I had a similar problem with a Garret Sharps, sent it to Lee Shaver and he fixed it. I recommend the following:
1) Call Lee Shaver
2) Call Lee Shaver
3) Call Lee Shaver

if that doesnt work, call Lee Shaver.
You can send in the breechblock without having to send in the entire rifle. 
I hope this helps.
Joe S

Isn't or wasn't Lee the US factory service rep?

I know John and I have no reason not to believe him. But I also have a friend who has since passed who had to send his new CPA back to them three times and did not have to go through any of that. Why I could not honestly say but only know he did not have to jump through all of those mentioned hoops? I personally have only had to do this once, I had Ruger 77 in 25-06 and the tang cracked right across the safety mortice opening and the trigger would no longer work. I took it to my gunsmith and local gun store owner and I asked him to fix it and he said let me send it back to Ruger first. Keep in mind this rifle had seen allot of use not abuse and the throat was actually shot out. I had also re-bedded it and also done my own trigger work. Before he sent it off he asked do you want another 25-06 coming back or possibly something else. I said I would prefer to have a 270 instead knowing full they would not do such a thing but he still insisted that he wanted to. Long story short sometime later and said come and pick your new rifle up. And all I had to pay for was another background check as obviously the serial number and the rifle itself would no longer registered as being the same. And to wait the required days along with some other minor charges and the total for the entire ordeal only came to 67 dollars and change. 

Californians may ship a gun directly to the manufacturer or to another FFL holding gunsmith, and take direct delivery of that gun on return.

If a dealer ships the gun to the manufacturer on behalf of the owner, then it depends whether the dealer enters the gun into their inventory before shipping in order to transfer the gun to the manufacturer rather than just shipping.

The complexity of California gun law is onerous enough by itself. Sadly, it is often compounded but the (cough) legal acumen of various sharp minds in the firearms business. We are subject not only to the law, but a particular dealer's interpretation. I expect many retailers are unfamiliar with the details of the law in this area and just do what they do for any other delivery.

On this forum, we have almost all seen the common misinterpretations of statute around antique firearm status. Californians are constantly burdened with similar thoughts from the sharp legal minds behind the counter at the gun shop. I have, more than once, been asked to do a 4473 on an antique gun, by a dealer who knows no better. All we can do is decide whether to acquiesce or refuse.

I have no idea why I felt compelled to editorialize on this particular subject this morning, but there you have it