.308 x 1.15 jackets, pk/250
	Quantity in Basket: None Catalog No.: J-30-115 Price: $70.00 Shipping Weight: 1.50 pounds 458 available for immediate delivery
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This is a straight taper wall .30 caliber jacket, made for the medium weight open tips such as 140 to 175 grain, and lead tips in the 180-190 grain range. Lighter weights can be made by using the BB-1/4 (yellow) polymer "bullet ball" in the base with a shorter lead core on top, moving the center of gravity slightly forward while keeping the same length with lighter weights, such as 100-130 grain range. Over-all length is 1.15 inches, diameter about .3065, sold in packages of 250 jackets, or boxes of 1300, or cartons of 6500. The weight is 42.7 grains, and the proper core ID is about 0.250 inches although the jacket will accept a 264 diameter core (but this would trap air in the bottom) You can telescope a .264 (6.5mm) jacket inside the J-30-115 jacket to make a multi-jacket or partition-style bullet or to double the wall thickness and extend the length. The jacket tapers from about 0.021 inch walls at the base to 0.014 inch near the mouth. This allows for a controlled expansion with velocity. The proper diameter of core seating punch is typically 0.2775 inch diameter, which is too snug to fit by hand but maintains a good seal while the jacket is being expanded under pressure in the core seating operation. Most beginning bullet makers think that the punch is "too big" because it won't easily fit the jacket by hand. But the jacket is .3065 inch diameter before the core is seated. It expands to nearly .308 (about .3078 or so in core seating). The difference is also the same on the ID expansion of course. So a punch which would fit easily by hand before pressure is applied would let lead spurt out around it as soon as the jacket became larger under pressure. If the jacket tends to stick on the punch, use less or even no lube on the jacket OD, and wipe a little lube on the punch OD. This will help the jacket stay in the die when you lower the ram, pulling the jacket off the punch. Also try holding the pressure at the top of the stroke for a slightly longer time, half a second to a second or so. That lets the jacket and lead expand slightly more than a quick up and down stroke allows. Finally, make sure that you are using enough pressure to actually expand the jacket against the die wall (but not excessive amounts that could break the die) If the jacket is not fully expanded to the die walls it cannot grip them and it will not be pulled off the punch on the down stroke, This is often presumed to be "sticking" caused by too big a punch, when really it is just the lack of enough expansion to grip the die ID and be pulled off the punch. And finally, make sure that the seating punch actually is sized for the particular length of core you are using. Obviously if the jacket wall tapers, a longer and heavier core will be seated at a larger ID portion of the jacket than a shorter, lighter core. So the diameter of the core seating punch needs to be relatively close (.001 inches or so) to the ID of the jacket for a given length of core. A core that weighs 100 grains will sit further down in the jacket than one which weighs 125 grains. The tapered jacket wall presents a smaller ID to fit for lighter cores. To get the right size of core seating punch for a given core weight, specify the weight when ordering punches for your core seating die, and specify that this jacket is to be used with it. There is some range of diameter mis-match that still works OK, but the further the OD of the seating punch gets from the ID of the jacket, the more likely you are to have lead spurting around the punch or digging up of the jacket wall from the punch edge, sticking the punch in the jacket. Also both too large and too small of a core seat punch for a given core length will cause the bullet to be undersized and tapered. This is because the pressure doesn't evenly expand the jacket when the punch is allowing pressure to escape around it or is digging into the jacket wall instead of applying all the force to the lead core.

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