Username:

Password:

Author Topic: Gamo CFR IGT with a difference.  (Read 532 times)

Offline Novagun

  • NZ Airgun
  • Hero Member
  • *
  • Posts: 618
  • Mana 9
    • View Profile
Gamo CFR IGT with a difference.
« on: September 13, 2016, 04:52:09 PM »
Mr Gamo had a carbine version of the CFR. A nice short compact rifle.  The look of it took my fancy and I have borrowed it for a while to have a play. Trouble is that I will have to give it back.

The rifle has had the barrel shortened for some reason by about 150 mms. The trouble with that is that the cocking underlever got shortened by the same amount so that the original muzzle break and cocking lever catch could be used. That made it a two handed heavy effort to cock and impossible for someone of slight build.  The barrel is dated 2010.

I had misgivings about the rifle but loaded up and bang. It was bad. About 60 mm groups at 12 metres.
My first thought was the plastic muzzle brake so off that came. Quite easily. Whoever shortened the barrel has had the barrel in a lathe and reproduced the splined tit that holds the brake on the shortened version and the similarly the end of the cocking lever. It was a tidy turning job and no marks on the as new bluing.

I looked at the muzzle and the chamfer on the crown has been reproduced not quite concentric with the bore. I am not sure how much of a detrimental effect this has, if any. I noticed glints of light on the crown that I thought were sprags on the rifling from turning. The magnifying glass showed that the edge of the chamfer was pitted. I think the turning tool has broken out tiny chips of steel. That ruined the crown. So with the gentle use of a sharp twist drill, turned by hand,  I have taken off a sliver of steel and cleaned it up. A polish with a brass screw and compound has it as good as I can get it. It was surprising how soft the steel in the barrel is and how easily and cleanly the sliver pared off. There is nothing I can do about the off centre chamfer.

Next was good barrel clean. A flood with turps and lots of patches. There was residue of the brown rusted preventative in the barrel apart from dirt.

The rifle is fitted with a Gamo 3 – 9 x 40 non AO scope. Pretty good. I suspect that parallax is set at about 25 to 30 yards and that is ideal for the rifle.
A proper airgun scope that is every bit as good as any budget scope. By that I mean excluding the expensive ones favoured by the  FT  chaps. So far ahead of my  4 x 32 Centre point. It does not have mil dots and has a solid illuminating centre dot at the centre of the cross hairs. Clear picture even at the edges of the field of view. Perfectly suited to the rifle. Just good.

A few shots showed the rifle to be shooting quite well. About 10 – 12 mm groups at 12 metres. That I think could be improved on by finding the right pellet. Maybe fatigue from cocking didn’t help. Still very hard to cock.

The cocking lever had to be lengthened so I have sleeved a length of aluminium tube over the end and secured it firmly so there is no movement. A steel tube sweated on would be better but steel would put more weight on the end of the lever. If the change is to be permanent I have an old CFX lever that I can swop over. The lever is now 140 mms longer and the rifle is cockable with one hand.

To accommodate the extra length of the lever I have shortened a Gamo muzzle brake by about 60 mms and cut the bottom off it so the lever, now minus the spring loaded catch can close up to the barrel. It is held closed with a plastic clip. Same as my CFX.

I am not happy with the muzzle brake because they are made in three pieces that slip together and the grub screw that holds the brake to the barrel holds everything together. It is not 100% rigid. If it rains tomorrow I will get a piece of Delrin and turn up what I prefer on the muzzle.

So far accuracy has improved, cocking effort is now manageable. The black plastic stock is comfortable, the thumb hole/open pistol grip is very nice to use. The sight of it grows on one with familiarity.

Power is quite good. The radiate test shows penetration to be about the same as a Challenger with the CFX rolling breach so comfortable recoil and I suspect enough for rabbits and possums.
Photos to come when I sort out the home made muzzle brake.

