Stripping my s/h 0.22 Remington Express Compact

[Mr.Fixit-Norm]

Pics to go with the info above . All the below are taken as they came out of the gun !

Norm

[TonyL]

Excellent detail and pictures, Norm.

Re that extra preload afforded by the top hat, I was going to suggest maybe just collapsing a coil. But, looking at the spring ends (a little "kinked over" or just the picture angle?), I think I might be tempted to take a little off each end / re-grind square? A little bit of polishing and correct lubrication should reduce friction slightly, possibly raising power and speeding the firing cycle up slightly as well as smoothing things out? If a little too much had to come off the spring to "square it up", as you know, some preload washers will sort.

[Mr.Fixit-Norm]

Excellent detail and pictures, Norm.

Re that extra preload afforded by the top hat, I was going to suggest maybe just collapsing a coil. But, looking at the spring ends (a little "kinked over" or just the picture angle?), I think I might be tempted to take a little off each end / re-grind square? A little bit of polishing and correct lubrication should reduce friction slightly, possibly raising power and speeding the firing cycle up slightly as well as smoothing things out? If a little too much had to come off the spring to "square it up", as you know, some preload washers will sort.

Thanks Tony, re the spring ends I think it’s the picture angle. I used my phone to take the picture looked at it and thought it looks odd but the actual spring is straight and the ends are quite good. When I polished them slightly there are some little bits that remained unpolished ( I only did it by hand on some 400 wet and dry with oil on ), so I could carefully grind them a bit flatter, that would lose maybe 1-1.5mm of preload as well which would be a plus.

[Mr.Fixit-Norm]

The replacement piston seal has turned up today so I’ll start the reassemble tomorrow. I’ve had two go’s at making a top hat for the spring but failed miserably each time

The problem is that it’s such a thin delicate piece to make that I’m finding it’s beyond my machining capabilities

I made the first top hat ok but then it went pear shaped when I tried to drill the 11mm hole down the middle, then I tried to do the hole first then machine the head and shaft, that failed as it was too thin and wouldn’t hold in the lathe properly.

I’ve decided that if I can ensure the spring ends are perfectly squared off and polished and I use the ptfe(?) preload washer inside the piston sleeve then the spring when suitably lubricated should run smoothly enough. ( it certainly can’t be any worse than it was ! )

Norm

[TonyL]

Like you say, Norm, it's going to be much nicer than before anyway due to the hand finishing / smoothing out / relubing anyway, so all wouldn't be lost. If you possibly could, though, that top hat would give even more support and aid refinement. I wonder if you could insert a small "stack" of suitably sized washers into the piston nose, giving a nice, flat bearing surface and then an easier prospect for turning up the top hat? Although you'd then need to further reduce the spring due to that extra preload..And, if you were to proceed, also ensure that there's enough clearance between the top hat and guide to still allow cocking, as per your previous build.

[Mr.Fixit-Norm]

Like you say, Norm, it's going to be much nicer than before anyway due to the hand finishing / smoothing out / relubing anyway, so all wouldn't be lost. If you possibly could, though, that top hat would give even more support and aid refinement. I wonder if you could insert a small "stack" of suitably sized washers into the piston nose, giving a nice, flat bearing surface and then an easier prospect for turning up the top hat? Although you'd then need to further reduce the spring due to that extra preload..And, if you were to proceed, also ensure that there's enough clearance between the top hat and guide to still allow cocking, as per your previous build.

Well, if at first or second you don’t succeed, and not wanting to let you down I decided to try a third time !! I finally managed to make a very nice top hat which is a perfect fit both in the spring and inside the piston sleeve

It has to have a short stub as the existing spring guide is quite long, and I may have to cut the chamfered end off the guide to ensure it doesn’t foul on the top hat.

My next concern, and this is where I need some guidance, is the new piston seal. I finally managed to fit it after leaving it in very hot water for 5 mins but it’s very tight in the cylinder, so much so that where it has to clear the various cutouts in the cylinder I had to use a small flat screwdriver to push the seal down past them At this point I pulled it back out as I don’t think it would’ve come if it had been pushed in all the way

I only inserted it up to the beginning of the cocking slot as I’m thinking it’s way too tight and somehow needs to be altered ??

Can anyone suggest how I do this please as I do not want to bugger it up

Cheers,
Norm

[Mr.Fixit-Norm]

This is the assembly order, just in case I’d confused anyone

The spring end with the top hat looks on the skew but it’s the camera angle. I do still have some slight polishing to do on the spring ends but now I’m running a top hat it’s probably not quite as critical ( well unless someone says otherwise )



Norm

[Dansofield]

really good to see the parts like this, makes the description so much easier to follow

[Mr.Fixit-Norm]

really good to see the parts like this, makes the description so much easier to follow

Yes, I thought it would be a bit easier as it’s got a slightly different arrangement in the inside of the piston to what I’ve seen before with the stepped flange.

