David P. Herne
Well-Known Member
Gentlemen,
After initiating the project the summer of last year, I am FINALLY aboard the 6.5x284 bandwagon with many of the rest of you fanatics! (This one was chambered with a Pacific Tool & Gauge 6.5x284 Norma reamer.) But now I'm really nervous about the rifle. After brooding all weekend at work about where I was gonna start as far as working up loads, I pulled out all my cartridge assembly equipment last night and immediately, there was a problem! The neck in the chamber of this rifle is apparently so tight that it wouldn't accept the Stoney Point OAL length gauge case! The new Lapua cases it accepted readily, however. So I decided to determine OAL in the subject chamber/throat via the old, redneck method: I seated 10 139-gr Scenars considerably 'overlength' into ten of the new, fully prepped Lapua cases and then mashed them into the rifle's chamber one by one. This wasn't easy, I should add. In fact, I was ready for the bolt handle of that Nesika Bay Model L to snap right off! When it didn't, I was left even more impressed with Nesika Bay actions than ever before. At any rate, 5 of these dummy cartridges came out to a length of 2.505" with the other 5 measuring as short as 2.501" and as long as 2.508". I then assembled a dummy cartridge to a length of 2.485", placed it in the chamber, gently closed the bolt behind it and then reopened it. It met with no discernible resistance going into or coming out. At last, I assembled 10 rounds to this length using the forementioned components with 48.0 grains of VV N160 and 10 with 50.0 grains of VV N165.
Now here's the thing. As all of you 6.5x284 nuts know, 2.505" from bolt face to ojive in this particular cartridge is pretty **** short when using 140-gr class match projectiles. And if I recall correctly, it seems that one of the many things I've learned from you guys is that tighter necks as well as shorter chambers and/or cartridge lengths mean higher pressures when all other variables are held constant! But even more significant here, is that even though many of you are assembling your 6.5x284 ammo with 52, 53, and even 54 grains of RL22 (a propellant of very similar burn characteristics to VV N165), your chambers may not have such tight necks or such short throats! Nonetheless, its the loads sitting there with 48.0 grains of VV N160 that make me more nervous. Still, many of you are loading with around 50.0 grains of propellants having similar burn characteristics (e.g. H4350). It's just that the VV manuals I have from one year to the next vary dramatically as to what are the maximum amounts of the subject propellants in the subject cartridge. For example, 2001 lists 53.0 grains of N160 as the max charge, while 2002 says it's only 47.3 grains!
Whaddya think, fellas?
Dave
After initiating the project the summer of last year, I am FINALLY aboard the 6.5x284 bandwagon with many of the rest of you fanatics! (This one was chambered with a Pacific Tool & Gauge 6.5x284 Norma reamer.) But now I'm really nervous about the rifle. After brooding all weekend at work about where I was gonna start as far as working up loads, I pulled out all my cartridge assembly equipment last night and immediately, there was a problem! The neck in the chamber of this rifle is apparently so tight that it wouldn't accept the Stoney Point OAL length gauge case! The new Lapua cases it accepted readily, however. So I decided to determine OAL in the subject chamber/throat via the old, redneck method: I seated 10 139-gr Scenars considerably 'overlength' into ten of the new, fully prepped Lapua cases and then mashed them into the rifle's chamber one by one. This wasn't easy, I should add. In fact, I was ready for the bolt handle of that Nesika Bay Model L to snap right off! When it didn't, I was left even more impressed with Nesika Bay actions than ever before. At any rate, 5 of these dummy cartridges came out to a length of 2.505" with the other 5 measuring as short as 2.501" and as long as 2.508". I then assembled a dummy cartridge to a length of 2.485", placed it in the chamber, gently closed the bolt behind it and then reopened it. It met with no discernible resistance going into or coming out. At last, I assembled 10 rounds to this length using the forementioned components with 48.0 grains of VV N160 and 10 with 50.0 grains of VV N165.
Now here's the thing. As all of you 6.5x284 nuts know, 2.505" from bolt face to ojive in this particular cartridge is pretty **** short when using 140-gr class match projectiles. And if I recall correctly, it seems that one of the many things I've learned from you guys is that tighter necks as well as shorter chambers and/or cartridge lengths mean higher pressures when all other variables are held constant! But even more significant here, is that even though many of you are assembling your 6.5x284 ammo with 52, 53, and even 54 grains of RL22 (a propellant of very similar burn characteristics to VV N165), your chambers may not have such tight necks or such short throats! Nonetheless, its the loads sitting there with 48.0 grains of VV N160 that make me more nervous. Still, many of you are loading with around 50.0 grains of propellants having similar burn characteristics (e.g. H4350). It's just that the VV manuals I have from one year to the next vary dramatically as to what are the maximum amounts of the subject propellants in the subject cartridge. For example, 2001 lists 53.0 grains of N160 as the max charge, while 2002 says it's only 47.3 grains!
Whaddya think, fellas?
Dave
