knockemdown
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Originally Posted By: newmexicokidI have talked to Mike before about the 6DTI and it is impressive but my problem with it is the barrel length required for it to perform at its best. He told me the ideal barrel length is 22". That is too long for me around here. I am shooting a 6.8spc right now with an 18" barrel and that is as long as I want to go. I have talked about it before here but where I hunt here in NM most shots are under 250-300 yards and really 90% are under 100 so there is really no need to have a long gun. So my question here is about the barrel length required for the 243lbc and the 6x68 to work best. I am pushing 90gr TNT to almost 3000fps right now with my 6.8. Is there any advantage with these other rounds over what I have now? I would prefer to shoot something much lighter. I used to shoot 55gr ballistic tips with my 243 over 4000fps. Can you approach that with any of these wildcats? I need a good balance of barrel length, velocity, and bullet weight.
Hi, broken record here chiming in again.
As a comparison to your 6.8SPC/90 gr. TNT @ 3K, my .25DTI will push a 90gr Sierra @ 2980 from that same 18" of barrel.
Essentially, as you go UP in bore size when using the same parent case, you can get away with LESS barrel length. This is due to a more efficient use of the powder capacity of that particular parent cartridge. Powder charger being equal, a bigger bore = less barrel needed to burn it fully.
True, the various 6mm based 6.8SPC wildcats want a 22" barrel to shine, especially the DTI since it hold more powder than the 6-6.8 or 6 WOA. Consider that a 6mm wildcat can throw a 75grainer ~3200fps with a 22" tube. Using the same parent case (same capacity), the larger bored .25 DTI wildcat can launch a .257 cailber 75 grainer @ ~3200 fps with only an 18" tube!
True, opting for the 6mm variety will offer a slighly higher b.c. Some might argue that increased b.c. is always an advantage! But in the real world, the increased b.c. of a .243cal 75Grainer over a .257cal 75grainer only translates into 0.4" less drop & 1.2" more drift @ 300yds with a 200yd hunting zero. That said, on a general hunting rig shooting from improvised field positions, I'll happliy opt for carrying & swinging 4" less barrel length and suffer the negligible 1/2" drop/ 1" drift disadvantage @ 300yds.
Again, bigger bore = less barrel needed! That's why the 6.8SPC works great with even a 16" tube...
If most of your shots are close, it only makes sense (to me) to go with a the ease of toting a shorter barreled rig in the field. I've had/have ARs from 16" HBars, to 24" fluted bulls and the 18"er is the bees knees for me. Lighter, easier to carry, yets still holds & points steady. And the larger bore size (comparatively) will issue more "smackdown" on your intended quarry, which is never a bad thing...
As for comparing ANY 6mm based 6.8SPC wildcat to a .243Win, there IS no comparison. Anyone reporting different is blowing smoke rings. Rightly so, ~36gr vs. ~54gr powder capacity is not a fair fight! The undeniable advantage of the .243Win might be lessened if you hamstring is with a ridiculously short barrel, but the .243 is still in a higer trophic level of horsepower. If you want that type of speed from an AR, you need an AR-10 in .243WIN, or an AR-15 in .243WSSM, since fps doesn't come for free
And again, you'll need some barrel length to realize that potential...
Different strokes for different folks, just tossing some arbitrary numbers around to ponder!!!
Good luck with your decision & have fun deciding
Hi, broken record here chiming in again.
As a comparison to your 6.8SPC/90 gr. TNT @ 3K, my .25DTI will push a 90gr Sierra @ 2980 from that same 18" of barrel.
Essentially, as you go UP in bore size when using the same parent case, you can get away with LESS barrel length. This is due to a more efficient use of the powder capacity of that particular parent cartridge. Powder charger being equal, a bigger bore = less barrel needed to burn it fully.
True, the various 6mm based 6.8SPC wildcats want a 22" barrel to shine, especially the DTI since it hold more powder than the 6-6.8 or 6 WOA. Consider that a 6mm wildcat can throw a 75grainer ~3200fps with a 22" tube. Using the same parent case (same capacity), the larger bored .25 DTI wildcat can launch a .257 cailber 75 grainer @ ~3200 fps with only an 18" tube!
True, opting for the 6mm variety will offer a slighly higher b.c. Some might argue that increased b.c. is always an advantage! But in the real world, the increased b.c. of a .243cal 75Grainer over a .257cal 75grainer only translates into 0.4" less drop & 1.2" more drift @ 300yds with a 200yd hunting zero. That said, on a general hunting rig shooting from improvised field positions, I'll happliy opt for carrying & swinging 4" less barrel length and suffer the negligible 1/2" drop/ 1" drift disadvantage @ 300yds.
Again, bigger bore = less barrel needed! That's why the 6.8SPC works great with even a 16" tube...
If most of your shots are close, it only makes sense (to me) to go with a the ease of toting a shorter barreled rig in the field. I've had/have ARs from 16" HBars, to 24" fluted bulls and the 18"er is the bees knees for me. Lighter, easier to carry, yets still holds & points steady. And the larger bore size (comparatively) will issue more "smackdown" on your intended quarry, which is never a bad thing...
As for comparing ANY 6mm based 6.8SPC wildcat to a .243Win, there IS no comparison. Anyone reporting different is blowing smoke rings. Rightly so, ~36gr vs. ~54gr powder capacity is not a fair fight! The undeniable advantage of the .243Win might be lessened if you hamstring is with a ridiculously short barrel, but the .243 is still in a higer trophic level of horsepower. If you want that type of speed from an AR, you need an AR-10 in .243WIN, or an AR-15 in .243WSSM, since fps doesn't come for free
Different strokes for different folks, just tossing some arbitrary numbers around to ponder!!!
Good luck with your decision & have fun deciding