Calibre change on Rapid Mk2?

[Guesty]

I've got an FAC Rapid Mk2 in .20, and I'm thinking about swapping it over to .22.
It's got a Ben Taylor reg running at about 1950PSI, not a modified Theoben reg. Apart from the obvious barrel and mags, what else would need to be changed? I'd be after the most accurate barrel available, up to a maximum of 18" long. I assume a Career barrel would be best? If I did swap over could the reg be left alone, or would it need adjusting?

Thanks,

Guesty.

[R0B]

Hi Guesty,

You'd need to add a probe assembley to your list. You would probably be best taking advise from ben as to reg pressure, but I can't see why it would have to change.......you'd just have to be happy with whatever FT/LBS it was doing. You'll likewise have to apply for a variation to swap from .20 to .22. As for barrels, Theoben's own have always been good enough for me (but I am a naff shot). There are plenty of choices out there.........again, speak to Ben or Theoben. You could stick with a standard 16" barrel, you'd just get a few less shots and little less power........Oh, you might have to check the exit hole on your silencer will take a .22 pellet

Robin

[Guesty]

Thanks Rob.
It'd be nice to keep the reg the same pressure (to save a few quid!), but I suspect that with a longer barrel in .22 that I'd be too powerful to use AA Fields / JSB pellets. I think they'd be around the supersonic mark, which would make for awful accuracy?
C'mon you FAC Rapid guys, give me a clue.

Guesty.

[Rapidnick]

I would be interested to know why you would want to spend the money involved in changing? Most shooters doing the change go the other way FROM .22 TO .20 as they become convinced about terminal energy, downrange accuracy etc being better in .20. There is however no doubt that .20 ammo is expensive and that the choice is poor and that .20 shooters are vulnerable to a reduction in quality of their chosen pellet unless they buy enough to last them for ever-and who does that?
I own a Rapid 2 FAC in .22 set to 35 ft lb which gives me around 70 shots per fill with 21.3 grain BisMag pellets. I have contemplated a swap to .20 so I am really interested in your view. I have to tell you that this Rapid 2 is the BEST air rifle I have ever owned, it is really good-but so it should be and I haven't yet used the MFR which many people on this forum feel handles better.
I think you know now that to convert you will need a new barrel, magazine and probe. As you also know, the longer barrel is more economical with air and that is what Theoben fit as standard to a FAC Rapid 2. Some people prefer the handling of the shorter barrel in FAC Rapids, I really don't mind either. Even with the longer barrel you should be OK with the JSB pellets (16 grains) because at, say, 35 ft lb-the formula says 992 fps but Bismags are certainly fine (860 fps) and that is what I use. Talk to Ben- if you go ahead with this he MUST be the man to advise you and to do the work.

[baz]

I recently fitted a HW 21 inch barrel to my FAC Rapid (.22) reason being that Ben Taylor has them ready to fit and at reasonable price

It shoots superbly using JSBs or Bismags, I have previously fitted quite a few makes of barrel to Rapids, Lothar Walther are a good choice too, and probably the best value of the lot would be a BSA as they are very good value for money and easily available

baz

[Shed tuner]

Matt, no way will it go anywhere near supersonic if you keep the same reg pressure, more like 900-950 fps.

Personally, I think the arrival of the 16 grain JSB and all it's clones (AA/Daystate/Ripp) has blown away the argument for .20 at FAC levels.

It used to be that a 14.3 grain .20 premier with a BC of 0.032 represented the best balance of trajectory and downrange energy. However, with the JSB having the same BC, and with the extra efficiency of .22 over .20 making up for the 30 fps that the JSB would otherwise be down by, they have the same trajectory, but the .22 has a tad more power and makes a bigger hole.

Also, of course, you have far more alternative pellet choices.

at 12 FP, .20 gives you another 5 yards (all things being equal) over .22.

In addition to my own BC testing, have a looksee here....

http://www.straightshooters.com/ourtake/sup12grid.html

NB the Daystate figure of 0.028 is rather low - 0.032 is more usual



HTH - JB

PS AXL, why .177 FAC ? Would be 24 FP, approx 1000 fps with 10.5 grain stuff (BisMags or CPHs) .177 is a very small hole with nil expansion, doesn't increase your range as much as a .22 FAC would IMHO (i.e. killzone remains small as damage is limited)