257 BLACKBIRD (250-7 Blaser) Finish Chamber Reamer with Flush-Grooves (JGS – Live Pilot – 0.140″ Freebore – 0.289″ Neck

$269.00 $257.00

Out of stock

SKU: JGS 250-7Blaser 0.289" neck 0.140" Freebore Categories: ,



The first 6 shooters to purchase their reservation for this reamer will have the opportunity to name the cartridge beyond the placeholder name 250-7 Blaser. When you checkout please message BJB on FB with your vote. We will have JGS rename the cartridge when we get 6 votes.

257 Black Maxx
257 Blackbird – after the SR71 Mach 3+ plane – THIS WAS CHOSEN BY THE FIRST CUSTOMERS UNANIMOUSLY!
257 Jackpot
257 High Roller
257 Pit Boss – this was the original name of the 257 Blackjack cartridge but a few MFG’s wanted a more standard name when we were heading toward full commercialization.

One 257 BLACKBIRD (250-7 Blaser) Finish Chamber Reamer with Flush-System Grooves (JGS – Live Pilot – 0.140″ Freebore – 0.289″ Neck. The dimensions in the print above will be adjusted to 140 FB and 289 neck when the revision submission for renaming are requested.

This reamer is a “No Neck-Turn” reamer to be used with Norma 7 Blaser brass necked down using the Newlon Precision Dies that will be manufactured before these reamers arrive in early September.


Limited run of 257 BLACKBIRD tee shirts will be printed in September with this first image on the front and the image below with the TEST PILOTS on the back.

BACK with TEST PILOTS’ Call Signs (if you buy one of the remaining 7 reamers before they sell out and before September we can add your Call Sign to this list).


Additional information

Weight 1 lbs
Dimensions 10 × 2 × 2 in