So that is what I did on a dismal cold Wellington day.
« Last Edit: September 14, 2016, 05:39:57 AM by Novagun »

Offline Davey

  • NZ Airgun
  • Hero Member
  • *
  • Posts: 617
  • Mana 6
    • View Profile
Re: Gamo CFR IGT with a difference.
« Reply #1 on: September 13, 2016, 05:01:13 PM »
Interesting to hear how that one goes. I chrony'd it ~900fps with a 7.5gr pellet a couple weeks ago (about 13.5ft/lb). I highly doubt the G-challenger is running that hot though.


With the short length and backwards centre of mass I imagine it would be quite good for point-shooting indoors/short range eg birds, rats or such. Nice to hear you've sorted the barrel issues.


EDIT: I wonder if you could have a variable length on the underlever so that it could have the easier cocking but still stay compact? eg. a hinge in the middle or sliding and locking tube..
« Last Edit: September 13, 2016, 05:03:05 PM by Davey »
The spreadsheet guy.

Offline Novagun

  • NZ Airgun
  • Hero Member
  • *
  • Posts: 618
  • Mana 9
    • View Profile
Re: Gamo CFR IGT with a difference.
« Reply #2 on: September 13, 2016, 06:20:45 PM »
Right Davey. Perhaps, in fact it must be putting out more power than the Challenger. It certainly is harder to cock. The overall length is still the same short carbine. The cocking lever now runs through under the muzzle break to the very end of the brake and that gives it the extra length.

After the Delrin brake will be a longer screw on the trigger adjustment and I think that will make a big difference.

PS I thought about something different for the cocking lever but the options were too complicated and too hard to make precisely enough and simple is best every time.
« Last Edit: September 13, 2016, 06:30:59 PM by Novagun »

Offline Novagun

  • NZ Airgun
  • Hero Member
  • *
  • Posts: 618
  • Mana 9
    • View Profile
Re: Gamo CFR IGT with a difference.
« Reply #3 on: September 16, 2016, 08:56:16 AM »
Well we had another wet day so the CFR progressed a little. The solid muzzle brake is installed with a very tight fit. No movement. The underside has a semi-circular grove worked into it so that the cocking lever sits in it and parallel to the barrel. It runs right to the end of the brake giving extra length leverage so you can cock with one hand.  Still hard to do but manageable. The overall shortened length of the rifle remains the same.The additional length of the extension is tube, covered in black tape just to make it black, and although firm may wobble a bit on firing. I can’t tell.

There is some lever overhanging from the plastic clip holding the lever so that might be detrimental. Maybe a solid steel lever right to the end might help or it might make things worse. Only one way to find out. Maybe a different brake that accommodates the clip closer to the muzzle would be better.

The rifle as it is a revelation in pellet pickiness.  JSB 8.4 gns shoot like Manneken Piss on a breezy day and FTT not much different. Edguns, which are fundamentally the same as JSB, shoot quite well but the supply is nearly exhausted so they are not much of an option. Accupels and Crossman Premier Light are not too good.  The best are the heavier pellets such as H & N Barracuda, Silver Points and even Crow Magnums. So far I think accuracy is not good enough. I am sure a CFR is capable of better than what I am getting. Five shots at 12 metres leave a hole of about 12 – 15 mms on the paper.
I am going to try some Gamo TS 10s. They are cheap enough and who knows they might just work.
If anyone round Wellington has half a dozen .177 Crosman Premier Heavies (black stamp) that I can try I would appreciate a PM.

A longer adjustment screw has improved the trigger. I had to dismantle it to check on the length of the new screw. The trigger is made of hardened steel sears with a plastic blade and die caste frame with a plastic screw fastened cover. Time will tell how it lasts but it is very neatly made and easy to dismantle and reassemble. Much easier than the Hatsan Quatro and the old Gamo trigger.













