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280 ai

Finally went to the range today, and put the first shots through my new Christensen Arms Ridgeline .280 Ackley. I was shooting through my OCL Hydrogen-L 7.62 suppressor with the new OCL ZR0-DTA 5/8-24 direct thread mount. It’s a ridiculously lightweight setup for a 9” can. You really don’t even notice it on the end, as far as weight goes. It also sounds excellent!

So far still working on load development, so no results to post yet. I did notice that Christensen really cuts the chamber throats short on these. As a handloader, I’m not a fan. They are seated pretty deep into the case neck, even with Berger 168 VLDs. There’s plenty of room left in the magazine well, so I wish they would cut them a little bit longer (more normal). At almost 2 grains less than book load max, I’m already seeing pressure signs and ejector swipes. 😐 I hope it shoots good. But that kind of pissed me off seeing as to how much this rifle costs. I might have to have a gunsmith cut (extend) the throat some, so I can seat the bullets farther out, and they won’t be taking up much needed case capacity to help relieve some chamber pressure.

On top sits an older Zeiss Conquest MC 3-12x56 30mm FFP scope. I’ve had this scope for nearly 15 years. It’s been on quite a few different rifles. It’s sitting in a set of Seekins Precision rings, on an EGW HD base.

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Finally went to the range today, and put the first shots through my new Christensen Arms Ridgeline .280 Ackley. I was shooting through my OCL Hydrogen-L 7.62 suppressor with the new OCL ZR0-DTA 5/8-24 direct thread mount. It’s a ridiculously lightweight setup for a 9” can. You really don’t even notice it on the end, as far as weight goes. It also sounds excellent!

So far still working on load development, so no results to post yet. I did notice that Christensen really cuts the chamber throats short on these. As a handloader, I’m not a fan. They are seated pretty deep into the case neck, even with Berger 168 VLDs. There’s plenty of room left in the magazine well, so I wish they would cut them a little bit longer (more normal). At almost 2 grains less than book load max, I’m already seeing pressure signs and ejector swipes. 😐 I hope it shoots good. But that kind of pissed me off seeing as to how much this rifle costs. I might have to have a gunsmith cut (extend) the throat some, so I can seat the bullets farther out, and they won’t be taking up much needed case capacity to help relieve some chamber pressure.

On top sits an older Zeiss Conquest MC 3-12x56 30mm FFP scope. I’ve had this scope for nearly 15 years. It’s been on quite a few different rifles. It’s sitting in a set of Seekins Precision rings, on an EGW HD base.

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Same chamber issue with my mpr .338lm
 
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Same chamber issue with my mpr .338lm
I heard they order all their reamers with short throats, because they want them to shoot really well with factory ammo, since most factory ammo is seated to a really short (SAAMI) COAL. Which really sucks for those of us who handload. They really should offer free throat reaming for those that want them. I mean, this is basically a $2,000 rifle that can’t hardly be loaded for. That’s stupid. Most people buying rifles in that price range roll their own. 🫤
 
I heard they order all their reamers with short throats, because they want them to shoot really well with factory ammo, since most factory ammo is seated to a really short (SAAMI) COAL. Which really sucks for those of us who handload. They really should offer free throat reaming for those that want them. I mean, this is basically a $2,000 rifle that can’t hardly be loaded for. That’s stupid. Most people buying rifles in that price range roll their own. 🫤
100%agreed
 
Yeah, when you're damn chambers are shorter than most factory ammo, and other brands of rifles, you might need to switch up some shit. Most people buying $2,000+ rifles aren't shooting factory ammo out of it. My groups today were absolute shit. Best group I got was just under MOA at 100. HOWEVER, that was only the first 25 rounds, and it might not have settled in yet. AND, my Zeiss's FFP fat duplex reticle was covering up the whole damn bullseye so I couldn't stack any shots...It was terrible.

So, I finished up shooting the 25 rounds accepting I was basally just there to fire-form them, and break-in the tube a little bit. And, when I came home, I immediately dug though the safe to find a rifle I don't shoot, and swapped the Zeiss for a Vortex HST 6-24x50 VMR-1 MIL just to use during the load development phase. And once load development is done, I'll put the Zeiss back on for hunting. But for now, a 12x scope with a fat FFP duplex reticle isn't going to cut it. 🤦🏼

It honestly does (IMHO) look better with the Vortex on it, so we’ll see how it goes…I might eventually drop a Zeiss V6 5-30x50 ZBR (w/ target turrets) on it. But, gotta get the fucker shooting first... Still heading uphill for now. Hopefully we'll have some better developments after the 2nd round of 25 (next weekend).

