Reply With QuoteI have an extension socket with a holder for it. Plenty long enoughOriginally Posted by look no hands
Registered User
as you know I'm not saying it doesn't work, just that it's not optimal...The first British built Magnum springer of the 1970s, the Webley Vulcan, had a 2.5mm transfer port.
I've used 2.5mm ports on a number of guns without problems.
Always looking for any cheap, interesting, knackered "project" guns. Thanks, JB.
Registered User
I have an extension socket with a holder for it. Plenty long enough
Always looking for any cheap, interesting, knackered "project" guns. Thanks, JB.
Even better looking than a HW35
Oh you lucky lucky bas****I have an extension socket with a holder for it. Plenty long enough
Pete
Far too many rifles to list now, all mainly British but the odd pesky foreigner has snuck in
Even better looking than a HW35
Well I've been playing around with one of my BSA Challengers today and thought I'd measure the transfer port whilst the barrel was off, well the length is 13mm and diameter is 3.3mm, I bought some extra long drills the other day ranging from 3mm to 4mm., so it would be interesting to see how efficient those measurements are for that rifle.
Pete
Far too many rifles to list now, all mainly British but the odd pesky foreigner has snuck in
Lost love child of David Niven and Victoria Beckham
No mention of calibre...does it not influence the optimum size of TP required?
Even better looking than a HW35
Sorry .22 with a 10" barrel.
Pete
Far too many rifles to list now, all mainly British but the odd pesky foreigner has snuck in
Registered User
Get yourself a cheap pin vice and hammer a long steel rod up the back end. Make sure you wrap the widest part in tape so it doesn't scratch the inside of the cylinder.
Professional biscuit dunker ;)
Been out of the game for a long time now and can’t find any of my old notes on 77k with a 25mm piston. What’s the best starting place for these? 3.6mm springs to mind but I don’t trust my memory lol. .22 if that maters...
Lost love child of David Niven and Victoria Beckham
I wasn't referring to your post specifically just the OP's theory in general.
Even better looking than a HW35
Oops!
And there's me thinking you cared
Pete
Far too many rifles to list now, all mainly British but the odd pesky foreigner has snuck in
Registered User
holy revival - bruce is back from the dead - long time mate, how are you ?
Start with 3.4 and test
Always looking for any cheap, interesting, knackered "project" guns. Thanks, JB.
Professional biscuit dunker ;)
thanks Jon, nice to be backholy revival - bruce is back from the dead - long time mate, how are you ?
Start with 3.4 and test
I scrolled the page up too fast and it fell off
I know nothing about this subject as my following question will indicate
I'm assuming the transfer port is directly behind the pellet, so why aren't the ports the same size as the pellet calibre?
Registered User
'cos that'll be too bigI know nothing about this subject as my following question will indicate
I'm assuming the transfer port is directly behind the pellet, so why aren't the ports the same size as the pellet calibre?
Interestingly the old pre-wat BSA underlevers were made like this, as the loading tap was reamed through. They benefit massively from being sleaved down to 3mm or so - more power, less harsh..
Another practical reason is to stop your pellets falling back into the cylinder through them
Always looking for any cheap, interesting, knackered "project" guns. Thanks, JB.
Holder of nine NSRA gold medals
Any void space has to be filled with the air that the piston is compressing, so a port larger than necessary will also reduce the maximum potential pressure.
A while back I made a number of screw-in ports for a chap who was experimenting with a Walther rifle. The screw-in ports started out as brass grub screws that would screw into a tapped 'port', and they were all primarily drilled 2.0mm. Then with a taper reamer I opened them out, one by one, from 2.1mm in 0.1mm increments up to 3.0mm which was the largest he wanted. I reamed them back to front, if you follow me, so that the hole in the port diverged marginally, as this ought to give a better flow characteristic than a port that got smaller.
I made the taper reamer from silver steel and the taper was chosen so that I could easily judge the bore size by the depth the reamer had entered.
I think a taper reamer is a better way to go than a twist drill; it would be remarkable if a twist drill was that accurate, as any imperfection in the grind will make it cut oversize.
www.shebbearshooters.co.uk. Ask for Rich and try the coffee
Posting Permissions
