Max Owner
CGN Ultra frequent flyer
Heeya heeya heeya.
Last bold part............. You aren't reading something on the internet and believing it, are ya?
Help for a 308 Rifle
- Thread starter I.C.U.
- Start date
Heeya heeya heeya.
Last bold part............. You aren't reading something on the internet and believing it, are ya?
help for a 308 rifle
Mysticplayer:
I don't quite understand what you're saying about this subsonic stuff.
I understood that a bullet going from a high MV (several 1000 fps) and slowing down thru the speed of sound (1000 fps or 340m/s) i.e. going subsonic causes it to become unstable and it then starts to tumble. I experienced this with a 20 inch (actualy 19 ½ inch) tubed Rem 700 VS 308 Win. when I couldn't get enough MV out of a 168 SMK. (47 gr Varget, bolt sticking) As the bullets tumbled they:
1- started to require lots more elevation (than the predicted ballistic chart) to get to 1000 yds
2- keyholed in the target
3- started to hit all over the place (become innacurate)
I know this is what happened and not the rifle barrel being shot out because I could do fine at 1000 yds with my 155 SMKs with 46 gr Varget (ex. 82/90)
out of the same 19½ inch barrel. This was in 2002 before I started to shoot Lapua Scenars. Also, I believe the twist on the factory Rem 308 Win is fast enough to stabilize even 180 gr bullets (1-10?) as I shot some of these at closer ranges with success.
So, I was under the impression that if you cannot retain a minimum of 1000+ fps from a bullet at a specific max range then you can't get it to go that far .... accurately.
Can you please clarify? I think it might help a lot of our fellow shooters to understand long range shooting limitations. Thanks. Serge
PS: I believe my 7mmSTW is still above 1000 fps (with a good margin) up to 1600 yds. with 180 VLDs at 3050 fps MV (Broughton 27½ inch. mag. sporter 1-9 inch twist tube, 81 grains of H1000 in Win. cases) so I might even hit the one mile mark. Can you confirm this?
Mysticplayer:
I don't quite understand what you're saying about this subsonic stuff.
I understood that a bullet going from a high MV (several 1000 fps) and slowing down thru the speed of sound (1000 fps or 340m/s) i.e. going subsonic causes it to become unstable and it then starts to tumble. I experienced this with a 20 inch (actualy 19 ½ inch) tubed Rem 700 VS 308 Win. when I couldn't get enough MV out of a 168 SMK. (47 gr Varget, bolt sticking) As the bullets tumbled they:
1- started to require lots more elevation (than the predicted ballistic chart) to get to 1000 yds
2- keyholed in the target
3- started to hit all over the place (become innacurate)
I know this is what happened and not the rifle barrel being shot out because I could do fine at 1000 yds with my 155 SMKs with 46 gr Varget (ex. 82/90)
out of the same 19½ inch barrel. This was in 2002 before I started to shoot Lapua Scenars. Also, I believe the twist on the factory Rem 308 Win is fast enough to stabilize even 180 gr bullets (1-10?) as I shot some of these at closer ranges with success.
So, I was under the impression that if you cannot retain a minimum of 1000+ fps from a bullet at a specific max range then you can't get it to go that far .... accurately.
Can you please clarify? I think it might help a lot of our fellow shooters to understand long range shooting limitations. Thanks. Serge
PS: I believe my 7mmSTW is still above 1000 fps (with a good margin) up to 1600 yds. with 180 VLDs at 3050 fps MV (Broughton 27½ inch. mag. sporter 1-9 inch twist tube, 81 grains of H1000 in Win. cases) so I might even hit the one mile mark. Can you confirm this?
Mystic Precision
CGN Ultra frequent flyer
- Location
- Summerland, BC
Going from supersonic to subsonic and loosing accuracy is a point that has been discussed alot of late and unfortunately, many of the conclusions are wrong. But repeat it often enough and it becomes fact.
There is apparently little to no turbulence when a bullet goes transonic. This was illustrated and debated on benchrestcentral by literally rocket scientists. high speed photography amounst other really high tech test gear showed that the bullet dropped through the sound barrier without much fuss.
What I am discussing here is paraphrasing what was posted so some info may be a bit off. I am no rocket scientist but have a decent grounding in aerodynamics.
Where the problem comes is that the aerodynamic balance of the bullet is changed when they go subsonic which causes some bullets, like the 168gr MK, to go unstable and tumble.
Gyroscopic stability (spin stability) had little effect on this issue. Spinning faster doesn't help. As long as the bullet was stable from the muzzle out, it would have enough spin stability when it went subsonic (spin stability actually increases)
Also, differences in the nose/meplat cause varying amounts of drag which cause bullets to string. Bullet drag is much more pronounced when it goes subsonic as the sonic bow wave is gone. big reason why LR BR shooters want their bullets to stay supersonic on target. Issues with nose drag is reduced/eliminated - why some shooters feel meplat trimming is important.
