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PostPosted: Sat Apr 24, 2021 3:41 pm 
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Joined: Mon Apr 12, 2021 11:04 pm
Posts: 307
Location: Lower Mainland, BC
Yeah, BC is something. There are reasons people pay for it.

Yeah, these rifles are fun too. On the low end. Yes, I'm keeping it simple, not sure how much I really want to do to this Optimus. Job 1 is the piston liner.

_________________
Stephen
low- / mid-level springers

.177 Cometa Fusion, Vantage 3-9x40
.177 Cometa Fenix LT, Endurance 4-16x50
.22 Cometa Fenix, Airmax 3-9x40


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PostPosted: Sat Apr 24, 2021 5:49 pm 
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Joined: Mon Apr 12, 2021 11:04 pm
Posts: 307
Location: Lower Mainland, BC
Ok. What'd I find out, what'd I do?

I took the foggy scope off and put it away. B'bye. I took off the rear fibre optic sight, bagged it. I cleaned and oiled the barrel. The breech seal is pristine, like it had never shot anything. I took off the beautiful wood stock. Every screw I turned wasn't tight; I wouldn't say loose exactly, but not snug; stock screws, scope, even the breech bolt, barely holding. I put it in the compressor, opened it up. I think Crosman tidied up their production since my vintage 2008ish Phantom. The parts and assembly on the Phantom were just a little rough, too much gunky lube, things like that. The Optimus was almost dry by comparison, seemed good though. But I did find condensation in the tube opposite the trigger and a little in the piston. The trigger operation seemed more modern and smoother. The whole trigger assembly seemed tidier, a bit more solid. I'll still likely overhaul it at some point, it's fine for now. When I pulled out the piston, the seal wasn't cut up and I was able to reinstall it without damage, too. I don't think I'm even going to bother to polish those cuts. I'll probably smooth the edges in the cocking channels. Cocking was chunky, probably has lots to do with the skinny spring. The spring has a nice little bow on it, maybe the rifle was stored fully cocked.

But yes, the real thrill was discovering that I had yet a 3rd dimension of piston. I've tried to quickly to imagine which combinations of spring and piston I could put in these 2 rifles. Cool. And the spindley spring.

Ok, dimensions of these things. I'd like to point out first that in these forums, I sometimes see the dimensions of the piston in some odd mm dimension. Also, I'm seeing it measured to where it meets the seal? or the end of the dove or something? I don't get it. I'm not opposed to metric, I use either but whatever you're measuring sort of chooses the unit. And this rifle looks to me like it was designed in imperial units. The piston itself is 1" in diameter, that sort of tells you right there that you should measure the thing in inches. Ok. And when I measure the thing, I measure from the end to the front of the seal. The piston always has a seal on it, I suppose you could say that's the piston assembly. The only time I don't have a seal on it is about 20 seconds when I put on a fresh seal. So the piston with the seal, that's the piston. That's my little gripe.

Anyway, I'm stoked to have all 3 pistons. Here are the dimensions

short piston . . . . .5 15/16"

medium piston . . . . .6 3/4"

long piston . . . . .7 3/4"

You can see these are inch dimensions. Decimal inches are great, too. Especially since I got a digital caliper.

I believe I have 2 of the high power springs and one feeble one. I've looked at the coils and the length of these springs, I think it's moot. With the springs I've got, the only thing that matters is the thickness of wire. In decimal inches:

strong spring - .125" - which I know to be 1/8"

wimpy spring - .1" - 1/10"

There. Imperial units. Sorry

So yes, I noted these exciting dimensions, cleaned and lubed the parts real well and slapped it back together. And, I started shooting.

So, I had removed the foggy scope I got with it, and put on my newer one. Man, I'm not fond of those 4x32 CentrePoint scopes. It's almost clear in the middle but soft around the edges. It's like a old Star Trek episode where some doey-eyed babe is falling for Kirk or one of the crew, the sappy music is starting to play and the cameraman has smeared vaseline on the lens of the camera, like they used to do, to give the image a soft, romantic glow. Well, there's no doey-eyed babe here, and I'm not Capt. Kirk. I just wanna see the damned target. Instead I'm peering through this hazy donut. Sheesh.

