280 AI project revisited

Your scope appears (in my vision) to be a NightForce. Is that correct?
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It's a simple budget vortex Diamondback tactical 4 x 14, since where I shoot I can only get out to about 375 yds max it's more than enough. I do have a Nightforce SHV which is probably destined for my next MDT project in 7mm STW.
 
Went out and shot a second group, five cartridges of 180 VLD's driven by RL 22. Now that I'm starting to get brass cycled through my new barrel, I'm really enjoying the Redding Competition Bushing Neck sizing die, the 280AI works really well with it. I also like FC's nickle-coated brass a whole lot. I had to take my truck into the shop--so I had to make do shooting off the hood of my Pontiac Vibe. The five shot group would have been stellar (for me) had I not pulled the one shot. I do think the longer forend makes for more accurate shooting.

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In times like these I'm thankful that 7mm isn't all that popular in the US, just scored a 500 count box of these pills.

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Went out this morning and shot a couple of groups of my 6mm ARC (66 gr flatbase) and the new 190 vlds in the 280 AI. There was a gusty crosswind varying from 10 t0 20 mph and that seemed to push the small ARC bullets around easily (though bad technique may have contributed some to it.

This is the low end charge of the 190 vlds out of my 280 AI after I got on paper. The very first shot for some reason flew wide at a higher pressure/velocity than the rest of the group, not sure why that is, maybe I didn't catch extra powder while loading the cartridge or some other factor cranked up the start velocity. When I adjusted the ave vel and ST dev minus the first shot the group was quite consistent. The vel data looks rather anemic for serious long range shooting at first glance--but when I plugged it into a calculator using a G7 BC I was rather surprised to see it would remain supersonic past 1500 yds and the energy well over "deer-approved" to 1000 yds. Drop at 1000 yds looks around 28 MOA. Not bad for a relatively soft-recoil low-end charge, I could see shooting this all day with no worries of shoulder tenderizing. I'm not sure how well the bullet would remain stabilized, though. The excellent Criterion match barrel has an 8 twist and berger's calculator says that should be good enough.

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Thanks for that roper--doesn't surprise me that the 284 win crowd is also taking a close look at this bullet--it's a "threshold breakthrough" design. Thank God for Brian Litz who is obsessed with designing optimal bullets at affordable prices! I have a 284 win AR I built and I may try it out just out of curiosity, though I'll probably have to hand feed it as I doubt it would clear the magazine or mag well of the receiver. The barrel is only 22" too. Theoretically, the 280 AI should have a distinct advantage in case capacity and seating flexibility. And, crazy as it sounds, the 280 AI is one of the most elegant looking cartridges there is--dare I say it, it's one darn sexy-looking cartridge.:)

I still have some more charge weights to go and might get up to the "magic 2,750 fps", but it's hard to move on when you hit a node like this.
 
I shot the next two charge weights today and easily reached 2750 fps with a mid range charge, I still have four more and 2+ grains to go, and my anticipated 100% fill charge should still be well below max pressure, so I'm guessing I'll easily hit 2,800 fps at least.
 
stagpanther, My 280AI and 284 (long action)have Lilja 27" barrels. The 280AI been shooting 175gr ABLR/180gr Berger VLD using R-26 @ low 3000fps
 
Unfortunately I don't have RL 26--it has been unobtanium for quite some time. I do have lots of RL 23 and so far it seems quite nice. My barrel and the 190 vlds seems to like it too.
 
Will do. Had a temporary setback--my caldwell wobble table stripped out one of the set bolts' nuts, it was bad enough before but now is useless until I figure out a fix. they are a rare company dedicated to helping shooters shoot less accurately with much of their product line IMO.;)

I hope you get your receiver soon.
 
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Hey roper--I'm finding that there are significant case length differences between the manufacturers, Nosler's own brass seems to come it at the SAAMI spec for cartridge minus the tolerance; around 2.51 +/-; every one else's comes in at 2.53 or so (hornady specifies 2.525 as their case trim length). I'm going to verify what my chamber was cut to, but I was wondering what you have experienced.
 
stagpanther, Hornady,Sierra,Nosler, manual have max 2.525" Sierra has trim 2.515". Hodgdon/Hornady have trim 2.530". I trim 2.515"

If you look at Hornady manual for 280AI they max case length for their 280AI case @ 2.590".

Most of my 100 Peterson cases are 2.5285" and my Nosler 200 case 2.5255".

I think alot got things mixed up since trim on 280 is 5.300". I got new Hornady manual coming see if the correct it.

If you fire form using 280 case you should be max @2.525" I check mine length that way.
 
I just bought 100 new Nosler cases via gunbroker--none of them even come close to 2.525--they are all 2.510 to 2.514. Judging by the SAAMI specs for the chamber (presumably submitted by Nosler) the case length of 2.525 does seem optimal. Why is Nosler's own brass too short for that? Beats the heck out of me. I confirmed with Criterion today that they do in fact use the SAAMI/Nosler specs to cut the chamber. I'm making a wild guess the the other brass that is much longer is "backward compatible" with 280 rem.

MarkCO: since you bought the same stuff from the same outfit--I'm curious what your brass measures.:confused:

PS; the hornady manual I have has max case 2.590 and trim 2.530
 
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stagpanther, First off the Nosler and Peterson brass I have, shoulders are round and once fire formed will be sharp. Length going to change.

If you think cases are too short, what I would do is call Nosler and both boxes should have run #'s.
 
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