Picked up my CDG on the way home from work yesterday and assembled it last night.
First impressions: Very nice machine work. Neat how the action and bolt shroud blend together. Giant ejection port makes it easy to load AW mags without through the ejection port if you don't want to drop the mag. Completely toolless takedown is cool, but you have to be careful when compressing the firing pin spring not to launch anything or push sideways and tweak the firing pin tip on the bolt cross pin. Bolt lift out of the box is good, but isn't quite as smooth as my Archimedes-- but my Archimedes has about 4500 rounds on it plus dryfires so it's nice and worn in. Adding a bit of moly grease to the cocking ramps on the CDG really smoothed it out and it should get smoother after some use.
Bolt handle on the CDG is much more difficult to pivot than my Archimedes since the CDG uses a dedicated heavy pivot spring while the Archimedes bolt handle piggybacks off the firing pin spring. The stiffer bolt pivoting on the CDG is a good thing IMO as the CDG bolt handle is very unlikely to pivot unless you have a stuck case and really have to yank on the bolt, whereas with the Archimedes if you run the bolt fast and hard up against the rear stop you can sometimes feel the bolt handle give a bit. The CDG handle with the stiffer pivot spring makes the bolt handle feel more "solid" when running the bolt fast.
Had to clearance the trigger hanger a bit for a Bix'n Andy tacsport 2 stage safety lever, not big deal, I've had to do that for Bix's and other triggers in other trigger hangers. Also had to sand off the front of the oversized Bix safety lever knob so the safety would fully disengage (again, not a big deal, have had to do that before.) Unlike the Archimedes which 100% needed a low sear (all 3 of my Archimedes measure 0.154" pin to cocking piece height, and that's right at the bottom of the acceptable range even for the low sear on the Bix chart) the CDG had a 0.177 pin to cocking piece height which means it can use any of the Bix sears, but the medium (default) sear is the one right in the middle of the acceptable engagement window according to the chart, so I used the medium sear. Much like my Archimedes I set the Bix in the CDG up for 9oz first stage and 1lb 6oz break (13 oz break, the first stage on a Bix is just rotation of the trigger shoe before it contacts the lower sear lever) and had no issues with the firing pin following the bolt. Trigger timing is super easy with the CDG trigger hanger.
Dimensionally, the action, PVA barrel, and new Alpha 22GT brass were all very close; based on depth mic and gauge block measurements it looks like the brand new brass will only have to grow 0.003"-0.0035" on the first firing, so no excessive case stretch. Just for the sake of more data, the receiver face to bolt face dimension between 3 Archimedes (with 5 bolt heads between them) and the CDG all fall within a 0.0013" total window, the measurements ranged from 0.8242" to 0.8255". No issues with the tip of the extractor contacting the conical breech even dropping a case in the chamber and then closing the bolt to make the extractor snap over the case rim (extractor to breech contact was an issue someone else had on a build earlier in this thread, so I figured I should check.)
Before I spun the 22GT barrel on, I decided to bolt the CDG into a stock and play with some 223 and Accurate mags using the flat breeched .223AI barrel from my Archimedes. The small diameter 223 rounds slip through the 6 o'clock lug cutout and get presented very low on breech face, so the conical breech is a must with the CDG and the small diameter .223 cartridge. Has anyone got a .223 CDG up and running yet? I'd love to hear how the feeding is. My current .223AI Archimedes build runs perfect and feeds excellent, and I still have another unbuilt short action Archimedes in the safe I was planning to use for a lightweight 223AI build since the Archimedes has a full feed ramp optimized for single stack mags like the 223 mags. However, if the CDG feeds .223 smoothly and reliably I may consider selling the unbuilt Archimedes and picking up another CDG, because down the road if I ever decide to switch to a .308 family case I ran run AW mags in the CDG, but I'm limited to single stack only with the Archimedes.
The CDG fit into a mini-chassis in a Manners TCS with no mods needed for the trigger hanger, but I did have to shorten the magazine latch about 0.025" for AW mags to latch in place. They sit all the way up against the magazine stops in the CDG. I need to call Manners and order a replacement magazine latch to keep in inventory.
Now I have to load some initial test/break in loads, and also need to rob a scope from another rifle for now. I bought an S&B 3-20 (non-ultrashort) for the CDG initially since I was planning on keeping it around 10-10.5# with a light barrel and HNT26 stock for varmint use; the S&B 3-20 non-US is super clear with a huge FOV, forgiving depth of field, and only about 32oz... a very nice crossover scope. However, I ended up changing to a much heavier barrel profile and dropped the CDG in a Manners TCS with a steel arca rail, so weight savings is no longer a concern (lol!) and now I want something with more top end mag than the 3-20. Have a Razor Gen 3 on order to try that will go on the CDG, but it's probably 3 months out. For now I'll probably rob an S&B 5-25 off one of my AIs to put on the CDG for testing and load development.
I'd love to get some test rounds loaded up this week and go test this weekend, but it's supposed to be 108-110F both days this weekend... the pool sounds more inviting than the range, and unfortunately I think the neighbors wouldn't like me shooting from the pool.
Looking forward to using it as soon as the weather cools off a bit.
Also, I noticed that ARC now has 3 different weights of striker springs for the CDG on their website; 70N (16#, standard), 80N (18#), and 100N (22.5#). The website does say to ensure your trigger is timed correctly before trying heavier striker springs if you're having light strikes. I had a Gen 1 Nucleus with with the 16# striker spring and never had any issues in about 3000 rounds of use, but I know others had light strikes. Haven't heard any complaints about light strikes on the CDG yet, but there are heavier striker springs if you're having issues or just want the most striker energy possible.