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Joined: May 2015
Posts: 708
Campfire Regular
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Campfire Regular
Joined: May 2015
Posts: 708 |
The barnes bullets seem to produce fine accuracy, but I'm wondering why a lot of guys say you need to run them way off the lands (.100"+). I've tried from .025" - .100" off and find that I achieve better accuracy/precision with the bullet closer to the lands (.025" off). You say you've ran a lot of Barnes bullets, is there a sweet spot for most Barnes bullets? In terms of seating depth and distance off the lands, or jump as some guys call it.... I'll admit, I'm new to Barnes bullets, as I usually use partitions, Hornady interlocks, Sierra GK, and WW power points on big game. Finally decided to give in and give the Barnes a try.. I’ve shot a lot of Barnes in a bunch of rifles, and 0.050” off the lands nearly always gives excellent results. I’ve not had a Barnes really shoot till it’s .050 off and quite often .075-.100” has been better in a number of rifles. Not saying you’re not getting fine accuracy, but I usually get one outta the group till I sink them a bit deeper. Lots of folks report seating to the middle of the top groove and getting pretty good results as well. I’d tend to agree with that as that’s about where I’ve ended up with a few. Every once in a while a load shoots best for me seated deeper than 0.050” (up to 0.125” off the lands, IIRC), but on average 0.050” has been a sweet spot. According to Quick Load (QL), mono metal copper bullets require an additional 2 900 psi to over come pull-out resistance and engraving into the rifling, compared to a cup/core design. 0.050" off the rifling reduces the start pressure by 1 460 psi. This puts the hand loader into more of a safety zone. I have run the Barnes "X" in a lot of calibers and weights since 1992 and have found that powder charge is where the tuning takes place, no real reference to 'bullet seating depths' , other than that, will the loaded round fit comfortably in the magazine or is ~0.010 to 0.015 off the rifling. So, bottom line is the mono-metal offers more resistance to pull out and engraving, increasing the jump will reduce start pressure up to a point.
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Joined: Mar 2006
Posts: 14,507
Campfire Outfitter
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Campfire Outfitter
Joined: Mar 2006
Posts: 14,507 |
The barnes bullets seem to produce fine accuracy, but I'm wondering why a lot of guys say you need to run them way off the lands (.100"+). I've tried from .025" - .100" off and find that I achieve better accuracy/precision with the bullet closer to the lands (.025" off). You say you've ran a lot of Barnes bullets, is there a sweet spot for most Barnes bullets? In terms of seating depth and distance off the lands, or jump as some guys call it.... I'll admit, I'm new to Barnes bullets, as I usually use partitions, Hornady interlocks, Sierra GK, and WW power points on big game. Finally decided to give in and give the Barnes a try.. I’ve shot a lot of Barnes in a bunch of rifles, and 0.050” off the lands nearly always gives excellent results. I’ve not had a Barnes really shoot till it’s .050 off and quite often .075-.100” has been better in a number of rifles. Not saying you’re not getting fine accuracy, but I usually get one outta the group till I sink them a bit deeper. Lots of folks report seating to the middle of the top groove and getting pretty good results as well. I’d tend to agree with that as that’s about where I’ve ended up with a few. Every once in a while a load shoots best for me seated deeper than 0.050” (up to 0.125” off the lands, IIRC), but on average 0.050” has been a sweet spot. According to Quick Load (QL), mono metal copper bullets require an additional 2 900 psi to over come pull-out resistance and engraving into the rifling, compared to a cup/core design. Interesting note, but that will very much depend on the configuration of the bullet (number and placement of relief grooves, driving bands, etc.). I wouldn’t be surprised if that figure was calculated for same-same configuration between C&C and mono, with no relief grooves like in the case of the original X-bullet.