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I have found IMR-8133 and a 175 ELDx to be VERY accurate and faster than I expected out of a 30" bbl 280AI. I'm new to the cartridge and I am really liking it with said combination. IMR-7977 seems to be good as well abut still working on that one. I just traded for a Christensen like the one above yesterday and haven't messed with it yet. It will be my 3rd 280AI and 6th Christensen Ridgeline. As with any Christensen "rebed" the action and your groups will be cut in half. Simple fix for a lazy manufacturer
 
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At almost 2 grains less than book load max, I’m already seeing pressure signs and ejector swipes.
I have 6 of those Ridgelines, ( 243Win, 7mm-08, 280AI x2 6.5CM and 28 Nosler) and every one of em max out at mid book loads. You will NEVER get boox max loads. You will pop primers and ruin brass, have sticky bolts etc. at anything over mid book loads. Check your speed it will be there. Drove me nuts at first too. I too dont like the "short throat" but have learned to shoot long Ogive bullets and the problem is moot now.
 
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I have 6 of those Ridgelines, ( 243Win, 7mm-08, 280AI x2 6.5CM and 28 Nosler) and every one of em max out at mid book loads. You will NEVER get boox max loads. You will pop primers and ruin brass, have sticky bolts etc. at anything over mid book loads. Check your speed it will be there. Drove me nuts at first too. I too dont like the "short throat" but have learned to shoot long Ogive bullets and the problem is moot now.
Yeah, but a damn 168 VLD sits so deep into the case…. It’s frustrating. Here’s how deep I have load them, and this is only like 0.007” jump off the lands. 🤦🏼

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Yeah, but a damn 168 VLD sits so deep into the case…. It’s frustrating. Here’s how deep I have load them, and this is only like 0.007” jump off the lands. 🤦🏼

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I wanted to shoot that bullet too. I never got it to shoot very good. I switched over to the 160 Sierra HPBT NOW keep in mind it’s a hunting bullet and it’s not got a real high G7 but that’s of a buck will shoot with 7977 or reloader 22.
 
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I wanted to shoot a bullet to I never got it to shoot very good I switched over to the 160 Sierra HOBT NOW keep in mind it’s a hunting bullet and it’s not got a real high G7 but that’s of a buck will shoot with 7977 or reloader 22.
Well, I really want to shoot the new Berger 175 Elite Hunters, but can't seem to find them anywhere... It has a hybrid ogive, so they would be a bit more forgiving than the VLD's. My custom 7mm RemMag LOVES the Berger 168 VLD's and IMR 7977. The hunting load I use for it has an ES of 3, and an SD of 1. It's the most consistent load and rifle I've ever shot. It's groups are in the 0.3xx" range. Being a magnum, to avoid excess heat and wear & tear, I only shoot 3 shot groups with it...Same with most of my long-action cartridges. I typically shoot 5-shot groups with my short-actions and AR's.

Best group of the day today was 60.5 gr of 7977... Still not where I want it to be, but most folks would call it good. My gripe is that I should be able to get a $2000 rifle shooting better than this with handloads... Seeing as to how I have loaded for factory barreled rifles that shot sub-1/2 MOA at 100.

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After swapping the scopes, scrubbing the barrel, now having fire-formed brass to my chamber that I neck-sized for consistent neck tension, re-measuring the chamber for jump distance, and seating them 0.010” off… It’s showing some real promise.

All groups were shot with my Otter Creek Labs Hydrogen-L w/ their ZR0-DTA mount.

I think 60.0 grains is the sweet-spot. That’s probably what I’ll stick with. Next trip I will be taking the MSv2 for velocity testing and getting my ES and SD for the load so I can build my dope chart.

