XS-B18 I'm no expert and I'm a bit puzzled....

[texgunner]

First off I want to give a shout out to Mike Melick for digging up a couple breach seals for the old XS-B18 rifle I have, this rifle has been an excellent shooter for several years now, but the breach seal was just wore out and flush with the receiver so I figured it would be a good idea to replace it so everything would be sealed up again like it should be, no on to my issue and question.

I have been able to shoot dime to nickel size groups out to 20-25yds with the rifle using Stoeger 8.64gr X-Field Pellets until today after I replaced the breach seal, I did have to shim it a few thousands to get the height to just a few .001" above flush so that it would seal good, all that looks just like it did when gun was new now and I can tell I have a very good seal, probelm is that my accuracy is gone right out the window with this gun now, and I mean out the window....... like 3-4" groups at 30ft now.....! LOL
this rifle is all over the place now, I still have the same cheap little Tasco 4x32 pronghorn scope on it, which isn't the greatest scope by any means but it has always held an excellent zero and worked nice on this rifle for hitting soda pop can size objects all day long out to 40 yds or so.

Any of you experts here think the increased velocity from replacing the seal is my problem and maybe I need to a couple other pellets to see if I can find something it may like better now? I'm just amazed that replacing the breach seal could have made this gun shoot so different, it isn't good enough for hunting at all now, I have never had one of my air rifle shoot as bad as this thing is shooting now and it was one of my most accurate rifles.

Any advise or ideas are much appreciated, I plan to go to wally world tomorrow maybe and pick up a can of Crosman Premier HP's and run some lead through it to see if it will start coming back together, if not I'm not sure what I will do with this one,I emailed Mike and hope he can shed so light on this for me, I think he may be gone to a shot show so I may not hear back from him for a few days so I thought I'd post this and pick a few other peoples brains on the matter.

Thanks, Shan 

[Blue]

I think I read somewhere that if the breech seal is too proud, it can produce vertical stringing.  You'll see the shots line up more or less in a vertical line.

If that's the pattern you're seeing, try backing off on the shim(s) behind the new seal (or give the new seal time to set a little).

Other than that you could check to make sure your stock screws and barrel pivot haven't become a little loose.

Just my first thoughts early in the mornin'.  I'm sure there'll be more ideas as the sun comes up.

Blue

[Gertrude]

Just as a test,... I think I'd remove the shims completely, and shoot a couple of groups.
 Then,... if no improvement is made, I'd try the old seal in it again for another couple of groups.

 That way, you will have established a baseline, and possibly found a cause and/or effect.

[texgunner]

Thank you Blue and Ron,

I'll check everything over again and I may try a slightly thinner shim under the seal, the old seal got seriously damaged when I removed it and the paper shim that was under it from the factory got tore up also, I tried to use the original shim but it made the seal stick up so much the barrel wouldn't lock into place, so I made a shim from .012" mylar which wasn't enough and the shim was a bit recessed, so I made another that is .008" I know I can easily reduce height by .005" with another shim I have made up so I may try that and see what my results are.

I've added a couple pix here to show how the seal looks in the breach currently.

Thanks again for the replies and suggestions, texgunner

[texgunner]

Ok I have some results to report, after the rifle sat through the night it seems the seal has become better conformed since being pressed tightly, I decided to take a few shots before making any changes to seating depth of seal in breach and have found that the Stoeger X-Field 8.64 grn pellets don't seem to group well anymore after the FPS increase from the new seal, but I run 5 Predator 8.0 grn pellets through it at 27ft and the group tightened up nicely, by the way these shots were not from a rest, just sitting on couch with rifle propped on my knee so results are not as precise as they would be from a solid rest.

below are some pix of the target results of how it's shooting now with the X-Field pellets and the Predators, I'm going to town in a while to pick up a can of Crosman Premier HP's and see how they act, it seems that the rifle is gonna settle down as is, just need to try a few pellets to find out which it will end up liking the best, the Crosman Premiers have worked very nicely in this rifle in the past so hopefully that will still be the case, if not I'll order several 25ct samples off of ebay like I did for my Benji Disco and do some range testing from a solid rest and hopefully get this thing back to where it was so I can be confident when I pull the trigger on a bird or a fuzzy tailed Tree Rat.

Peace, texgunner

[2nd RCHA]

Sorry to Chime in, But I need help removing the rear safety from my QB-18, Any Help??Thank's, Andy.

[texgunner]

Sorry to Chime in, But I need help removing the rear safety from my QB-18, Any Help??Thank's, Andy.

