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> .308 win boattail partition bullet-first of its kind
.308 win boattail partition bullet-first of its kind
@ 05:32 pm (GMT) |
charlie porterhello shooters, 7/6/13I have on the drawing board a new concept of creating a boattailed partitioned .308win 155 grain bullet as an initial trial weight for 300 yard light game shooting. factories cannot make this this design nor have ever offered it. the bullet will have a reversed inner jacket/core assembly swaged into a main .30 caliber jacket topped off by inserting and swaging a lead core on top that will be formed in a point form die as either a conventional soft point or a flush lead tip meeting the end of the jacket at a .065 diameter point. the core will be soft pure lead and the jacket will be highly formable copper allowing easy frontal expansion right down to the partition. the boattail will be .190 in long by 8 degree taper providing optimal base drag reduction. the form factor of the bullet will be .590 g1 and the g1bc will be .395-slightly higher than the sierra 150 gr gk at .386. it has become obvious through studying nathans knowledge base that he tremendously favors the flat base partition bullet design. however the flat base allows partition bullet knock -about by the wind and also the rear core is prone to separate upon great impact resistance. my boattailed partion design with enclosed rear core solves both problems. it will be a while before I begin prototyping and test firing such a bullet- so in the meantime id appreciate thoughts about this concept. thanks-Charlie [email protected] 508-244-8898 derry nh usa |
Replies
@ 09:26 pm (GMT) |
Nathan FosterRe: .308 win boattail partition bullet-first of its kindSounds great Charlie, just ideal.Because the front portion of the Partition is very soft, it sheds weight on impact very easily. This enables the Partition to produce disproportionate to caliber wounding at somewhat lower velocities than many other bullets, particularly the new core bonded bullets. The Partition is most emphatic at 2200fps or above, but is quite adequate for clean killing down to 1800fps. The trouble is, without a boattail, many of the Partition bullets in various calibers reach 1800fps rather quickly, limiting effective range. The rear core separation occurs (in my tests) with SD's lower than .274 on round bone with a diameter of 2" or greater. If the bone is hit square, the bullet may pass through or if it is a small caliber being used beyond its limits, may become lodged in the bone or joint. But if the bullet hits this round bone slightly off center, it can tumble, at which point the rear core separates. On Bovines, core penetration thereafter is reduced to as little as 6". So the benefits would be threefold. |
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@ 10:57 pm (GMT) |
charlie porterRe: .308 win boattail partition bullet-first of its kindthanks Nathan for your kind reply. i really enjoy your technical and practical field experience present in your knowledge base. originally- i gained my shooting experience in the military with the m14 rifle eventually making hi master ranking in over the course shooting with the m852 168 gr sierra round. from there i became an experimental reloader for the .308win for long range shooting -acquiring an interest in bullet design and swaging. originally i was going to swage .30-30 bullets using the old silvertip aluminum nose cap and market them and still may- as they are missed by many shooters as a reloading component. but i feel my concept of a .308win boattailed partition bullet that i have described on your forum would spark big interest as a bullet that would solve many problems you describe in your bullet knowledge base. a bullet that would have the ballistic efficiency of the sierra gameking bullet combined with the penetrating power/integrity of the nosler partition bullet. the one major weakness in most of these soft point spritzer point bullets is the lead tip damage that can occur causing inconsistent bc's in flight. that why im in favor of a design like the matchking but with the lead extruded flush with the tip into a small .065 dia formed in a special point form die. when the time comes-i would like you to field test them - and when they are ready for field use- id like to advertise them on your site as i can tell youre a real pro. right now im working closely with dave corbin in the development of the various dies and punches required and that's where im at at this point. my plans are for 155gr and 165gr weights or 150 and 160 gr weights for the .308win shooter for the flattest trajectories for this medium case capacity cartridge as a superior 300 yard bullet. i hope you enjoy reading this and if you have any suggestions to make based on your field experience -id love to hear them.sincerely Charlie [email protected] 508-244-8898 |
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