.[/QUOTE]
Norma actually proved it in a lab.
A member here (Baribal) blew up a M-96 swedish mauser with a light load...
Secondary Explosive Effect.
post #40 in this thread. http://www.canadiangunnutz.com/forum/showthread.php?t=408737&highlight=secondary+explosive
I dont' think this would there would be any issues using Trail boss as it takes up so much space in a case.
4895's can be downloaded quite bit too. See the hodgdon website .
- Location
- Somewhere on the Hudson Bay Coast
I keep hearing about detonations, but propellant powder can't detonate if we adhere to the definition of the word, which indicates the presence of a shock wave. PO Ackley probably hit on the true cause of rifles destroyed by small charges of slow burning powder. He suggested that the powder charge is driven into the neck and shoulder of a bottle neck case forming a plug; the resulting build up of pressure in the chamber quickly exceeds the strength of the rifle.
If subsonic rather than low velocity loads are what you seek, a bulky fast burning powder combined with a long for caliber flat based round nose bullet with a long bearing surface produces the best results. Lapua makes a very nice 200 gr banded bullet with an optimal profile for subsonic velocity. Other hazards you might encounter include bullets that become stuck in the bore, so be sure to check the bore after each shot. If he doesn't chime in, PM Suputin who is CGN's subsonic guru. If you really want to load subsonic ammo, the .45 Auto is a nice round.
If subsonic rather than low velocity loads are what you seek, a bulky fast burning powder combined with a long for caliber flat based round nose bullet with a long bearing surface produces the best results. Lapua makes a very nice 200 gr banded bullet with an optimal profile for subsonic velocity. Other hazards you might encounter include bullets that become stuck in the bore, so be sure to check the bore after each shot. If he doesn't chime in, PM Suputin who is CGN's subsonic guru. If you really want to load subsonic ammo, the .45 Auto is a nice round.
Last edited:
There is no reason to think that loading subsonic ammo is any more or less dangerous.
If you follow published loading data from a reliable source, and double check to be certain.
Hodgeon's site lists loads with trail Boss, Tightgroup, and Clays all around 1060-1175 fps in their test barrel.
I have tried clays with 168s. Lots of fun, low noise, good accuracy.
If you follow published loading data from a reliable source, and double check to be certain.
Hodgeon's site lists loads with trail Boss, Tightgroup, and Clays all around 1060-1175 fps in their test barrel.
I have tried clays with 168s. Lots of fun, low noise, good accuracy.
Be careful with "subsonic" loads and case volume, I use SR 4759 a bulky powder specifically designed for reduced loads that fills the case better than pistol and shotgun powders. You also need to consider rate of twist, bullet weight and stability meaning your "subsonic" mouse fart loads might keyhole.
Read the link below on .308 reduced loads, the photo below is a bolt action .308 dismembered and destroyed with only 3 grains of powder in a reduced load. (detonation)
http://guns.connect.fi/gow/QA6.html
http://members.shaw.ca/cronhelm/DevelopSubsonic.html
http://www.snipershide.com/forum/ubbthreads.php?ubb=showflat&Number=1447370
Clean burning, accurate "BUT" my loads are "supersonic" and I still pull the trigger, light a cigarette, and take three puffs while waiting for the bullet to hit the target. (these below are for shooting rats in the cellar when I'm out of .44 magnums)
Thanks for the info I will read through it .