This is what is called High Jacking a thread, you should post your question in the correct place not in the thread I started here, you should post your question in this area and start your own thread... (:~)

http://www.gatewaytoairguns.org/GTA/index.php?board=3.0

texgunner

[texgunner]

Found what may be my biggest problem with the XS-B18, scope mounts are not holding on receiver, I noticed that the scope had slid back close to 1/4" so I'm now I plan to get a better mount on it which I have ordered and probably a better scope while I'm at it and then I can get a good shooting session in to find out what pellet this thing is gonna like the best and if the Stoager pellets were the issue after the seal change or if it was the scope moving around the entire time that was causing my issues, I'll update this thread as I move along with this rifle, thanks again for all the comments and advice, I'm new here but can tell already that this is a great place to be and there are a bunch of great people here.

texgunner

[2nd RCHA]

Terribly Sorry,,,,No Dis-Respect intended there, Amigo, and as I said "Sorry for Chiming in", but I'm at my wits end, I've posted this question more than a few times, Just felt sort of Invisible. Once again, Sorry to've upset you. Cheer's, Andy.

[texgunner]

Terribly Sorry,,,,No Dis-Respect intended there, Amigo, and as I said "Sorry for Chiming in", but I'm at my wits end, I've posted this question more than a few times, Just felt sort of Invisible. Once again, Sorry to've upset you. Cheer's, Andy.

You didn't upset me at all brother, I was just saying what I did because I was thinking you would get more attention to your question if it was put somewhere other than here in this thread, sorry if I came across as being upset, that wasn't my intension at all, when words are all we have to go by and we cant see expression or hear tone of the voice it's easy to type things out in a way that can be taken wrong, you did NO harm to me here at all....

I'm thinking your QB-18 may be the same basic gun as my XS-B18 it's been so long since I have had this thing out of the stock I can't even remember for sure what the trigger group looks like or maybe I could help you with the question you have on removing the safety, I'll do some digging and see what I can come up with and if I find something useful I'll post it here for you bro.

txgunner


EDIT:

After doing a quick search on youtube, I can see that the QB-18 is a different looking trigger and safety than my XS-B18, sorry cant help on this one Andy.

[texgunner]

Just a short update here on the XS B18 rifle on mine, lately the last few time I have got it out to shoot I've shot it indoors at 10 meters, it has been shooting horrible with every pellet I've tried and it seemed like the fps had fallen because even at 10 meters there was a space between when I heard the rifle shoot and then I would hear the pellet hit the target, I knew that wasn't right with this gun because it had shoot at much higher velocity in the past, as I tried several different pellets yesterday I noticed the power continuing to drop off until I could aim at top of target and pellet would drop over 12" at 10 meters and I heard a different sound from the rifle on the last 4-5 shots, the cocking effort still seems the same but power has gone, I'm assuming I have a blown out piston seal and possibly a broken spring, I wont know until I get into it when I have the time.

Could anyone here please point me in the right direction for a new spring and piston seal for this rifle, I'm sure it shares the same parts as other Chinese rifles but I don't know which ones it would be, and I was also wondering if since it's a clone of the Gamo 220/440 rifle, will the Gamo spring and seal work in the XS-B18....?

Any advise and a point in the right direction will be much appreciated.....


Thanks, texgunner

[Blue]

I go to Air Rifle Headquarters for my piston seals.

If it's the same B18/19 that Crosman uses, I think the Apex Small ($10) is the one that fits.

I've never bought a spring but I think he's got them too.  Everything's pretty well labeled as to what it fits but if you're not sure, I bet Jim can help you figure out your options.

Blue

[LAalex]

Shan, if you could post some photos of the rifle it may be helpful in.  I may be wrong, but I think the B18/19 platform is a clone of the Gamo 220.  If so, Crosman will be the source for the cheapest parts.  ARH will have springs and seals of higher quality, but a bit more pricey.  QB18 IIRC is a SAG rifle and different rifle altogether.  Check out the "Chinese Airgun Portal" link at the top of China Gate it is full of info about Chinese AG's.

Scotty

[texgunner]

Thanks fellas,

From what I have read, the XS-B18 is a clone of the 220/440 Gamo rifle and yes it is the same as the B18/19 so I will go on that and see what I can dig up.

Here are some pix I dug up.

