Hatsan BT65 Caliber Change

[jamjam]

Newb question here: what is involved in changing over from a .177 to a .25 on a BT65?

Hatsan was no help, citing something about serial numbers on the breech, and how they couldn't do it. If I just order parts (hopefully all the necessary ones) without stating the reason, it shouldn't be a problem.

So what would I need?

Thanks!

[Long_Gun_Dallas]

I'm willing to bet the receiver is bored for each sized barrel specifically.  As well as the ports being sized for that caliber, likely different hammer springs, maybe valve springs, too.  If they say it can't be done, that doesnt mean it cant.  It just might be more trouble than it's worth.

[Rallyshark]

Hatsan is correct about the stamping on the breech from a legal standpoint.  Some areas won't allow .25 or even .22 air guns, so Hatsan has to cover there rear on that front.  Believe it or not, the only real difference between calibers is the barrel, probe, and magazines.  A .25 barrel will fit in there just fine.  All barrels are the same diameter.  Hatsan changes as little as possible between calibers on their guns.  So yes, you can do it, but I don't know if it would be worth the trouble. 

Theoretically, all you'll need is a .25 probe, barrel, and magazines.  There are parts that MAY need to be altered, like the transfer port, and possibly the hammer spring adjusted?  I think it would just be easier to just buy a .25, or even sell the .177 to help finance the .25.  You're probably looking at $150+ in parts to do the change. 

[Verminstalker]

You would also need to change the parts on the LH side of the receiver that rotate the magazine since the different calibers index at different points due to round count.

[jamjam]

Ooh! That last one would have slipped past me!

Thanks for all the responses. The parts may cost a fair amount, but if I put it off for a while, as in I may only do this at a future date, it hopefully wouldn't seem so bad. I was just considering this if I could get a BT65 at a really good price. The thought of a cheap 65 FPE is pretty appealing.

[Hobbyman2007]

James ,

There are quite a few .25 caliber guns that will do 65FpE quite easily . For the most part ports and hammer spring will get you there . If you’re serious about making power the Kral bottle guns would make a really good candidate IMO and are available in Canada. Send me a PM if you need a fellow Canadian to up the power on your gun .

[fatmike]

I have a bt65 .25 with a wood stock that was 300$ us.  Wait and watch for sales on hatsan usa. Wonderful gun but a bit heavy.

[Animmo]

Sorry for beeing late to the party.
I have a question, what if you want to do the opposite? you want to switch your hatsan bt65 .25 barrel with a .22 barrel.
Would that be possible? I guess you would just have to reduce the power so you won't shoot supersonic. Or what do you guys think?