machined drive band bullets?

Discussion in 'Rifles, Bullets, Barrels & Ballistics' started by tony m, Mar 24, 2014.

  1. tony m

    tony m Well-Known Member

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    What do you know of cutting edge and gs custom products .Others? Suggestions? have load data from both companies 270 win and 7x57.Gs has an intersting approach. .277 110 gr based on rifles rifling twist of model 700 1/10.hunting load for kudu,elk sized game.
     
  2. jfseaman

    jfseaman Well-Known Member

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    I gave the CEB 308 140grs a try just to see what the machining was like.
    I have not gotten hands on the GSC

    1 The machining is incredible
    2 The accuracy was very fine
    3 Like all copper, go lighter and faster
    4 They are CA legal

    I plan on getting more CEBs.
     
  3. MudRunner2005

    MudRunner2005 Well-Known Member

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    I have 2 boxes of Cutting Edge bullets that I won in a contest...I can't justify shooting them. They cost $70 for 50 projectiles. What if my guns like them? Bergers are already expensive enough...

    So, they will probably sit in their boxes for the rest of my life......Unless I get bored. Then I might sling them downrange sometime. LOL
     
  4. HarryN

    HarryN Well-Known Member

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    I completely admit to being a beginner, but here are my thoughts on the subject:

    a) The US military has been under pressure to move away from lead (and DU) bullets, especially for ones carried by field solders (as opposed to artillery).

    There are major programs ongoing to move toward lead-free bullets and a lot of development money is being spent to make this happen. Of course, their needs are somewhat different than those of a "hunting" bullet, but they consume so many rounds compared to the civilian population, that lead-free / copper or brass machined bullets could come to dominate production volume over the next 20 years.

    I am not sure if it maters, but machining the bullets offers the potential of bringing the supply line closer to a battle zone.

    b) Law enforcement, perhaps the second largest consumer, will follow the lead of the military.

    c) Machined bullets (with drive bands) have been used in artillery and tanks for a long time. They are a well proven method of performance enhancement, friction reduction, and improved gas seal. (your car has used the concept for years - piston rings) Of course, they have the option of using tungsten / DU rounds and we don't, so our options are smaller.

    d) Machining a bullet "might" offer the "potential" of tuning a bullet further than could be achieved with a cast / swaged bullet manufacturing approach. I don't claim expertise in this area, but you can sort of see this in the CEB product line, which has products clearly focused on different applications, lower FPS expansion potentials, and "thick" vs. "thin" skin animal products.

    e) The other area that the military is interested in is reducing the weight of ammo carried by soldiers. To this end, they have been testing rounds even smaller than the 5.56 NATO to the even smaller 5.7x28 and plastic cases to replace brass. Reloading is not part of the concept with these products.

    I don't have a crystal ball, but when the US Army talks (and spends) things happen and directions get set.
     
  5. HarryN

    HarryN Well-Known Member

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    The part about the copper bullets that you have to watch out for is to make sure your rifle barrel twist is fast enough to use them. As the bullet gets longer, it has to rotate faster to remain stable in flight, and high weight copper bullets get long quickly.

    The whole lead free conversion direction is one reason I am considering to change caliber from 270 win to something larger, such as (moderate power) .338 or even .375 if my shoulder could handle it. (I have doubts)

    The nice thing about reading the technical details about CEB bullets is that you can look at a series of rounds in for instance 270 / 338 / 358 / 375 and compare the ballistic coefficients within the same design family and supplier.

    I don't really understand why, but it appears that the .338 size tends to have some of the highest BC, sometimes by 2X compared to the others, for instance in the Raptor ER version.

    My interpretation of BC is that a bullet with a BC of .4 will loose velocity at 50% of the rate of one with a BC of .2, regardless of mass and diameter, but that might not be entirely correct.
     
  6. jfseaman

    jfseaman Well-Known Member

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    Yeah, what then...

