I have a Proof 22-250 with 8 twist. It is a SAAMI cut barrel so setup for the short 55 grain bullets. 69 VMAX and 70 gr Hammer Hunters must set very deep into the case due to the short chamber. I intend on having it reworked to accommodate the longer bullets and just let the 55 grain bullets jump as best they can. Not really sure if I will get the optimal which would be all of the bullets shoot well. Hopeful.
I talked to the gunsmith today. He’s ordering the barrel. He’s done a couple 788’s with Barlien 7.7 twists in 22-250 AI. Showed me some results from customers running 75 grain ELD -M’s and 77 grain Sierra MK’s and they were impressive.
As you know, the 788 has rear-locking lugs. if you check carefully, not all of those locking lugs make uniform contact. Rear locking lugs leade to more bolt thrust.
The issue is that the AI runs some serious pressure, you may experience premature pressure signs in the AI.
I have had at least a dozen 788's if not more, all variants except the 44 mag and 30/30. Shot out a few when the jackrabbit population went crazy from the mid '80s to mid '90s.
You may think I am nuts, but the Rem 783s are a better action than the 788 and they are machined very, very true, including a very fast lock time. I have had several custom barrels put on 783s, Boyd's stocks, and Timney triggers, and they sure behave like custom rifles when you look at the targets.
I started running into high-pressure issues with the 243 in how the rear locking lugs leade to case stretching..
Another good action is the Thompson Center Venture but do not know about after-market triggers for this action. Howa is one heck of a strong action, but I shy away from actions with metric threads.
Remember that the 783s are machined very, very true, this is a great platform to build an inexpensive custom out of, and you will be heads and shoulders better off than a 788. I got my first 788 in 1969 when I was 14, and paid $99 for it! Check them out! The floating bolt head like a Savage, steel magazine with durable construction, and super fast lock time, and I re-spring the triggers on mine. Even the recoil lugs on the 783s are much truer than the 700s! The 783s are the old Marlin x7.