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Well, I really want to shoot the new Berger 175 Elite Hunters, but can't seem to find them anywhere... It has a hybrid ogive, so they would be a bit more forgiving than the VLD's. My custom 7mm RemMag LOVES the Berger 168 VLD's and IMR 7977. The hunting load I use for it has an ES of 3, and an SD of 1. It's the most consistent load and rifle I've ever shot. It's groups are in the 0.3xx" range. Being a magnum, to avoid excess heat and wear & tear, I only shoot 3 shot groups with it...Same with most of my long-action cartridges. I typically shoot 5-shot groups with my short-actions and AR's.

Best group of the day today was 60.5 gr of 7977... Still not where I want it to be, but most folks would call it good. My gripe is that I should be able to get a $2000 rifle shooting better than this with handloads... Seeing as to how I have loaded for factory barreled rifles that shot sub-1/2 MOA at 100.

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Hers a nice little horsing around at the range today at 300yds group with some 160Sierras and IMR 7977. Not too bad for a over the counter deer rifle.
 

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Due to the ATF screwing everyone with eForms right now, pushing them WAAAAY beyond the original 90 day [typical empty government] promise… My new Otter Creek Labs Hydrogen-L, which is going to be my dedicated hunting rifle can, looks like it will be quite a while before It gets approved. Probably after deer season, knowing my luck. 🙄

So… I decided to snatch the heavy KeyMo setup off my Nomad-LT, and put my spare ultralight Otter Creek ZR0-DTA titanium DT mount on it, and I’ll probably end up using it this season.

Looks pretty good on the new Ridgeline .280 Ackley… Pretty damn lightweight, too. Definitely packable. OAL with the 24” barrel is 52” from the floor to the end of the can, so it’s a longboi for sure…. But if you needed to, you could just wait to screw the can on once you’re in the stand. The OCL ZR0-DTA mount only adds 1/16” to the length of your suppressor, just enough to have a thick enough flange to mount securely and strongly to the back of the can, and recesses the barrel threads up inside the blast chamber for virtually zero extra length.

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That’s how I do my all CAs. Just put em on when I’m in the blind. My 16” 6.5 is so short I just leave it on. I’m going to TRY To shoot the 280 AI without a can this year and see how it works. It is so stinking long the can makes it like a yardstick.
 
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Shot 25 more rounds, and a 3-shot group today with the Nomad-LT on there. POI shift from my previous zero with the Hydro-L and ZR0-DTA, and my Nomad-LT with a ZR0-DTA, was only 0.3 MILs low, and dead-on left & right. So, not bad at all. Kind of impressive, actually.

Here’s the group.

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Yeah, but a damn 168 VLD sits so deep into the case…. It’s frustrating. Here’s how deep I have load them, and this is only like 0.007” jump off the lands. 🤦🏼

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I'm telling ya don't worry about the COL. if it shoots good at .007 off the lands go with it. So many guys get all bent otta shape cause their bullets aren't seated way out. Every stinking one of my Christensens shoot FASTER than book with LESS powder and shoot good hunting size groups (<.5MOA). Whats not to like about less powder and more FPS? Have you checked it with a Labradar or Magneatospeed? all of mine are 100-175 FPS faster than all the books say with given charge. I hate to see you get all messed up over how far they stick out of the brass. Something else to consider is do they cycle from the mag in the "heat of battle" seated way out there? Do they even fit? Most of the time those really long loads don't cycle well in my experence. Id check the speed before I got all upset.
 
I'm telling ya don't worry about the COL. if it shoots good at .007 off the lands go with it. So many guys get all bent otta shape cause their bullets aren't seated way out. Every stinking one of my Christensens shoot FASTER than book with LESS powder and shoot good hunting size groups (<.5MOA). Whats not to like about less powder and more FPS? Have you checked it with a Labradar or Magneatospeed? all of mine are 100-175 FPS faster than all the books say with given charge. I hate to see you get all messed up over how far they stick out of the brass. Something else to consider is do they cycle from the mag in the "heat of battle" seated way out there? Do they even fit? Most of the time those really long loads don't cycle well in my experence. Id check the speed before I got all upset.
I remeasured using my orange box Hunting VLDs, and it sat them 2.688”, so I’m running them at 2.678”, which is 0.010” off the lands, since I will be using them for hunting. So far, it’s doing ok. I’m averaging anywhere from 0.750” down to 0.350” groups. Which, is acceptable for right now, since I don’t have any shots over 500 yards on deer, so I’d say it’s fine for now. I do need to chrono the load for my dope chart. I will be doing that this upcoming weekend. I’ll report back my velocities. Also, after fire-forming the cases, I was able to fit 60.0 gr of 7977 in there without it being a compressed load. The shoulder area expanded roughly 0.005” at the shoulder/wall junction after the first firing, so I know that helped with capacity a fair bit. 👍🏼
 
