Barrels unhooking only when dry fired.
 

Often the initial response to people when encountering the issue of a gun's barrels not unhooking is to let the hammers down and then try it. Sometimes it works and other times it is a different, more complicated issue. I too have dealt with some guns that will only unhook if un-cocked. It is not a major inconvenience, unless the gun has ejectors. Not that a Parker cannot be cocked with the forend off, but it can be a pain.

For some time now I have wondered what is going on mechanically that makes the gun not unhook unless it is un-cocked. And I think I may be onto something with some recent diagnosis I was doing on a gun for another issue. I believe this issue is related to the bolt trip assembly. Most specifically, the spring loaded plunger in the trip assembly. Either the plunger gets worn or the spring gets weak or gummed up and does not apply enough downward pressure on the cocking slide thus causing unhooking issues.

I need to do more testing and tinkering to confirm if this is in fact the root cause, but I was led to this when I was having to do some bolt work on a VHE today. In order to save time in breaking things down over and over again, I had the action assembled off the stock and I removed the trip assembly so that I was able to easily remove and re-install the bolt without having take the trigger plate off. With no trip in the gun, the barrels would not unhook unless it was dry fired. When the trip was back in, all worked fine.

Or am I finding something out that is already known?

I did find that out with a very gummed up one, cleaned out the spring hole so it work freely and it worked fine after that, scott

Yes; the spring-loaded plunger in the trip assembly is a notorious culprit in the "won't unhook unless fired" syndrome. That along with the cocking slide return spring being damaged or crudded up beyond function.

Years ago, hand-loading for my 28 ga., I changed powders (was using 800X) to a coarser-grained powder and immediately noticed trouble from time to time opening he gun. Close examination showed individual grains of unburnt powder had blown back into the action around both the bolt trip release. Just those tiny obstructions were enough to bind up the action. Once I changed powders, the problem went away.

At the first Greenwich Fine Arms Show about 7 years ago, a man and his kids showed up with "Grandad's old duck gun", a well-worn 30" VH 12 ga. in the 105XXX SN range that would literally not do anything - open, cock, fire, etc. With the man's permission we removed the trigger guard and floorplate on a side table. When we took the floorplate up, it looked like someone had taken a huge dollop of wheel bearing grease, packed the action, then screeded the excess off with a straightedge. You literally could not see any of the internal parts! Whatever lubrication had been over-applied over the years, it had congealed and almost solidified in the action. We held the action over a trash barrel and blasted all the crud out with Gunscrubber, then a light pass with WD 40, wiped off, and lightly oiled it. Reassembled it and everything worked like a champ. The owner said he could not ever remember the gun having been disassembled and cleaned during its lifetime.

Oh yeah, I have found un burnt powder in areas of guns. Commonly on water tables. From pulling spent shells out

The unhooking slide spring is a common culprit for the not unhooking at all scenario, but not usually the only when fired case.

Brian, you certainly know your Parkers, and gun mechanics as well. My 12 VHE was made in 1928-1929, and has the later revised 4 piece action. A friend has his grand-dad's PH with Twist steel barrels made in 1898- no bolt insert and the earlier style action. He has similar problems, even though he keeps the gun clean and reasonably crud free- and does not over-lubricate either. So I am wondering if the difference in action parts, as well as crud and spring fatique may also be part of this situation. And FWIW, I did buy that older 12 Lifter No. 1346 from Mr. Kunzer this past Wednesday. You replies to his questions under General Discussions helped us both in evaluating this older Old Reliable. Thanks-GF:bowdown:

Brian

Look into the barrel hook, spring and plunger. I have seen several cases where the barrel hook has compressed the leading edge of the lug slot. Simply swage the edge to limit the travel of the hook.

Brad