    Another product that I can't get in the quantities I want.:D
     
  7. Canadian Bushman

    Canadian Bushman Well-Known Member

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    Harry

    Youve pointed out the benifits to non lead monos, now go over the draw backs.
     
  8. jfseaman

    jfseaman Well-Known Member

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    I'll put my 2 cents in as I have hundreds of coppers down range.


    • You have to use a lighter bullet for caliber making it harder to reach the same BC as lead.
    • Copper is just not going to as far for weight as lead.

    Accuracy is not an issue if you go faster and lighter.

    I haven't developed a 'rule' yet comparing mono weights to jacketed lead for the same use. I think I need a lot more data. Darn, more shooting.

    Example: My 1/12 twist Weatherby Mark V in 270 Wby barely shot jacketed lead 130's. Before Barnes published the load, I decided to figure out what 95 grain TTSX would do. Turned it into a laser. I easily got near 4000fps but accuracy was at 3668fps. "Flat" to 400 yards (no hold adjustments) with +1000lb of energy at 400 yards but it starts to fall off quickly after that. Fine for lots of game.
     
  9. MudRunner2005

    MudRunner2005 Well-Known Member

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    That's why I won't shoot the CE bullets I have. I'm not risking it liking them. My Bergers are already shooting incredible, so I don't see it getting much better. But it's hard to justify $70 for 50 projectiles... It's hard enough to justify $70-80 for 20 loaded rounds of ammo for those who don't reload. Which is why I started reloading in the first place. LOL
     
  10. Canadian Bushman

    Canadian Bushman Well-Known Member

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    Way more expensive
    Low sectional density
    less energy on target
    usually slower out of a barrel.
    Do not obturate to the bore
    Take much longer to manufacture and harder to maintain weight, diam, and surface finish - why they will always be more expensive
    Need assistance expanding
    Ridiculous advertising - chalk this one up to preference


    I produced thousands of monolithic bullets. I got tired of machining, measuring, and weighing them.
    I went back to spending my weekends shooting, shooting bergers.
     
  11. HarryN

    HarryN Well-Known Member

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    I agree completely with the negative comments about mono / machined bullets.

    For me personally, I am sort of stuck with them living here in CA, so I try to find silver in the cloud.

    In fact for me, there is an even worse effect than their individual shooting costs, since the sectional density / bullet mass is substantially worse, I am more or less forced to move up in caliber to accomplish the same mass x velocity effect as my existing 270 win.

    I don't mind owning a second rifle, but it is one thing to "want one", another to be sort of "pushed" into it for no real improvement over what I have. A moderate .338 type setup (not a lapua, maybe 338-06 or 338 Federal) I can probably handle, but it only will get slightly better than if I just could used Bergers in my 270.

    To really gain in performance would mean pushing up to .375 size and that is heap of more recoil than my 270. I am not really sure my body can take it without some serious padding and muzzle brake management. I am 55, not 25, so that sort of punishment doesn't get better with age.
     
  12. Gerard Schultz

    Gerard Schultz Well-Known Member

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    I understand that monometal bullets are still treated as one category of bullet and that, to some, all monos must be the same.

    Just as one would not expect the same results in jacketed lead bullets, from a 180gr match hollow point and a 180gr bonded core partition style bullet, one must not put all monos in the same category.

    This is not anyone's fault, it simply means that differences have not been recognised and highlighted.

    Take this list, for example.

