FAC air whats the benefit ?

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darran77
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FAC air whats the benefit ?

Thu Aug 23, 2018 5:45 pm

Just what extra do you get from an FAC air rifle?
So we have the oppotunity of getting an FAC air rifle, but where do we start i like my TDR in .177 and with the flat trajectory i can take (not bragging) bunnys out to 50+ yards easily (in the perfect weather conditions) , and if i was to up it to FAC would it be better for distance and accuracy etc , or would i be better going up in calibre,22,25 ++ and would a rifle in this larger calibre have the same flat trajectory as my .177. The other thing is what about slugs would they be better than the heavier diablo pellets.
Lots of questions before i buy a 22lr.
Daz
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143granville
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Location: barwell leicestershire .

Re: FAC air whats the benefit ?

Thu Aug 23, 2018 7:51 pm

I went for .22 rabbits out to 70 yards knock down power
is so much better .
on pigeons at 60 yards the other week not hardly a flap
I am on 27 flb on the theoben can get 44 if I need it not
as accurate at 44 plus so much air used for the same job.

zero at 45 yards so from 20 out to 50 yards very little hold under or over .

using 16 grain pellets seem most accurate .

atb paul.

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tonyc
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Re: FAC air whats the benefit ?

Thu Aug 23, 2018 9:18 pm

You would need about 20ft lb in .22 to get the same trajectory as a 12ft lb .177. FAC will give higher velocities and additional range... +25 yds maybe.

The velocity limit for a diabolo pellet is around 920-950fps. Beyond this the pellet loses stability and accuracy. This puts the practical power limit at around 18-20ft/lb for .177 and 36-40ft/lb for .22, depending on pellet weight.

At the same muzzle velocity, the .22 will give a flatter trajectory than .177 as it has higher ballistics coefficient and holds its energy better. For example, 18ft lb .177 will have roughly the same POI at 70 yds as 30ft lb .22. But, as granville says, the .22 will have more knock down power: over twice the energy at 70 yds (2x at 50 yds, 2.5x at 80yds).

I don't see much point in .25 in UK. You'll won't get longer range compared to .22 and the extra energy has no use as there is no legitimate air-rifle quarry that needs it.

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TenMetrePeter
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Location: Luton Beds UK

Re: FAC air whats the benefit ?

Fri Aug 24, 2018 6:10 am

Wasn't mentioned in detail but expect to get only 20 to 40 shots depending on what model you get.
S400 MPR Precision with TMP alloy stock.

https://www.youtube.com/channel/UCaCf9G ... A-mGhZQlGw

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tonyc
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Re: FAC air whats the benefit ?

Fri Aug 24, 2018 3:53 pm

Air Arms claim the new regulated 510 will do 60 shots at 32ft lb, 50% more than the un-regged FAC. I don't know if AA are doing a regged FAC TC (don't like the look of them) but that would double the shots. If you want much more you will have to go for a buddy bottle like Theoben... about 400 shots I believe.

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143granville
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Location: barwell leicestershire .

Re: FAC air whats the benefit ?

Sun Aug 26, 2018 7:23 pm

60 shots on the theoben mk1 unreged .
but 44 flb 36 .
think .22 gives you more chose of pellet as well
.25 i would leave for that reson .

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darran77
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Re: FAC air whats the benefit ?

Fri Aug 31, 2018 3:49 pm

Sorry about the delay in getting back to the post, been hunting bunnys.
regarding power then i can see how the .22 would be superior.
However
The velocity limit for a diabolo pellet is around 920-950fps. Beyond this the pellet loses stability and accuracy. This puts the practical power limit at around 18-20ft/lb for .177 and 36-40ft/lb for .22, depending on pellet weight
using a slug instead of a diabolo would this be more stable in flight and been heavier hold energy down range ?
daz
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tonyc
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Re: FAC air whats the benefit ?

Fri Aug 31, 2018 8:32 pm

Diabolo pellets rely mainly on the skirt to achieve stable flight whereas slugs rely on gyroscopic forces. So slugs need a higher twist rate than the standard air rifle barrels - from memory I think 1 in 12 down to 1in 9 whereas air rifles are typically 1 in 16 to 1 in 18. There is a barrel twist calculator for subsonic bullets here http://www.geoffrey-kolbe.com/barrel_twist.htm

Pellets with an intermediate profile (there is a name for it but I can't remember) like the JSB Jumbo Monster are possibly the best compromise... but I have no direct experience.

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