.177 FAC.....

[andyfr1968 772]

Hi, folks.

 

Does anyone have any exprience with .177 guns running at around 22ft-lbs??

 

A mate of mine recently got his FAC changed with a slot for airguns added and I'm trying to help him set up his rifle. The problem we're having is finding a suitable pellet.

 

We've tried all the useual suspects, RWS, AA, H and N etc and what we're finding is that they're all fine up to around 30 yards and then the groups start to fall to bits, by the time they're out past 40-45 yards, they've all opened up from around half an inch to anything up to 4 inchs...

 

All the pellets we've tried are mid weight that group anything like, around 8.5 grains and it's spitting them out at around 1100 FPS. We've tried heavy pellets, JSBs, Barracuds, Loguns and it just does not group at all with any of them

 

HELP!!!!

 

Cheers.

 

Edit to add.... The gun's a Diana 52 and we do have access to a chronograph.

Edited January 15, 2011 by andyfr1968

[zini 1,939]

Hi Andy,

 

i would try Bisley Magnums mate.

 

My FAC Storm running at either 24 or 54 FP loved them.

 

Si

[stoaty 171]

tried Bisley magnums their usually just the job for fac .177??

Stoaty

[stoaty 171]

beat me to it Zini lol

Stoaty

[andyfr1968 772]

Thanks, Lads but the Mags are exactly the same as the Baracudas we've tried and the gun just doesn't seem to like them at all

[millsy44 72]

Drop the power down until you find accuracy, you might have to sacrifice a few ft lbs but itll be worth it for the improved groupings try 18 ftlbs or round about that area.

Edited January 15, 2011 by millsy44

[pianoman 3,584]

Hi Andy.

Spring or PCP? What make?

 

Your chief problem here is the level of power. 22ft/lb is very strong for .177. Maybe, it's a tad too strong.

 

Chances are the ammo you've tried is not gripping the rifling properly, but skidding over it and losing gyroscopic stability at targets over 30 yards range. When I got into FAC air .177 with my TX200HC, my gunsmith warned me about how power levels higher above 16 ft/lbs are very difficult to get a stable enough pellet for. My TX200HC is a shade under 17ft/lbs and it's very powerful and utterly accurate with 4.51mm AA Field. If you cannot find a stable enough pellet, you are going to have to reduce the power level mate.

 

ATB

 

Simon

[andyfr1968 772]

Thanks, Simon and Millsy.

 

Sorry, lads, editted to add it's a Diana 52

 

It's an odd one this, we did some testing on it today with Baracudas, Dymnamic TM1s (which my own 52 loves...) and JSB Exact 8.44 grain....

 

Over a ten shot string the JSB's averaged 1092 FPS, 22.35ft'lbs, Dymnamics 944 @18.8, Baracudas 907 @ 19.44. There was no more than 12 FPS difference between any of the individual strings.

 

All of the heavier pellets group OK for plinking but not anywhere near what I'd call well enough for field use, around 2 to 3 inchs at around 50 yards but their flightpath is at least consistant.

 

Out of all the others we've tried so far, H and N FTTs and RWS Superfield group the best, pretty much a one hole group at 30 yards but by the time we've moved out, they're out to anything up to 4 inchs...

 

I guess we'll just have to keep on trying....

 

Cheers.

Edited January 16, 2011 by andyfr1968

[sureshot11 1]

My Rapid at 21.5 likes Crossman prems 10.5gr the ones in cardboard box not tins will do pellet on pellet 50 yards .

[J Darcy 5,871]

Tell him to get a rimfire instead. All that power won't make him a better shot IMO.....

[andyfr1968 772]

My Rapid at 21.5 likes Crossman prems 10.5gr the ones in cardboard box not tins will do pellet on pellet 50 yards .

 

Thanks, Sureshot, we've not tried those yet. I had a 52 on ticket in .22 many moons back and Premiers were the only pellet it liked. I'll tell him to have a look on ebay

[andyfr1968 772]

Tell him to get a rimfire instead. All that power won't make him a better shot IMO.....

 

He already has one but on one of his shoots there's a footpath issue, so they'd only pass the land for airgun.

 

You're dead right though, power's feckin' useless if you can't put it in the right place

[ghillies 209]

you'll find eather barrels too short, or the velosities are at the 'sonic' band, depending on pellet/barrel theres a velocity band of 950 fps to about 1200 1300 feet persec, its basicaly flying the pellet on the sound barrier boom, accuracies poo'd up a bit. drop or raise the power... match the barel and pellet... acuracy will get better, next is the gun up to it? could be sporadic spring/piston/cap etc or just the pcp internals not being up to realeasing that mutch, so a huge power inconsistancy pellet to pellet.(try 17-18fps...and tune it.)

 

if you search the net, ive long lost addy, you'll also found the boating effect and tail effect, or something like that. sub 12fps you need a good skirt, fac a good head, or something like that. as the power goes up theres a fraise to exsplain it....the pellets spread up the barrel.

 

 

theres more...but not for public intrests for obvious reasons. (consult your gunsmiths lol....if they cant sort it no bugger can, or you got the rong person).

Edited January 15, 2011 by ghillies

[andyfr1968 772]

you'll find eather barrels too short, or the velosities are at the 'sonic' band, depending on pellet/barrel theres a velocity band of 950 fps to about 1200 1300 feet persec, its basicaly flying the pellet on the sound barrier boom, accuracies poo'd up a bit. drop or raise the power... match the barel and pellet... acuracy will get better, next is the gun up to it? could be sporadic spring/piston/cap etc or just the pcp internals not being up to realeasing that mutch, so a huge power inconsistancy pellet to pellet.(try 17-18fps...and tune it.)

 

if you search the net, ive long lost addy, you'll also found the boating effect and tail effect, or something like that. sub 12fps you need a good skirt, fac a good head, or something like that. as the power goes up theres a fraise to exsplain it....the pellets spread up the barrel.

 

 

theres more...but not for public intrests for obvious reasons. (consult your gunsmiths lol....if they cant sort it no bugger can, or you got the rong person).

 

I was wondering if it may be velocity related, Ghillies, as I know it's around the trans-sonic area and funny things can happen to a projectile at those kind of speeds

 

If we can't find a pellet that works the way the gun is now, I'll start taking coils off the spring one at a time and keep on testing with a lower power...

 

Cheers.

[pianoman 3,584]

Well an FAC springer does not like the heavyweight Bisleys, that's pretty certain. I'd agree with your decision to reduce power in the spring. 22-plus Foot Pounds output, while perfect for .22 spring rifle, is way too much power for .177 calibre in my humble opinion. Get her power down towards mid teens and she'll sweeten up I'm certain Andy. Great rifle for it to begin with mate.

 

Simon