    1. Way more expensive - More expensive than regular, unbonded, lead core bullets, but so are lead core premium bullets. It all depends on the job at hand.
    2. Low sectional density - This is not a factor because monos are faster and penetration is determined by the expanded diameter and the momentum of the bullet. Momentum is has weight and speed elements, not just sectional density. I welcome any test to prove this with GSC hollow points. They will always go deeper and straighter than jacketed lead, despite being lighter. It depends on how they are designed to work.
    3. usually slower out of a barrel - This may be true for some monos out there but definitely not with GSC drive band monos. We find that, with similar pressure, we can run GSC bullets faster than equivalent weight jacketed lead core bullets. Couple that to the lower weight and GSC bullets go even faster.
    4. Do not obturate to the bore - This is an additional wear factor because with most monos being under size, there is gas leaking past the bullet all the way from the case to the muzzle. That is why, with GSC bullets, we do not make them under size. The bore is sealed from the case, even better than with jacketed lead bullets that obturate once pressure reaches a certain level. All the gas is used to drive GSC bullets and there is no blow past at any stage.
    5. Take much longer to manufacture - This is true. Well made monos are turned one by one and not stamped out in a press.
    6. harder to maintain weight, diam, and surface finish - I differ from that opinion. The uniformity is easy to maintain and does not change from batch to batch. Unless a bullet is improved, it can only change shape if the program with which a bullet is made, changes. GSC bullets that are made in the USA now, are the same as the ones we have been making in South Africa for the last 20 years, because the cnc programs are the same.
    7. Need assistance expanding - Some monos may need this. GSC hollow point bullets do not and expand to double caliber from impacts as low as 1600fps. That is even lower than some bonded core jacketed lead bullets. Design differences with other monos are key here.
    8. Ridiculous advertising - I fully agree. Some claims that are made by manufacturers are really over the top. That is not confined to monos but to all bullet manufacturers.

    HarryN, use the GSC 270110HV in your rifle and be pleasantly surprised. The principle of recoil reduction is to use a lighter bullet and to use a faster powder. Here you will do both without sacrificing any performance.
     
  13. Canadian Bushman

    Canadian Bushman Well-Known Member

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    Im glad you chose my post to use, i really wanted to debate these topics deeper, and am honored to do it with such an esteemed individual.

     
  14. Gerard Schultz

    Gerard Schultz Well-Known Member

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    This will always be the case. One cannot compare the cost of turned bullets to the cost of stamped bullets. Stamped bullets are made faster and that brings the cost down. But there is a downside to stamped bullets as well. There are limits to what can be done with stamping technology. It is dependent on dies that wear out and has to be replaced and stamped shapes are limited to what one can do with them. Turning means that one can design and draw the perfect shape and then make it. There are much fewer limitations with turning and stamping is only cheaper.

    For a given twist, monos are lighter than jacketed lead bullets because it is the length and shape of a bullet that determines how it works, not the weight. A properly designed mono that is lighter, but the correct length for a given twist, will in any case go deeper than a heavier bullet, regardless of whether the heavier bullet is a mono or a jacketed bullet. So, do not compare weight to weight, the weight is of no importance. It is the work that a bullet can do that determines its usefulness.

    Weight for weight, GSC will always launch faster than any other grooved mono or jacketed lead core bullet. So you may be right when it comes to other bullets but this is one of the areas where we respectfully ask not to be compared to the generic idea of what a mono is. With GSC bullets we are always lighter than traditional bullets but it must be remembered that BC often increases with speed as well. With a lighter bullet going faster, shapes are very close in BC and speed brings many advantages with monos.

    This may be right with usual monos but GSC has solved the problem and they seal as well as jacketed lead bullets. This is another area where we respectfully ask not to be compared to other monos because our design is different. If a bore is so bad that a jacketed bullet has problems sealing it, we tend to recommend replacing the barrel as it is no longer within spec.

    You put your finger on it. CNC lathes are usually similar but thermal growth is not a problem because choose a make of machine where this is not a problem. Also, we replace inserts more often than most. We have had a number of companies have a look at our QC to see how we do it. See the About Us section on our South African site.

    You are right. Monos will never disintegrate completely, that is their strong point. With a well designed mono, one gets a reliability of terminal function that is much better than any other bullet, including some monos.

    I hope I have answered some misconceptions and bear in mind that we do not know it all and development/improvement of our product never stops. We are always looking for areas to improve and input from users is always welcome.