Opening up HW95k transfer port

[eyebull]

New hunting permissions beckon and while I have absolute confidence in the LGV from 10-40 yds it's a fat old lump and no good for a walkabout, nor am I over keen on attaching sling mounts to the competition stock. The ideal would be a light to medium weight springer in .177 which was meant to be my 95k.

However was never happy enough with the accuracy or useability of my HW95k in .177 to hunt with it; Goes without saying that it got a basic clean, deburr and relube, and I added a TBT shortstroke kit which did improve things slightly, but I think I'm going to take the next step and open up the transfer port, as well as fit a newer style piston seal.
It's do or die - if it all goes pete tong then I suppose I'll have to sell the leftovers on here and buy a HW99S!

Would appreciate any and all advice as to correct procedure for opening up the port without access to lathes and mills, hand and power tools only - was going to use a drill to open it up to 3 or 3.2mm, and then a hand reamer to open it up to 3.5. Is this a terrible idea? Will that leave burrs on the inside of the comp chamber? If so what is the best way to deburr? Should I expect power to increase substantially? (lack of power is not currently an issue, if anything I could lose half a ft/lb).

[Shed tuner]

use a hand reamer.. start with 1/8" 3.2mm

3.4 / 3.5 will probably be optimal, and will prob give you around a foot pound

[Brano]

How about a calibre change to smooth it out. A replacement .22 barrel might prove straight forward.

[eyebull]

use a hand reamer.. start with 1/8" 3.2mm

3.4 / 3.5 will probably be optimal, and will prob give you around a foot pound

How much will each reamer take off in a go? Do I need to have one for each 0.1mm increment? Because that could get spendy...

How about a calibre change to smooth it out. A replacement .22 barrel might prove straight forward.

Already have a silky smooth .22 HW95 bought from a member here, however I much prefer .177 for hunting unless at fixed ranges (e.g ambushing at a feeder) because of the more forgiving trajectory. The trick is finding or fettling a rifle of reasonable weight that's as forgiving!
Should have got it in full length rather than Carbine tbh.

[Shed tuner]

How much will each reamer take off in a go? Do I need to have one for each 0.1mm increment? Because that could get spendy...
.

they have a lead in.. typically around 0.2 - 0.4mm. Imperial 1/8" reamers are dirt cheap on the bay. You can also get taper reamers, which are fine, but you have to go from both sides, and are not so good on longer ported rifles like a 95.

so basically you just buy a 1/8" and say a 3.4mm and you are covered...

[eyebull]

they have a lead in.. typically around 0.2 - 0.4mm. Imperial 1/8" reamers are dirt cheap on the bay. You can also get taper reamers, which are fine, but you have to go from both sides, and are not so good on longer ported rifles like a 95.

so basically you just buy a 1/8" and say a 3.4mm and you are covered...

Thanks for that, reamers now on the way. I'll report back with results once I get round to it.

[TORNADOS7]

Don't would be my advice, they need weight up front buddy, I had a mate machine up a weight to replace one of the hair curler sections in the silencer, made a world of difference to the accuracy...

Drop the short stroke, leave the guides in place, add weight to the silencer and set @ 10.5-11.0...

Ps, they're not much better in .22 either although they will shoot @ 11+ easier...

[Racing]

In all honesty i fail to see the absolute "need" for a reamer in the application.
Just drill the thing out and be done with it i say.

Difference in performance is about nil to all deadly ppl.

[eyebull]

Don't would be my advice, they need weight up front buddy, I had a mate machine up a weight to replace one of the hair curler sections in the silencer, made a world of difference to the accuracy...

Drop the short stroke, leave the guides in place, add weight to the silencer and set @ 10.5-11.0...

Ps, they're not much better in .22 either although they will shoot @ 11+ easier...

Have a heavyish steel silencer on there atm, may try knocking up a weight for it but I do want to give this a go.
I've bought the reamers now, I have to

In all honesty i fail to see the absolute "need" for a reamer in the application.
Just drill the thing out and be done with it i say.

It's just about avoiding having burrs in the compression chamber that could become swarf in the future. If I could get to the other side then I'd just drill no problem.

