Fitting Barrels

[Harry Collins]

Both hooks caught the cocking leaver, but not enough to catch the sears. Im going to file the space forward of the hook to see if giving it more travel will work. The barrels original to the gun has more travel space and I will try to match it.

[edgarspencer]

The issue is probably not the cocking hook, but the length of the extractor rod.
You can confirm that by seeing if the extractor on the original barrels will still lift up further when the gun is fully opened. It likely will, a small amount. Now, try to see if the extractor of the 'new' set will move up, when you think it's fully opened. It probably won't, meaning that the extractor is being limited by it's retaining screw. Two ways to remedy this are either dressing the end of the rod until the gun cocks, or elongating the recess on the extractor rod, on it's forward edge.