Construct 3 how to limit amount of bullets fired

#Construct 3 how to limit amount of bullets fired series#

It is possible to find a combination that will easily have the bullet sitting right on or very near the lands at the get-go. The main good is that, indeed, any and all bullets are going to be closer to the lands in a round loaded to magazine-length.Д«ut the вЂњtwoвЂќ in the things that influence jump is bullet selection. IвЂ™ve written on that one a few timesвЂ¦ДЄ shorter throat has goods and bads. 223 Remington chamber and a 5.56 NATO chamber. That is the leading difference between a SAAMI-spec. The closer the lands are to the chamber neck area the shorter the jump will be with any bullet. ThatвЂ™s the space that defines the transition from end of the chamber case neck area to entry into the lands.

The one is that the influence of rifle chamber specs with respect to either more or less jump is pretty much exclusively in the leade or throat. This sort of вЂњfine-tuningвЂќ is strictly a (careful and knowledgeable) handloaderвЂ™s realm. When a bullet touches the lands at rest, pressures will, not can, spike. For safetyвЂ™s sake, no factory loaded round is going to approach lands-on seating structure. However, with selection there is also limitation.

Getting a bullet to sit close to the lands when the round is chambered requires either some trickery in chambering specs or, mostly, bullet selection. A box magazine sets the effective limit on overall cartridge length. WeвЂ™re almost always going to be dealing with some amount of jump, unless one or two things can be manipulated to reduce or eliminate it. Get one HEREДealing with an AR15, or any other magazine-fed rifle, assuming we are wanting the rounds to feed from the magazine, is that thereвЂ™s a finite cartridge overall length that will fit into the magazine. Use it to determine the current distance to engage the lands for any bullet youвЂ™ll use (it works also as a way to monitor throat erosion). There are other ways to find it, but the Hornady LNL Overall Length Gage makes it easy. If you find the cartridge overall length, which really means bullet seating depth, that touches the lands (coincides with land diameter) then subtract that from what you then measure when the bullet is seated deeply enough to fit into a magazine box, that right there is the amount of jump. Gages that measure this distance (Hornady LNL for instance) arenвЂ™t necessarily going to provide perfect coincidence with land diameter, but still provide an accurate bullet seating depth that touches the lands.

22 caliber with 0.219 diameter lands, then the first point along the nosecone of a bullet thatвЂ™s 0.219 is the distance. The first point of вЂњmajor diameterвЂќ on a bullet is what coincides with the land diameter in the barrel. Namely the longer and spikier вЂњvery-low-dragвЂќ type bullet profiles. However! The reason bullet jump matters - usually - is largely, almost exclusively, because of some bullet profiles being more finicky than others. Adjusting bullet seating depth can make a big, big difference in shot impact proximities. Yep, he had read my books and a few others and developed the impression that minimizing bullet jump was one crucial component to maximizing accuracy. The subject of bullet jump became the dominant topic. He wanted to have the best accuracy he could buy, and thatвЂ™s a worthwhile pursuit as long as thereвЂ™s a budget that supports it. This fellow had been involved in competition long enough to decide to stay with it, and was re-upping his AR15 upper with a new custom barrel. The one was a regrouping equipment project for USPSA-style practical rifle competition, and the other was for a desire to maximize accuracy, which is to minimize group size. Last week I had a long phone conversation with a fellow who had been bitten by two bugs, two somewhat conflicting bugs (at least seemingly so on the onset). Glen Zediker HereвЂ™s jump: itвЂ™s the distance from the end of the case neck portion of the chamber to the first point the bullet will engage the lands or rifling.Д«ullet jump: the open space a bullet must span until its first point of sufficient diameter engages the barrel lands.

#Construct 3 how to limit amount of bullets fired series#

This series takes a look at why it matters, and also when it doesnвЂ™tвЂ¦ The distance a bullet travels to enter the lands is a topic of much concern to the precision shooter.