Poly tipped bullets like the Amax have two advantages. Their planform (secant ogive) is apparently more stable over extreme distances and that poly tip ensures a high amount of consistency in drag. Berger VLD's share a similar planform and my only experience (80gr VLD 22cal) showed promise BUT some problems as well (I did experience some extreme vertical stringing).
The only other bullet I have seen fail was the 175gr MK out of a HS custom 308. That same bullet in several other rifles did superbly two weekends ago. Left with more questions then answers on this one.
My 6.5 Mystic pushes a 139gr Scenar quite happily to 2400yds. Leaving at 2900fps, it should go subsonic around 1400yds so I am well and truly subsonic. Accuracy was really good given the winds. more shooting to follow as the weather warms up. I don't trim meplats.
The Lapua has a more tangent ogive then secant shape so bullet planform is not necessarily a deciding factor on subsonic survival.
Bullet aerodynamic balance is and I have no way to eye ball that.
Read my post on the 223 out to a mile and you can gain more insight into my thoughts on this matter.
Ultimately, some bullets will happily go subsonic, some will not. The only way to know is to point the rifle at the sky and launch lead. Muzzle velocity is not too critical but going faster does help with the amount of elevation you need way out there. And you will need ALOT.
I can say with certainty that all the Amax bullets I have shot over the years had no issue going subsonic and I have used pretty much all the cals.
The 75gr and 80gr Amax will make the trip to a mile no problem. The Berger is uncertain and unlikely to test further (cost and availability).
For the 308, I know the 155gr Amax will make the trip cause I have shot them to 1450yds with zero issue. Never bothered with the heavier ones but don't expect any trouble. No idea on the MK's as I don't like them. Never shot any Scenars as I left the 308 before testing.
If you have a load that does well at 1000yds, push it out to at least 1200yds with 1400yds being ideal. The bullet will either stay stable or fly wildly.
If it makes the transistion to subsonic flight, you just need to crank the rifle up.
Jerry
There is apparently little to no turbulence when a bullet goes transonic. This was illustrated and debated on benchrestcentral by literally rocket scientists. high speed photography amounst other really high tech test gear showed that the bullet dropped through the sound barrier without much fuss.
What I am discussing here is paraphrasing what was posted so some info may be a bit off. I am no rocket scientist but have a decent grounding in aerodynamics.
Where the problem comes is that the aerodynamic balance of the bullet is changed when they go subsonic which causes some bullets, like the 168gr MK, to go unstable and tumble.
Gyroscopic stability (spin stability) had little effect on this issue. Spinning faster doesn't help. As long as the bullet was stable from the muzzle out, it would have enough spin stability when it went subsonic (spin stability actually increases)
Also, differences in the nose/meplat cause varying amounts of drag which cause bullets to string. Bullet drag is much more pronounced when it goes subsonic as the sonic bow wave is gone. big reason why LR BR shooters want their bullets to stay supersonic on target. Issues with nose drag is reduced/eliminated - why some shooters feel meplat trimming is important.
Poly tipped bullets like the Amax have two advantages. Their planform (secant ogive) is apparently more stable over extreme distances and that poly tip ensures a high amount of consistency in drag. Berger VLD's share a similar planform and my only experience (80gr VLD 22cal) showed promise BUT some problems as well (I did experience some extreme vertical stringing).
The only other bullet I have seen fail was the 175gr MK out of a HS custom 308. That same bullet in several other rifles did superbly two weekends ago. Left with more questions then answers on this one.
My 6.5 Mystic pushes a 139gr Scenar quite happily to 2400yds. Leaving at 2900fps, it should go subsonic around 1400yds so I am well and truly subsonic. Accuracy was really good given the winds. more shooting to follow as the weather warms up. I don't trim meplats.
The Lapua has a more tangent ogive then secant shape so bullet planform is not necessarily a deciding factor on subsonic survival.
Bullet aerodynamic balance is and I have no way to eye ball that.
Read my post on the 223 out to a mile and you can gain more insight into my thoughts on this matter.
Ultimately, some bullets will happily go subsonic, some will not. The only way to know is to point the rifle at the sky and launch lead. Muzzle velocity is not too critical but going faster does help with the amount of elevation you need way out there. And you will need ALOT.
I can say with certainty that all the Amax bullets I have shot over the years had no issue going subsonic and I have used pretty much all the cals.
The 75gr and 80gr Amax will make the trip to a mile no problem. The Berger is uncertain and unlikely to test further (cost and availability).
For the 308, I know the 155gr Amax will make the trip cause I have shot them to 1450yds with zero issue. Never bothered with the heavier ones but don't expect any trouble. No idea on the MK's as I don't like them. Never shot any Scenars as I left the 308 before testing.
If you have a load that does well at 1000yds, push it out to at least 1200yds with 1400yds being ideal. The bullet will either stay stable or fly wildly.
If it makes the transistion to subsonic flight, you just need to crank the rifle up.
Jerry
Heeya heeya heeya.
Last bold part............. You aren't reading something on the internet and believing it, are ya?
