Swaging Bore Runner type 458 Solids
Posted: Thu Dec 24, 2009 1:42 amWas just recently asked if the groves of a BORE RUNNER type solid fills up with the excess material when we swag them to .451 and thus end the advantage of the groves in the side of the bullet reducing drag. Of course swaging any solid is slightly more problematic than a lead based bullet, but this is not the thesis here and in any event is only just a procedure to swag such bullets.
The short answer is no, the groves are not eliminated by this swaging.
Yes, there is excess material that enter the groves and is better seen under magnification. It is so slight and thin that during tests, no reduction in speed was possible to accurately measure, nor were pressures increased by the VERY SLIGHTLY filled in groves (the swaged material, under pressure, just flows to the bottom of the grove and in no-way hinders the internal ballistics). In all testing, the swaged bullet material in the groves was far less than the normal fouling a barrel's rifling will put into the same groves (this data from actual swaged recovered bullets).
Conclusions: Any concern of this type is totally unfounded by repeatable real world, in the field, science. There are other concerns in swaging these bullets and worrying about the groves isn't one of them. If you are a beginner reloader, you might better pass on doing any kind of swaging until you become comfortable in your safety procedures or reloading in general for that matter. Read, Read, Read, first and the many reloading manuals are a great source..
Post Script: This is in answer to a hate filled question, that came to me by someone that hates the fact that our cartridge isn't using a mere Pistol Bullet or should only use pistol bullets and assumably, the implications of our good work, threatens the existence of the other big bore AR's. I can't help the Hateful Winers (and that's what they are), the Flat Earth types, but I can say this.. .."The Earth does indeed go around the Sun and the 450 Bushmaster was the first, might be the last and is the best all around big bore semi-auto, ever in the history of Firearms" (Yeah I Know, they'll be back for more at that one).. "Swage This" indeed, there is work already done, right here on this board, by some serious gentlemen that makes this suggestion laughable, if it weren't so demeaning to their hard earned work, therefore I answered the questioned..
The short answer is no, the groves are not eliminated by this swaging.
Yes, there is excess material that enter the groves and is better seen under magnification. It is so slight and thin that during tests, no reduction in speed was possible to accurately measure, nor were pressures increased by the VERY SLIGHTLY filled in groves (the swaged material, under pressure, just flows to the bottom of the grove and in no-way hinders the internal ballistics). In all testing, the swaged bullet material in the groves was far less than the normal fouling a barrel's rifling will put into the same groves (this data from actual swaged recovered bullets).
Conclusions: Any concern of this type is totally unfounded by repeatable real world, in the field, science. There are other concerns in swaging these bullets and worrying about the groves isn't one of them. If you are a beginner reloader, you might better pass on doing any kind of swaging until you become comfortable in your safety procedures or reloading in general for that matter. Read, Read, Read, first and the many reloading manuals are a great source..
Post Script: This is in answer to a hate filled question, that came to me by someone that hates the fact that our cartridge isn't using a mere Pistol Bullet or should only use pistol bullets and assumably, the implications of our good work, threatens the existence of the other big bore AR's. I can't help the Hateful Winers (and that's what they are), the Flat Earth types, but I can say this.. .."The Earth does indeed go around the Sun and the 450 Bushmaster was the first, might be the last and is the best all around big bore semi-auto, ever in the history of Firearms" (Yeah I Know, they'll be back for more at that one).. "Swage This" indeed, there is work already done, right here on this board, by some serious gentlemen that makes this suggestion laughable, if it weren't so demeaning to their hard earned work, therefore I answered the questioned..
sorry fellas, early morning here.