I remeasured using my orange box Hunting VLDs, and it sat them 2.688”, so I’m running them at 2.678”, which is 0.010” off the lands, since I will be using them for hunting. So far, it’s doing ok. I’m averaging anywhere from 0.750” down to 0.350” groups. Which, is acceptable for right now, since I don’t have any shots over 500 yards on deer, so I’d say it’s fine for now. I do need to chrono the load for my dope chart. I will be doing that this upcoming weekend. I’ll report back my velocities. Also, after fire-forming the cases, I was able to fit 60.0 gr of 7977 in there without it being a compressed load. The shoulder area expanded roughly 0.005” at the shoulder/wall junction after the first firing, so I know that helped with capacity a fair bit. 👍🏼
Good deal man my fire forming loads are MEH at best after that its on! Mine likes 7977 as well with 162s. Dont know If I mentioned it but all 6 of my Christensens will max out BEFORE book max. Normally about 2 grains BUT BUT BUT the speed will be there. They cut them chambers short and tight. It used to give me crazy head but after the second one I messed with I got over it when I figured the speed is there. Them reloading books are just a reference not the law. I hope you bust a big critter this year. If you can find any Retumbo or 8133 try some 175 ELDX or some 180 Bergers. Dont know why buy they shoot very good in both of my 280 AI Ridgelins
 
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New video is up comparing the Dead Air Nomad-LT and the Otter Creek Labs Hydrogen-L on my new Christensen Arms Ridgeline .280 Ackley Improved.

 
Found 4 more boxes of 7mm Berger 175 Elite Hunters the other day, now they’re on their way to me… So I decided to stop using the 168 VLD’s, and break open the 1 box I already had on-hand to start load development with the Ridgeline .280 AI. 😏
 
Found 4 more boxes of 7mm Berger 175 Elite Hunters the other day, now they’re on their way to me… So I decided to stop using the 168 VLD’s, and break open the 1 box I already had on-hand to start load development with the Ridgeline .280 AI. 😏
My 280AI RidgeLine likes em. I found 3 more lbs of 8133. That is a good combo in mine. Too bad they quit making it. 7977 wasn’t too bad.
 
All Enduron powders. Rumor has it they can’t get the stuff to make it IDK. It’s crazy. Damn Rona messed everything up.
Guarantee the powder drought was purposely designed by our government. Just like hoarding all the primers, by ramping up demand for ammo for BS agencies that will never use it, just to keep it out of our hands. 😡
 
Has anyone contacted Christensen and asked about having the chamber reamer deeper?
It might be worth a telephone call...
Just my $.02

Copper
 
26” light hunter barrel
Norma cases
Fed gold match primer
162gn ELDX
61.3gn Adi2213sc (H4831)
3.720” to ogive
10rounds gives
Average 3013 fps
SD 8.1
ES 23
 
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@christensenarms Ridgeline 24" .280 Ackley Improved with Berger 175 Elite Hunters, IMR 7977, Nosler .280 AI brass, and CCI 200 primers... Chrono'ing at a multi-session average today of 2,741.5 FPS muzzle velocity. Quieted down with my newly released from NFA-jail TBAC Magnus-HUB w/ an Otter Creek Labs ZR0-DTA mount.


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More powah! You can get those things faster, but with an SD like that, it's hard to argue changing anything. Good looking rig.
 
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175 ELDX over 55.8 grn of Stabal 6.5
100 yds
5 shot average 3006 fps es of 13 fps
Barrel is a proof cf 1-8. 24"
 

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More powah! You can get those things faster, but with an SD like that, it's hard to argue changing anything. Good looking rig.
If I dropped back to the faster IMR 7828 SSC, I can get more velocity, over the slower 7977 powder. But the 7977 is such a consistent and temp-stable powder, it's hard to argue with the results.
 
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