What is your load data for the 8208 and 175 TSMK's? I have a 4 lb container of 8208 that I use for my 20 Practical. Thanks
Need .308 Win 1,000 yd load assistance
- Thread starter Skeeter
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What is your load data for the 8208 and 175 TSMK's? I have a 4 lb container of 8208 that I use for my 20 Practical. Thanks
This is my load data worked up with an Oehler 43. 11 mils to 1000 at 5600' with a 100 yard zero and transonic at 925 yards. With a longer bbl and 200 fps more - if possible it would be 9.1 mils and still supersonic at 1000.
I load for my buddies 20" SPS, which I believe is 1:12. He shoots both bulkets with Varget. 44.3gr in Lapua regular 308win cases. MV with 175SMK is 2580fps, 175 TMK is 2550. At 400' AMSL it is doing pretty well on steel at 1k.
Would I encourage him to shoot it F TR? Yes, so he got his feet wet and could decide what to modify with some personal expierence.
Of course, work up. My expierence with a HUGE Remington chamber and this lot of Varget may be totally different than yours.
Would I encourage him to shoot it F TR? Yes, so he got his feet wet and could decide what to modify with some personal expierence.
Of course, work up. My expierence with a HUGE Remington chamber and this lot of Varget may be totally different than yours.
Ref: Precision shooting Magazine November, 2007 Article by Roy Chandler on the XM3 Marine Corps Sniper Rifle.
Iron Brigade Armory did a lot of experimentation for DARPA with an 18.5" .308 out to 1000 yards. They were quite successful with a barrel shorter than 20" They stated that in order to accomplish what they wanted, they had to go to a 10" twist Hart 6 groove barrel. The ammo that they used was Black Hills 175 gr. Match ammo. They said that the Army tried to cut down their M24 and the Marines M40 series rifles. They had a 12" twist and an 11.25" twist and they were not accurate at distance. The 10" twist Hart was critical to obtaining accuracy with a barrel of 20" or shorter at distance. Remember that the 168gr. Sierra was designed as a 300 meter international CISM bullet. It has a 13 degree boat tail ant will not fly accurately beyond about 800 yds. The old military M1 bullet has a 9 degree boat tail and will fly supersonic past 1000 yards. You might contact IBA and ask them about this project.
Hope that this helps.
Iron Brigade Armory did a lot of experimentation for DARPA with an 18.5" .308 out to 1000 yards. They were quite successful with a barrel shorter than 20" They stated that in order to accomplish what they wanted, they had to go to a 10" twist Hart 6 groove barrel. The ammo that they used was Black Hills 175 gr. Match ammo. They said that the Army tried to cut down their M24 and the Marines M40 series rifles. They had a 12" twist and an 11.25" twist and they were not accurate at distance. The 10" twist Hart was critical to obtaining accuracy with a barrel of 20" or shorter at distance. Remember that the 168gr. Sierra was designed as a 300 meter international CISM bullet. It has a 13 degree boat tail ant will not fly accurately beyond about 800 yds. The old military M1 bullet has a 9 degree boat tail and will fly supersonic past 1000 yards. You might contact IBA and ask them about this project.
Hope that this helps.
Spin it faster, yeah that makes sense. This just reminded me that Todd Hodnett tested a 14" 308WIN barrel 1-8" twist and shot it to a mile with FGM 168's. With the standard 1-11.25" twist they could never see impact and had no idea where it was hitting.
Berger 185 Match Hybrid Target bullet (has a BC of .569) and if I can move it out of the barrel at over 2500'/sec I should be able to stay Supersonic past 1,000 yards.
Per my calculator using the 2600' altitude they should make it even farther. Per the Berger manual they like the 1:11 twist rate which mine has. With 44.0 grains of RL15 and a 24" barrel they list them moving at 2,600'/sec. Placing this data into my ShootersNotes and only adjusting for barrel length I'm getting 2528'/sec. If I plug that into my calculator it appears (in theory) I'm golder to past the 1,200 yard mark now.
What do you all think?
Per my calculator using the 2600' altitude they should make it even farther. Per the Berger manual they like the 1:11 twist rate which mine has. With 44.0 grains of RL15 and a 24" barrel they list them moving at 2,600'/sec. Placing this data into my ShootersNotes and only adjusting for barrel length I'm getting 2528'/sec. If I plug that into my calculator it appears (in theory) I'm golder to past the 1,200 yard mark now.
What do you all think?
44 grains might be a little warm for the 185 depending on case capacity. With the 185 your max velocity will be right around 2600 fps so I would load to that velocity. RL15 is very temperature sensitive so load to that velocity and develop / test load in the highest temps you can that way it will always be shootable. If BC holds true you will be supersonic to 1150 yds.
XTR
F-TR obssessed shooting junkie
I just saw this. 20" barrel, you are using a sand wedge off of the tee on a par 5. Good luck.