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Joined: Apr 2005
Posts: 30,934
Campfire 'Bwana
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Campfire 'Bwana
Joined: Apr 2005
Posts: 30,934 |
The barnes bullets seem to produce fine accuracy, but I'm wondering why a lot of guys say you need to run them way off the lands (.100"+). I've tried from .025" - .100" off and find that I achieve better accuracy/precision with the bullet closer to the lands (.025" off). You say you've ran a lot of Barnes bullets, is there a sweet spot for most Barnes bullets? In terms of seating depth and distance off the lands, or jump as some guys call it.... I'll admit, I'm new to Barnes bullets, as I usually use partitions, Hornady interlocks, Sierra GK, and WW power points on big game. Finally decided to give in and give the Barnes a try.. I’ve shot a lot of Barnes in a bunch of rifles, and 0.050” off the lands nearly always gives excellent results. I’ve not had a Barnes really shoot till it’s .050 off and quite often .075-.100” has been better in a number of rifles. Not saying you’re not getting fine accuracy, but I usually get one outta the group till I sink them a bit deeper. Lots of folks report seating to the middle of the top groove and getting pretty good results as well. I’d tend to agree with that as that’s about where I’ve ended up with a few. Every once in a while a load shoots best for me seated deeper than 0.050” (up to 0.125” off the lands, IIRC), but on average 0.050” has been a sweet spot. According to Quick Load (QL), mono metal copper bullets require an additional 2 900 psi to over come pull-out resistance and engraving into the rifling, compared to a cup/core design. Interesting note, but that will very much depend on the configuration of the bullet (number and placement of relief grooves, driving bands, etc.). I wouldn’t be surprised if that figure was calculated for same-same configuration between C&C and mono, with no relief grooves like in the case of the original X-bullet. I believe you are correct, Jordan
I got banned on another web site for a debate that happened on this site. That's a first
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Joined: May 2015
Posts: 708
Campfire Regular
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Campfire Regular
Joined: May 2015
Posts: 708 |
The barnes bullets seem to produce fine accuracy, but I'm wondering why a lot of guys say you need to run them way off the lands (.100"+). I've tried from .025" - .100" off and find that I achieve better accuracy/precision with the bullet closer to the lands (.025" off). You say you've ran a lot of Barnes bullets, is there a sweet spot for most Barnes bullets? In terms of seating depth and distance off the lands, or jump as some guys call it.... I'll admit, I'm new to Barnes bullets, as I usually use partitions, Hornady interlocks, Sierra GK, and WW power points on big game. Finally decided to give in and give the Barnes a try.. I’ve shot a lot of Barnes in a bunch of rifles, and 0.050” off the lands nearly always gives excellent results. I’ve not had a Barnes really shoot till it’s .050 off and quite often .075-.100” has been better in a number of rifles. Not saying you’re not getting fine accuracy, but I usually get one outta the group till I sink them a bit deeper. Lots of folks report seating to the middle of the top groove and getting pretty good results as well. I’d tend to agree with that as that’s about where I’ve ended up with a few. Every once in a while a load shoots best for me seated deeper than 0.050” (up to 0.125” off the lands, IIRC), but on average 0.050” has been a sweet spot. According to Quick Load (QL), mono metal copper bullets require an additional 2 900 psi to over come pull-out resistance and engraving into the rifling, compared to a cup/core design. Interesting note, but that will very much depend on the configuration of the bullet (number and placement of relief grooves, driving bands, etc.). I wouldn’t be surprised if that figure was calculated for same-same configuration between C&C and mono, with no relief grooves like in the case of the original X-bullet. Probably, as mono's come with more or less grooves or none at all. The start pressures are probably the same as pull out and resistance to the rifling is still there, however, once engraved (in one bullet bearing surface length) the resistances is now the total bearing surface less the groove diameter. On a 30 caliber Barnes TTSX the groove diameter is 0.292", this makes the grooves 0.008" deep and generally lands and grooves in rifling are 0.004". The grooves effectively shorten the bearing surface, therefore reducing resistance between the bullet and the bore. Anyway , it is something to be aware of. The values offered by QL give some perspective of what is going on with mono-metals compared to cup/core or coated bullets.
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