I only fired about 25 shots, they were all over the place. I didn't even see where some of them went, it was a half-used target page, too. and it was after midnight. I don't really know what condition the barrel's in, I lubed the seal and chamber with a couple few drops of silicone, it was probably dieseling a little. I shot a bunch of old Superdomes I had, and a bunch of the Grizzlies that came with the rifle. And yes, a fair bit of twang going on with that little shooter. It takes quite a knock to break it. It has a different lock than the Phantom, it’s a little bar rather than the mating bevelled post.

What am I gonna do? I'm gonna shoot a whole bunch more pellets. And I'm gonna make a piston liner. I did it sight unseen for the Phantom, I can do it with this one. I still have the material that I used from the caliper packaging. I don't really want to throw more money at it but I'm gonna have to find another scope. I'll review the other thread for that recommendation.

Ok, I think that’s it. Sort of entertaining. We’ll see. Have a great weekend

_________________
Stephen
low- / mid-level springers

.177 Cometa Fusion, Vantage 3-9x40
.177 Cometa Fenix LT, Endurance 4-16x50
.22 Cometa Fenix, Airmax 3-9x40


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PostPosted: Sat Apr 24, 2021 8:55 pm 
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Joined: Mon Apr 12, 2021 11:04 pm
Posts: 307
Location: Lower Mainland, BC
Hey guys

I shot 20 or so. Windage was fine, it was just going up and down a lot.

Then I lit up the Chrony. It read 10 in a row no problem. Huge spread, then it just plummeted. What does it mean?

Thanks


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IMG_0313 copy.JPG
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_________________
Stephen
low- / mid-level springers

.177 Cometa Fusion, Vantage 3-9x40
.177 Cometa Fenix LT, Endurance 4-16x50
.22 Cometa Fenix, Airmax 3-9x40
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PostPosted: Sat Apr 24, 2021 9:40 pm 
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Joined: Thu Oct 13, 2005 4:20 pm
Posts: 2374
Location: Spruce Grove AB
I would check the breech seal. If that's good, I'd look at the piston seal. If you took it apart and reassembled without deburring the holes and slot, you could have damaged the seal. Very Easy to do.


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PostPosted: Sun Apr 25, 2021 1:06 am 
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Joined: Mon Apr 12, 2021 11:04 pm
Posts: 307
Location: Lower Mainland, BC
eSteve wrote:
Ok. What'd I find out, what'd I do?

The breech seal is pristine, like it had never shot anything.

When I pulled out the piston, the seal wasn't cut up and I was able to reinstall it without damage, too. I don't think I'm even going to bother to polish those cuts.


What I've just done, though, is match the pellets. Gonna see what that does

_________________
Stephen
low- / mid-level springers

.177 Cometa Fusion, Vantage 3-9x40
.177 Cometa Fenix LT, Endurance 4-16x50
.22 Cometa Fenix, Airmax 3-9x40


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 Profile  
 
PostPosted: Sun Apr 25, 2021 8:47 am 
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Joined: Mon Apr 12, 2021 11:04 pm
Posts: 307
Location: Lower Mainland, BC
Good morning

Ok. When I did the Chrony yesterday (see photo) there were VERY extreme spreads, more than I had ever seen with my Phantom. The last two shots got dramatically slower still. I stopped.

Later, I went back for a few more shots, no Chrony. Something was not right inside the tube. Two strange things happened.

1. I sort of lost the first stage of trigger pull. The trigger would move to the second stage with zero resistance. I got off maybe 3 shots like this

2. It misfired. The piston was released, but there was resistance. Then the piston sort of juttered forward. Tock tock tock. I recocked and shot the pellet. I stopped.

I thought that the thin spring may have broken.

I opened the rifle first thing, I've been working on it. The spring is not broken. Everything looks fine. I've been looking at the trigger package. It seems fine.

The trigger adjustment screw had been quite stiff to turn. A bit tricky to feel it stop. I turned it out and back in. It's loosening up a little. I'm quite sure I was able to set it on the stop comfortably.

I'm trying to imagine any other resistance. The only thing I've come up with is the cocking channels in the tube and piston. I'm smoothing those areas now.

I'm going to make a piston liner and install that.

I'm thinking of replacing the thin, slightly bent spring with the strong spring, temporarily, to see if that helps. I'm not sure more power helps, though.

Whaddya say guys? Any ideas?

