Technical question re tap-loaders

[andrewM]

I have a technical question for the technicians and experts, here.

I have noticed, after firing my tap-loaders (BSA Standard/Webley Mk3) that there is usually a tiny amount of 'give' in the loading tap. Thus, before firing, the loading tap must be returned downwards to its firing position. However, after firing, there is a tiny amount of movement that becomes possible, as the loading tap can then be pressed downwards again, but by only a tiny fraction of a measurement. It seems that the exercise of firing slightly lifts - by a tiny amount - the loading tap.

This, I suppose, could occur if the receiving barrel entry point is slightly larger than the loading tap - ie the entrance to the barrel is slightly tapered inwards from the entry point (where it is fractionally wider). Otherwise, the barrel entry point would have to be exactly equal in size to the loading tap and positioned precisely as the slightest variance would clip the pellet.

Assuming I am correct in my observations, I presume that the loading tap would then move very slightly as it re-centred itself to the most aerodynamic position, to allow the air - and pellet - to pass most efficiently through the barrel (rather like a weather vein seeks the path of least resistance).

I am most happy with the accuracy output, especially from my 1920s BSA, which suggests nothing untoward is occurring. Still, I am curious about the observation above.

Perhaps anyone with any technical knowledge could add to my theory or disprove it!

[Ragle Jnr]

I suspect the recoil is responsible for the movement and/or the tap is slightly too slack. Can you hold the tap lever while firing and see if it stays still? If slack, perhaps placing a tissue over the area and firing will show air escaping? Nth David

[cringe]

Hi, a simple way to find if your "tap's" are working : dry fire your rifle with the tap in load position, then slowly turn tap to fire position, you want to hear a nice slow hisssssssss! that means it's working. But I am not too sure how to check for alignment? can you see into the loading port? does it look "off-set?" if so you may need to experiment with some sort of shims? best regards Al.

[andrewM]

Thank you both for your replies.

The loading taps seem quite firm. I have tried holding the tap in position, at firing, and then the problem does not occur.

It could be a consequence of recoil.

The question is open as to alignment. Were I the designer, then to avoid an exact alignment between loading tap and barrel, which would be quite a task, I would have opened the circumference of the barrel at the point of entry from the loading tap, then reducing it a fraction of an inch later, which would feed the pellet into the barrel. This, I suspect, is what they did and, if so, it might account for the very slight movement which, I suspect, is not peculiar to my guns alone! I am just wondering if indeed this is how they designed these.

[mrgeoff]

Strip the rifle spring out so you can see all the way thru the tap. A bore scope may help!

[Dan944]

Yes I was going to say similar to Geoff above”
When I have striped any of my tap loaders I have always installed and oiled the tap loader with it in the firing position and then looked straight down the cylinder from the rear with a tourch to make sure he tap hole and barrel hole align!

All the best
Daniel

[bill57]

With a tap loader, if it's shooting accurately, then there's nothing to worry about. If it's not, and you have addressed all the normal causes of inaccuracy, then you need to inspect the fired pellet. Firing into a bucket of water with folded towels in the bottom usually does the trick, allowing you to recover an undamaged pellet. If the bucket's plastic, then a metal plate under the towel is also a good idea - don't ask how I know!

If the pellet shows even rifling striations all round, all is well. If, however, the marks are more defined on one side, and perhaps even not present on the other, then you have tap/barrel misalignment and a probable cause of inaccuracy. You can scratch a reference mark inside the pellet skirt, and note it's position before firing. If any misalignment is present, this will let you work out where it is, ie is it in the horizontal or vertical plane.

As to fixing tap misalignment, unfortunately that's a whole new area.

[cringe]

Hi, before you go for a major strip down, I suggest you check this : the loading tap should be held in position by a 'tiny' spring & a 'tiny' ball bearing, if the spring has failed or the bearing lost, or some times a groove can be worn into the cover plate, so the bearing will not locate in dimples. not telling you "how to suck egg's" you may be already aware of this. I had a similar problem & if any body knows ? where can I get those tiny springs & bb's ? regards Al

[andrewM]

Thanks everyone. I think I will try the pellet/bucket of water test just to check all is well. I suspect the tiny movement is either some backwash, or recoil or the pellet/air finding the path of least resistance - the latter point assumes that the loading tap opens into a slightly larger circumference in terms of the barrel, which then tapers.

A