BSA Cadet Breech Seal Suggestion

[masd]

I have a BA serial Cadet (1947-51) and it had a 70 year old leather seal but still shot well. Still, needed replacing. After reading other's posts about how they replaced the angled breech seal on their Cadets, I decided to do it my way. Thought I would share the results here. I should note, however, that I have a decent workshop so many may not have access to the tools here. However, that said, the tools I needed are quite common in many people's workshops. The below description follows on from removing all previous leather residue from the breech seal hole.

I got a brand new car tyre valve free from a local tyre fitting company. (Amazon link just so you can see the part I mean, https://www.amazon.co.uk/sourcingmap.../dp/B00E0KYFHA). You can't use old ones which have been cut off as you need the heavy section at the bottom. Cut the valve at the bottom of the brass tube which runs inside the rubber (look from the bottom to determine where this is).

Then I drilled it out to 6mm by hand on a drill press [or you can use a cordless] (this is significant as you ideally shouldnt grip it with pliers at it will distort but at the same time this is hard as the rubber has a lot of sticking friction). Then I pushed it onto the shank of a socket adapter (right hand item in the picture at https://www.amazon.co.uk/Socket-Exte...qid=1530686960). Get it onto the round section of the shank of the adapter.

Then put into a cordless drill, get your belt or disc sander (not an orbital or palm sander) and put the drill into the opposite direction of the sanding machine's movement - if the drill runs in the same direction it will negate the effect of the sander. Then use the sander and the drill combination to, like a lathe, turn down the rubber (make sure it's parallel!) to the correct OD of the breech (I seem to recall it's about 16mm but please check yours as I might be wrong). Once you are at the correct OD, chamfer one end slightly so that it will go into the breech hole more easily. Then stop and then drill out the core of the seal to the correct size (I think it's about 8mm, but again please check yours). You'll need to let the drill run for a while to essentially grind out the excess material. You could also put a round file in a drill and try that if you think you can get the correct diameter. When it's the correct, use some lubricant (gun oil, GT85 etc) to help it into the hole. You should probably note that I left mine slightly oversized and took very small amounts off a number of times while trying to fit to ensure as accurate a fit as possible.

Once it is nicely bedded (check the distance into the hole - something like 8mm at the top and 3mm at the bottom), GENTLY sand off the excess. If you aren't really gentle the sander could rip the seal out and damage it. Get it to the point where your breech closes nicely (mine was about 0.5mm proud). I did not need to remove my barrel for this. Shoots very nicely now!

Anyways, hope that will help some of the others out there. I did it because I am a cheapskate and didn't want to pay £6 for a seal which I would have to modify when I could pay £0 for one I'd need to modify. Sorry no pics of the work but hopefully the description was useful.

[series2a]

Seems a bit of a waste of time for only £6

[Benelli B76]

I buy polyurethane tube off the evil bay and cut with scalpel just above the breach using a thin washer as spacer. Can make dozens cheaply.

Baz

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[masd]

Seems a bit of a waste of time for only £6

True, but if you read the comments of others, many have ruined their replacements and had to buy a number of times and still are in the same boat. Poly tube of the right dimensions is, agreed, an easier option.

[I. J.]

True, but if you read the comments of others, many have ruined their replacements and had to buy a number of times and still are in the same boat. Poly tube of the right dimensions is, agreed, an easier option.

Totally agree. Ive given up fighting leather breech seals into place and now use 'O' rings. If its an angled breech I use part of one first. They even look tidier.

HTH
Ian

[series2a]

Totally agree. Ive given up fighting leather breech seals into place and now use 'O' rings. If its an angled breech I use part of one first. They even look tidier.

HTH
Ian

I'm a bit of a purist when it comes to restoring so Leather is the only option for me.