[texgunner]

I'm gonna email ARH and ask about the correct spring and seal I will need for the B18, I have broke down several chinese air rifles and put automotive type moly grease on the springs and not knowing any better put a dab of 3 in 1 oil in as chamber lube and on all other moving parts, since coming to this forum I have learned that the silicone oil is the way to go and I want to be sure I use the correct spring grease and apply it right if I'm able to find the parts I'm needing, being a big powder burner guy and since I been working on them all my life I just assumed that the same oils would be fine for the air rifles, I see now that I was wrong so I want to go back together with this little B18 the right way so it will shoot good and last, I think I bought this rifle back in 1999 if I remember right so I figure a new spring might serve it well along with the seal, I'd love to get the performance up as good as possible so I can get good results with the heavier .177 pellets, when I first got this rifle it would shoot completely through a soft white wood board that was 3/4" thick with the pointed Crosman pellets, I was very impressed and I killed several squirrels and many birds at up to 45-50 yards in some cases, it was very accurate and I even took several coons and Opossums and few few other country side pesky animals I cant mention here...LOL!

I figure the best way to make sure I get what I need is to just give ARH a call and get the right parts coming if they have them.

Thanks again for all the excellent advise and if anyone has anymore ideas on how I should go about getting this gun back in good as new or better condition please let me know, I'm all ears and wanting to learn all I can about doing this right.

Peace, texgunner

[Paul68]

The ARH Tarantula and E3650 springs work with the B18/19. The apex small seal is for the piston.

The Tarantula spring produces very good power, better than stock, but I have to state that I had two break in less than 2k shots. And that was in a gun that was fully cleaned up, honed, smoothed, and lubed. The 3650 produces less power but a nicer shot cycle. You'll probably need to shim the 3650

[texgunner]

The ARH Tarantula and E3650 springs work with the B18/19. The apex small seal is for the piston.

The Tarantula spring produces very good power, better than stock, but I have to state that I had two break in less than 2k shots. And that was in a gun that was fully cleaned up, honed, smoothed, and lubed. The 3650 produces less power but a nicer shot cycle. You'll probably need to shim the 3650

Thank you sir, I just ordered the Tarantula spring and the apex small seal, I didn't order any of the moly paste grease though, seems $8 is a bit much for a dab of moly grease, I have some high grade moly grease and I'm thinking I may take a dap out and mix in some dry graphite and use that for lubing the piston and outer edge of the seal, I do plan to purchase some high quality silicone oil for the chamber lube though since all I have and normally use on my PD rifles is 3 in One oil.

Looking forward to getting the new spring and seal, and thinking it may be necessary to shim the spring for best power, do you have any idea how much I may need to shim the spring, I noticed that Air Rifle Headquarters offers some shims and it seems like the .150 shim was recommended for the Tarantula & E3650 springs to get power up a bit, I have many tools and even a lathe and mill so I can make whatever I need pretty much, I guess I may have to experiment and see what I come up with, my next purchase will be a chrony so I will be able to tell what my results are,I want accuracy over raw power but I also want as much power as I can get and still be accurate from 30-50yds with around 10+ grain pellets in the .177, maybe I'm asking to much from this old china gun, but it will be fun tinkering to see what I can get from the old gal, in it's out of the box state, it was a real winner and hit harder than any air rifle I have ever owned as far as fps goes, my old Benji 342 & 347 and the old Sheridan 5mm/.20 silverstreak are good guns with plenty of terminal power out to a reasonable distance but the XS-B18 would out shoot all of them in the FPS category, hoping to get that back and maybe just a tad more with the better seal and spring, I'll be building a scope stop for the XS-B18 also, I haven't been able to keep a scope solid on it yet so I'll be using better mounts and I will either drill and tab the receiver and install a stop or I will make a stop and braze it to the receiver while I have the rifle apart so I can keep a scope solid on this rifle.

Thanks again for all the great advise and help

Peace, texgunner

[Paul68]

The ARH Tarantula and E3650 springs work with the B18/19. The apex small seal is for the piston.

The Tarantula spring produces very good power, better than stock, but I have to state that I had two break in less than 2k shots. And that was in a gun that was fully cleaned up, honed, smoothed, and lubed. The 3650 produces less power but a nicer shot cycle. You'll probably need to shim the 3650

Thank you sir, I just ordered the Tarantula spring and the apex small seal, I didn't order any of the moly paste grease though, seems $8 is a bit much for a dab of moly grease, I have some high grade moly grease and I'm thinking I may take a dap out and mix in some dry graphite and use that for lubing the piston and outer edge of the seal, I do plan to purchase some high quality silicone oil for the chamber lube though since all I have and normally use on my PD rifles is 3 in One oil.