« Last Edit: September 16, 2016, 09:02:51 AM by Novagun »

Offline Novagun

  • NZ Airgun
  • Hero Member
  • *
  • Posts: 618
  • Mana 9
    • View Profile
Re: Gamo CFR IGT with a difference.
« Reply #4 on: September 16, 2016, 11:37:33 AM »

Offline Novagun

  • NZ Airgun
  • Hero Member
  • *
  • Posts: 618
  • Mana 9
    • View Profile
Re: Gamo CFR IGT with a difference.
« Reply #5 on: September 21, 2016, 08:57:29 PM »
Interesting afternoon and I bumped into a combro.  Using Baracuda pellets 10.63 grains the shortened barrel CFR IGT shot 681 fps - 10.8 ft lbs. The standard barrel Challenger IGT with the
CFX breach block shot 662 fps - 10.2 ft lbs. The standard Challenger with the small transfer port shot 440 fps - 4.5 ft lbs.  The pellets were too heavy but all I had with me.
Maybe the shortened barrel on the CFR had less drag than the longer barrel. It has a noticably stronger recoil probably because of the lighter plastic stock. The Challenger with the small transfer port had a rougher shot cycle.

Offline Ding0z

  • Full Member
  • ***
  • Posts: 202
  • Mana 5
    • View Profile
Re: Gamo CFR IGT with a difference.
« Reply #6 on: September 21, 2016, 11:33:47 PM »
I have a Gamo IGT in the warehouse, if you wanted to tinker with the trigger.    I don't shoot it.  Was going to get a trigger upgrade, but haven't gotten around to it, since I got caught by the PCP Virus.   :)   
** New rifle **
Steyr LG110   - Niko Stirling Diamond Sport 10-50x60


Daystate Panther MK4 - Falcon T35

Leapers 8x32x56 (No rifle for the this yet)

Havin a blast

Offline Novagun

  • NZ Airgun
  • Hero Member
  • *
  • Posts: 618
  • Mana 9
    • View Profile
Re: Gamo CFR IGT with a difference.
« Reply #7 on: July 28, 2017, 10:57:46 PM »
I got hold of the old Gamo CFR just for a play. It was freezing cold and the gun itself was very cold. On top of that it had not been shot for a long time.  I put a few pellets through it and it did not shoot very well.
It seemed to be a bit erratic. A barrel clean made no difference so I thought maybe the piston seal was defective.

I took it apart and the seal was in pretty good shape; no nicks or scratches on the skirt. However the face of the seal was embedded with particles of metal. The seal had been hitting the rear of the rotary breach block. The breech block is coated with some sort of grey metal that looks to have been applied by electrolysis. The percussion from the seal had flaked off bits. The whole thing had to come apart for a wash out and re-lubrication.
While it was in bits I tended to the crown chamfer that was concentric with the barrel but not the bore because the bore is off centre. A bit off the end with a cut off wheel and a polish for sprags in the bore and that part seems good

I did not have a replacement Gamo seal so I used a reshaped hydraulic seal. That works well and power is about the same according to the radiata penetration test. There is some cushioning effect with the softer seal as the slam of the piston into the back of the breach block is gone or at least much reduced.

The longer screw for the second stage adjustment of the trigger has failed. The screw has stripped the pot metal trigger case. I am not going to replace that. Just take the screw right out and fashion an adjustment that works on the trigger blade itself. Maybe I can make it much easier to adjust than the original screw so you can have a light trigger to play but quick to adjust back to a bit heavier for walking in the paddock.

If it doesn't work out then re-tap the original hole for a thicker screw.

