280 AI project revisited

[stagpanther]

Have 100 pieces of new Nosler inbound. Just need the action now.

Don't suppose you can pm where you found it? ; )

[MarkCO]

Originally Posted by stagpanther

Don't suppose you can pm where you found it? ; )

Done

[stagpanther]

thanks.

[sako2]

Stag i dropped it to make sure i wasn't going overboard. I will start upping the charge now to see what happens.

[stagpanther]

Good luck!

[stagpanther]

UPS, after canceling delivery date three times, has updated the info on my paint package--they don't know where it is. So ordered some stuff from Brownells this time, it too will likely be shipped by UPS but maybe it will get here anyway, my "problem" shipments seem to be mostly with stuff originating from Midway, which is ironic since their "nitro" shipping used to get to me very fast.

[stagpanther]

Stag i dropped it to make sure i wasn't going overboard. I will start upping the charge now to see what happens.

Just out pf curiosity--I switched up to H4831 today and the results were pretty much the same, one shot out of each group was a way out deviation in velocity. So my conclusion is that there is either something wrong with my cartridges not being equalized or something in my set-up is changing pretty dramatically with warm up. I notice it's the first shot that usually is the "deviant"--but sometimes it's extra slow, other times it's extra fast. Magpro combined with the 180 to 185 gr VLDs makes for some very impressive velocity and energy, not really behind the 300 wby magnum by very much.

[sako2]

We're headed down the same road. The other day when i shot it was drizzling. I don't know if that affected the last shot. I did notice some of my cases have a lot of powder residue on the outside of the neck. Others are spotless.

[stagpanther]

PS--The package with paint mysteriously showed up today (!)--even though it still hasn't been updated on the tracking info. Whatever, just glad to finally have it after 2 weeks. The paint didn't quite match, but it's acceptable IMO. I have truck repair issues to attend to; but as soon as I can I'll whip up some cartridges and see how it runs. The forend extension remains easily removable.

[stagpanther]

Couldn't help myself--took a break from working on the truck and got a few shots off--noticed the difference immediately in being able to hold the reticle steady and virtually eliminating any muzzle lift. The only drawback I realize is I now have one less thing to blame for lousy groups.

[sako2]

Nice work.

[stagpanther]

Nice work.

It's been a fun one. I won't mention that in my test I still managed one shot that was an outlier.

[lefteye]

Your scope appears (in my vision) to be a NightForce. Is that correct?

[stagpanther]

Your scope appears (in my vision) to be a NightForce. Is that correct?

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.

[stagpanther]

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.

[stagpanther]

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.

[stagpanther]

My AR patience coefficient has run out temporarily, so I'm going to try these bullets with RL23.

[stagpanther]

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.

[old roper]

Stagpanther, This from another site

https://forum.accurateshooter.com/th...4-win.3999348/

[stagpanther]

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.

[stagpanther]

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]

I went all the way up to 57.8 grs--still lots of case capacity to spare.

[old roper]

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

[stagpanther]

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.

[MarkCO]

Keep posting Stag...I'll keep reading...and waiting for my barreled action. All else is ready.