.25 barrel dilema

[ped]

i'm in a real dilema with how to proceed with a .25 build
in the uk my prefered barrel blank has been out of stock for 5 months i recently got a drop in barrel from al and about the same time got a s/h .22 bnm breech which had come with a .25 mag
a light bulb went on in my head and a .25 middle was ordered from sergio,now i've got all the parts together i'm faced with a difficult choice
to fit al's barrel to the bnm breech i'm going to have remachine it as the tp hole doesn't line up
my options are
1 remove the o ring groove on th barrel
pro's a couple of mins to do
cons altering a extremly well engineered barrel that then would have to be completely duplicated to use on other builds
don't really want to do this
2 make two barrels out of it
pro will give me a .25 pistol barrel and i'll be able to use the longer part on the rifle
cons .25 in a pistol with our power regs is a bit hit and miss plus i really want between 14" and 18" for the rifle barrel,my .25 king rat has a 10" barrel but i have to run at 1350psi to get the power up to 11fpe and i want to run at 800psi
don't really want to do this
3 use al's barrel on another build
pro's ive a 2260 hpa build thats been sat in the cupboard for 12 months that it would fit on luverly
cons means finding another .25 barrel which is finding hard to do although i did see on the b&a site that they have 18" .25 barrel machined to fit the crosman breech fo $45 but unfortunately they won't now ship to the uk at all
this is my choice at the moment as al's barrel is extremely well machined and i'll struggle to duplicate it and i wouldn't feel right altering it
so my question is what would you do
ped

[K.O.]

Ped all I can say is I would have a very hard time cutting the barrel...

[breakfastchef]

Use the barrel from Al for its intended purpose on another build. If you cut it you will feel sick afterwards. The same barrel could be used on future builds if you keep the transfer port intact.

Are BSA barrels not available to you? I would think those would be pretty awesome.

[bgmcgee]

I have to agree on not altering that gipetto barrel. You know if you do you will be kicking yourself.  Time will come for another barrel.

[ped]

thats pretty much what i'd decided when i started this thread but thanks chaps for confirming i was making the right decision
i've now fitted al's barrel to a steel breech and put it on a 2260 tube for a future build
so now i'm looking at my options the bsa barrel is my first choice but they have been out of stock for quite a time,the walther barrels are a bit too pricey so the 18" one from b&a is looking favourite at the moment
ped

[Gippeto]

Odd.

Did Sergie say which barrels his breech is set up to use? Doesn't sound like a Marauder barrel would drop in either. (1/2" on the od....transfer port is ~ .050" further toward the muzzle than the 13xx/22xx barrels.)

While I realize the issue is essentially resolved, I would prefer you be able to build as you had planned. Is it perhaps possible to alter the .22 cal "middle" to work with the barrel I sent?

Some pics if you've the time???

And...thank you for the kind words.

Regards,

Al

[ped]

i'll get some pics later al i tried a std 22xx barrel and the port is 2mm(approx) too far forward due to the .25 mag being thicker the .25 middle block has to be thinner so the tp hole is virtually at the point where the barrel hits the back of the middle block
i looked at reaming the middle block back but i would then loose the strength where the magazine locates
what i'm planning is to bore into the middle block 2mm with a 9mm endmill then step the barrel at the breech(bit like a muzzle on a 13xx barrel) this way i can still have a bit of a leade before the tp and still have structual integrity for the magazine rotating boss i need to set the breech up with the .25 block and probe to see where the probe is in relation to the tp
i never intended for your barrel to be fitted to a bnm breech al the opportunity arose when i got the s/h breech with a .25 magazine so it's no hardship and it looks pretty good on the 2260, i'm now thinking of leaving it polished as i do like the black and silver contrast
ped

[ped]

bit of an update on this i managed to get one of the b&a barrels(many thanks to david for sending me it) and machined the end down to fit the bnm breech
this build has thrown more opportunities to change things(problems) than any i've built in the past first of all the new bnm middle set came with a rear handled probe not the side handled probe -sergio sent me a replacement straight away top man
next i found that two of the magazines wouldn't index properly and pellets were difficult to load -took a couple of thou of the boss that the magazine sit on and used a tapered ream on the middle block ream which solved that
when i started testing for power i found that even with the restrictive bnm tp and a std spring i was way higher than i'm allowed -- i lightened a std hammer to 42g which brought the power down but was still a tad high,so i made a 32g one (this is made from the front part of a std hammer and an ally sleeve with a screw in pin) which dropped the power to 9fpe so a brass spring guide with 4mm of preload built in was added to give 11.3fpe with 31.02gr barracudas 
now here's where my problems really started i made a shroud and went to the range to try and zero her using all the different types of pellets i've got and after trying them all couldn't get any to group (15yds rested) the targets looked like i'd shot them with a shotgun- i removed the shroud  no change so i tried a couple of different scopes still no change, i tried a single shot tray  no improvement
thinking i must have a burr in the leade that i hadn't seen when i checked it i chambered a pellet and pushed it all the way through the barrel(when i checked earlier i pushed it back through from the muzzle )i found the pellet undamaged but my accuracy problems were due to two tight spots at about a third and two thirds along the length -i first lapped the barrel with some fine wet and dry at the two points which eased the tight spots then fire lapped the barrel with fine grinding paste(this isn't the best way to do this but was all i had)
i when i tried it groups had tightened up with some pellet giving 3 shots in one ragged hole then two fliers, next step i decided to try choking the barrel muzzle and redoing the crown (which appeared to be ok) this improoved some pellets but made one brand worse and still wasn't acceptable
as a last resort i decided to chop the barrel at the last choke point which has done the job and  not wanting to waste a 71/4" piece of barrel i machined the offcut down to 7/16" before i cut it off so i now have a pistol barrel as well
chopping 71/4" off the barrel only lost me 30fps so that supprised me as i was expecting to lose double that
just got to make a new shroud and bring the power up a bit
ped

[targettgii]

That was a handful of work ped you got it straight though good job.

[ped]

cheers tom i think all the work was worth it but i must admit i nearly scrapped the barrel
a few pics of the targets first one is the first test results the second is after the barrel had been lapped and the muzzle choked and the last one is after i chopped the barrel
ped

[ped]

a few more pics these are as she looks now without the shroud and the new .25 pistol barrel and breech which is now ready to fit
ped

[droid]

Cracking job mate.

The mad scientist won in the end

[bgmcgee]

Gosh darn bunch of work there ped. But looks like the final results were well worth the effort.  Cool looking shooter you got there sir.

[targettgii]

Great looking shooter ped well worth the effort.

[K.O.]

Lot of work but in the end .

I used a BnA .25 barrel on my project also luckily I got one with no tight spots and is pretty accurate at 25 yards. I will be getting  version 2 of the

valve soon... I love shooting these things but have found out I have a heck of a lot of fun building them also...