So far I have had a few shots just squeezing the trigger back along the excessive creep until I think it is near let off and then take shot. Not really satisfactory and I won't know how well it is shooting until I sort out the trigger.
« Last Edit: July 28, 2017, 10:59:56 PM by Novagun »

Offline Novagun

  • NZ Airgun
  • Hero Member
  • *
  • Posts: 618
  • Mana 9
    • View Profile
Re: Gamo CFR IGT with a difference.
« Reply #8 on: July 29, 2017, 08:55:55 PM »
Had another bit of a play with the CFR today. I arranged a device to shorten the very long creep on the trigger.
All it consists of is a piece of black ptfe cut in a wedge shape and with a slot cut along its length. That it secured to the trigger guard with a 4mm bolt. it can be adjusted using the bolt in the slot to prevent the trigger using the whole length of the first stage. All it really does is allow the let off to be set so that most of the travel in the first stage is restricted. Now has a crisp let off but the trigger pressure is at factory setting. That is light enough for general shooting. It is not advanced engineering, it is black so it is inconspicuous and it works.

I measured the barrel and it is 10.5 inches long. The Delrin muzzel brake adds another 4 inches. That is really just a tube for the pellet to fly through unhindered but in gives a place for the cocking lever to sit without sticking way out past the muzzle. It needs that extra length to make cocking effort reasonable. The rifle is very much carbine length and would be good for possuming in an orchard.  It is a very good back yard plinker 

I can't say precisely what I did right but the rifle is now not pellet picky. Shoots wadcutters,  JSB 8.4 grains and Barracudas just as well as each other. That is at 15 yards and so far have not tried 25 or more yards.
Nice rifle to handle and shoot, easy to work on and considering the history of its butchery not bad.

Accuracy is satisfying. As good as any sporting rifle but not as good as a top grade gun.
Worth the effort playing with it.
Photo to come.
« Last Edit: July 29, 2017, 09:32:05 PM by Novagun »

Offline Pauly5

  • Hero Member
  • *****
  • Posts: 1610
  • Location: Porirua
  • Mana 28
  • Go ahead, make my day!
    • View Profile
Re: Gamo CFR IGT with a difference.
« Reply #9 on: July 30, 2017, 12:28:17 AM »
Are you still shooting your 77 and 95? I know there's others too, but I haven't heard tale of them being shot lately.
You really need to get to know how to load photos. I will try and have one of my lunches and show you.
HW98
HW97k x 2
HW40 (copy)
Daisy 953
Hammerli AR20
P-Rod
1377
Zoraki 22

Offline Novagun

  • NZ Airgun
  • Hero Member
  • *
  • Posts: 618
  • Mana 9
    • View Profile
Re: Gamo CFR IGT with a difference.
« Reply #10 on: September 04, 2017, 09:29:31 PM »
Got the Gamo CFR back again. This time I took the Gas Ram out of it and replaced it with a standard CFX spring. The rifle is a little bit twangy and that is noticeable after the gas ram. That might be because I made the rear spring guide just a little bit small. Maybe I'll get round to making another one.

Still shoots fairly well with JSBs and H&N but not too good with Baracudas. It seems to have changed its preference to RWS Superdomes and they are are not nearly as well formed as the other mentioned.
Trigger is about as good as I can get it. There is just a tiny bit of creep before let off. That limits the consistency of the shot cycle.
Power is a bit down on the gas ram but still enough to be useful and I still enjoy using it.
The test will be with the RWS pellets at the small bore range. Didn't take any last time I was there.

I am trying to make up my mind which is best, wire spring or gas spring. At the moment I am favouring wire spring but that might change. Wire is certainly no less accurate.

The Challenger is on the back shelf and can stay there for a while. Maybe I should try that with a wire spring.  I am starting to think that gas rams are not as good as I hoped they would be.


Offline Novagun

  • NZ Airgun
  • Hero Member
  • *
  • Posts: 618
  • Mana 9
    • View Profile
Re: Gamo CFR IGT with a difference.
« Reply #11 on: September 23, 2017, 05:03:18 AM »
I thought I had the trigger set up pretty well but then I changed the second stage screw for one about 1 mm thicker with a rounded end and the trigger is better. I hope it improves my score at the range

Now an odd thing;
i was shooting wad cutters at the range and I put one in back to front. I couldn't pick it out and didn't have a rod so I just shot it. Not much difference in accuracy shooting it back to front