Thanks

_________________
Stephen
low- / mid-level springers

.177 Cometa Fusion, Vantage 3-9x40
.177 Cometa Fenix LT, Endurance 4-16x50
.22 Cometa Fenix, Airmax 3-9x40


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PostPosted: Sun Apr 25, 2021 10:28 am 
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Joined: Fri Jan 22, 2010 1:17 pm
Posts: 4145
Location: Kingston, ON
Hey Steve, I love your enthusiasm. The springers you have, Phantom and Optimus, are just about identical - depending on the year of manufacture they may have different breach blocks with the stationary jam on the compression tube being either a beveled pin sticking out or a straight transverse cross pin. Other than that, the early Crosman B18/19 trigger blade in the Phantom is likely a stamped steel POS that can't be done much with. The Optimus will have the cast trigger blade, and I'll tell you again, Do the ETA mod on it - it becomes the same as the expensive GRT III trigger for the cost of a setscrew.
From your description of the Optimus issues, the piston is dragging. so check it for burrs, check the cocking slot for burs, etc. If you suspect the breach seal is leaky, put a shim under it - you can use dental floss for example. Make sure the rifle isn't desiling by cleaning out all the oil before chronying. It could be the weak spring and piston combo are giving you a sub 400 fps powerplant that diesels to get you higher speeds.
But keep on tinkering, that's how you will lean and get the hang of it. Then... you will need a TX200 or HW97. It's nice to learn how they work, for what its worth, and then to get one (or more) that you can shoot 10/10 into the same hole every time. :drinkers:
Post some pictures of your Optimus parts we can tell better what its problems may be.

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Iacio ergo sum


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PostPosted: Sun Apr 25, 2021 11:17 am 
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Joined: Mon Apr 12, 2021 11:04 pm
Posts: 307
Location: Lower Mainland, BC
Thanks Duke.

I’ve looked at some trigger mods, I don’t know what ETA is.

Ok. Photos of piston liner production.

There’s the liner material cut to size plus 1/4” to wrap behind the spacer.

I’ve cut the notches in the liner so it doesn’t bind behind the spacer.

There’s the finished liner in the piston.


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_________________
Stephen
low- / mid-level springers

.177 Cometa Fusion, Vantage 3-9x40
.177 Cometa Fenix LT, Endurance 4-16x50
.22 Cometa Fenix, Airmax 3-9x40
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PostPosted: Sun Apr 25, 2021 11:19 am 
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Joined: Mon Apr 12, 2021 11:04 pm
Posts: 307
Location: Lower Mainland, BC
Photos of piston liner production, part 2.

There’s a view inside the piston. Pretty tidy.

Ready to file the spacer, to decrease the diameter to allow for the liner thickness.

There’s the bits: newly reduced spacer, piston with liner, and spring.


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IMG_0319 copy.JPG [ 112.73 KiB | Viewed 518 times ]
IMG_0320 copy.JPG
IMG_0320 copy.JPG [ 182.87 KiB | Viewed 518 times ]

_________________
Stephen
low- / mid-level springers

.177 Cometa Fusion, Vantage 3-9x40
.177 Cometa Fenix LT, Endurance 4-16x50
.22 Cometa Fenix, Airmax 3-9x40
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PostPosted: Sun Apr 25, 2021 11:43 am 
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Joined: Thu Oct 13, 2005 4:20 pm
Posts: 2374
Location: Spruce Grove AB
Did you reduce the size of the top hat to fit the sleeve?


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PostPosted: Sun Apr 25, 2021 12:55 pm 
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Joined: Mon Apr 12, 2021 11:04 pm
Posts: 307
Location: Lower Mainland, BC
Ok. Look at this. It’s insane. 17m

On the left are the shots I took last night when it misfired and I thought the spring was broken.

All I did was smooth the cocking grooves where I thought it might be binding. Carefully cleaned the compression chamber. I built that liner, it’s my second one. Lubricated carefully, not too much, not too little. Put a little moly on the sear and lever. Put it together, just put the scope back on the mounts.

I just took those 2 shots on the right. Incredible! Just like that! Bang, bang! Insane! I am so stoked!!

Those liners are amazing! It’s way quiet, twang is gone! Recoil dampened. This is the stuff! It’s so much fun!

Thanks you guys so much for schooling me! And for your support.

I gotta eat. Cheers


Attachments:
IMG_0321 copy.JPG
IMG_0321 copy.JPG [ 114.47 KiB | Viewed 516 times ]

_________________
Stephen
low- / mid-level springers

.177 Cometa Fusion, Vantage 3-9x40
.177 Cometa Fenix LT, Endurance 4-16x50
.22 Cometa Fenix, Airmax 3-9x40
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PostPosted: Sun Apr 25, 2021 1:03 pm 
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Joined: Wed Jan 05, 2011 12:35 pm
Posts: 11296
Location: P.G. B.C.
How does it group? That's the proof in the pudding.
A group would be 5 or more shots.