Looking forward to getting the new spring and seal, and thinking it may be necessary to shim the spring for best power, do you have any idea how much I may need to shim the spring, I noticed that Air Rifle Headquarters offers some shims and it seems like the .150 shim was recommended for the Tarantula & E3650 springs to get power up a bit, I have many tools and even a lathe and mill so I can make whatever I need pretty much, I guess I may have to experiment and see what I come up with, my next purchase will be a chrony so I will be able to tell what my results are,I want accuracy over raw power but I also want as much power as I can get and still be accurate from 30-50yds with around 10+ grain pellets in the .177, maybe I'm asking to much from this old china gun, but it will be fun tinkering to see what I can get from the old gal, in it's out of the box state, it was a real winner and hit harder than any air rifle I have ever owned as far as fps goes, my old Benji 342 & 347 and the old Sheridan 5mm/.20 silverstreak are good guns with plenty of terminal power out to a reasonable distance but the XS-B18 would out shoot all of them in the FPS category, hoping to get that back and maybe just a tad more with the better seal and spring, I'll be building a scope stop for the XS-B18 also, I haven't been able to keep a scope solid on it yet so I'll be using better mounts and I will either drill and tab the receiver and install a stop or I will make a stop and braze it to the receiver while I have the rifle apart so I can keep a scope solid on this rifle.

Thanks again for all the great advise and help

Peace, texgunner

You don't need to lube the chamber with silicone oil at all, it will just cause strong detonation. Just use moly on the piston and all metal to metal contact points instead. The plain "moly" grease you get from the automotive or hardware store is just regular grease with a tiny bit of moly added. It is a poor choice for air rifles. The ARH moly is very high moly content grease and is far more effective.

A drop or two of silicone oil on the piston button will help when installing the new seal.

Check the lube guides in the GTA library for more detailed info.

[texgunner]

The ARH Tarantula and E3650 springs work with the B18/19. The apex small seal is for the piston.

The Tarantula spring produces very good power, better than stock, but I have to state that I had two break in less than 2k shots. And that was in a gun that was fully cleaned up, honed, smoothed, and lubed. The 3650 produces less power but a nicer shot cycle. You'll probably need to shim the 3650

Thank you sir, I just ordered the Tarantula spring and the apex small seal, I didn't order any of the moly paste grease though, seems $8 is a bit much for a dab of moly grease, I have some high grade moly grease and I'm thinking I may take a dap out and mix in some dry graphite and use that for lubing the piston and outer edge of the seal, I do plan to purchase some high quality silicone oil for the chamber lube though since all I have and normally use on my PD rifles is 3 in One oil.

Looking forward to getting the new spring and seal, and thinking it may be necessary to shim the spring for best power, do you have any idea how much I may need to shim the spring, I noticed that Air Rifle Headquarters offers some shims and it seems like the .150 shim was recommended for the Tarantula & E3650 springs to get power up a bit, I have many tools and even a lathe and mill so I can make whatever I need pretty much, I guess I may have to experiment and see what I come up with, my next purchase will be a chrony so I will be able to tell what my results are,I want accuracy over raw power but I also want as much power as I can get and still be accurate from 30-50yds with around 10+ grain pellets in the .177, maybe I'm asking to much from this old china gun, but it will be fun tinkering to see what I can get from the old gal, in it's out of the box state, it was a real winner and hit harder than any air rifle I have ever owned as far as fps goes, my old Benji 342 & 347 and the old Sheridan 5mm/.20 silverstreak are good guns with plenty of terminal power out to a reasonable distance but the XS-B18 would out shoot all of them in the FPS category, hoping to get that back and maybe just a tad more with the better seal and spring, I'll be building a scope stop for the XS-B18 also, I haven't been able to keep a scope solid on it yet so I'll be using better mounts and I will either drill and tab the receiver and install a stop or I will make a stop and braze it to the receiver while I have the rifle apart so I can keep a scope solid on this rifle.

Thanks again for all the great advise and help

Peace, texgunner

You don't need to lube the chamber with silicone oil at all, it will just cause strong detonation. Just use moly on the piston and all metal to metal contact points instead. The plain "moly" grease you get from the automotive or hardware store is just regular grease with a tiny bit of moly added. It is a poor choice for air rifles. The ARH moly is very high moly content grease and is far more effective.

Ok thank you for the great advice, im not new to air guns as far as using them but Im new to knowing the proper care of the springers so I really appreciate the advice about the grease, I can across a type of grease on ebay that has a high PTFE content that is recommended for springer air rifles also, just wondering if its as good as the moly paste....
Im gonna call first thing in the morning and have some moly paste added to my order so maybe Ill get the seal, spring and moly all at the same time.

Shan

[Blue]

There's a "bundle" of moly, heavy tar, and clear tar.  Everything you need to tune a springer and cheaper than buying each separately.  You'll have enough to do multiple tunes.

Blue