115 gr. tubbs out of a 6-284
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Tried it. We shot various loads ranging from H4350 all the way to N160 and pretty consistently ran into pressure problems at or less than 3100 FPS.
We then tried the 115's in a .243 winchester and a .243 AI. With the .243 winchester we easily ran them beyond 3100, and with the AI have no problem running them 3200 FPS+ . I can't give you a technical explanation as to why, maybe the .243 winchester or the .243 AI is just a more efficient cartridge, but the results were un-mistakable. If you've got a new 6mm BBL and velocity is what you want, skip the 6-284.
Mike
We then tried the 115's in a .243 winchester and a .243 AI. With the .243 winchester we easily ran them beyond 3100, and with the AI have no problem running them 3200 FPS+ . I can't give you a technical explanation as to why, maybe the .243 winchester or the .243 AI is just a more efficient cartridge, but the results were un-mistakable. If you've got a new 6mm BBL and velocity is what you want, skip the 6-284.
Mike
I would say that you are getting pressure because those powders are too fast for the bigger case. I would try H-1000, RL-22, 25, and Retumbo in that case with a heavy for caliber bullet like the 115 DTac. Seems weird to me that a case with more capacity would not be able to exceed,even marginally for an extreme overbore situation) the velocity of a smaller case albeit with less efficiency. 
Yes, strange indeed. Something going on here but I don't think it's the powder. 4350 should give higher velocities than that and 160 is getting pretty close to 4831 in burn speed. Did you experience the same thing with other bullets and other powders? How long a barrel?
The late Skip talbot shot a 6/284 years ago and he was getting very high velocities using R22. I think Rich M. got as high as 3200 with the 107s with R19 and 4350 both.
Ray
The late Skip talbot shot a 6/284 years ago and he was getting very high velocities using R22. I think Rich M. got as high as 3200 with the 107s with R19 and 4350 both.
Ray
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John Southwick runs Sierra 107s at about 3250 fps, using RL 22. He has taken them as high as 3400,at 3300' altitude), but gets better accuracy at 3250. This is with a 28" barrel. I don't think you should have problems reaching 3200 fps with the 105s/107s with the right selection of powder.
John Southwick runs Sierra 107s at about 3250 fps, using RL 22. He has taken them as high as 3400,at 3300' altitude), but gets better accuracy at 3250. This is with a 28" barrel. I don't think you should have problems reaching 3200 fps with the 105s/107s with the right selection of powder.
I don't know, but I can tell you this:
Our goal was to try to come up with something that will out-do a 6.5 142 MK running around 2975 in wind drift which is around where most of my fellow F classers run them.
My first thought, 6-284. We chambered a new krieger, and ran into excessive pressure at less than 3100 FPS. This was shot with moly coated bullets. I asked around, and was told by several pretty knowledgeable shooters that they in the past have been able to get more out of a .243 AI than from a 6-284. Didn't make sense to me since case capacity is considerably less, but decided to try it.
Chambered another krieger,31" finished)in .243 AI. Went through several powders, including H1000, N165, N160, and H4350. H1000 filled the case up without running into excessive pressure.,Too slow). On the other end of the spectrum, H4350 left alot of unfilled case, but ran into excessive pressure at 44.0 grains and was still getting less than 3150 fps.
N160 wasn't bad in terms of velocity vs. full case, but it wouldn't shoot.
I shot as much as 50.0 gr. of N165 which ran them 3200 +, but was shot early in the morning when it was cool. I shot it again in the afternoon when it was considerably warmer, and it was TOO hot.,We're in Louisiana at sea level and it is very hot here).
I worked it down some, and finally, the best for me relative to full case vs. velocity, vs. accuracy was 48.5 gr. of N165. This yielded a mean velocity of a little over 3,150 fps, and with CCI BR 2's had an ES of 27 FPS and a SD of 9 over a 20 shot string. This was shot over an Oehler 35 P with 17 ft. screen spacings.
ALL LOADS WERE SHOT WITH COATED BULLETS. Don't shoot this load at all with uncoated bullets, and work up slow no matter coated or not.
In conclusion, I can tell you that I certainly am no physicist, but after about 250 rds. fired in total between a 6-284 and a .243 AI, that's where we wound up. Maybe you guys can figure it out.
What do you think?
Mike
Our goal was to try to come up with something that will out-do a 6.5 142 MK running around 2975 in wind drift which is around where most of my fellow F classers run them.
My first thought, 6-284. We chambered a new krieger, and ran into excessive pressure at less than 3100 FPS. This was shot with moly coated bullets. I asked around, and was told by several pretty knowledgeable shooters that they in the past have been able to get more out of a .243 AI than from a 6-284. Didn't make sense to me since case capacity is considerably less, but decided to try it.
Chambered another krieger,31" finished)in .243 AI. Went through several powders, including H1000, N165, N160, and H4350. H1000 filled the case up without running into excessive pressure.,Too slow). On the other end of the spectrum, H4350 left alot of unfilled case, but ran into excessive pressure at 44.0 grains and was still getting less than 3150 fps.
N160 wasn't bad in terms of velocity vs. full case, but it wouldn't shoot.
I shot as much as 50.0 gr. of N165 which ran them 3200 +, but was shot early in the morning when it was cool. I shot it again in the afternoon when it was considerably warmer, and it was TOO hot.,We're in Louisiana at sea level and it is very hot here).
I worked it down some, and finally, the best for me relative to full case vs. velocity, vs. accuracy was 48.5 gr. of N165. This yielded a mean velocity of a little over 3,150 fps, and with CCI BR 2's had an ES of 27 FPS and a SD of 9 over a 20 shot string. This was shot over an Oehler 35 P with 17 ft. screen spacings.
ALL LOADS WERE SHOT WITH COATED BULLETS. Don't shoot this load at all with uncoated bullets, and work up slow no matter coated or not.
In conclusion, I can tell you that I certainly am no physicist, but after about 250 rds. fired in total between a 6-284 and a .243 AI, that's where we wound up. Maybe you guys can figure it out.
What do you think?
Mike
I don't know why Ray. It makes no sense to me, just as the gentleman above brought out, that a case with less capacity albeit considerably overbore wouldn't edge it out.
I by no means am backing into a corner and saying this is the way it is, but it is what we've found for these 2 BBL's.
No matter how you get it, 3150 with a .570 BC bullet is quite a bit better in drift than where most people are running 6.5 bullets.
I hope someone has an answer or suggestion, as I am still playing with it and really had my heart set on actually shooting in a match at 3200 + on some windy day in the future.
BTW: My come-ups from a 100 yd. zero to 1000 is 18.5 minutes! Not too bad.
Thanks,
Mike
I by no means am backing into a corner and saying this is the way it is, but it is what we've found for these 2 BBL's.
No matter how you get it, 3150 with a .570 BC bullet is quite a bit better in drift than where most people are running 6.5 bullets.
I hope someone has an answer or suggestion, as I am still playing with it and really had my heart set on actually shooting in a match at 3200 + on some windy day in the future.
BTW: My come-ups from a 100 yd. zero to 1000 is 18.5 minutes! Not too bad.
Thanks,
Mike
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