Slygunner,
Welcome to the Club! I have a Rem 700 BDL, Shilen SS Barrel, that is chambered for the .17/222 magnum improved (40) and I have encountered the same problem.
About 3 years ago, I noticed that as I increased the overall loaded length to keep the bullet about .015 inches from the lands as the throat eroded, feeding problems began to develop. Also, about 1 year ago I began using the 30 grain bullets from Hammett and Kindler, and these were about .090 -.115 inches longer than the 25 grain Hornady Hp (.560 inches), and similar problems occured.
I also own a Rem 700 BDL that is currently chambered for the .22/250 AI. So recently I did some measurements of magazine and components for both the .222/223/222 magnum, etc magazine box with spacer, and also the 22/250, 243, 308, etc without spacer. The results were:
Rem 700 Short Action -17 Rem, .223 etc bolt
Magazine Box
Interior Length without spacer - 2.850 inches
Spacer width - 0.440 inches
Interior length with spacer - 2.410 inches
Magazine Follower
Length - 2.300 inches
Width at front - 0.612 inches
Width at back - 0.687 inches
Magazine Spring
Length at top 1.775 inches
Length at bottom - 1.775 inches
Width .504 inches
Rem 700 Short Action .22/250, .243,etc bolt
Magazine Box
Interior Length 2.850 inches
Magazine Follower
Length - 2.770 inches
Width at front - 0.630 inches
Width at back - 0.794 inches
Magazine Spring
Length at top - 2.475 inches
Length at bottom - 2.655 inches
Width - 0.504 inches
I also loaded up some dummy cases to various loaded lengths to try and identify at what length the loading appeared to deteriorate. My tests showed that once about 2.260 inches was exceeded, the reliablility of the feeding started to decline, and by 2.320 inches it had almost become totally unreliable.
I then took both rifles around to my gunsmith's house and got his opinion on how to solve the problem.
He and I both agreed that the best solution seemed to be to extend the length of the existing follower to 2.770 inches which is the same length as the follower in my 22/250.
He believed that the best method to extend it would be to cut off about .25- .300 inches from the existing .222 mag follower, and then cut off the amount required from another similar .222/222mag etc follower that when tig welded to the front of the other follower would take the overall length to 2.770 inches.
Then to provide sufficient support to the follower and prevent it from diving when the loaded round is pushed forward by the bolt, obtain a magazine spring from a 22/250, etc and substitute it for the existing follower, as luckily the spring used for both boltfaces is the same width.(ie .504 inches)
We quickly dismissed the idea of using a 22/250, .243 follower and grinding it down to the correct width, as the design makes that impractical.
Currently, I have purchased the spare spring from another .22/250, and am awaiting my gunsmith to send me a spare follower from a 222 etc. I will let you know in due course how the experiment progresses.
Regards, Brian.