[TORNADOS7]

Have a heavyish steel silencer on there atm, may try knocking up a weight for it but I do want to give this a go.
I've bought the reamers now, I have to

Fair enough buddy, out of interest what silencer are you running on yours , I'm also looking for a heavier silencer for my current .22/95k...

Ps, I'd thought about reaming the transfer port on my Xocet but decided against it in the end, the biggest difference was a reduction in piston weight, standard was 273grms and a proper tooth rattler, currently it's @ 255 and the difference in shot cycle is massive, so much softer/less aggressive than before, this gun has smashed just about every scope I've very put on it over the years, looking to reduce further still if I can, 240 would be nice...

[eyebull]

Fair enough buddy, out of interest what silencer are you running on yours , I'm also looking for a heavier silencer for my current .22/95k...

Ps, I'd thought about reaming the transfer port on my Xocet but decided against it in the end, the biggest difference was a reduction in piston weight, standard was 273grms and a proper tooth rattler, currently it's @ 255 and the difference in shot cycle is massive, so much softer/less aggressive than before, this gun has smashed just about every scope I've very put on it over the years, looking to reduce further still if I can, 240 would be nice...

Its a Sportswaffen Schneider 'SWS' branded one, it weighs 176.5g compared to 113g for the standard HW moddy and is about 25mm shorter and 3/4mm narrower than the HW. Less effective at actual moderation obvs.
As I said earlier my biggest mistake was getting the k version - I've spent a lot of time trying in various forms to get the perfect smooth shooting light/mediumweight Carbine in the smaller (and tragically less efficient) calibre, and came to the conclusion that in .177 at least, you can either have short and smooth, or light and smooth, or short and light, but you can't have all three without some serious engineering work and a sacrifice to the airgun gods.

[robs5230]

Its a Sportswaffen Schneider 'SWS' branded one, it weighs 176.5g compared to 113g for the standard HW moddy and is about 25mm shorter and 3/4mm narrower than the HW. Less effective at actual moderation obvs.
As I said earlier my biggest mistake was getting the k version - I've spent a lot of time trying in various forms to get the perfect smooth shooting light/mediumweight Carbine in the smaller (and tragically less efficient) calibre, and came to the conclusion that in .177 at least, you can either have short and smooth, or light and smooth, or short and light, but you can't have all three without some serious engineering work and a sacrifice to the airgun gods.

Getting the 95 right demands a fair few correct components and modifications to be done in harmony.
Doing modifications in isolation, or using the wrong modifications together, is unlikely to work.

Before you open out the TP, I'd seek further information from those who recommend this action, about other aspects of their setup. Spring spec / weight, spacers, piston sleeve, piston seal and preload etc.
You need to understand what will happen as a result of your intended modification, and what changes you may need to make in tandem, before making those changes

[eyebull]

Getting the 95 right demands a fair few correct components and modifications to be done in harmony.
Doing modifications in isolation, or using the wrong modifications together, is unlikely to work.

Before you open out the TP, I'd seek further information from those who recommend this action, about other aspects of their setup. Spring spec / weight, spacers, piston sleeve, piston seal and preload etc.
You need to understand what will happen as a result of your intended modification, and what changes you may need to make in tandem, before making those changes

Oh I'm aware that this on its own won't be a magic bullet. It currently has the stock spring but I'm prepared to fit a softer one if required (and I'm thinking it might be). It currently has a tbt ss kit and this can be removed if needed, and preload can be played with. Plus the newer style seal to be added. More muzzle weight.
Lots of variables at play, and if it needs to be stripped down a half dozen times to get it right then I'll do that. Basic aim is to get it running in the high 10s to low 11s with as little stress and drama as possible which hopefully will translate to shootability.

[Shed tuner]

I can think of no realistic scenario where opening up the 95's port to at least 3.3mm could be detrimental, except possibly a short stroke (20mm extension) to make a 6 FP bell target rifle.

[eyebull]

So today is the day for this, put a few pellets through the 95k to warm it up, and then a couple through the chrono - horrible shot cycle, and only 4.5 ft/lb!
Had to run a couple of other guns through it to double check, and they came out as expected. So must be a knackered piston seal, breech seal is looking a little flat too. Luckily I have replacements for both.
So time to get this thing stripped. Fingers crossed I get this sorted before it gets dark, otherwise it might have to sit until next Saturday for accuracy testing.