A bit boring really

[Dornfelderliebe]

One especially but not exclusively for engineers & tuners.
Can a barrel be bored out slightly in the case of an imperial .25 (.243) to the modern 6.35mm which to my uneducated mind, might not mean loosing the rifling.

Looking at fired pellets I never see rifling marks on the head but does any one with a BSA quarter bore see this with metric 6.35 pellets.

I guess taking a .22 barrel out to .25 would be a step too far.

[Blackrider]

Sounds very ambitious but I know your pain having past encounters with that particular caliber !
Good luck !

[Waddy]

I'd be interested to hear an answer to this. I've got two quarterbores, a Hatty 55 that is 6.35 and will shoot any .25 pellet, and a Sirocco with an Impact Airairms .25 that is VERY fussy & even what it will shoot has to be more or less rammed into the breech. So much so that it's one of the main reasons I'm swapping the barrel back to the original factory .22 one.

The other solution is a pellet sizer, but it's a fairly tedious task.



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[Shed tuner]

a barrel is basicaly made by drilling out the bore, than pulling a broach thru it to create the rifling. (ok there are alternate ways, but think of the context here).

so could you drill it out slightly larger and have new rifling done ? Sure, but I guarantee it'll cost way more than a new barrel.

One thing I've done in the past is bored out a barrel to 8mm, and inserted a skinny 8mm OD barrel liner in your chosen calibre. Easier with shorter barrels. and only sensible if new barrels are not readily available and to preserve originality. Harper did a similar thing with brass barrel liners in .25

HTH - JB

[angrybear]

One especially but not exclusively for engineers & tuners.
Can a barrel be bored out slightly in the case of an imperial .25 (.243) to the modern 6.35mm which to my uneducated mind, might not mean loosing the rifling.

Looking at fired pellets I never see rifling marks on the head but does any one with a BSA quarter bore see this with metric 6.35 pellets.

I guess taking a .22 barrel out to .25 would be a step too far.

.243" is iirc 6.18mm so in theory not much needs removing, the problem would be finding a reamer long enough to go through a barrel.
I could never use modern 6.35mm pellets as they got shaved trying to load them.

Have you tried Marksman .25 pellets ? 6.2-6.25mm from memory & were accurate in my Supersport.

Waddy : have you tried JSB kings ? my .25 Rapid is rubbish with anything else, but again if it's too tight you might be damaging the pellet forcing it in,
so Marksman as above being a smidge smaller might be worth a go.

[look no hands]

I had the same problem with a .243 BSA Lightning barrel, it was so tight that even BSA Pylarms wouldn't fit properly and still needed a pellet pusher to seat home, I even reamed out the breach a bit, I sold it on and bought a proper .25 BSA Lightning barrel, not had any problems since, it only seems to like JSB/Air Arms .25 pellets though.

[BC312]

The old bore size you don't want will be the reamer or drill guide. Rather than broach the rifling in the new hole which will have to be perfectly smooth it would be best to open up to fit a liner, if not satisfied then you can swap a liner back to another calibre.

[rapidresponse1]

very interesting

[angrybear]

I had the same problem with a .243 BSA Lightning barrel, it was so tight that even BSA Pylarms wouldn't fit properly and still needed a pellet pusher to seat home, I even reamed out the breach a bit, I sold it on and bought a proper .25 BSA Lightning barrel, not had any problems since, it only seems to like JSB/Air Arms .25 pellets though.

Not sure if you're aware, but the size of Pylarms got changed by Gamo and initially the tin was the same, which caught people out.
I reported it to BSA who were unaware at the time (2012) and that was when the label was changed, I posted a thread about it at the time.

[look no hands]

Not sure if you're aware, but the size of Pylarms got changed by Gamo and initially the tin was the same, which caught people out.
I reported it to BSA who were unaware at the time (2012) and that was when the label was changed, I posted a thread about it at the time.

I did buy a few tins at the time and also noticed the slight change of tin design, the .243 barrel I bought from Knibbs was a 'Seconds', so I expect it had failed QC by BSA for maybe being to tight and ended up in Knibbs spares and got sold off cheap.

[evert]

Barrels can be bored out and rifled to larger diameters. This requires specialized equipment and a lot of skill.
Broaching existing rifling to larger diameter is perhaps theoretically possible but I have never heard that anyone has done it.

The rude answer is that when you need to ask about these things, the equipment and skills needed are not readily accessible to you,
and anyone able to do the job would charge more than the cost of buying a new barrel.

The short answer is that you should just sell the barrel you have and buy the barrel you want

[Dornfelderliebe]

Barrels can be bored out and rifled to larger diameters. This requires specialized equipment and a lot of skill.
Broaching existing rifling to larger diameter is perhaps theoretically possible but I have never heard that anyone has done it.

The rude answer is that when you need to ask about these things, the equipment and skills needed are not readily accessible to you,
and anyone able to do the job would charge more than the cost of buying a new barrel.

The short answer is that you should just sell the barrel you have and buy the barrel you want

Thank you Evert and Every body who has answered.
Sadly the barrel I want ( to start a winter project ) is no longer available new. I want to make a .25 Meteor using a S/H BSA barrel and wondered whether I could open up an imperial sized barrel to fit the H&Ns but will settle on Marksmans as per Angry bear's advice.
Both makes of pellet work well in my 99 already.

[Shed tuner]

as myself and a couple of others have said, you could bore out your existing barrel and have a liner fitted.

[Waddy]

I found the marksman pellets fitted the bore but were inaccurate. Another chap at the range also had & .25 and also found them to be poor at hitting the target, he was using a really good PCP, so should have been more accurate.


They are very cheap though, I got 1000 for about 30 quid off the bay.


@Angrybear, I've not tried JSB kings, they are a tad heavier than the H&N FTT but lighter than the Barracudas so probably worth a try, thanks for the suggestion.


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[Dornfelderliebe]

I have taken Shed tuner's advice and ordered an FX barrel liner. A 380 mm 6.35 Superior standard, apparently the Heavy version is meant for slugs this version should be good for lighter pellets.

I could not find any standard versions for sale in blighty and the others seemed to be out of stock anyway. This was ordered from Spain.

IF it gets here from Spain and IF my local engineer who did my Meteor hinge bolt conversion will oblige my winter project will be back on.

Now that I have spent £91 can any body tell me about FX barrel liners quality wise.