I achieved 2675-2700 with a 26" barrel. 1000 yds was no problem. RL 15 was my 185 Berger powder. At the time I wasn't aware of temperature sensitivity. It performed great on the hot days of July out west for me. For me the 185s out performed the 175 bergers hands down making the 1000-1200 yd mark. Not so sure with a 20" tube. Think your starting out with a 200fps handicap before pulling the trigger.
48.3 imr 4064 Thats super hot!
nice group! Mine also groups like that at 100 yards but that doesn't convey to 1,000 yard accuracy since mines falling out of the air around 850 yards.
I did call the Sierra Techs and got one of them on the line yesterday. He said the 168 SMK was never intended to be anything more than a 300 meter bullet and for the most part is good to about 800 yards. He said right around this yardage the bullets go into transonic which they don't handle very well and stability falls apart. He said I would need to keep the 168 bullets velocity at 1,000 above 1,250/sec to have any chance of consistency.
He recommended the 175 SMK with RL 15 starting at 43 grains and work up slowly while checking pressure. Said I would need the muzzle velocity to be right around 2,550'/sec to maintain a stable transition into transonic at 1,000 yards using my 20" barrel and 1:11.25 twist. He said if I can be around 1,200'/sec at 1,000 yards it should shoot them very well.
He also mentioned not going to the tipped SMK as the bullet is shorter to the ogive and I would not be able to seat the bullet close enough to the lands due to the long freebore my chamber has.
So my plan is to load 175 SMKs with RL15 in increments and test fire until I hit the 2,550'/sec velocity, check for pressure, if all is okay, test them on the range at the 800, 900 & 1,000 yards to see what happens.
Thanks everybody!
Skeeter
I did call the Sierra Techs and got one of them on the line yesterday. He said the 168 SMK was never intended to be anything more than a 300 meter bullet and for the most part is good to about 800 yards. He said right around this yardage the bullets go into transonic which they don't handle very well and stability falls apart. He said I would need to keep the 168 bullets velocity at 1,000 above 1,250/sec to have any chance of consistency.
He recommended the 175 SMK with RL 15 starting at 43 grains and work up slowly while checking pressure. Said I would need the muzzle velocity to be right around 2,550'/sec to maintain a stable transition into transonic at 1,000 yards using my 20" barrel and 1:11.25 twist. He said if I can be around 1,200'/sec at 1,000 yards it should shoot them very well.
He also mentioned not going to the tipped SMK as the bullet is shorter to the ogive and I would not be able to seat the bullet close enough to the lands due to the long freebore my chamber has.
So my plan is to load 175 SMKs with RL15 in increments and test fire until I hit the 2,550'/sec velocity, check for pressure, if all is okay, test them on the range at the 800, 900 & 1,000 yards to see what happens.
Thanks everybody!
Skeeter
Some of us have spent quite a bit of time shooting .308WIN at 1000 yards. We try to reliably hit a 10" circle in literally all conditions.
No one is using a 20" barrel. No one I know of is having any real success at all shooting anything lighter than 185 Bergers. In my opinion it is an exercise in futility to try to develop something that will make hits reliably on a small target at 1K with a 20" barrel 308, or for that matter with 175 SMKs. You are giving up too much. You might make a few hits in ideal conditions. But when is that?
Get a 26" 10 or 11 twist heavy barrel and shoot Berger 185's as hard as it will take them accurately. It works. You might find something that fits in the magazine. I doubt it, but maybe.
Shooting long range is about wind reading. You have got to have complete confidence in the rifle / ammo system, otherwise you won't be able to tell why your shots are hitting where they are. A lot of people have invested a lot of time and effort in dev'ing the 308 at 1K. My point is that you won't be able to learn anything because your rifle isn't up to the task.
Long range is a purpose built rifle. You can't fool ballistics, and the wind at 1K is really something.
No one is using a 20" barrel. No one I know of is having any real success at all shooting anything lighter than 185 Bergers. In my opinion it is an exercise in futility to try to develop something that will make hits reliably on a small target at 1K with a 20" barrel 308, or for that matter with 175 SMKs. You are giving up too much. You might make a few hits in ideal conditions. But when is that?
Get a 26" 10 or 11 twist heavy barrel and shoot Berger 185's as hard as it will take them accurately. It works. You might find something that fits in the magazine. I doubt it, but maybe.
Shooting long range is about wind reading. You have got to have complete confidence in the rifle / ammo system, otherwise you won't be able to tell why your shots are hitting where they are. A lot of people have invested a lot of time and effort in dev'ing the 308 at 1K. My point is that you won't be able to learn anything because your rifle isn't up to the task.
Long range is a purpose built rifle. You can't fool ballistics, and the wind at 1K is really something.
Well said. I tried to make the point early in this thread that a 20 inch 308 will not work at 1000 yards. Then folks made a lot of replies that were not relevant to the 20 inch barrel, they were for longer barrels. Then I gave up trying to help.
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