...Nope. I owned a pre-Accutrigger 112 FV which is the identical action to the Stevens. I know all too well about the crappy stock and trigger that won't go below roughly 3.5lbs weight pull without losing use of the safety.I've actually tried to buy a FP MacMillan on (2) different occasions now but couldn't locate one either time. In each instance, I ended up buying something else.
I've read that others were experiencing the same thing - unfortunately.
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Mystic Precision
CGN Ultra frequent flyer
- Location
- Summerland, BC
You guys would have much better success getting a base Savage then buying a stock and barrel and assemble. Who knows when the import issues will be resolved.
Then, when will the demand in the US taper off enough to get a few up here.
Start with the new FCNS in 308/243. These should be around $500ish. Sell off the parts you don't want for some cost recovery. The mag and bottom metal will transfer to the McM/HS/Choate/Stockade stock. Just make sure whoever you are talking to understands this is for the New Gen center feed det mag.
The action screw holes are different as is the bottom inletting.
Order a stock in whatever style floats your boat.
Barrel as you see fit and put it all together.
Likely have a much better shooter for a little more then the factory rifle (maybe the same price/cheaper?????) AND it will actually get done.
Jerry
PS someone is making lighter trigger springs but I have yet to get my hands on any. Supposed to put the pull down around the 1.5/2lbs range and is a one minute retrofit into the Stevens. Some polishing will help but they are stiff as they come from the box.
Then, when will the demand in the US taper off enough to get a few up here.
Start with the new FCNS in 308/243. These should be around $500ish. Sell off the parts you don't want for some cost recovery. The mag and bottom metal will transfer to the McM/HS/Choate/Stockade stock. Just make sure whoever you are talking to understands this is for the New Gen center feed det mag.
The action screw holes are different as is the bottom inletting.
Order a stock in whatever style floats your boat.
Barrel as you see fit and put it all together.
Likely have a much better shooter for a little more then the factory rifle (maybe the same price/cheaper?????) AND it will actually get done.
Jerry
PS someone is making lighter trigger springs but I have yet to get my hands on any. Supposed to put the pull down around the 1.5/2lbs range and is a one minute retrofit into the Stevens. Some polishing will help but they are stiff as they come from the box.
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Thanks Epoxy7,
I'll check that one out also but I am looking for more a 26" to 28" barrel.
Keep in mind with .308 the 26" barrel only offers about 40 fps over the 24". A shorter barrel is often more accurate (tons of threads already on this). I find that the 24" barrel is handier, less weight and balances better.
The other thing to keep in mind is that the 5R uses a pollygonal rifled barrel rather than the traditional. You may very well gain a few more FPS over a traditonal barrel due to this style of rifling. It's definately a lot easier to clean.
The rumour about the barrel on these rifles is that they are extras or the barrels that didn't make the cut for the M24 Sniper rifle. Considering they are both 1 twist in 11 1/4 and 5R rifling. I would say it's a good bet that they are the extras and or ones that didn't make the cut.
Ivan Smythe
CGN Regular
- Location
- Northern BC
I.C.U.,
my two cents, for what it's worth.
this is a rig i put together and was very pleased with.
Savage 10 FCP .308 w/McMillan stock, 26" 1/10" rate of twist barrel. $1200
Nightforce rings and bases (20 m.o.a. bases). $300
Bushnell Elite Tactical 6-24x50mm Scope, 30mm tube, side parallax adj., mildot reticle. $700
i had the gentlemen at Corlane's put on a muzzle brake for $200
the muzzle brake is not necessary but makes it easier to call your own shots.
i chose this rifle because of the 1/10" rate of twist, it allows me to launch 190gr SMK's, which makes it a true long range rifle. IT, will hit targets easily out to 1000 yds, the rest is up to you.
good luck and good shooting.
as per,
i.
my two cents, for what it's worth.
this is a rig i put together and was very pleased with.
Savage 10 FCP .308 w/McMillan stock, 26" 1/10" rate of twist barrel. $1200
Nightforce rings and bases (20 m.o.a. bases). $300
Bushnell Elite Tactical 6-24x50mm Scope, 30mm tube, side parallax adj., mildot reticle. $700
i had the gentlemen at Corlane's put on a muzzle brake for $200
the muzzle brake is not necessary but makes it easier to call your own shots.
i chose this rifle because of the 1/10" rate of twist, it allows me to launch 190gr SMK's, which makes it a true long range rifle. IT, will hit targets easily out to 1000 yds, the rest is up to you.
good luck and good shooting.
as per,
i.
Thanks again,
I was looking at the 700SS 5R Milspec from Frontier. Looks like a good deal.
Thanks Ivan Smythe,
Would I be able to do that with the Remington models? For example, take the action only and do like you did. Pick a better stock, different barrel, muzzle brake and so forth. There is a lot of info to take in. I'll start shooting and learn the ropes this Summer.
Thanks klrklr
Dante, ya sometimes I go there but parking is sick. I'll check out the Savage. The pic on your last post isn't showing.
TRG22 at LeBaron. That's one I have not seen so I'll go and ask them some info.
Thanks Mugen