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Daryl


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PostPosted: Sun Apr 25, 2021 1:46 pm 
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Joined: Mon Apr 12, 2021 11:04 pm
Posts: 307
Location: Lower Mainland, BC
Daryl wrote:
How does it group? That's the proof in the pudding.
A group would be 5 or more shots.

I knew that pin was an anomaly. Still cool though.

I started shooting for the 3/4" and got off these 5 shots. Not stellar, but it was shooting nice. Then bad news, that seal started sticking in the chamber again. I was knocking the bottom of the rifle to get it to walk forward. I just dropped some silicone into the transfer.

I thought of putting on a old seal. But it seems I'll likely be polishing the compression chamber. Whaddya think?


Attachments:
IMG_0322 copy 2.JPG
IMG_0322 copy 2.JPG [ 123.67 KiB | Viewed 514 times ]

_________________
Stephen
low- / mid-level springers

.177 Cometa Fusion, Vantage 3-9x40
.177 Cometa Fenix LT, Endurance 4-16x50
.22 Cometa Fenix, Airmax 3-9x40
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 Profile  
 
PostPosted: Sun Apr 25, 2021 2:13 pm 
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Joined: Fri Jan 22, 2010 1:17 pm
Posts: 4145
Location: Kingston, ON
Piston looks good (Crosman long piston), seal looks good. Rifle shoots like crap.. I suggest getting up a 10 m range. See if you can get 5 shots groups with a single hole, ragged one hole is good. The Optimus should be able to do that with good pellets. For no pal, even at 17 m the groups can go to ratshit with the wrong pellets. Also, some of the scatter could well be you so backing off to 10 m and practicing with your hold, trigger squeeze, follow through and breathing untill you can mahe a 5 shot ragged hole at 10m.

To be honest, I started out same as you with a Benji Classic (same as Phantom) and couldn't get it to group consistently no matter what. Then I get my HW97 and with all the practice I had was able to pick of bitter nuts 10/10 at 20 yards with it. That's like a 1/2" group at 20 yards - non pal .22 cal. at 10m, easy single hole. It showed me what was me and what was rifle and the Classic wasn't going to make 1/2" group at 20m. ever. I did manage to tune it - but I replaced the alive jam, the breach washers, the spring guides, seal, added piston liner, etc, etc. After I had been trough a half dozen or so Crosman B18/19 I swore off them. But history shows that I never keep my swear offs, so I've had a few since and they can be made to shoot ragged hole at 10 m, but you need luck and patience and a lot more $ than they are worth.
Keep tinkering. :drinkers:

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Iacio ergo sum


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PostPosted: Sun Apr 25, 2021 2:35 pm 
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Joined: Mon Apr 12, 2021 11:04 pm
Posts: 307
Location: Lower Mainland, BC
Dukemeister wrote:
Piston looks good (Crosman long piston), seal looks good. Rifle shoots like crap.. I suggest getting up a 10 m range. See if you can get 5 shots groups with a single hole, ragged one hole is good. The Optimus should be able to do that with good pellets. For no pal, even at 17 m the groups can go to ratshit with the wrong pellets. Also, some of the scatter could well be you so backing off to 10 m and practicing with your hold, trigger squeeze, follow through and breathing untill you can mahe a 5 shot ragged hole at 10m.


Sorry, Duke, it's a medium piston, not the long one. I don't know how this rifle shoots, and either do you. I just got it yesterday. I don't want to shoot 10m, I'm never going to shoot anything at 10m. At some some point I'm going to start shooting 13m, but for now I'm shooting 17m, because I can. I don't need to shoot a single hole, a half inch or inch would be fine. I'm learning plenty about pellets, I matched the container of 500 that I got with this rifle, last night. Please post pictures of your scale and matched pellets.

But you seem to have missed the point. The rifle doesn't shoot. I've got to open it up again and sand the thing. Sheesh.

Thanks, I've got work to do

_________________
Stephen
low- / mid-level springers

.177 Cometa Fusion, Vantage 3-9x40
.177 Cometa Fenix LT, Endurance 4-16x50
.22 Cometa Fenix, Airmax 3-9x40


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 Profile  
 
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