6mm 65-68 gr FB with different ogive`s ??????????
- Thread starter mr.big
- Start date
Lee Martin
Active member
To echo what others have said, here are some quick rules of thumb (none are absolutes....every bullet is unique to itself). Given the same jacket length and base:
1) Lower ogive = lower BC = more bearing surface. Usually easier to keep in tune however.
2) Higher ogive = higher BC = less bearing surface. Often trickier to keep in tune
3) Neck tension is predominantly tied to the powder. Examples - N133 likes heavier tension, LT-32 generally likes light tension
My method for tuning a new bullet:
1) Initially I seat to jam length
2) Powder is tested over a 2.0+ grain window in 0.3 gr increments. I like running up to where bolt lift just becomes stiff
3) Neck tension is initially set relative to what that powder supposedly prefers ("supposedly" being a placeholder). I shoot a lot of LT-30 and LT-32. Normally I begin with 0.0015" to 0.002" tension
4) Once I find a few charges that look like nodes, I'll adjust seating depths. I start with Jam+0.005" and move back in 0.005" increments.
5) The last change is to go up or down a bushing for my best couple of loads. So if I start with 0.002" tension, I'll try 0.001" & 0.003" and see if the gun likes those better
As mentioned before, the only result that matters is the paper. Theory means little if it doesn't translate to real world performance.
Good luck,
Lee Martin
www.singleactions.com
1) Lower ogive = lower BC = more bearing surface. Usually easier to keep in tune however.
2) Higher ogive = higher BC = less bearing surface. Often trickier to keep in tune
3) Neck tension is predominantly tied to the powder. Examples - N133 likes heavier tension, LT-32 generally likes light tension
My method for tuning a new bullet:
1) Initially I seat to jam length
2) Powder is tested over a 2.0+ grain window in 0.3 gr increments. I like running up to where bolt lift just becomes stiff
3) Neck tension is initially set relative to what that powder supposedly prefers ("supposedly" being a placeholder). I shoot a lot of LT-30 and LT-32. Normally I begin with 0.0015" to 0.002" tension
4) Once I find a few charges that look like nodes, I'll adjust seating depths. I start with Jam+0.005" and move back in 0.005" increments.
5) The last change is to go up or down a bushing for my best couple of loads. So if I start with 0.002" tension, I'll try 0.001" & 0.003" and see if the gun likes those better
As mentioned before, the only result that matters is the paper. Theory means little if it doesn't translate to real world performance.
Good luck,
Lee Martin
www.singleactions.com
Agree....
Here's another problem with bullets. You buy 500. Oh! that's a lot. If they don't shoot.
But, when you go back to the bullet maker. Those bullets are long gone..........
Another problem. I spent 3-4 yrs shooting with a bad stock. 4 and 1 all the time(sometimes a nice small one thrown in.).
Everyone tried to help....Jack Neary told me to go back to what used to work.
So I pulled out this old rifle.
And it was not me, bullets, maybe powder(XBR-8208), and not my set up(i had changed to a Farley front rest and another rear bag.), flags good, not enough practice-maybe......
Found a little bump on the side of the stock. About 2" back. Moved the stop post back on the Farley. Holy Cow!
Another problem. BAD STAINLESS STEEL FOR THE BARRELS. It lasted a 6 yr period(2009-2015).
So I am told.
Just found another bad barrel. From 2011.
Barrel #2 lasted 400 rounds. Heavy bolt lift after 7-8 shots. Needed to clean every group.
Barrel # 3 dumped at 1500 rnds. Heavy bolt lift with every shot. Even a clean barrel.
Bore scope has been paid for twice now.
Lands were uneven. Barrel #2 First inch good. Then for 6" the top and bottom lands got narrow/width smaller.....
Barrel #3 uneven all the way down the barrel....
Yea. It's a big wonder. Is it the bullets? Wilbur posted a story about Jeff Fowler and his bullets. 2 different lots. Lot 1 great. Lot 2 no bullets touch. Difference. Different lead cores???? Wow. That make my head hurt. Bump on stock made my head hurt. Good thing I had another rifle....
Guess, maybe I should have let someone shoot a problem rifle.....??????
The littlest thing can screw up a good day......A friend had a loose lock nut on the peg/post/foot of his rest....another had his rest too close to the bench(the base actually was bouncing off the concrete. He would take his hand off the joy stick. And did not feel the shock.), loose scopes or bases, couple weeks ago another friend, had a 2" group. 5th shot his rear rest slid of the bench. He barley grabbed his rifle. Too much ice on the bench....
But, when you go back to the bullet maker. Those bullets are long gone..........
Another problem. I spent 3-4 yrs shooting with a bad stock. 4 and 1 all the time(sometimes a nice small one thrown in.).
Everyone tried to help....Jack Neary told me to go back to what used to work.
So I pulled out this old rifle.
And it was not me, bullets, maybe powder(XBR-8208), and not my set up(i had changed to a Farley front rest and another rear bag.), flags good, not enough practice-maybe......
Found a little bump on the side of the stock. About 2" back. Moved the stop post back on the Farley. Holy Cow!
Another problem. BAD STAINLESS STEEL FOR THE BARRELS. It lasted a 6 yr period(2009-2015).
So I am told.
Just found another bad barrel. From 2011.
Barrel #2 lasted 400 rounds. Heavy bolt lift after 7-8 shots. Needed to clean every group.
Barrel # 3 dumped at 1500 rnds. Heavy bolt lift with every shot. Even a clean barrel.
Bore scope has been paid for twice now.
Lands were uneven. Barrel #2 First inch good. Then for 6" the top and bottom lands got narrow/width smaller.....
Barrel #3 uneven all the way down the barrel....
Yea. It's a big wonder. Is it the bullets? Wilbur posted a story about Jeff Fowler and his bullets. 2 different lots. Lot 1 great. Lot 2 no bullets touch. Difference. Different lead cores???? Wow. That make my head hurt. Bump on stock made my head hurt. Good thing I had another rifle....
Guess, maybe I should have let someone shoot a problem rifle.....??????
The littlest thing can screw up a good day......A friend had a loose lock nut on the peg/post/foot of his rest....another had his rest too close to the bench(the base actually was bouncing off the concrete. He would take his hand off the joy stick. And did not feel the shock.), loose scopes or bases, couple weeks ago another friend, had a 2" group. 5th shot his rear rest slid of the bench. He barley grabbed his rifle. Too much ice on the bench....
The C-Bar's have been doing very good
in both 65 and 68 gr. Won the Okla st hv with them last weekend. Larry Scharnhorst, TK Nolan, Darrel Loker and others have had good results also. Every lot is tested out on the range before they go out the door.
Not saying that they are magic but they are good.
Richard
in both 65 and 68 gr. Won the Okla st hv with them last weekend. Larry Scharnhorst, TK Nolan, Darrel Loker and others have had good results also. Every lot is tested out on the range before they go out the door.
Not saying that they are magic but they are good.
Richard