I had a new Ridgeline that was a little stiff on it’s very first shot and required some significant effort by the third shot to get the bolt open. I had marks on the case head with factory loads and thought it was a headspace issue, as some have speculated here. It ended up just being a sticky...
I used this one:
https://www.ebay.com/itm/Remington-Bolt-knob-Black-1-1-4-quot-x-3-4-quot-5-16-x-24-Thread-/232379153815?txnId=1669245050013
Just slightly longer and much cheaper than the Christensen.
I have one on one of my bows in a Fast Eddie. Honestly, the sight I love the most is my Apex Covert Pro with the LED dot. The sight picture is so clear and uncluttered. I haven't found the need to quickly use the second dot when hunting. In most cases I have time to re-dial. I'm considering...
I shoot an RX3 at 70/29 with 300 Axis, 50 grain insert, 25 grain Iron Will collar, and 125 grain head and my arrows are 29.5”. They tune fine and bareshafts are bulletproof holes unless my form is off. Inconsistent tears are usually shooter related.
The collar is shorter than the brass insert, so no effect on the spine in the manner you’re thinking of. It does affect spine because of the additional weight, which was calculated for in the estimates posted.
What the collar will do for you is help the end of the shaft resist splitting or...
I could, but most of the time I have hard impacts to my arrows it's when I'm pushing the limits of my range during practice and that's when the collar is of most benefit. I just picked up a larger Block Vault target and all is well again.