If you cannot source one off a forum member you can snag one off our pre-sale here (we'll see this in August):
https://jaoutdoors.com/product/xlr-4-0-pre-order/
You might look into the new hornady CX line.
I know you stated barnes, however - If you haven't tried the Barnes LRX lineup - that is another good one to test. Inside 600 the LRX has worked great for us.
7 PRC Hornady Precision Hunter Ammunition is in stock ready to ship @ jaoutdoors.com
https://jaoutdoors.com/product/hornady-precision-hunter-ammunition/
7 PRC, 6.5 PRC 22'' barreled actions are available now (only 1 of each) as of 5/3/2023. All others are made to order. Give us a call!
https://jaoutdoors.com/product/tikka-barreled-action-builder/
XLR Long action remington 700's are available for pre-order here:
https://jaoutdoors.com/product/xlr-4-0-pre-order/
ALL the popular colors available in remington 700 SA inlet:
https://jaoutdoors.com/product/xlr-element-magnesium-chassis/
I was in a similar situation years ago - 6.5 SAUM & 6.5 CM filled the gap nicely.
6.5 PRC & 6.5 CM quality factory ammunition is darn near everywhere - that would get my vote.
We've built a few 300 norma's off the kelbly - as well as several 338 lapua ai. One is nearing its end of life, we will have to pull the barrel to check for lug setback - all in all, very pleased with kelbly in the lapua bolt face!
Frustrating for sure! I sure would love to find one myself, awesome little rifles. I haven't seen any available on the dealer side for a good 3+ years.