Polygon barrels for airguns

[salvin]

Hey Roberto, would not blame the barrel for those groups. Can be difficult to shoot a gas ram accurately - even though 2" at 30 sounds terrible.

Scope OK? Maybe it's moving about inside.

Also removing the barrel may be less than easy, although having taken a look at your site, it seems that you know your stuff quite well.

Belive me, I tried everything possible to make this rifle shooting better...but no way. For this reason I'm thinking to swap the barrel, it's a sort of last chance.

Probably part of the problem is the pellet choice; in this caliber the market is quite poor, only the Diana dome 19.75 give acceptable groups. Other brands/models are simply useless.

Anyway .25 barrels on springers/gas ram are particularly pellet-fussy, especiallly if you go up with the power (I own also a terrible W&S Patriot same caliber).
On pcp irguns things goes different, I shooted a Rapid 12/250 @ 50FP and it makes beautifull groups with 30 grains Baracuda (up to 100 yds or so...).

[hwtyger]

Is yr HW90 FAC or 12Ftp?
In FACtrim they usually shoot terrible unless you let off some pressure!
They're over pressurized from factory!
They should shoot well with either baracuda or FTT.
If you stíll wish to change the barrel, buy another HW one. About 72 euro's in germany..

[air-tech]

My take on this, Roberto, is that the barrel has nothing to do with it.

A smoothbore barrel can get better groups than that.

The gun's recoil on the other hand probably has a lot to do with it. As hytyger is suggesting, try de-tuning a bit.

If the velocity drops too much because it's a .25, you may consider buying a used, complete with breechblock, HW barrel off here, in .22. Not sure whether it would have to be a 90 barrel or if other HW break barrel guns barrels c/w breechblock will fit - you'll have to find that out for yourself.

Personally except in PCPs at 40-50 ft/lbs+, I am not a fan of the .25 - too much commitment needed!!

One other thing to check - the lockup of the barrel. *Possibly* the recoil may be causing the barrel to "open" which of course would be no good. However I would expect vertical groups in such case.

[salvin]

My take on this, Roberto, is that the barrel has nothing to do with it.

A smoothbore barrel can get better groups than that.

The gun's recoil on the other hand probably has a lot to do with it. As hytyger is suggesting, try de-tuning a bit.

If the velocity drops too much because it's a .25, you may consider buying a used, complete with breechblock, HW barrel off here, in .22. Not sure whether it would have to be a 90 barrel or if other HW break barrel guns barrels c/w breechblock will fit - you'll have to find that out for yourself.

Personally except in PCPs at 40-50 ft/lbs+, I am not a fan of the .25 - too much commitment needed!!

One other thing to check - the lockup of the barrel. *Possibly* the recoil may be causing the barrel to "open" which of course would be no good. However I would expect vertical groups in such case.

My 90 is FAC, actually runs @19FP, but have tested it from 15 up to 21..same story. Completely inconsistent.
Sometimes there are some good spots, but nothing special, average groups are always 1,5-2" (with the best pellets..).

Belive me when I say I've tried everithing: seals, gas ram seals, schrader valve, muzzle recrowning, barrel joining new washers, lapping the barrel and so on. Also tried a new barrel of same caliber...
Tested also a couple of different 90 same caliber but no difference.
I know about the recoil management, ma dont think this is the issue (I've a bit of experience, owning many other FAC airguns: Eliminator, Patriot, HW80, Diana 52...).

Really I think there are no other things to do..., except to test a new barrel, meaning a different kind of barrel. For this reason I was thinking on polygon, or may be at the Taylor's smooth-twist...

In my experience, the only springer in 25 that is capable to shot good groups at FAc levels (18-21FP) is the Diana 48/52; with a good tuning kit prints 1,5-2" at 50 yards...

So, make this rifle shooting better groups is becaming a real challenge for me.

every suggestion is well accepted

[air-tech]

Sell it Roberto!!

My 52, was frustrating for me, shooting the same groups as you shoot with yours, at 50M - under 2". I sold it... actually I did a deal on a 54.

I can get true sub-1" groups at 50M with the 54 (plenty of shots, not just a 3 shot "group").

Anything that shoots 2" at 30yd should be launched in a catapult, the group may be better that way...

[salvin]

Sell it Roberto!!
...

no...could be useful for short range ratting, very short range...something like the lenght of the stock. It wear a solid Ginb stock, perfect for smashing their heads

Sell it Roberto!!

My 52, was frustrating for me, shooting the same groups as you shoot with yours, at 50M - under 2". I sold it... actually I did a deal on a 54.
I can get true sub-1" groups at 50M with the 54 (plenty of shots, not just a 3 shot "group").
Anything that shoots 2" at 30yd should be launched in a catapult, the group may be better that way...

Yes, 48/52 can be a bit frustrating, but if well tuned are quite good springers.
I own an highy tuned 52 in 177 running 18-19FP quite well, able to print 1-1,5"@50yds. It's heavy and hard to shot but I like it anyway.
I dont like 54, lots have recoil absorption system issue...

[air-tech]

no...could be useful for short range ratting, very short range...something like the lenght of the stock. It wear a solid Ginb stock, perfect for smashing their heads

HAHAHA lol good one...

Don't know about the 54's "problems" whatever the issues could be would be very easily fixable. Saying so, not "defending" my gun - it really is not one of my favourites and I did a lot of work on it internally to make it acceptable to my tastes. It does around 22 ft/lbs in .22 and likes Crosman Premier a lot. I only bought it because I had had enough of the 52 and I got a good trade in deal - as long as it was for a 54

I still have a monster muzzle weight for the 52, in my desperate attempt to make it shoot more accurately. It was in .177 and with lightweight pellets, loaded for fun, I would often get some going supersonic!!

[stillair1]

I seem to remember Theoben were selling spare 90 barrels presumably with breech block a while ago.

[hwtyger]

Did you chrono it Salvin to check consistancy?
FAC HW90's, expecially with lots of grease inside, are prone to burnt pistons..
(seals). Might also check inertia weight, wether that's loose or not. Most don't work even when new..Makes it shoot a tad better.(less piston bounce).
What pellets did you try sofar?
I assume you knów you have to keep the stockbolts etc tight?