Also if someone is taking one of these apart for the first time it’s always nice to have pics to see what’s what

[Mr.Fixit-Norm]

Right, I decided after reading through some old threads on piston sizing that it was probably safer to assemble it as even if the piston seal is tight it may well ease off and bed in after 40-50 shots.

Well that was the plan, I carefully greased everything up ( enough bumslide from nicks kit ) used my sash clamp spring compressor and fitted it back in the stock. So far so good, I tried to cock it, noting that the cocking effort was quite hard but it wouldn’t engage with the sear

Puzzled I took the stock off and tried cocking it to see if it was spring bound but as far as I could see it wasn’t. Then it occurred to me that I’d taken 6mm off the plastic spring guide to allow for the 5mm taken up by the top hat flange and the ptfe slip washer but what I’d forgotten about was the length of the spigot on the top hat

I’m guessing the reason it won’t cock is the spring guide is hitting the top hat spigot

Looks like it’s coming apart again tomorrow, I’ll reduce the spigot slightly and will probably have to shorten the plastic spring guide as well.

I think the excessive cocking effort is partly due to the tight piston seal so once I’ve sorted the cocking problem I’ll resist reducing the spring till I’ve put 40-50 pellets through it

Norm

[pothunter]

I've never had a play with a Remington, but my route would be to debur the cocking slot and polish the inside of the cylinder using wet and dry wrapped round a dowel.

I would then thoroughly clean the cylinder and try to introduce the piston and seal, if it was very tight I would start to size the seal using very fine wet and dry.

A parachute seal expands as the piston goes forward and the pressure increases, the majority of the seal should be a gentle interference fit, when it is right it will just about drop under it's own weight when held vertically, but stop when you put you finger over the transfer port.

If the unsized seal is used when will the power level settle down, 50, 100, 500, 1000 shots, who knows?

Just my take on it.

[TonyL]

Good guidance from pothunter.

If a seal was only just a little too tight, maybe better to let it run itself in, as sized seals, it seems, do tend to wear quicker in most people's experience. If it's far too tight, as said, it could take many, many shots to run in and will contribute to the higher cocking effort.

[TonyL]

Norm, well done for sticking with this and putting the work in. As you say, it's likely the guide / top hat clearance. Although it might be a pain to try and make yet another top hat, personally I'd like a longer top hat to give more support to the front and reduce the length of the rear guide to accommodate. But it's up to you and I know it's been a faff.

I don't know what the quality of the piston seals for these is like and if sizes vary greatly? I also wonder if, maybe, Lyn does his own or can offer advice on uniformity of size of available seals. If the quality was at question, and if the right engineering tools were available, this might make for an ideal candidate for switching to an 'O' ring in a future project. Cheaper seal replacement, too.

[steveiep]

To reduce the trigger pull a little, you can remove 2 of the 3 washers from under the sear engagement screw (ahead of the trigger).
That should still give safe engagement, but reduce the amount of pull to a more acceptable level.

Lyn Lewington (Venoman) does/ did an aftermarket brass replacement trigger that isvery nice.

Inside the piston, at the front, is a step that is a "pseudo" top hat that centres the spring.
As you have spotted, the best thing isto cover it with a delrin washer, then you have a flat surface for your new "actual" top hat to bear against.
As another has pointed out, you may then have to shorten the rear spring guide, if it fouls on the underside of the new tophat.

It is not unusual for the rifles to come from the factory with some dried brown crud on the internals.
It is probably intended as lubricant, but just isn't.
Clean off and re-lube as you would any springer.

[Mr.Fixit-Norm]

Thinking about it, I think you and pot hunter are right on both the piston seal and the top hat !

The seal is a very tight fit and certainly won’t move in by hand and as pothunter says it may take a lot longer to wear in which would be a real pain
I could at a real push go back to the old seal, it was making 11ftlbs with that in in its dry unfettled state so can’t have been that bad, even if it did look a bit old, and at the end of the day, like with the 35, it’s not power I’m after but a smooth easy cocking stroke and accuracy

I was concerned about the cocking rod not going through the centre of the spring guide if I made it shorter, but thinking about it they’re shorter on other guns so probably nothing to worry about, and with my new found top hating skills I shouldn’t have an issue making a longer one

I’m not sure my lathing skills are up to making an O ring piston head modification, it’s a shame my late mate Martin Cooper isn’t still with us, the Original 66 he gave me had one in that he made and it worked perfectly.